January 1993 - Silicon Chip Online

Outer Front Cover
Feature: The Silicon Chip 5th Birthday Sweepstakes
Contents
Publisher's Letter: Sound quality is not perfect in rack hifi system
Project: Peerless PSK60/2 2-Way Hifi Loudspeakers by Tom Manning
Project: Build A Flea-Power AM Radio Transmitter by Darren Yates
Vintage Radio: Restoring a 1920s kit radio by John Hill
Project: High-Intensity LED Flasher For Bicycles by Darren Yates
Serviceman's Log: The customer is always right? by The TV Serviceman
Subscriptions
Project: A 2kW 24VDC To 240VAC Sinewave Inverter; Pt.4 by John Clarke
Feature: Remote Control by Bob Young
Product Showcase
Feature: Panasonic's Super-Quiet Dot Matrix Printer by Darren Yates
Feature: The Story Of Electrical Energy; Pt.22 by Bryan Maher
Back Issues
Order Form
Market Centre
Advertising Index
Outer Back Cover

This is only a preview of the January 1993 issue of Silicon Chip.

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You Could Win A Ford Festiva Sedan! - AUSTRALIA'S DYNAMIC ~ - ELECTRONICS MAGAZINE i tom\)at\ loul\s\)ea\(.et ~'JS\em 1o ~u\\l\ ,nese compact \oudspeakers w\\\ be \ust r\gnt \or many h\\\ entnus\asts. ,hey are based on h\gh-(\ua\\ty Peer\ess dr\\/ers & de\\\/er b\g penormance. YOU COULD WIN \ \ \ \ \ THREE CAD \ \ \ \ \ \ \ \ \ THE GRAND PRIZE IS ONE FORD ESTIVA3 DOOR SEDAN VALUED AT $15 ,2 INCLUDING ON-ROAD COSTS. . I ~~~~ ave you driven lately? .;\ r~ \1'1......... . .... ' -""""""-"'"'-··••.,. ~ AV-COMM A SATELLITE DISH AND TWO RECEIVER SYSTEMS - SOFTW'ARE PACKAGES HTC ,;; AROUND SOUND PROCESSO VIDEO/AUD60p~~ER AMPLIFIER C PHONO OR 120W STER AMP WITH MAGNET! STEREO PREMICAMPLIFIEA - ONE uamo ONE PAIR OF JAMO LOUDSPEAKERS ONE PAIR OF PEERLESS r~:Y~:EAKER KITS ONE PAIR OF DYNAUDIO ~~JDSPEAKERS SYSTE THREE PHILI SCOPE METERS PROUDLY SPONSORED BY Have you driven a Ford ... lately? . ,,.,11 !ttrttsS-1+=uamo AV-COMM ) e PHILIPS A-ONE 'Ill W , , , .::::======= Vo/.6, No.1; January 1993. FEATURES 1 The Silicon Chip 5th Birthday Sweepstakes Enter & you could win a car - lots of other prizes as well 79 Panasonic's Super-Quiet Dot Matrix Printer by Darren Yates It uses a revolutionary new print head to beat the noise 82 The Story Of Electrical Energy, Pt.22 by Bryan Maher The Balmain & Ultimo power stations BASED ON HIGH-QUALITY Peerless drivers, these compact 2-way loudspeakers deliver big performance & will be just right for many hifi enthusiasts. Construction starts on page 16. PROJECTS TO BUILD 16 Peerless PSK60/2 2-Way Hifi Loudspeakers by Tom Manning Small in size but big on performance 26 Build A Flea-Power AM Radio Transmitter by Darren Yates Learn about AM radio transmissions 40 High-Intensity LED Flasher For Bicycles by Darren Yates Make sure you can be seen after dark 58 A 2kW 24VDC To 240VAC Sinewave Inverter, Pt.4 by John Clarke Building the four main PC boards SPECIAL COLUMNS 32 Vintage Radio by John Hill Restoring a 1920s kit radio 44 Serviceman's Log by the TV Serviceman The customer is always right? 66 Remote Control by Bob Young Installing & adjusting the low-cost speed controller; Pt.3 88 Amateur Radio by Garry Cratt Remote monitoring of radio transmissions DEPARTMENTS 4 Publisher's Letter 6 Mailbag 8 Circuit Notebook 57 Subscriptions Page 70 Product Showcase 98 Ask Silicon Chip 100 Notes & Errata 101 Order Form 102 Market Centre 104 Advertising Index HAVE YOU EVER wondered how signals are transmitted to your AM radio? Build this flea-power AM transmitter & find out. Details page 26. THIS HIGH INTENSITY LED flasher fits inside a special bicycle tail light case & is much more effective than the standard unit. If you're quick, you can even obtain a free PC board for this project. See page 40. SPECIAL NOTICE: lack of space has prevented us from publishing the constructional details on the MAL-4 microcontroller this month. This article will be published in the February issue. JANUARY 1993 3 Publisher & Editor-in-Chief Leo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) PUBLISHER'S LE'I*I'ER Technical Staff John Clarke, B.E.(Elec.) Robert Flynn Darren Yates, B.Sc. Reader Services Ann Jenkinson Sharon Macdonald Sales & Marketing Mgr. Sharon Lightner Phone (02) 979 5644 Mobile phone (018) 28 5532 Regular Contributors Brendan Akhurst Garry Crall, VK2YBX Marque Crozman John Hill Jim Lawler, MTETIA Bryan Maher, M.E., B.Sc. Jim Yalden, VK2YGY Bob Young Phot ography Stuart Bryce Editori al A dvisory Panel Philip Watson, MIREE, VK2ZPW · Norman Marks Steve Payor, B.Sc., B.E. SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. A.C.N. 003 205 490. All material copyright©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Magazine Printers Ply Ltd, Alexandria, NSW; Macquarie Print, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $42 per year in Australia. For overseas rates, see the subscription page in this issue. Liability: Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. Editorial & advertising offices: Unit 1a/77-79 Bassett Street, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 979 5644. Fax (02) 979 6503. ISSN 1030-2662 4 SILICON CHIP Sound quality is not perfect in rack hifi systems Have you surveyed the hifi scene lately? Over the last few years , the hifi market has changed quite dramatically and is now divided in two broad ranges of products: rack systems and "separate" components. Rack systems are widely available from department stores and discount houses and typically range in price from around $800 to $1500 or thereabouts. By contrast, "separate" hifi components such as CD players, tuners, tape decks and loudspeakers are now only available from specialist hifi stores and there the sky is the limit as far as price is concerned. Trouble is, the aforementioned rack systems are generally labelled as "hifi" but most of them are not. While just about all rack systems these days incorporate a CD player and a dual tape player with Dolby B and perhaps C noise reduction, these in themselves do not make a system hifi. The truth is, compared to the sound quality available from even modestly priced "separate" components, most rack systems are downright ordinary. They're good enough to satisfy Mr & Mrs Joe Average but a long way from what can be achieved. Nor can you really expect a lot more. If you have a look at all the features that are thrown into rack systems costing around $1000, you should realise that it is not just the styling that is "well rounded" - a lot of corners have been cut inside as well. If a system is advertised as having 400 watts PMPO (meaning "pea_k music power output") you would be downright naive if you expected it to have a real power output of much more than 20 watts per channel. And take a look at the speakers. If they have three drivers in each cabinet, have Masonite backs and only weigh about 3kg, then you can hardly expect high quality. What you're getting for your money is gimcrack and not a lot more. On the other hand, today's rack systems do give good value in terms of operating convenience (full remote control) and good reliability. That is a legacy of the great improvements that have taken place in electronic componentry over the last decade or so. If you want to buy a rack system for convenience, compact size and low price, by all means do so. But remember that you are not buying a hifi system. What you are buying is an updated 1990s version of the old furniture sty led stereogram. The difference is that today's rack system can qe given an easy upgrade by replacing the loudspeakers with a system purchased from a specialist hifi store. Or you could build them yourself using the plans described in this issue. Ultimately though, if you want a hifi system, there is no short cut. You will be committing yourself to spend quite a lot of money to buy the very best that you can afford. You will probably spend quite a few thousand dollars. But having carefully considered and then spent your money, you can expect many years of pleasure and satisfaction. Leo Simpson Blue Led's Micron T2440 MK II Quality "lla11d Hads" Ethernet Cables by Mr. Geoff Wood Esq. ·14mcd <at> 20mA 3mm - $3.50 10+ - $3.15 5mm - $3.50 10+ - $3.15 FINEST 185 Soldering Station (BNC male/BNC male 50 ohm) 12 volt 6.5 AHr Gel Cell Battery 2mtr $7.95 ' 3 mtr $8.95 5 mtr $10.95 10 mtr $16.95 20 mtr $24.95 50ohm BNC Terminator $3.90 on/y$49.95 * Electronic Temperature Control. * Low Voltage Ceramic Element. * Adjustable Temperature Range, 320,350,380,410,440 deg. C. * LED Bargraph Readout. * Zero Voltage Switching. * Grounded Tip. RG58 BNC crimp plugs $2.50 RG59 BNC crimp plugs $2.50 BNC "T" piece $7.95 BNC joiners $3.35 RG58 50 ohm cable $0.85/mtr Quality BNC crimp tool $64.95 PluG FkEE tlliG Mont// got a 12 volt <at> 450MA Cltargor (8&450) wortll l/8'. ({5 SCSI (50 way cent.) * SCSI to 0B25 cable $12.95 * SCSI to SCSI cable $12.95 * SCSI Terminator $15.95 * 12 months warranty. only $159.95 Pl11G FkEE tltlG Mo11tlt roeoivo:1- 250g Goldor, wortll /7.({5 I - Golder Guekor tool, wortlt Ill q5 I - PCB lloldor, wortll lt/.50 Total Va/110 /:Lt/. 40 Bur ill 611/k (/0 or Moro} a11d got /Of off. 2 way Data Switch Boxes Pl11Ga FkEE * DB-25 or Centronics type - only $39.00 SPIRAL HARNESS WRAPPING 1![---.-■ Available in two sizes. 12325 Min. I.D. - 6m~m.&~---=~ 140mm 12volt 55watt 13mm. \ Fog Lamp Kit Great for · * 2 - 140mm Fog Lamps * Auto Power Off. * Max/Min/ Av. Recording. * Freq., Cap., Temp. * Relative & % Modes. * 3.75 Digit Display. * 4000 count. * Bargraph Display. * Plus more! * 12 months warranty * Programming Mode. only $195.00 NARVA NARfUI NARVA 2 - Lens Protectors AlAflUA . * 2 - *55W Halogen Globes Hl.N. lfJ"1 * Relay, Switch and Wiring Kit NARVA r • wiring looms. Keeps wiring neat. · Available only in black. only $1.95/mtr. 41 pc. T-Bar Driver & Bit Set Portasol Profes Gas Soldering lr Set contains:1pc - Driver Handle. 3pc - Phillips Bits. 4pc - Slotted Bits. 4pc - Allen Bits. 2pc - Square Bits. 6pc - Torx Bits. 9pc - Metric Sockets. 9pc - SAE Sockets. 1pc - 1/ 4" Skt. Adaptor. 1pc - Bit Adaptor. 1pc - 90° Adaptor. * * * * * * * * * * * * Equiv. to 10 - 60 watts. Kit Includes:* Soldering tip. * Hot knife. * Blow torch. * Hot blow. * Handy case. Now$69.00 Confusing Voice Messages Delays or Periods of Silence Unusua l Dial Tones Fr ustrated Callers ~ 4=-- ~ Gavo /10.({5, pluG roeoive a FkEE ea11 of PortaGol gaG, wortll /6.({5 PLCC Extractor Tool 12v DC to 240v AC Inverter ~ only $159.00 Female IDC:IDC10 - $1.95 IDC14 - $1.95 IDC16 - $1.95 IDC20 - $2.75 IDC26 - $2.75 IDC34 - $2.75 IDC40 - $2.95 IDC50 - $4.60 Male IDC:IDC10 - $2.95 IDC14 - $3.50 IDC16 - $3.95 IDC20 - $4.50 IDC26 - $4.95 IDC34 - $5.50 IDC50 - $6.95 * "'i"NO "'i"NO "'i"NO "'i"NQ Installs in minutes on ANY PHONE SOCKET. Total Flexibility. Will even operate with a Modem. * 140 watts. Now$22.95 IDC Connectors only$14.95 TDA2822 - $5.95 TDA2030 - $9.95 Valves * 6L6 - $14.50 * EL34/6CA7 - $ 14.50 * 12AX7 - $10.50 * * * * * * * * * * * * * * Bargain Software for IBM - All one price - Only $9.95 ea. ( Available in 3.5· & 5.25.) ENTERTAINMENT: * Goodbye Galaxy * Paganitzy * Shrapnel City * House of Horror * Jungle of Doom David Reid Electronics A. C.N. 001-3 72-3 72 ENT. (cont.) * Wolfenstien 3D * Mahjongg VGA EDUCATION: * Sky Globe * Blackjack EDUC. (cont.) Amy's 1st Primer Word Rescue PC - Fastype Animated Math Animated Alphabet 127 York St, SYDNEY 2000 P.O. Box Q103,SYDNEY 2000 Ph: (02) 267 1385 Fax: (02) 261 8905 * Hugo 11-Whodunit * Forbidden Planet * Chinese Checkers * Crystal Caves * World Empire ENT. (cont.) * * * * * UTILITIES: * Viruscan * Toy Box 11 APPLICATION: * Lable Magic * As Easy As t.•'<4 I( ~· ~~a~flo '(lf; APPL. (cont.) Print Partner FormGen 11 Draft Choice Resume Profes * * * * ( When ordering , please specify disk size ) Postal Charges $5 - $25 ......... $4.00 $26 - $50 ······ $6.00 $61 - $100 ..... $7.00 $101 - $499 .. $9.00 $500 • ............ FREEi MAILBAG Futile vintage radio conversion I have just finished reading John Hill's article on "Converting A Battery Set to Mains Operation" in the October 1992 issue of SILICON CHIP and I am left with one overwhelming question - why? Mr Hill starts his project with two rough but authentic 193 5 table model Radiola battery sets. At the end of his arduous labours he is the proud (?) owner of what might be called a Frankenstein's (Hill's?) monster. This monster is part AWA, but with a largely Airzone circuit, a chassis hacked away to fit a "Red Line" power transformer, a non-original dial mechanism and an under-chassis appearance that he is not game to show since "it would make any purist throw up his hands in horror". What is so terrible about 700mW of audio output? Subjectively, it would be adequate for most listening situations and even if greater volume was so vital there are other ways it could have been achieved without destroying the authenticity of the set irredeemably. How about an outboard mains power supply to provide the necessary ''battery" voltages but also incorporating a more powerful audio amplifier to drive the loudspeaker? As it is, Mr Hill has effectively destroyed his two sets as authentic antique radios. The end result can probably best be described as a valve home-built radio (circa 1992) in an AWA Radiola cabinet. I suppose what Mr Hill does with his own gear is his own business but I don't think that a "conversion" such as this has any place in a column supposedly devoted to vintage radio. Clyde Witcombe, Belmore, NSW. Ring & tip labelling still applies I am involved in the repair of computer controlled telephone exchanges but I still find the "Serviceman's Log" articles very interesting. I am writing in response to your 6 SILICON CHIP story in the November 1992 issue about the repair of a phone answering machine. R and T on the circuit diagram simply means "Ring and Tip". This is a leftover from the plug and cord days of yesteryear. I hope you find this information helpful. R. Hill, Brisbane, Qld. Comment: Thanks for your letter regarding the R and T labelling. A number ofreaders have written to us on this topic. It should have had an "Editors Note" to explain the term but it was overlooked. The R and T terminology is still used in semiconductor data books on telecommunications devices (eg, Motorola), even though phone jacks have long since disappeared. Fighting light pollution is a worthwhile cause It is a delight to see an electronics magazine like SILICON CHIP highlighting the problem of light pollution. Having taken part in a little astro-photography and being keen to do more, I share your view entirely. The topic has received much attention in astronomy magazines and I would like to refer you to an article in the March/ April 1991 issue of "Southern Astronomy" (Vol. 4, No. 2, p.20-26). It describes how the problems of energy conservation and light pollution can be overcome by good design. But with the current trend for more light to combat violent crime, any call for better designed lighting to achieve the same aims and still provide adequate public safety doesn't rate. Besides, so many bad light fittings have been produced and we need to use them up like any other commercial product, otherwise it costs too much! With the advent of the low energy bulbs, it is even harder to justify on cost. The mentality is the brighter the better, as this gives the greatest psychological feeling of safety, even if correctly designed lighting can do SILICON CHIP, PO Box 139, Collaroy Beach 2097. the same job without polluting the sky. So I think it will be quite some time before councils will insist on lighting that protects people (safety) but avoids wastage. "Southern Astronomy" gives the addresses of "The Association Against Obtrusive Lighting". There are two branches, as follows: (1). The Secretary, AAOL, PO Box 1023, Croydon, Vic 3136. Telephone (03) 723 4356; and (2). The Secretary, AAOL, PO Box 363, Springwood, Qld 4127. Telephone (07) 208 4321. I hope SILICON CHIP and other magazines take up the challenge to highlight the savings that can be achieved by designing light fittings to protect all interests. Dieter Kuenne, Ascot Vale, Vic. Comment: "Southern Astronomy" magazine has since published additional material regarding obtrusive lighting in their July/August 1992 issue. The addresses for the Association Against Obtrusive Lighting" remain the same. Where to get fuel flow sensors I refer to the "Ask Silicon Chip" pages in the December 1992 issue regarding a source of fuel flow sensors. A number of Australian produced cars have fuel computers fitted and these have flow transducers. In particular, Commodores from 1984 in the Calais could be a source for non fuel-injected cars or later models if fuel injection is used. I assume that the only difference is to accommodate the higher fuel line pressure in an EFI car. I also recall that the VK model specified a number of pulses per measure of fuel in the owner's handbook for calibration purposes. I hope this helps. Keep up the good work in the magazine. Glen Percy, Melbourne, Vic. Comment: thanks for the information. It may be possible to obtain these as new parts or from a wrecker's yard. ., When we in 1989 decided to design Australia's finest range ofloudspeakers, we soon realised the potential we had on our hands. By designing and building the speakers in Australia, and by using the ultimate drivers available, we could challenge the best loudspeakers from around the world. With this in mind we now set out to achieve our gool. The choice of drivers was obvious: DYNAUDIO. They are known the world over as being the finest drivers available. The high cost however, makes their use prohibitive for those speaker manufacturers who only produce mas, mruket speakers. Our intention though, was not to make another mas, mruket range of loudspeakers, but rather Australia's finest. , • ~i '; · it 'i ' "~ The next step was to appoint a design team. The ideal team should have not only the best technical qualifications and facilities, but also a great love and appreciation for music. With the design team chosen, work began in February 1990. Now followed an exhaustive but rewarding 14 months of intensive research and development. Numerous prototypes were built and refined until each model fulfilled its objectives: Being the finest in its class. The listening panel comprised not only the design team, but also Hi-Fi critics and leading audio dealers from around the country. Each prototype was compared against the more expensive imported equivalents until the design team was fully satisfied. lnJune 1991 Australia's finest range of loudspeakers was released : DYNAUDIO IMAGE. WE HAVE OONE All WE CAN ..... NOW rrs UP TO YOU! Acknowledgements: Acoustical Design: Glen Leembrugen & Dauid Connor, Sydney Australia Dynaudio Driuers: Mark Tharup & Peter Larsen, Skarulerborg Denmark Solen Capacitors: Dennis Quellet, Quebec Canada Bi-wiring Terminals: Ben Fan, Taipei Taiwan Monster Cable: Noel Lee, San Fransisco USA Cabinet Builder: Scott Krix, Hackham Souih Australia Listening Panel: Glen Leembruggen, Dawi Connor, Pat Hayes , Les Cardilini, Philippe Luder, Dahl Murphy , Carlo Di Martino , Craig McNeil, Michael Henriksen, Dauid]acobs , Tom Manning For more infurmation and name of nearest dealer please contact: Scan Audio Pty. Ltd., P.O. Box 242, Hawthorn Vic 3122 Ph.(03)4292199 Fax(03)4299309 CIRCUIT NOTEBOOK Interesting circuit ideas which we have checked but not built and tested. Contributions from readers are welcome and will be paid for at standard rates. r----1 I I 1 I I I +9V LINK PINS 3 AND 9 FOR BARGRAPH DISPLAY + 100 .047+ 16VWi 3 100xLED L-9 18 17 5 AUDIO INPUT 16 15 6 IC1 Lll3918 7 14 VR2 10k 13 68011 12 11 10 2 .,. +9V .,. 4 .,. 8 3 2 10 4 11 16 100k 4 IC2 4017 8 7 VR1 200k 6 14 . IC3 555 2 + 5 .,. 1 16VWi LED VU scanner display This circuit provides an eye catching display, which can be described as either a "time-scanned LED VU meter" or as a low resolution solid state audio oscilloscope. The audio signal is fed into pin 5 of an LM3916 dot/bar display driver (ICl). However, instead of driving the 8 SILICON CHIP .,. 15 .,. 13 .,. The circuit can drive the LED display in either dot or bargraph mode. Note that the 4017 can be cascaded, which means that the circuit can be expanded to include more LEDs. conventional 10 LEDs, its outputs are connected to a matrix of 100 LEDs, arranged in 10 columns of 10. Each column is driven by a separate output from a 4017 CMOS decade counter/ decoder (ICZ), so that only one column is operated at any one time. The 4017 is clocked by 555 timer IC3. This operates as an astable oscillator, so that the column drive outputs cycle through continuously. VRl varies the oscillator frequency and thus.the LED scanning rate, while VRZ acts as a brightness control for the LEDs. The circuit as shown produces a "dot mode" display, rather like an oscilloscope. For "bar mode", pin 9 of the 3916 should be connected to pin 3 and +12V. S. Goebel, Picnic Point, NSW. ($30) Parking lights reminder LIGHTS S2 TO LIGHTS +12V7 Ever flattened the battery in your car by leaving the parking IGNITION S1 lights on? This circuit will save TO you from this indignity by beep' IGNITION ing a warning buzzer if you D1 1N4004 switch the ignition off with the headlights or parking lights still on. IC1 is a 4011 quad NAND gate IC, with gates IC1a-lC1c . wired as a switched oscillator. .,. If the ignition is on (ie, Sl closed), Ql is turned on via Dl and the 10kll resistor. This pclls pin oscillator and pulsing Q2 (and the 1 of ICla low, thereby disabling the buzzer) on and off via inverter stage oscillator and holding Q2 and the ICld. The buzzer is disabled by switching the lights off to remove buzzer off. When the ignition is switched off, power from the circuit. Finally, it's possible to simplify the Ql turns off. If the lights are still on, pin 1 ofICla is now pulled high via a circuit if you only want the buzzer to 10kll resistor, thereby enabling the emit a continuous tone. To do this, + BUZZER (1). substitute Q2 for Ql and link its base and collector leads together; (2) replace Ql's 10kll collector resistor with the buzzer; and (3) omit Ql and IC1 (plus the 4.7kll and 470kll resistors and the 2.2µF capacitor). Darren Yates, SILICON CHIP. Simple tester for IR remote controls -J_ PB1 .-------♦ 16VWi 220 2 + T FEIIALE XLR CONNECTOR 9V: ACTIVE .,. ...a... .,. LED1 Cable tester with LED indicators This circuit was designed to test microphone and instrument leads; ie, XLR-XLR, XLR Male-Phone, XLR Female-Phone and Phone-Phone. The circuit is very simple and uses four LED indicators to show the test resruts. By plugging in the cable and pressing the appropriate switches (Sl-S4), each lead can be tested for a short or open circuit. If the circuit is OK, the corresponding LED will light; if the circuit is open, no LEDs will light; and if the lead is shorted, more than one LED will light when each switch is pressed. D. Gardner, Castlemaine, Vic. ($20) T 9V I I ...a... l Ri If you suspect that your remote control transmitter might be on the blink, this simple circuit will provide a go/ no-go indication. A properly working remote control handpiece emits bursts of infrared light whenever a function button is pressed. This infrared light causes photodiode IRDl to conduct, thus turning on Ql and lighting LED 1. If no infrared light is present, IRD1 is reverse biased and Ql is held off by the 100kll resistor connected between its base and ground. Note that because there is no preamplifier stage, the circuit is not very sensitive and the range is limited to just a few centimetres. This means that the transmitter should be held close to IRDl during testing. Tun Gregory, Alberton West, Vic. ($20) JANUARY 1993 9 ARE YOU POWER HUNGRY? The new and improved Powerrnaster Mk2 kit gives you all the power you'd ever want for transceiver or bench-top power installations. Its flexible design allows you to choose the appropriate transformer for your desired power output level, opening up many possibilities for customising your own particular installation. nQ For example: CURRENT RATING: v Q VK POWERMASTE [1) TRANSFORMER CONTINUOUS s1a9 $109 QQQ ~ Just the thing for your do-it-yourself disco outfit! This reliable kit provides a high-energy ll_ash of white light which you con vary from l - l O flashes/ second. Ifs triggered by either an external source or its own internal oscillator and has both input & output trigger connectors, so that any number of these units con be linked to flash in sychronisation. Comes with all components, hardware, PCB, deluxe plastic cose, screened perspex front panel, linear l 00mm Xenon tube and a commercial high-efficiency reflector. .fr:\ \'.'.:Y" 5A BA JOA 20A 25A 25A M-2010 15A 20A 25A For those who remember the original Powermaster, the addition of a 20A panel meter to the kit plus provision for an optional 12V coolinJJ fan will make even higher power configurations possible with perfect safety. On the cosmetic side, the supplied cose Is r:iow an attractive black powder-coated steel unit - an advance over the previous bare aluminium box. Other improvements include: A front-panel overload protection reset switch and a_primary slow blow fuse with finger proof fuse holder. The kit includes all components (excepting those that depend on your choice of transformer), hardmre and a prepunched silk-screened chassis. Jan'93 Cot K-3400 Dec'92 MINI STEREO .AMPLIFIER Q CotK-5008 s229s DIESEL SOUND SIMUlATOR Q SURGE (PULSE) M-2000 M-2010 UPGRADED CotK-3400 PEAK (1 MINUTE) Ocl'92 Dec'92 fiWiifflf/l You'".'!l got your model,railmy looking great, but there's something mIssmg ......well, here s the solution to y~r problems: Our Diesel Sound Sick of your personal stereo's limitations? Why squash your earlobes with · Simulator Kit is easy _to build, fits inside most locomotives (speaker included) and takes its power from the rails. Whafs more using some very o pair of headi;ihones when this inexpensive kit con give you the flexibility of a home hI-fI on your desk! It uses your personal stereo as the 'brains' of clever _circ_uitry, the pitch r~flects the loco motor's speed ~ how's that for a r~llshc simulation! Supplied m Shortform with all components, PCB and the operation and uses a tiny 8-pin OIL device which contains two mm, speaker. amplifiers and is capable of delivering l watt into 8 ohms at 9 volts. Whafs more, supply voltage con range from 1.8V to 12V. Comes complete CotK-3030 with all components, PCB, hardware, front panel screened label and cose. AUDIO SWEEPER MOTOR SPEED CONTROLLER "fff:-:J!.!'1,_,~ ~ CotK-3085 $4695 Q [1] ~~-:== fill easy-to-build kit designed to regulate the speed on heavy-duty power tools. Ifs ideal for circular sawst electric drills, lawn edgers, jig-saws, sanders, gnnders and other equipment rated at 5 amps with a 'brush' type motor. This improved design has a higher current rating and uses a Triac rectIfIer instead of on SCR. It also monitors the back-EMF voltage from the motor so, though the drill speed is controlled, it won't bog down when the gomg gets tough. Complete with.deluxe pre-punched black anodised screened front panel, components, PCB and flush-mounted mains socket. 10 SILICON CHIP CotK-7352 QQQ Here's a useful kit for audiophiles, sound experts, enthusiasts and anyone interested in sound. This very affordable audio test system analyses the perfo_rmance (treble, mid and boss) of speakers, speaker enclosures filter circuits and room acoustics. It consists of a sweeping audio test signal generator and a metering amplifier which measures the results. Comes complete with a deluxe pre-punched front panel, plastic instrument cose, PCB, hardware (including dB meter), components, mic. insert and plug pack. '92 <at>Sept I ., . . I, ELECTRON IC CIRCUITS ! '. I ~_, ' ""' ✓ ✓ ✓ ✓ ✓ ✓ ✓ "' ✓ ✓ ✓ ✓ -I ✓ "' ✓ "' ✓ THE ENCYCLOPAEDIA ELECTRONIC CIRCUITS VOLUMES 2, 3 & 4 ✓ ✓ ✓ ✓ ✓ ✓ Volume 3 Cot B-1760 $5695 Volume 4 Cat B- 1762 Essential reference material for the professional (or amateur) electronics technician. If you're looking for a circuit for a particular application, it's either in here or there's something very close. These volumes ore also ideal as project idea-starters. THE ART OF SCIENCE Whether you're just starting out in electronics (or any other scientific field), or someone with decades of experience, this book will supercharge your thinking and procedures. Very entertaining reading, 'The Art of Science' covers all stages of scientific practice, from choosing a field of experimentation through record-keeping and on to presenting your results! Everything you need to plan a successful Science career is right here! $3495 Cat B-1300 ELECTRONIC CIRCUIT CARDS AND SURFACEMOUNT TECHNOLOGY illSlll;iffl&i 1 . 1,fil.l A must for anyone getting into circuit cord design or manufacture, this book lays it all out for you: From Standards to card layout, on to materials and processes and including testing and ordering components, everything you need to know! Cal B-1620 $4995 AMPLIFIER CIRCUITS Why go to the trouble of designing a circuit from the ground up when the building blocks are already available? Whether you want complete, proven designs that are ready to build, or a stepping-off point for your own original work, this is the book for you. Hos over 250 designs for just about any application you could ever need! Cat B-1744 B 1434 MODERN OSCILLATOR CIRCUIT ENCYCLOPAEDIA Want instant access to more than 250 of the latest practical, ready-louse oscillator circuit designs? Then buy this book! Covers over 16 major types of circuit including: Audio, Burst, Sine-Wove, TTL, RF and Crystal. Cat B-1742 $2995 RADIO AMATEUR'S DIGITAL COMMUNICATIONS HANDBOOK Interested in the high-speed world of packet communications? Chances ore, if you haven't already bought this book, you're probably a little confused about the many modes and options available. Fear not everything you need to know is contained in this one book - all the popular techniques are explained in plain English, even hints on equipment and software selection! Cat B-2405 $2995 ]ANUARY 1993 11 Audiophile Quality Loudspeakers FOR UNDER $400! fossemble them in just minutes, then sit back & enjoy the best sound money can't buy! We don't sell these speakers fully assembled, so this is the only way you can get them. But we can tell you that you'd be hard pressed to find ready-made speakers this good for under $800! The kit's famous Peerless brand speakers' superior performance and craftsmanship in design and manufacture have been recognised by true Audiophiles and professionals throughout the world for nearly 70 years. In fact, many of the top speaker manufacturers use Peerless drivers in their top-end range. The Peerless speaker kit consists ot HARDWARE KIT: Woofers: 2 l 74mm Polypropylene cone with soft foam surround and high temperature voice coil. Col C-2106 Tweeters: 2 25mm Dome tweeters Cot c-2101 Crossovers: 2 2500Hz 2 way Speaker filling, tapered ports, badges, glue, plus all necessary screws and fasteners. Cot A-2456 $2 6 9 SELECT FROM OUR EXTENSIVE RANGE i1::::::::ttJ::::: :::i/::::r::::::::::t:!i:i!i!::::::::t]]i!:::]:l: OF PEERLESS SPEAKER DRIVERS: t::::f::::::::::tt:::1::j::: 1 :::::::::::::: 216MM (8") WOOFER 250MM ( 1O") WOOFER Specifications: Impedance Frequency Response Resonance Frequency Sensitivity ( l w/ l m) Power-handling (RMS) Total Q Factor Specifications: 8 ohms 33-3000Hz 33Hz 91 dB 90 watts 0.44 VAS 125 litres Magnet Weight 430g Suggested Enclosure 30- 70 litres CotC-2110 Impedance Frequency Range Resonance Frequency Sensitivity ( l w/ l m) Power-handling (RMS) Total Q Factor s1199s 8 ohms 32-3000Hz 32Hz 89 .5dB 80 watts 0.44 VAS 83 litres Magnet Weight 235g Suggested Enclosure 15-40 litres CotC-2108 $89 95 174MM (6.5") WOOFER 100MM (4'') MID-RANGE Specifications: Specifications: Impedance Fr~uency Range Resonance Frequency Sensitivity ( l w/ l m) Power-handling ([~MS) Total Q Factor VAS Magnet weight Suggested Enclosure 8 ohms 48-3500Hz 48Hz 88dB 60 watts 0.55 22 litres 235g 8-20 litres Cat C-2106 s799s Impedance Frequem,y Range Resonance Frequency Sensitivity ( l w/ l m) Power-handling (RMS) Total Q Factor Magnet Weight 8 ohms l 000-9000Hz 900Hz 90dB 60 watts Cot C-2104 $6995 1.3 l00g Ultra high performance! 25MM ( 1") DOME TWEETER 25MM ( 1") DOME TWEETER Specifications: Specifications: Impedance Frequency Range Resonance Frequency Sensitivity ( l w/ l m) Power-handling (RMS) Magnet Weight Cot C-2102 8 ohms 2000-20,000Hz 1400Hz 90 .5dB 120 Watts· 235g s599s • If used with 4000Hz, l 2dB/octove crossover. Impedance Frequency Range Resonance Frequency Sensitivity ( l w/ l m) Power-handling (RMS) Magnet Weight CotC-2101 8 ohms 2200-20,000Hz 1080Hz 89dB 100 Watts· 100g s499s • If used with 4000Hz, l 2dB/octove crossover. Data Sheets: Full Data Sheets on all our Peerless speakers are available through your nearest Dick Smith Electronics store. 12 SILICON CHIP Building New Speakers Or Upgrading Your Old Set? SEE US FOR THE BEST PRICES ON Drivers and Accessories Speaker Box Lining Need More Input Jacks? Quality innerbond: Light, clean and easy to handle, it's the recommended density for most speakers. Weighs approximately 300g/sq . m and is 25mm thick by 700mm wide. Available cut to any length from our bulk roll. Cat C-2662 Stereo Audio/Video Switch Box This great-looking switch box solves the problem. It's ideal for CD, Video or any extra audio components you want to connect. Provides three inputs and one output. It's well built and the switches have a nice, positive feel. Get one and quit swapping cables! Speaker Grill Cloth Speaker enclosures looking a little shabby? This quality speaker grille cloth is easy to fit and will have those old boxes looking like new in minutes! In l m x l .5m pack. Cat C-2095 $595/m 2-Way Crossover 3-Way Crossover Just the thing if you're building a new speaker system, these are approximately 3kHz crossover frequency and 8 ohms impedance. Cat C-2512 A great crossover for three way systems; It's a 2 inductor network with non-polarised capacitors, giving crossover frequencies of l .5kHz and 5kHz • Cat C-2513 rn~;::::'.:==="=~""''!J:. - IN PUT+ 3WAY DtVI OINC. NE rwom<. Sm or more $5.06/m Piezo Ceramic Tweeter This amazing little tweeter handles up to 40 watts continuous. Its frequency response is from 5kHz to 27kHz and it con be used ) with or without a crossover. Cat C-2005 $ 1995 3•1• ' " --- 0 QUALITY HI-FI SPEAKER DRIVERS Replacin9. or up-grading your speakers? Then see us first! Build that high quality speaker system you've always dreamt of, for less than you d imagine possible. All have polypropylene cones and foam suspension for smooth response across the frequency range, 300mm ( 12'') Woofer 250mm (10'') Woofer Nominal Specifications Nominal Specifications Frequency Response Nominal Diameter Piston Diameter Baffle Opening Nominal Impedance Znom d.c. Resistance Rdc Resonant Frequency Is Total Q Qts Equivalent Compliance Vas Sensitivity <at> l W <at> l M S Frequency Response 40-5000 Hz Nominal Diameter 250mm Piston Diameter 21 0mm Baffle Opening 233mm Nominal Impedance Znom Bohms d.c. Resistance Rdc 6. l ohms Resonant Frequency Is 30Hz Total QQts 0.45 Equivalent Compliance Vas 115 litres Sensitivity <at> l W <at> l M S 90dB SPL Frequency Response 55-6000Hz Nominal Diameter 162mm Piston Diameter 128mm Baffle Opening 142mm Nominal Impedance Znom Bohms d.c. Resistance Rdc 6ohms Resonant Frequency Is 60Hz Total Q Qts 0.87 Equivalent Compliance Vas 16 litres Sensitivity <at> l W <at> l M S 87dB SPL Suggested Enclosures Suggested Enclosures Sealed Volume Vb Vented Volume Vb Tuning lb Cat C-2041 Sealed Volume Vb Vented Volume Vb Tuning lb Cat C-2042 25 -5000Hz 300mm 250mm 277mm 8 ohms 6.2 ohms 25Hz 0.45 260litres 90dB SPL Suggested Enclosures Sealed Volume Vb Vented Volume Vb Tuning lb CatC-2040 50-75 litres N/A N/A $7995 50 litres 40 litres 26Hz $6995 162mm (6.5") Midrange 25mm (1") Dome Nominal Specifications Tweeter Frequency Response 2Hz-20kHz Coil Impedance 8 ohms Sensitivity lOOdB/W +/-3dB<at> lW0.5m Magnet Weight 152g Cat C-2044 $2495 10-15 litres N/A N/A $39 95 .......... ~ Playmaster 30/30W Stereo Amp Excellent performance and specifications have made the Playmaster series of amplifiers the popular choice of kit-builders for years. This 30/30W stereo amp is no exception ... it's a classic piece of equipment that will do most music systems proud . Construction is made easy by mounting all components (including heatsinks) on one PCB. Full form kit comes with all components, PCB, all hardware, pre-punched rack-mount case and silk screened front panel. Cat K-5600 EAAprll '92 $249 ]ANUARY 1993 13 SILICON FILLED SPLICE CONNECTORS Cat H-5658 $495 ONLY PACK OF 100 ~ 500m OF CABLE Pre-tinned, it's ideal hookup wire for most purposes other than high voltage. Stock up at this great price' CatW-2289 Normally $25 This Month 500 Metre Roll $2 0 For home or vehicle alarm installations, these switches keep control of the alarm in the hands of the rightful owner. Standard Keyed Switch Cot L-5290 $8.95 Small Keyed Switch Cot L-5295 $9.95 Mini Tubular Key NEIN Cot L-5296 $10.95 Lorge Tubular Key NEIN Cot L-5291 $12.95 Ideal for low voltage designs, breadboards ore foster, easier and cleaner than working directly onto PCB's. All kits ore mounted on a base-plate with non slip feet and holes tor binding posts and come with jump wires and binding posts. BREADBOARD KITS: Small - 800 hole, 160 buses & 4 distrib. buses Cat H-4020 $39.95 Medium - 1260 hole, 256 buses & 6 distrib. buses Cat H-4040 $49.95 Large - 2520 hole, 504 buses & 14 distrib. buses Cat H-4042 $19.95 X Large - 3200 hole, 640 buses & 6 distrib. buses Cat H-4022 $99.95 BREADBOARDS ONLY Af. obove, but without the base-plate, wires & posts. Small - 300 hole, 60 buses & 2 distrib. buses Medium - 630 hole, l 26 buses & 4 distrib. buses Large - 800 hole, 160 buses & l O distrib. buses JUMP WIRE KIT - 140 jump wires in l O colours & 14 lengths, all with 90° bend at each end. In plastic divider box. 5mm LEDs IN RED, GREEN, BRIGHT RED AND EVEN BLUE! =~: Drive your borgroph further! This new borgroph/orroy driver IC with peak hold is the some as you 'd find in most quality commercial stereos. Exclusive to Dick Smith Electronics, it leaves on indicator lit to indicate the most recent peak point. Bright Red Flashing NEW Green Flashing 5mm Cat Z-4042 $1so NEW High Brightness Red 5mm Cat Z-4072 $9.95 BARGRAPH AND V/U METER DRIVER IC C])-=t $195 Cat H-4030 NEW Forget about boring LED arrays forever! Now you con mix 'em up with our range of brilliant 5mm colour LEDs including the new blue LED with diffused white lens! 5mm Cat Z-4040 Cat H-4035 $10.95 Cat H-4045 $11.95 Cat H-4025 $19.95 NEW BLUE DIFFUSED LENS 5mm Cat Z-4005 $1695 CatZ-6291 Check For Availability 0 TWIN OUTLET EXTENSION LEAD 0 , HE.VJ It takes two! A l .8m extension lead with a heavyduty moulded double adaptor on one end. The doub.!f adaptor hos a hanger nole for added convenience. In safety yellow. $ Cai M-7070 1295 MAJOR DICK SMITH ELECTRONICS AUTHORISED STOCKISTS: NSW: ARMIDALE: New England Electronics 711655 BALLINA: Ballina Electronics 867022 BATEMAN'S BAY: Baycity Sight & Sour<! 725030 BATHURST: Electronic Frontiers 323933 BOURKE: Countrywide Services 722150 BOWRAL: Bowral Electrical Supplies 611861 BROKEN HILL: Hobbies & Electronics 884098COOTAMUNDRA: Cootamur<lra Music & Lile 422561 COffS HARBOUR: Coifs Harbour Electronics 525684 OENILlOUIN: Deni Electronics 813672 OUBBO: Chris's Hi R 828711 FORSTER: Forster Village Electronics 545006 GOULBOURN: Tunlive 221288 GRAFTON: Repairs & Spares 421911 GRIRRTH: Miatronics 624534 INVERELL: lnverell Electronics 221821 KATOOMBA: Niagara Photo & Sports 822800 KEMPSEY: P&K Richards 631134 LEETON: Leeton Audiotronic 532800 LIGHlNING RIDGE: Lightning Ridge Solar Power 29 1013 LISMORE: Oecro Electronic Services 214137 UTHGOW: Douroy Photographies 513173 MACKSVILLE: Macksville Electronics 682899 MOREE: Moree Electronics 522091-MUOGEE: Headware 723895 MURWILLUMBAH: StJings & Things 723684 NARRABRI: Namoi Computer Service 923274 NELSON BAY: Nelson Bay Elect & Hobbies 813685 NOWRA: Nowra Electronics 210722 PARKES: Strad Music Ctr 623366 PORT MACQUARIE: Hastings Computer Service 840255 RICHMOND: Silicon Crafts 784101 TAREE: Manning Electronics 512233 ULLAOULLA Coas1al Electronics 553989 WAGGA WAGGA: Phillips Electronics 216558 WALGITT: Walgett Electronic Centre 281111 WINDSOR: Hawl<esbury Electronics 776722 YN3S: Wannington Electrical 261411 YOUNG: Keitll Donges Electronics 821279 VIC: ARARAT: Jerram Electronics 522345 BAIRNSDALE: LH & lM Crawford 525677 BENALLA: North East Electronics 622710 CASTLEMAINE: Inspect Electrics 723m COLAC: Colac Electronics 312847 ECHUCA: Gilmour Electronics822956MILOURA: P\Jllman Auto Pro 232882 MORWELL: Roylaine Pty Ltl 3394..'ill ROOEBUD: Seatech Vic Pty Ltd 822225 SHEPPARTON: Andrew Guyan Electronics 219497 SWAN HILL: N)'ah District TV Service 329303 ST. ARNAUD St. Arnaud Appliances 9510EB WARRAGUL: Roylaine 234255 WARRNAMBOOL: Koroit St Elec Services 627417 WONTHAGGI : South Gippsland Photo Service 721411 QUI: AYR: Delta Electrix 831566 BLACKWATER: Cool Tronics 825827ilOWEN: Delpro Agencies 86 3477 BUNDABERG: Bel> Elkin Electronics 521785 CALOUNORA: Electr<>-mart 918533 DALBY: Hobby & Electronics 625770 EMERALD: Cooltronics 825222 GLADSTONE: Electronic Enterprises 726660 GOONOIWINDI: ClW Electronics 713411 INGHAM: Masons Electronics 763188 INNISFAIL: lnnisfail Hi.fi 612014 KINGAROY MO & MM Siegle 624535 LONGREACH: Longreach Sour<! & Communications 583307 MACKAY: Stevens Electronics 511723 MARYBOROUGH: Keller Electronics 214559 MOSSMAN: Mossman Electronics 982200 MT ISA: Outback Electronics 433331 NAMBOUR: Nambour Electronics 411966 PIALBA: Keller Electronics 283749 STANTHORPE Granite Belt Communications 813333 TAS: BURNIE: Electronic City 314760 DEVONPORT: Al Electronics 248322 SA: MT GAMBIER: Hutchesson'sCommunicaUon 250400 PORT LINCOLN: Basshams TV &Comp World 830075 WHYALLA: Eyra Electronics 454764 WA: ALBANY: Micro Electronics 412077 BUNBURY: Micro Electronics 216222 COWARAMUP: CPA Electronics 555448 GERALOTON: Direct Lighting 211278 KALGOORLIE: Today's Electronics 215212 MANOURAH: Mandurah Hi R 5812206 PORT HEOLANO: Ivan Tomek Electronics 732531 14 SILICON CHIP NIMROD SOLDERING KIT This butane-powered, temperature-controlled ( 400- l 300°C) soldering iron comes with many accessories: Includes stand, solder (with dispenser), tip cleaner, hot air lip, torch tip and hot knife tip. It's ideal for outdoor work (no power point required) and pocks neatly into its own cushioned case. ~ (;J/<at><at>%H liwminii#ii 0 rn 1-1J Ii $U I uc;JJ I Cat T-1395 1 s749s ~ t:JJ]JIJIIET!J ~=~ ==..= c:,== === =~ COMPUMETER Attention homebuyers, tradesmen, architects, estate agents or anyone else who needs to measure distances and prepare quotes: The Compµmeter is an ultrasonic tape measure that measures distances from 55cm to 12.5m at the touch of a button! It displays both metric and imperial measurements on its LCD screen, adds, does area/volume calculotions and hos a memory function. 5 $599 Requires 9V Batlery ~ AC VOLTAGE FINDER Now there's no need to put yourself at risk! This device detects the electromagnetic field surrounding cables, sensing any AC voltage above l 20 volts and warns you with both an LED and on audible 'buzz'. At this low price, there's no excuse for not having one! N(W Cat Q-1531 STOCK ARRIVING LATE JANUARY $1695 DS XPRUS NIMROD 0 === t/ CatQ-1407 NEW ~ Witff casseffe player & timer! 45MEMORY ALL BAND RECEIVER Open your ears to the world via shortwove. The Songean ATS-8 l 8CS is on easy to use digital all-bond world receiver, built to give you years of international listening pleasure. Covers local AM/FM bonds, Longwove and continuous Shortwove frequencies from l .62 to 30MHz. Features a built-in cassette deck, 45 memory channels and a large digital display which shows frequency, local/world times, memory channel selection and more! Also hos a large direct-entry frequency keypad and standby recording function. Cat-0-2842 A Pocket-Sized, Powerful Performer/ 70XLT SCANNING RECEIVER Listen in to the radio-using community with this VHF /UHF hand-held scanner. II hos 20 memory channels for storing your favourite frequencies, 8-bond coverage (66-88, 136- 174 & 4065 l 2MHz) and track tuning for improved reception. Complete with on inbuilt rechargeable NiCod battery pock, AC charger, carry case and a two-year warranty! Exclusive to Dick Smith Electronics! Cat 0-2740 $399 $269 uniden. SAN&EAN t, VIQ ll!U 0 1 /l ~ lt/J/11 (, & MAILORHR ARVICE Outside Sydney (FREE CaH) 008 22 6810 Sydney And Enquiries - (02) 888 2105 . FAX: (02) 805 1986 or write to OS XPRESS, PO BOX 321 N/ RYDE NSW 2113 All Major Credit Cards Accepted. O/Nite Courier Available. STORE LOCATIONS: NSW • Albury 21 8399 • Bankstown Square 707 4888 • New Store Location - Blacktown Shop 301, 22-24 Patrick St 871 77'12 • Brookvale 905 0441 • Bondi 317 1444 • Campbelltown 'Z7 2199 • Chatswood Chase 4111955 • Chullora 842 8922 • Gore Hill 439 5311 • Gosford 25 0235• Hornsby 477 8833 • Hurstville 580 111'12 • Kotara 56 2092 • Liverpool 600 9888 • Maitland 33 7886 • Miranda 525 'Z7'l2 • Newcastle 8111198 • North Ryde 8713855 • North Sydney (Greenwood Plaza) 184 9487 • Orange 818 400 • Parramatta 889 2188 • Penrith 32 3400 • Railway Square 211 3777 • Sydney City 287 9111 • Tamworth 88 1711 • Wollongong 28 3800 ACT • Belconnen (08) 253 1785 • Fyshwick 280 4944 VIC • Ballarat 31 5433 • Bendigo 43 0388 • Box HHI IIO 0899 • Coburg 383 4455 • Dandenong 794 9377 • East Brighton 592 2388 • Essendon 379 7444 • Footscray 889 2055 • Frankston 783 9144 • Geelong 232 711 • Melbourne City 399 Bizabelh St 329 &OU & 246 Bourke St 839 0398 • Richmond 428 1814 • Ringwood 879 5338 • Springvale 547 05'12 QLD • Booval 282 8200 • Brisbane City 229 9377 • Buranda 391 8233 • Calms 311 515 • Capalaba 245 2870 • Chermside 359 8255 • Maroochydare 791 800 • Rockhampton 'Z7 9844 • Southport 32 8033 • Toowoomba 38 4300 • TownsvHle 72 5722 • Underwood 341 0844 • SA• Adelaide City 232 1200 • Beverley 347 1900 • Elizabeth 255 8099 • Enfield 280 8088 • St Marys 'Z17 ff17 WA• Cannington 451 • Fremanue 335 9733 • Perth Citv 481 3291 • Midland 250 1480 • Narthbridge 328 8944 TAS • Hobart 31 0800 • Launceston 344 555 NT• Stuart Park 811977 STORES ACR088 AUSTRALIA AND NF# ZEALAND B 1434 ]ANUARY 1993 15 Save' inoney with th!s,easy-to-assemble ~it,. Peerless PSK60/2 2-way hifi loudspeakers Based on high quality but well-priced Peerless drivers, these compact loudspeakers will be just right for many hifi enthusiasts. Despite their small size, they deliver big performance! By TOM MANNING* When you consider the high price of good quality commercial hifi speakers, it is not surprising that kit speakers are as popular as ever. You save money as well as getting the satisfaction of building your own. This new *Scan Audio Pty Ltd, PO Box 242, Hawthorn, Vic 3122 . . 16 SILICON CHIP design uses components from Peerless, a name well known to many hifi enthusiasts, as this Danish company has been manufacturing quality speakers since 1926. Peerless speakers · have been unavailable for a number of years in Australia and only recently have returned to the market as a regular stock line from Dick Smith Electronics. But while it is good to see the famous Danish brand back on the market, there have been no current designs using Peerless loudspeakers. That is about to be remedied with the publication of this article. It is worth noting that while Peerless as & brand name has been more or less absent from the Australian scene for a few years, Peerless drivers are used in many famous speaker brands, such as Dali, Jama, Richter, Jansson, Bang and Olufsen, Celef, Yamaha, Vandersteen and Krix. If you were able to look inside the cabinets of these loudspeakers, you would find that Peerless drivers turn up in some Left: shown here on a bookshelf, the Peerless PSK 60/2 loudspeakers will perform equally well on stands or when wall-mounted using adjustable brackets. The bass/midrange driver selected for this design is the Peerless 174WF woofer, a 165mm unit with a cone made of polypropylene. This material is used extensively these days because of its rigidity and high degree of selfdamping. The cone has a soft foam roll surround which ensures a low frequency resonance and good damping. The 25mm high temperature voice coil enables the driver to handle relatively high power; up to 60W RMS, depending on the design of the enclosure. Thiele/Small parameters very expensive and esoteric designs indeed! This first Peerless do-it-yourself design will be an ideal match for the Studio Twin 50 Stereo Amplifier published in the March and April 1992 issues of SILICON CHIP. When driven by an amplifier such as the Studio Twin 50, the dynamic range from these Peerless speakers will be more than adequate for the vast majority of enthusiasts. Designated the PSK 60/2, which stands for Peerless Speaker Kit - 60 watt/2-way, these loudspeakers could serve as the main pair of speakers in your home, or as extension speakers or rear speakers in a surround sound system. They would be a good upgrade of the speakers supplied with many small rack hifi systems. They are small enough to be placed on your bookshelf, on stands or fixed to the walls with adjustable brackets. Woofer selection There are many factors to be considered when designing a new loudspeaker. One of the most important is the bass driver to be used in the sys- tern. At one time, the tendency was to select the largest possible woofer, say a 12-inch (30cm) unit, and then try to design the enclosure around it. These days, the approach is normally to use much smaller woofers, in the knowledge that a small driver in the correct size enclosure is a much better choice than a large woofer in too small a box. Most audio enthusiasts are aware of the pioneering research done in Australia during the 70s by Neville Thiele and Richard Small. Thiele documented the theory behind speakers in vented boxes, which was later expanded on by Small who analysed sealed and passive radiator designs. All good modern bass speakers are now designed with this analysis in mind. The key factors are: (1). · The free air or natural resonance, F 0 , of the driver. This is the low frequency at which the driver's impedance comes to a peak and where it exhibits the greatest cone excursion for a given applied voltage; (2). The total Q factor, Qt, of the Specifications Model ........................................ .................... ........ Peerless PSK 60/2 System .......................... ........................... ...... .......... 2-way bass reflex Woofer .............. ... .... .... ............ .. ......... .. ...... . 165mm Peerless 174WF Tweeter .... ........ ................ .. ............................... 25mm Peerless BOOT Rated Power ......................................................... ....... ....... 60W RMS Sensitivity ............................. ....................................... 88dB (1 W/1 m) Frequency Response ....................................: ... 55 - 20,000Hz (±3dB) Crossover Frequency .... ............ .............................. ............... 2500Hz Tuning Frequency .. ....................................... .. .... .. ....... ...... ......... 45Hz Impedance .............. .......... ...... ............ ... ............ ... ................... 8 ohms Internal Volume .... .. ........ .. .......................................... ............. 14 litres Dimensions ................................. ...... 420 x 215 x 235mm (H x W x D) Weight ................. ...... .............. .. ........................ ...... .. .... ....... ... ... 6.5kg JANUARY 1993 17 BrOel &Kj<Er Potentiometer Range: __ ~ d B Rectifi er : ~ Lower Lim. Freq.: _ _ . 50 _25 Measuring ObJ .: dB l74HF 26/72 6! woofer II ___ . Wr. S peed: ____lQQ mm /sec . Pape r Speed: ___ _]_ mm/ sec. - . ---:7 ~-- .d - - - - 4Q lQHz Q . -~ 'r----1 - --, -- -- -- ·-'-- 1;75 [2 ---· - - '--" _ '-·-"··-'· I I dB B 1- -- -1 --I- L.-tj__J_ ·----t-t-:t--i-••t f---- f-- - ~~:-t-± - ---==-- - ~~~ - ·---. - _ ------/ .___:. -- - -_-::: _ a~,oQ . --. - ;;:;.J;:z:' :=:~' ~ ~ . - - -- - 2010 ===·::x:. ::::::=::___ Ree. No.: _ l _ 10 Date: 20.2.90 s;gn.:....KL_ 0 · - ·--· - · \· --l---+ ➔ ·---+--+ r---i---1------+----+--+--+ - - - f..---.-.-- -+-· i..- 1--------l---+- -+---I- - _..._ .__,_l- 5 ~ .,.-- --+ 20 10 2 15 +----+___±::--+-+-+ 0 0 40 D A B C L,n. B C Un. ( 1612 / 2 :'231._ A Fig.I: this diagram shows the frequency response of the Peerless 174WF woofer when mounted on a flat baffle. The smooth curve shows its impedance characteristic. Its free air cone resonance is 48Hz, corresponding to the peak in the impedance curve. · Briiel & Kj<Er Potent iom et er Rang e: _~ dB Rectifier: ~ Lower Lim. Freq.: _ _l O _ Hz Wr. Speed:__J_QQ__mm/s ec. Pape r Speed: _ _ 3_mm/ sec. 50~25 Measuring Obj.: dB~__dH I 80DT 26/ 55 10,75 ·-t dBklB f- - tweJ!1.e.r-_-= 4 0. o~ 6 60 - ~-- . ---·~.t----+---+--=;= 1--f +--+--+ +- ~ --+-,-+-J.- Roe. No.: _ l _ 10 - + -t----t-l-4-- 5 -----1____..- Sign .:....K.L____ OP0124 - t- •-+-+- ,__, Oat e:...2D.,_Ll0 0 --+ +--+---y of-· 1 50 1 ~ult iply F~~q . Sc~I~ by: _ _1 ~__oo z:~olevel: _1_k_H_z~7□~~~B._ _ _ 5 _ 10 20 40 D A B C Un. A B C Un. (1612 / 2112 ) Fig.2: this diagram shows the frequency response of the Peerless 80DT tweeter. The smooth curve shows its impedance characteristic. Its resonance is 1080Hz, corresponding to the peak in the impedance curve. driver. This is the "quality factor" at resonance and indicates the combined effect of the driver's electrical and mechanical damping. (3) The equivalent volume, Vas, which is the volume of air (in litres) needed to obtain the same stiffness as the driver's suspension. Expressed more generally, Vas is an indication of the "springiness" of the suspension system. The Thiele/Small parameters for the Peerless 174WF are FO , 48Hz; Qi; 0.55 ; and Vas, 22 litres. Calculations with the relevant formulas indicate that an enclosure volum~ of 14 litres and a tuning frequency of 45Hz are suitable choices. The tuning frequency or box resonance, fB , is the frequency at which the air mass of the enclosure reso- nates with the air mass in the port. At this frequency, the driver's mechanical excursion and impedance will be L ..::____J ~ '°" ,.:, RL (a) C II f"" RL (b) Fig.3: low pass & high filters are the building blocks for crossover networks. The inductor in series with the resistor at left (a) blocks high frequencies & therefore functions as a low pass filter. The capacitor in series with the resistor at right (b) blocks low frequencies & therefore functions as a high pass filter. Price & availability The Peerless PSK 60/2 loudspeaker kits will be available exclusively from selected Dick Smith Electronics stores. The prices are as follows : Complete kit for two speakers, including cabinets .. ...... .... ............ $399.00 Complete kit for two speakers, without cabinets ........................... $269.00 Woofer only (DSE Cat. C-2106) .. ......... .......................................... $79.95 Tweeter only (DSE Cat. C-2101) ... .. ............................................... $49.95 18 S1ucoN CmP at a minimum, but the output from the vent (port) will be at its greatest. This can be seen from the impedance plot of the system (Fig.8), where the impedance dips to a minimum between the two low frequency peaks. Tweeter selection The choice of a suitable tweeter for a 2-way speaker can present designers with problems. The tweeter needs to be at least as efficient as the woofer and its frequency coverage must complement that of the woofer so that the overall frequency response of the system is as smooth as possible. As can be seen from the chart diagram of Fig.1, the 17 4WF woofer has a reasonably smooth response over most of its range, culminating in a small peak in the 2-3kHz region. Its efficiency is quoted as 88dB at 1 metre, for an input of 1 watt. A suitable match is the Peerless 80DT dome tweeter. Its efficiency is slightly higher, at 89dB, and as its response plot of Fig.2 shows, it is quite smooth over its bandpass, with a resonance peak just above lkHz. Thus, it can be teamed with the Peerless 174WF woofer without using an overly complicated crossover network. The BODT tweeter features a 25mm This photo shows all the components for one loudspeaker system: the prefabricated cabinet & grille cloth frame, one woofer, one tweeter, one plastic port, the crossover/terminal panel assembly & various self-tapping screws. voice coil with an aluminium former and a woven textile dome. Crossover design Selecting the woofer and its box size and matching it with a suitable tweeter is the relatively easy part. The crossover design is the hard part and, more than anything else, determines the sound quality and tonal characteristics of a speaker system. In a 2-way system, low pass and high pass filters are combined to divide up the frequency spectrum. The simplest low-pass filter consists of an inductor in series with the woofer, while the simplest high-pass filter is a series capacitor with the treble driver. This is illustrated in Figs 3(a) and 3(b) respectively. Now, let us say we have a crossover frequency of ZkHz, an arbitrary figure but one that is used often enough. In order to obtain an overall flat fre R1 5.60 5W INPUT PEERLESS 80 OT TWEETER Fig.4: the complete crossover network has a 6dB/octave low pass filter for the woofer and a 12dB/octave high pass filter for the tweeter. The resistor provides some attenuation to match the tweeter sensitivity to that of the woofer. quency response, we require each driver's output to be reduced to half power (-3dB) at this frequency. The values of the components in the crossover network must be such that their reactance equals that of the drivers at ZkHz. This should provide a flat frequency response when the outputs are added together. In addition to inductive and resistive effects, the mechanical and acoustical characteristics of the drive units makes the task of building crossovers less than easy. If we applied the results of the above example to our speaker system, the frequency response WOllld probably exhibit an excessive amount of output at around ZkHz, due to the fact that both drivers have peaks in this region. The solution may be to roll off the woofer below ZkHz, and then cut in the tweeter at around 3kHz or so, ef- JANUARY 1993 19 Men~1uing Oh1ect ,_ .PS I( ::. .6J2 / df-:..!.·-?l_~ -~/_ ) __ _ ---~ _q__ dfj t.evel lkrnge: lm~Jc:HJance Range: _2___~: Zero Ze,o M ern>u1i11g 'N • . • ____ M Co t1t J11 ;. 1, Level (FuncJom~nta l): _ ---·- _____ rlB Level (Harmonic ). ______ ____ dB ,• r,m 'f /\)( 1~ :,1,1-,,.:: <J _ . ________ ITif'n / 56 C 120 60 30 12 25 10 80 40 60 30 5 6 40 5 20 10 2 +P Fig.5: this diagram shows the electrical response of the PSK 60/2 crossover network when connected to resistor loads. The reactive nature of the speakers will modify this response. ONLINE: Uented/15 dB Graph ESCAPE: Select Graph CASD Driver Para.rieters: Fs (Hz): 48 Qts: .55 Vas (U: 22 Box Para.Meters: Ub(U:14 Fb (Hz): 45 O.L:? Filter Para.~ters: Fp (Hz):NONE O.:NONE Cursor (Use F1-F4): -25 ID Hertz: 100 Do you uish dB: 2.26 50 10D saa (c) SDS Fig.6: this is the computer predicted bass response of the Peerless 174WF woofer in a 14-litre enclosure. The response is 3dB down at 55Hz & slopes at 24dB/octave below that. fectively eliminating the peaks in each driver. The simplest type of crossover is a first order type, providing a roll-off of 6dB per octave beyond the crossover frequency. This means that above the 20 SILICON CHIP Final design The final design uses a box measuring 420mm high, 215mm wide and 235mm deep, giving an internal volume of14 litres. The port is a slightly tapered unit of 45mm internal diameter and 114mm in length. The computer predicted bass response of the woofer has the -3dB (half power) point at 55Hz, with a slight peak in the response at 100Hz - see Fig.6. The measured frequency response of the Peerless PSK 60/2 loudspeaker system is shown in Fig. 7. The response is within ±3dB from 100Hz to 20kHz. The slightly ragged response below 500Hz is due to reflections in the measuring room. The impedance plot of Fig.8 shows a typical response, with a minimum of close to 6Q at 45Hz (the tuning frequency) and a maximum of 24Q at 85Hz. This means that it will cause no problems at all with typical stereo amplifiers. Subjective performance to sa.ve response gra.ph? (YIN) Da.te: 10-28-1992 load drops by 6dB for each halving in frequency. This is why this type of crossover is referred to as a '6dB/octave' filter. The crossover network finally designed for this speaker system is shown in Fig.4. It employs a 6dB/ octave filter for the woofer but a 12dB/ octave filter for the tweeter, to prevent it from receiving too much signal at its resonance of just above lkHz. Hence, the tweeter is coupled to a network consisting of a 10µF capacitor and a 0.4mH inductor. The 5.6Q in series with the tweeter network provides a degree of attenu,ation in order to match the sensitivities of the two drivers and provide a good overall balance in the sound. The electrical response of the crossover network into 8Q loads is shown in Fig.5. crossover frequency, the low pass section of Fig.3(a) provides a 6dB decrease in signal voltage across the load with each doubling (an octave) in frequency. For the high pass section of Fig.3(b), the signal voltage across the The subjective performance of the PSK 60/2 is very good indeed. The speakers have a relaxed and neutral sound quality, with smooth and tight bass performance. The midrange and treble response is particularly detailed and clean . .Because of the relatively small cabinet size, stereo imaging is particularly good. Assembly procedure The PSK 60/2 is supplied as a complete kit, with cabinet woodwork and Fig.7: this is the measured frequency response of the Peerless PSK 60/2 loudspeaker system. The response is within ±3dB from 100Hz to 20kHz. The slightly ragged response below 500Hz is due to reflections in the measuring room. Br liel & Kja. r M easuring Ob i.: Peerless PSK 60/2 Impedance ...1.L Ree . No .c Da te c28/10/92 S 1~ OP 0124 10 20 Hz 50 Mu lti p ~y Fr eq. Sca le by: __ 10 0 _ __ 20 0 _ Fig.8: the impedance versus frequency characteristic of the Peerless PSK 60/2 loudspeakers. The minimum impedance is just on 6Q so these speakers will not present any load problems to solid state amplifiers. all components for two speaker boxes. The kits will be available exclusively through Dick Smith Electronics. The cabinets come as a flat pack which is simply wrapped around the rear panel and glued. Alternatively, you can purchase all the hardware, drivers and crossovers, etc, and then build the cabinets your- self. The general cabinet details are given in the diagram of Fig.9. If you elect to make your own cabinets, you will need reasonable woodworking facilities. We think that most builders will use the cabinet kits as they are well made, relatively inexpensive and give a professional finish. Assembling the kit of the PSK 60/2 The crossover networks are supplied fully assembled and attached to the spring-loaded terminal panels. No soldering is required - you just clip the leads to the driver terminals. is quite straightforward. No woodworking ability is necessary and you need only a Phillips head screwdriver and a roll of masking tape. Making the cabinets First, unpack and lay out all the various components (drivers, crossover parts and cabinets) and check that you have everything. Don't fully unpack the cabinets until you are ready to assemble them, to avoid the risk of getting them scratched. Tackle the assembly of the cabinets one at a time. The method of assembly is shown in Fig.10. You'll need a large, flat area to w ork on - the kitchen table or a hard floor, for example. Put down newspaper or plastic sheeting to protect both the cabinet and your work area. The cabinet sides come as a continuous length of vinyl coated 16mm-thick particle board, with the four panels separated by V-cut grooves - the vinyl coating holds th.e panels together. Lay out the long continuous side piece and note which are the two side panels (the longer ones), and which are the top and bottom. The bottom panel is the short piece at one end. When the cabinet is folded up, the join is at the bottom. Run a generous bead of the PVA glue supplied in the hardware kit into J ANUARY 1993 21 Fig.9: this diagram is included for those who wish to build their own cabinets. 70 HOLES: A • 146 DIA. B • 63 DIA C • 46 DIA. 150 420 7.5 TOP, SIDES, BOTTOM AND BACK 16mm HIGH DENSITY PARTICLE· BOARD BAFFLE 18mm HIGH DENSITY PARTICLE BOARD BAFFLE MOUNTED IN 8.5 x 18 REBATE MACHINED IN TOP, BOTTOM AND SIDES BACK HAS 50 DIA HOLE IN CENTRE FOR CONNECTIOR. 140 MOUNT BACK IN 8.5 x 16 GROOVE MACHINED IN TOP, BOTTOM AND SIDES 5.5 FROM REAR EDGE OF ENCLOSURE DIMENSIONS IN MILLIMETRES PEERLESS PSK60/2 LOUDSPEAKER SYSTEM 22 SILICON CHIP 1. Lay out the wraparound side piece on a flat surface & run PVA glue into the three V-cuts, the two ends & the rear panel rebate channel. 2. Wrap the sides around the rear panel (finish side outwards). 3. Hold the final corner together with masking tape. 4. Install the foam damping, run glue around the front panel rebate & install the front panel. Note: the small vent port (not shown in this diagram) should be next to the final join. Fig.10: this diagram illustrates the procedure for assembling the cabinets. Make sure that you install the front panel with the grey vinyl coating facing outwards & so that the final join in the cabinet is towards the bottom. each V-cut and the rear panel rebate channel but not the front panel rebate. Run a bead of PVA glue on the end V-cuts, too. Place the rear panel, with the black (finish) side outwards, into the rebated channel of the top panel. Now carefully wrap the sides around the rear panel, taking care not to stress the corner joints. Press the final side and bottom panel together and hold it in place with several strips of masking tape run around the corner - see Fig.10. If a little PVA glue oozes out of the joints onto the veneer, you can wipe it away with a damp cloth. Otherwise, it is easily peeled off once the glue has dried. Now run a generous line of glue into the channel for the front panel. You can then push-fit the front panel into position, making sure it goes in with the woofer hole downwards and with the grey vinyl coating on the outside. You should now leave the enclosure to dry for at least five hours. The next step is to fit the crossover and rear terminal panel assembly which is supplied as a complete unit with the kit. This is simply screwed into place on the rear panel with four countersunk screws. Next fit the damping material you'll need a piece of 25mm thick high density polyurethane foam to cover the rear panel only. This is supplied with the kit. Cut a hole to clear the crossover and driver wires and place it against the back panel. Because it is cut slightly oversized, it will sit firmly, otherwise you can glue it to the back panel. Mounting the loudspeakers You can now terminate the crossover wires to their respective drivers. The tweeter leads (grey + grey with Making your own crossover network If you're maKing your own crossovers, you will need to wind your own inductors. This can be done by hand, using bobbins with a diameter of 38mm and a coil length (between cheeks) of 41 mm. You could make your own bobbins from scrap timber. L 1, the 2.5mH choke, is 305 turns of 1mm enamelled copper wire. L2, the 0.4mH choke, is 104 turns of 1mm enamelled copper wire. All the crossover components can be hardwired and glued to a piece of timber. This can then be glued or screwed onto the -rear panel of the enclosure. JANUARY 1993 23 PARTS SUPPLIED IN HARDWARE KIT 2 Peerless 174WF woofers 2 Peerless 80DT dome tweeters 2 PSK-60/2 crossover networks mounted on terminal panels 2 bass reflex ports, 45 x 114mm 2 foam pieces, 25 x 185 x 390mm 8 male/female grille clips 2 Peerless badges 2 Peerless specification labels 1 bottle 125ml PVA glue 2 fig.8 connecting wires 1 strip black rubber feet (8 pcs) Screws for drivers & terminals Instruction manual Tools you will need Phillips head screwdriver Hammer Strong PVC or masking tape black trace) should be pulled through the tweeter hole and the woofer leads (red+ red with black trace) go to the woofer. Carefully check the polarity of each driver. The wire with the black trace is positive for both the woofer and tweeter. No soldering is required -you simply push the wire clips onto the relevant terminals on the speakers. Check your wiring once it's finished, then screw the two drivers in place using the self-tapping screws supplied. No gasket is necessary for the woofer or tweeter as the vinyl coating of the baffle does this job, as well as being decorative. Now you can push the pre-cut port assembly into place. This should be a firm fit. Fitting the grille cloth frame While the kits will have the cloth fitted over the grille cloth frames , you will have to fit the plastic clips. The baffle has four female clips while the grille cloth frame has four male clips. Fit the male clips first. These are fragile and can be broken if treated incorrectly. The recommended way to do it is to fit a female clip over each male clip and then lightly tap the base of the female clip to drive the male clip into its hole in the grille cloth frame. Do this for each of the four male clips. This done, remove the female clips 24 SILICON CHIP This photo shows how the speaker cabinets should appear when they are assembled. Note that the female grille clip sockets have been fitted to the front panel. and tap them into their four holes in the front panel. The grille cloth frame can then be fitted over the front panel and the speaker is finished. Do a final check. If you're sure everything is together correctly, hook them up, select some music and sit back and enjoy your new loudspeakers. We're sure you'll be impressed with them. Don't overdrive them As noted above, the Peerless PSK 60/2 loudspeakers can be used with amplifiers with an output power of up to 60 watts per channel. Even so, it is advisable never to turn your amplifier up to full volume, regardless of its power rating. An amplifier which is run into clipping, even for a short period, is capable of damaging the speaker voice coils. If the Peerless PSK 60/2 loudspeakers are used free standing, we strongly recommend that they be placed on stands so that the tweeters are at ear level when you are seated in your usual listening position. Not only will this allow you to better appreciate the trebl~ but it will prevent the likelihood of muddy and over-emphasised bass which happens when speakers are too close to the floor. For the same reason, we recommend that you don't place the speakers close to the corners of the room; it may boost the bass but the result will be "muddy" sound. SC LQQK Computer Requirements either, 1) IBM PC. PS2 or compatible, 512K. MSDOS 3.0, VGA card & Monitor CD ROM Drive OR 2) Apple Macintosh with CD Rom Drive. Why pay $1000's for encyclopedias? If you own a computer with a CD drive, then you can own the 22 vol NEW 1991 Grolier Electronic Encyclopedia for $160. Let the computer do the scanning! LQQK PARENTS SON"Y; PARENTS CD\ROM & SOFTWARE ~~I 2~ SONY LASER LIBRARY FAMILY. II COMPTON'S ENCYCL.OPEDIA , II MIXED-UP MOTHER GOOSE* • COMPUTER REQUIREMENTS (for package) XT/AT Compatible, 512k Ram. DOS 3.1 Hard disc drive - half size slot Recommended: VGA Monitor & VGA adapter Mouse * Requires VGA POPULAR CD ROMS DESCRIPTION - TITLE Battlechess Beethoven Symph No. 9 Bible Library Beauty & the Beast Chessmaster 3000 Encyclopedias: - Compton's Family - Compton·s Multimedia - Grolier 1991 Family Doctor Food analyst Games Pak No. 1 Games Pak No. 2 Great Cities No. 1 Great Cities No. 2 Guiness Book of Records Just Grandma and Me Kings Quest V Languages of the World Microsoft Bookshelf 1991 Edition Mixed up Mother Goose National Geographies Mammals Night Owl Shareware Ver. 6 Nurses Medical Partner Plant Doctor Publish-it Sherlock Holmes Sleeping Beauty Timetable of History, Science & Innovation VGA Spectrum Where in the World is Carmen San Diego Windows 3.1 - Microsoft Wing Commander- Secret Wing Commander- Ultima World Atlas l!!I NATIONAL. GEOGRAPHIC Iii SOCIETY'S MAMMALS* Not only Is this Software Educational - .It's fun too! - •, · Not only can this fantastic software package educate you and your children, it also can provide hours of entertainment. Info on 200 animals, photos, range maps, motion clips, essays and 155 animal vocalizations . . Translates to and from Chinese, Danish , English, Finnish, French, German, Italian, Japanese, Norwegian, Spanish & Swedish. Translations can be exported directly to WP packages (Chinese and Japanese display only). Includes the full text of 18 dictionaries in 12 languages. - equivalent to 132 dictionaries! • An interactive game designed to stimulate your child's imagination with full colour graphics and digitized sound, voices and music. · I· Compton's Encyclopedia (from Brittanica) contains full text of 26 volumes, 9 million words, 32,000 articles, 1500 illustrations including sound and speech recording. Forget flipping through volumes,. instead, follow key pathways on words and subjects - access information in the blink of an eye. BI LANGUAGES OF Iii THE WORLD $860 I I'll MICROSOFT WORLD ATLAS* - - PACKAGE CONTENTS Sony internal drive CDU 535 which supports CD Rom mode 1 & 2 & Audio Value $540 (one year warranty) Sony bus interface card (half card value $180) Software - 6 CD's as detailed - Value $998 Microsoft CD - Rom Extensions SPECIAL OFFER - see above □ as above plus animated sequences □ see above - (also MAC) □ Invaluable Information, 1500 Q & A's - (also MAC) □ USDA·s database, nutrients, calories - analyse foods □ Games - inc Chessmaster, Bruce Lee, Black Hole □ Games - inc Loopz, Puzzle Gallery, Robot Tank □ Tour London, New York, Sydney and 7 others □ Tour Berlin, Chicago, Rome, and 7 others □ Multimedia - the best seller plus pictures and sound □ A living book - childrens· interactive fun □ A classic game - now a classic CD □ See above □ Windows version - see above □ see above □ see above □ 600MB of IBM compatible code, 10,000 programs □ Nursing literature from Medline 1962-89 □ Text and Images on horticulture, weeds, etc □ DTP Program incl, WP, 69 fonts, 1000 clips · □ Consulting Detective - interactive game □ Interactive Fairytale - adventure game □ Timelines with sound and animation (also MAC) □ Clip art, animations, games, digitized music □ Deluxe version of the bestseller □ The best seller in compact format □ Popular game plus Secret Missions 1 & 2 □ Popular game plus Ultima V1 □ see above - (also MAC) □ . $410 $690 $160 $135 $90 $70 $70 $135 $135 $159 $90 $90 $159 $159 $90 $90 $90 $190 $90 $135 $90 $90 $90 $90 $135 $135 $90 $90 $90 r I I I I I I I I . This indispensable collection of reference materials includes the American Heritage Dictionary, Roget's II Electronic Thesaurus, the World Almanac and Book of Facts, Barlett's Familiar Quotations, and more. For added efficiency, all reference volumes interface directly with more popular word processing programs. The World Atlas brings the entire globe to your computer screen. This atlas, almanac and world fact book in one, gives you instant access to over 240 fully detailed, EGA/VGA colour maps and a huge database of international information. all for IBM (also Mac where shown) ORDER PRICE Chess with sound and animation □ $90 Microsofts musical journey (also MAC) □ $135 9 Bibles 3000 Sermons, 6 dictionaries □ $90 Classic story - music and sound effects □ $90 A classic game - now a classic CD □ $90 • BOOKSHELF 1991 CDU 535 DRIVE SPECS 5¼" Half-Height Internal 340ms avg. access time 150KB sustained data transfer rate 600KB burst data transfer rate 8KB buffer Output jacks for stereo and head phones , --------MAIL THIS COUPON TODAY (Allow 14 days for delivery) PRODUCT DESCRIPTION CD ONLY - GROLIER- IBM COMPAT CD ONLY - GROLIER- MAC SONY LASER LIBRARY - INC CD DRIVE CD ROMS AS TICKED OPPOSITE POSTAGE AND HANDLING Page Total $160 $160 $860 $8.00 TOTAL I enclose cheque, money order for$ .................... . or please charge my credt card (below) Mr/Mrs/Ms {please print) ..... ... .................... .. Address ........................ ,, ...................................... ....... . ............................................... Postcode ..................... Phone ..................................... Fax no ......................... . □ BANKCARD □ MASTERCARD □ VISA Card Number: I I I I I I I I I I I I I I I I I I II I I I I I II I ~:~~::·;~~~~:::::::::: : : : ::: :: : : : : : : : :: : : :: : I PELHAM PTY LTD I I .J L 1 ■1 Floor, 100 y.,,_ Road, Pennant HIii■ 2 1 20 Ph 102) 980 &98a Fax 102) NO &991 See ua al Booth 141, HOME COMPUTER SHOW, Melbourne Learn about AM radio transmission Build a tJea-power AM radio transmitter Have you ever wondered how music is transmitted to your AM radio? Build this experimental flea-power transmitter & find out. By DARREN YATES Most of us are pretty blase about AM radio these days but that doesn't mean you shouldn't have some idea of the basic principles involved. By building this experimental AM radio transmitter, you can learn how AM signals are transmitted and have some fun into the bargain. We've christened the device the "AM Micromitter" because of its "micro-power" output. This low power output has been deliberately designed in so that you cannot interfere with your neighbour's radio reception. In fact, the AM Micromitter only has a line of sight range of about 10 metres, in keeping with the experimental nature of the device. Essentially, the AM Micromitter is a complete AM radio transmitter that can broadcast both speech and music signals to an ordinary radio receiver, AM MICROMITTER The AM Micromitter can broadcast music or Morse code signals to an ordinary AM radio receiver. It is an experimental device with a range of about 10 metres. 26 SILICON CHIP as well as Morse code signals. The device uses one low-cost IC plus a handful of other parts and can be assembled in just a couple of hours. Basic principles So how does a simple transmitter work? The block diagram of Fig.1 shows a simple Morse code transmitter, which consists of a radio frequency (RF) oscillator, an RF amplifier and an antenna. The RF oscillator produces a highfrequency signal (called the "carrier") which is fed to the amplifier stage and thence to the antenna when the key is closed. By opening and closing the key, bursts of RF energy radiate from the antenna and this can then be picked up by a radio receiver. The bigger the amplifier and the more elaborate the antenna, the stronger will be the signal received by the radio. If we use a simple piece of wire for the antenna, the radio waves radiate with equal strength in all directions. However, with more refined antennas, it's possible to concentrate the RF energy in one direction and so increase the range. A somewhat different technique is necessary to transmit audio signals (ie, speech and music). In a Morse code transmitter, information is sent by keying the carrier on and off as we have just seen. By contrast, in an AM transmitter, the carrier is transmitted continuously but its amplitude is varied (or modulated) to encode the signal. Hence the term "amplitude modulation", or AM for short. Fig.2 shows the block diagram of an AM broadcast transmitter. As can be seen, the modulator stage is inserted between the RF oscillator and RF amplifier stages, while the audio input acts as the modulating signal. PCB and SCHEMATIC CAD ANTENNA KEY RF OSCILLATOR RF AMPLIFIER ' Fig.I: this block diagram shows a simple Morse code transmitter. It consists of an RF oscillator, a key & an RF amplifier which feeds an antenna. ! .: ~r !!I'., ANTENNA ~ If AMPLIFIER ·::t ~ : • i f.',"., . ... ,:d•'li'l'-,<',«,+~'tt! . ~ i :~ ) __________ __ _ RF OSCILLATOR MODULATOR RF AMPLIFIER AUDIO SIGNAL Fig.2: the block diagram for an AM transmitter. In this case, the carrier is transmitted continuously but is amplitude modulated by the audio signal. ~i i n: = ~ ~~~ .--., : 1 By using this arrangement, the instantaneous amplitude of the carrier signal is varied in response to the amplitude of the audio input. The resulting AM signal output from the modulator is fed to the RF amplifier and from there to the antenna. It can then be picked up by any standard AM radio receiver, such as a personal radio, car radio or clock radio, provided it is within about 10 metres of the transmitter. Fig.3 shows what a typical amplitude modulated signal looks like when displayed on an oscilloscope. In this case, we have a lkHz sinewave signal modulating a 760kHz carrier signal. Note that the top and bottom halves of the signal are mirror images. fed via a 22kQ resistor and a .00lµF capacitor to pin 10 of !Cl. IC1 is an MC1496 balanced modulator/demodulator IC. This device forms the heart of the transmitter and functions as the modulator stage. So most of the hard work is performed by this single chip. The audio signal is fed to pin 1 of IC1 via a 3.5mm jack socket and 50kQ potentiometer VR1. This pot sets the depth of the modulation that occurs in the carrier wave. The greater the signal into pin 1, the greater the depth of modulation and the greater the volume from your radio. This circuit arrangement produces a clean AM signal at the output of IC1 (pin 12) and this is fed to transistor 'i!J I I 11 ll 1111111I1 1111 1111 I EASY-PC • Runs on PC/XT/AT/286/386 with Hercules, CGA, EGA or VGA. • Design Single sided, Double sided and Multilayer boards • Provides Surface Mount support • Standard output includes Dot Matrix/Laser/Inkjet printers, Pen Plotters, Photo-plotters and NC Drill • Award winning EASY-PC is in use in over 12,000 installations in 70 Countries World-Wide • Superbly Easy to use • Not Copy Protected Options: • 1000 piece Schematic symbol library Circuit details Let's look now at the circuit details of the Micromitter - see Fig.4. Transistor Ql, diodes Dl and DZ, and their associated components form an RC phase-shift oscillator which produces a sinewave with a frequency of about 760kHz. This frequency is determined by the three 1.5kQ resistors and the three 330pF capacitors in the feedback network. Diodes Dl and DZ stabilise the gain of the oscillator and thus virtually eliminate unwanted variations in the carrier signal. The 2Vpp sinewave output appears at Ql 's emitter and is • ' , . ~ •:.~ . . . •~ ~•: ~•~: • Surface Mount symbol library • Gerber Import facility For full info 'phone, fax or write: Fig.3: this AM signal was produced by modulating a 760kHz carrier with a lkHz sinewave signal (scope settings lV/div & 0.2ms/div). BTC PO BOX432 GARBUTT 4814 QLD. PH (077) 21 5299 FAX (077) 21 5930 ]ANUARY 1993 27 ,--------------..----------------------1~-------+12V 2x1N914 01 1.5k ANTENNA 10k 3.3k 1k 10k 3.3k 3 5 1k 10 + 10k 7 IC1 MC1496N 16VW+ 10 12 1k 14 1.5k 7 1.5k 1k A U O I0 '-7 INPUT 7 100 + 16VWi B EQc VOLUME/ MODULATION DEPTH VR1 50k VIEWED FROM BELOW 10k IGO 10k VR2 50k 12VOC 300mA PLUG-PACK ~ L1 : 65T, 0.63mm DIA ECW WOUND ON A 50mm LENGTH OF 9mm DIA FERRITE ROD V I------e•--,+ AM MICROMITTER Fig.4: the final circuit uses a phase-shift oscillator based on Qt, D1 & D2 to produce a 760kHz carrier signal. This signal is then fed· into ICl, where it is modulated by an audio signal that's fed in on pin 1. The output at pin 12 then drives Q2 which in turn drives aerial coil Lt & the antenna circuit. Q2. Q2 then directly drives antenna coil 11 and the antenna via a 2200pF capacitor to radiate the signal. VR2 is used to adjust the modulated output at pin 12 for best results. By connecting the output of pin 12 to an oscilloscope, it's also possible to produce what is called a double sideband suppressed carrier waveform (DSBSC) by rotating VR2 to somewhere near its centre position. Power for the AM Micromitter comes from a 12V DC plugpack supply. Its output is fed in via on/off · 06112921. Fig.5 shows the parts layout and the external wiring. Begin the assembly by installing the wire links, then install the resistors and the MKT polyester capacitors. Table 1 shows the resistor colour codes but it's also a good idea to check each resistor with your digital multimeter to avoid any confusion. The electrolytic capacitors can be installed next, followed by the two diodes, the IC and the transistors. Note that these are all polarised devices, so make sure they are correctly oriented. The 3-terminal regulator (REGl) must be installed with its metal tab facing towards the centre of the board. The next task is to wind the coil switch Sl and applied to 3-terminal regulator REGl to derive a regulated +12V supply rail (note: a lightlyloaded 12V DC plugpack actually puts out about 16V, which is ample for correct operation of the regulator). The lOOµF and 47µF capacitors provide supply line filtering, while D3 protects the circuit against reverse polarity connection of the supply. Construction Most of the components for the AM Micromitter fit on a PC board coded TABLE·1: RESISTOR COLOUR CODES 0 No. ·Value 4-Band Code (1%) 5-Band Code (1%) · 0 2 1 22kQ 12kQ 10kQ 3.3kQ 1.5R:Q 1k!2' 4.7pQ 390Q red red orange brown brown red orange brown brown black orarrge .brown orange orange red .b·rown bro1.-.in gr.eer:i• ·red b~own . • ........ ,-':>, brown black red brown yellow viplet brown brown orange white brawn brown red red b1ack red brown brown red black red brown brown black black red brown orange orange black brown brown brown green black brown brown brown black black brown brown yellow violet black black brown orange white black black brown 0 0 0 2 0 6- 0 0 4 0 28 ·5 1 1 SILICON CHIP 12VDC PLUG-PACK -) ® ~} 47u n g,, '. , ~ AUDIO INPUT i:, 7812 3 Fig.5: install the parts on the PC board exactly as shown in this parts layout diagram. Inductor Ll is made by winding 65 turns of 0.63mm enamelled copper wire on a 50mm length of ferrite rod. Check the supply polarjty before making the final connections to the board. 1 ¼J WARNING! This project is an experimental device only and has been designed to teach the basics of AM signal transmission. Do not in. crease the power output of the ·device or attempt to increase the range by feeding it into a directional antenna, as this could cause interference to other users. (Ll) . This consists of 65 turns of 0.63mm enamelled copper wire on a 50mm length of ferrite rod. Before winding on the wire, wrap a couple oflayers of paper (about 40mm long) around the rod and secure the ends with adhesive tape. The 65 turns of copper wire can then be closewound onto the rod. Keep the turns tight and again use adhesive tape to secure the ends of the winding. By the way, the actual number of turns is not critical. As long as it is somewhere around 65, the transmitter will work OK. When the coil is completed, trim the leads to about 100mm, then clean and tin them so that they are ready to solder to the board. Don't connect them to the PC board just yet though that step comes a little later on. Final assembly A plastic zippy case measuring 130 x 68 x 41mm is used to house the PC board. The board is mounted on the The PC board is secured inside the case using machine screws & nuts, while Ll is fastened to the side of the case using plastic cabl~ ties. Use light-duty hook-up wire to complete the wiring between the PC board & all external components. bottom of the case, while the coil is secured to one side using two plastic cable ties (one at either end - see photo). Prepare the case by first attaching the adhesive label to the lid and drilling holes to accept the on/ off switch and volume potentiometer. This done, drill three mounting holes for the PC board plus four holes in the side of the case to <J.Ccept the two cable ties. Finally, drill two holes in one end of the case to accept the power socket and the audio input socket. JANUARY 1993 29 PARTS LIST 1 PC board, code 0612921, 102 x 53mm 1 50mm length of 9mm diameter ferrite rod 1 plastic zippy case, 130 x 68 x 41mm 1 12VDC 300mA plugpack supply 2 3.5mm jack sockets 1 SPST toggle switch 1 3-metre length of 0.63mm enamelled copper wire 1 50kQ log potentiometer (VR1) 1 50kQ 5mm linear horizontal trimpot (VR2) Semiconductors 1 MC1496N balanced modulator/ demodulator {IC1) 1 7812 3-terminal regulator (REG1) When all the holes are drilled, secure the coil using the cable ties and solder its leads to the PC board. The remainder of the wiring can then be completed using light-duty hook-up wire - see Fig.5. Make sure that the supply socket is wired with the cor. rect polarity. The AM Micromitter assembly can now be completed by securing the PC board to the bottom of the case and fitting the four rubber feet. Testing Now for the smoke test. Connect your plugpack supply, set VRl fully anticlockwise, switch on and check the voltage at the output of the 3terminal regulator {7812). If you don't get a reading of+ 12V, switch off i:r;nme- 2 BC548 NPN transistors (01,02) 2 1N914 signal diodes (D1 ,D2) 1 1N4004 rectifier diode (D3) Capacitors 2 100µF 16VW electrolytic 1 47µF 35VW electrolytic 1 22µF 16VW electrolytic 2 10µF 16VW electrolytic 1 0.1µF MKT polyester 1 .0022µF MKT polyester 1 .001 µF MKT polyester 3 330pF MKT polyester Resistors (0.25W, 1%) 2 22kQ 6 1.5kQ 1 12kQ 41kQ 5 10kQ 1 470Q 2 3.3kQ 1 390Q diately and check for wiring errors. Assuming that the supply rail is OK, feed an audio signal into the input, set VRl to mid-position and tune your receiver to about 760kHz. If the transmitter is working correctly, you should have little difficulty tuning into the signal. VRZ can now be adjusted for best reception. Initially, ,you should position the receiver about 30cm away from the transmitter. Once you've tuned into the signal, you can test the range of the transmitter. You should be able to obtain a relatively noise-free signal at distances up to about 10 metres, while the maximum range will be about 15 metres. If you have problems with a nearby radio station that operates on a fre- Fig.8: this is the full-size etching pattern for the PC board. Check your board carefully for defects before mounting any of the parts. 30 SILICON CHIP Fig.6: this photo shows a carrier wave that is almost 100% modulated. This is the limit for a distortion-free signal. Fig. 7: a carrier wave that is overmodulated results in a distorted output from the receiver. quency close to 760kHz, you can change the values of the 1.5kQ resistors or the 330pF capacitors in the oscillator. This will shift the carrier frequency and so allow you to operate on another part of the broadcast band. Using the Micromitter When the Micromitter is working correctly, you can experiment with different settings for VRl. As mentioned briefly before, by changing the level of the audio source that's fed into the Micromitter, you're changing what's called the modulation depth of the carrier wave. If the modulation depth increases (ie, if the audio level fed into the transmitter increases), then so does the volume from the receiver. There is a limit to how far you can go, however. Fig'.6 shows a carrier wave which is close to 100% modulated, while Fig. 7 shows a carrier that is over-modulated. This is caused by too much signal and results in a distorted output from the receiver. If you have a oscilloscope, you can observe these effects for yourself by monitoring the collector of QZ. SC ♦ . • ' • FLU KE AND PHILIPS - THE GLOBAL ALLIANCE IN TEST & MEASUREMENT It • .F•LUKE®• • • J ♦ • . . e • ♦ ♦ ♦ 7 0 PHIL_ IPS ♦ S E R I E S I I We've improved on a winner If you've waited for the next generation digital muhimeter technology, you've made the right choice. Now there is the new Fluke 70 Series II. We've made the world's most popular DMM's even better. At the top of the line, the new Fluke 79 and 29 blend high-performance features capacitance, frequency, a fast 63-segment bar graph, Lo-Ohms range, Smoothing"', faster ranges - and affordability. At the entry levnl, the new model 70, Fluke's lowest-priced DMM ever, delivers unparalleled Fluke quality and safety. Available from the following Philips Test & Measurement distributors: ALL STATES: SEP, Dick Smrth Electronics, GEC, Petro-Jee!. NSW: Ames Agency, Auslec, CLC Agencies, Consultant Technologies, David Reid Wholesalers, OGE Systems , Ebsen, Elect. Smith Projects, 'Basics· Redefined No matter which 70 Series II you choose, you get simple, one-handed operation. High resolution. And buih-in reliability. Automatic Touch Hold® - standard on eve,y model - locks the reading on the display and signals you with a beep. Leaving you free to concentrate on your work. not on your meter. There's also fast autoranging. A quick continuity beeper. Diode test. Automatic self.test Overload protection, even in the 10 amp range. And a sleep mode that automatically powers down the meter when you forget to. · Emcorp, lllawara lnd. Instrumentation, J.Blackwoods & Son, Lawrence & Hanson, Macelec, Novocastrian, Obiat, Stott Ind. Suppl., Tech Fast, Tecnico, Vincom. ACT: Advanced Instrument Services, Aeromotive Maintenance, John Pope Electrical. VIC: Auslec, Emcorp, Factory Controls, J. Blackwoods, Parallel Systems, Radio Parts Group. Best of all, eve,y 70 Series II is a Fluke, backed by a worldwide service network and 3-year warranty. i1 ·i Be Nq. 1 'th Fluke and Philips I QLD: Auslec, Colourview Electronics, Emcorp, Industrial & Marine Electrics, J.Blackwoods, LE. Boughen, Mass Electronics, Nortek, Solex, St Lucia Bectronics, Thomson Instruments. S.A: AW.M. TAS: George Haivey. W.A: Atki ns & Carlyle, Leda Electronics, R.S. Components. N.T: Industrial Suppliers & Switchgear J.Blackwoods. PHILIPS • VINTAGE RADIO By JOHN HILL Restoring a 1920s kit radio Regenerative receivers from the 1920s can provide quite a challenge when it comes to -restoration. This month, we look at the restoration of a kit radio from that era. I have made it quite clear in some of my past stories that I am not particularly interested in those old regenerative sets from the 1920s era. Sure, they're valuable and add interest to a collection, but they're not nice to listen to. Five minutes is about enough for me when it comes to those toneless horn speakers. Well, that's what I have said in the past! I have now changed my mind a little in this regard and recently spent a week or so of my spare time restoring an old mid-1920s 3-valve regenerative receiver. Perhaps one of the main reasons for my new interest in these truly antique _radios was the fact that this one was in really excellent condition, even if it was lacking its original loudspeaker. Most radios from the 20s are in an appalling state of disrepair and do not generate much enthusiasm as far as I am concerned. I paid top dollars for this unit because it was bought from an antique dealer. However, it is worth noting that the price came down by $130 when I showed interest in buying it. This goes to show that dealer prices are sometimes grossly inflated and one should never agree to buy without a little bartering. Although it looks factory made at first glance, items such as the hand This photo shows the headphone compartment in the receiver cabinet. Although it did not contain a pair of headphones, there was an interesting assortment of other odd bits and pieces. · 32 SILICON CHIP wound coil and the screwed together cabinet suggest that the set was originally packaged as a kit. Many early kit radios were fairly basic and often consisted of an open baseboard with a front control panel. My latest acquisition was a much better kit - one that came complete with quite a reasonable cabinet (presumably in pieces) . The cabinet is unusual in that it has a special compartment at the righthand end. Built-in compartments were often provided for battery storage but not so in this case. It appears as though the space was provided to store a set of headphones. Phone jack Although the set is capable of driving a loudspeaker, there is also a phone jack on the front panel which cuts out the output stage and taps the phones into the B+ line of the second valve. In other words: the set can be used as a 3-valver with a loudspeaker or as a 2-valver with headphones. The cabinet is in incredible condition for its age. It is structurally sound and undamaged except for a few minor scratches. These responded well to a touch up with a cloth soaked with shellac. All things considered, it is remarkable that something can survive so well for so long. According to the "law of averages", it should have been thrown out 50 years ago. Although there were no headphones in the cabinet compartment, it did contai.q a few other interesting items. There was a push/pull switch of the type used in the 1920s, a large openended spanner, a selection of grid leak resistors and an electoral card dated 1945. The back of the card had battery connection instructions written on it, so it seems as though the old 3-valver had remained in service up until that time at least. Cleaning & adjusting the mechanical parts is just as important as servicing the electronic circuitry in a restoration of this nature. This photo shows the restored dial & its companion tuning capacitor. The valves are of the 6V type: A609 regenerative detector, A609 first audio, and C603 output. The audio stages are transformer coupled. For reasons that will be explained later, the C603 was replaced with a B605. Initially, the set looked fairly original but this was not really the case. After a closer examination, it was obvious that it had undergone quite a few modifications over the years. The on/off switch was not original and neither were the reaction control capacitor or the filament rheostat. In addition, a replacement audio transformer had been incorrectly wired into the circuit and its mate had an open circuit primary winding. One notable aspect of the set was the fact that there was no provision for a "C" (bias) battery. Negative grid bias is essential for the correct operation of amplifying valves. Without it, signals are distorted, and the valve will draw excessive plate current. So why no bias battery? The explanation is that the valves were not totally without bias; there This hand-wound coil, along with the screw-assembled cabinet, the simple 3-valve format, and no maker's nameplate, gave the impression that the regenerative radio was sold in kit form. Build your own was a popular concept in the 1920s. was a source of bias but it was not immediately obvious. This bias comes from the filament supply and varies along the length of the filament which is also the cathode; ie, there is full battery voltage at one end and 0V at the other. The practical result is a bias equal to half the filament supply voltage. In some cases, particularly where 6V valves were used, this would be adequate , assuming a typical HT or "B+" supply of no more than 90V. In addition, the relatively high resistance of the transformer and loudspeaker windings would keep the HT current within reasonable limits. As a result, "C" batteries received less attention than might otherwise have been the case. More about this later. The restoration job At a practical level, there was quite a lot to do if this old set was to work again. I had no choice other than to go through it systematically, sorting out the problems as they came. My first step was to test all the valves. As it turned out, they were all in excellent condition so that was a good start! The control panel components were next on the list. The on/off switch was broken internally and was replaced with the one found in the headphone compartment. The filament rheostat was then stripped and The defective interstage audio transformer was replaced with a similar unit & the two serviceable transformers then painted to give them a uniform appearance. Open circuit audio transformer primaries are a common problem when restoring a radio of this vintage. JANUARY 1993 33 lfoc:aus() thl) audio trnnsfornwrs were of difforn nt colours. tlH)\' worn painted matt brm,,vn to gi\'() a uniform appearance. They worn llwn mou11t(1d on the circuit board in positions that covered up most of th e holes. Rewinding the coil The broken on/off switch (left) was replaced with the switch (right) that was found in the headphone compartment of the cabinet. The original coil looked a bit sad. There were loose windings and the wire insulation was quite grubby in places. Each of the three windings was removed and the wire strung out and washed with hot soapy water. It was then wound onto spools. The cardboard coil former was also cleaned and given a fresh coat of shellac. When the wire was rewound onto the coil former, the aerial winding was tapped in three places. Previously it had been a 17-turn winding but all three coils - aerial, tuning and reaction - were now about two turns less than in the original due to trimming the kinked leadout wires. This had no adverse affect on the set's performance and the rewound coil worked perfectly. It was finished off by reinforcing the aerial taps with glue and giving the windings a coat of shellac to hold them in place. Bias battery A number of alterations were also made to the circuit. A radio frequency choke was added and provision was made for a "C" battery. This was the reason for discarding the C603 output valve. The C603 is supposed to have This close-up view shows the front panel controls. The filament rheostat, tuning -40V grid bias, whereas the B605 that dial & reaction control make up the top row (from left to right), while below replaced it needs only -18V bias, at them are the on/off switch & the headphone jack. maximum plate voltage. One reason for adding the bias circuit was a decleaned, as were the tuning and reacmotive cut and polish compound. sire to see just how well the set pertion capacitors. This done, the valve sockets w ere formed at maximum HT voltage. These variable capacitors are of the dismantled and adjusted so that there Two 9V transistor batteries were was firm contact with the valve pins . used as a bias battery, with the centre plain bearing type and the bearings required lubrication and adjustment. Some socket connections were loose tap connection (-9V) biasing the A609 I also took the opportunity to reverse and would have given considerable first audio valve. The bias battery was the moveable plates of the reaction trouble if they had been left as they attached to the circuit board using capacitor. As they were originally fitwere. A drill shank can be used to double sided masking tape and is perted, the reaction· increased as the con- check socket tension. manently wired in. trol was turned anticlockwise. HowThere were numerous holes in the Getting the bias to work correctly ever, it seemed more logical to have a circuit board where the audio trans- was a problem. The set functioned clockwise action and reversing the formers had been mounted, indicat- OK on two valves but when the third plates achieved this effect. ing several past replacements. Audio valve was brought into operation, transformers, with their fine windings , · there was uncontrollable oscillation. The next step was to dismantle and clean the dial assembly, after which were a common source of trouble in I believe that this may have been all the components were re-assem- the old days. Fortunately, I had about caused by mounting the two audio bled on the control panel. The eboneight good transformers to choose from transformers in line with each other. ite circuit board was then stripped, and one similar in appearance to the It probably would have been better to cleaned and polished with an autoset's remaining good unit was selected. have mounted them at right angles to 34 SILICON CHIP Silicon Chip Binders A rear view of receiver after restoration. The wired in "C" battery (two 9V transistor batteries) can be seen between the two audio transformers. These beautifully-made binders will protect your copies of SILICON CHIP. They are made from a distinctive 2-tone green vinyl & will look great on your bookshelf. Price: $A11.95 plus $3 p&p each (NZ $6 p&p). Send your order to: Silicon Chip Publications PO Box 139 Collaroy Beach 2097 Or fax (02) 979 6503; or ring (02) 979 5644 & quote your credit card number. The finished receiver is hardly a thing of great beauty but is fairly typical for the mid 1920s. The nickname "coffin" was an apt description of early radio cabinets. each other, to minimise mutual interference between their surround electromagnetic fields. Positioning them the way I did (to cover up unsightly holes) was not the best way to install them, at least not electrically. However, the feedback problem was easily solved by installing a 1MQ resistor in the bias line to the first audio valve. That simple remedy isolated whatever it was that was causing the trouble without altering the bias voltage. According to a colleague, this cure suggests another possible factor contributing to the oscillation - coupling between the two audio stages via the common bias battery. Some of the audio voltage applied to the grid of the output valve could appear across the bias battery and, in turn, at the grid of the audio valve. The added resistor provided a degree of decoupling but a more elegant approach might have been to add a bypass electrolytic capacitor between the resistor/transformer junction and the negative HT rail. This would probably allow the resistor value to be substantially reduced. Once all the few minor bugs had been sorted out, the old battery powered regenerative receiver worked really well. To power the set, a small 6V motorcycle battery was used for the valve filaments and a relatively modern "B" battery eliminator for a high tension supply. It is interesting to note that many old battery triode valves have the recommended plate voltage marked on them. 20-lS0V is a common inscription and the Philips valve manual gives specifications at the full 150V. If the valves are correctly biased, these maximum plate voltages can give power outputs of between 0.SW and 0.75W (quite high for their day). So, casting caution to the wind, I decided to find out just what they could do. The result: these ancient receivers really fire up when the high tension voltage is increased. Previously, I have run similar sets at a conservative 90V but this time I have opted for the valve manual 's 150V maximum. The difference is unbelievable! Perhaps that is why I am now a little more enthusiastic about battery powered sets. Maybe some of these old receivers are better than I previously thought! SC JANUARY 1993 35 A-ONE k-ONE A-ONE A-ONE A-ONE ~ □ Resistance 0.1h-40M!l □ □ □ □ □ □ □ ~ < Escort ~ ~ ~ 0 I < r~., ~ Z 0 I < ~ ~ < EDM 83B M0122 PROFESSIONAL CLASS DIGITAL MULTIMETER WITH ANALOG BAR GRAPH ALL ESCORT DMM COMES WITH 3 YEAR WARRANTY PROFESSIONAL CLASS DIGITTAL MULTIMETER WITH ANALOG BAR GRAPH EDM-169 M0119 $189.00 EDM 81 B M0120 $207.00 3¾ digit, 40 x 60mm large LCD screen with • 3¾ Digit, Extra Large LCD. • Analog Bar Graph. • 14 Functions with AUTORANGING. DC V, AC V, DC A, AC A and Ohm . Frequency Counter 100Hz (0.1 Hz res) to 1000kHz Capacitance 4nF (1 pF res) to 40µF Diode Forward Voltage Test Audible Continuity Test Adaptor Input (1mV res) Data and Max/Min Hold Relative Mode Data Store and Recall Warning for incorrect input selected . analog bar graph • 0.5% DCV accuracy • Auto power off • Includes: autoranging for frequency test, function annunciators, data hold , max/min/avg record and audibl e readout . • 8 functions measurement ranges: □ DCV 100µV-1000V □ ACV 100µV-750V □ DCA 0.1µ A-10A □ ACA 0.1µA-10A □ Resistance 0.1!l-40M!l □ Audible Continuity Test D Diode Check □ Frequency Test 1Hz-4MHz SPECIFICATIONS EDM 82B M0121 VDC 400mV to 1000V, 5 auto ranges, 100µV max resolution , ±0.5% VAC 400mV, 4V to 750V auto, 5 ranges, 100µVmax resolution, ±1% ADC 4mA to 400mA auto, 10A, 4 ranges , 1µA max resolution, ± 1 % . AAC 4mA to 400mA auto, 10A, 4 ranges , 1µA max resolution, ±1.5%. Ohm 400ohm to 40Mohm, 6 auto ranges, 0.1 ohm max resolution, ± 0.7%. ~ < ~ 3487A 3¾ DIGIT ANALOG BARGRAPH DMM M0115 $143.00 FEATURES • 3¾ digit large LCD DISPLAY (74.8mm x 31.0mm) • Resolution of 4000 counts $269.00 • 3¾ digit, 40 x 60mm large LCD screen with analog bar graph • 0.5% DCVaccuracy • Auto power off • Includes: autoranging for frequency test, function annunciators, data hold , max/min/avg record and audible readout and high voltage warning detect. • True RMS READING FOR ACV and ACA • 12 functions measurement ranges : □ DCV 100µV-1000V □ ACV 100µV-750V □ DCA0.1µA-10A □ ACA 0.1µA-10A □ Resistance 0.1!l-4000M!l □ Capacitance 1pF-40µF □ Audible Continuity Test D Diode Check □ Frequency Test 1 Hz-20MHz □ Logic Level □ Inductance Test 1µH-40H □ dBm Modifier · !FINEST~ $250.00 • 3¾ digit , 40 x 60mm large LCD screen with analog bar graph • 0.5% DCV accuracy • Auto power off • Includes: autoranging fo r frequency test, function annunciators, data hold, max/min/avg record and audible readout and high voltage warning detect. • 12 functions measurement ranges: □ DCV 100µV-1000V □ ACV 100µ V-750V □ DCA0.1 µ A-20A □ ACA 0.1 µ A- 20A ~ ~ Capacitance 1pF-40µF Audible Continuity Test Diode Check Transistor hFE Gain Frequency Test 1Hz-4MHz Logic Level Temperature Test -20°C-1000°C. • 41 Segment analog bar graph • Data hold • Max/Min stores the highest and lowest readings • Relative display (offset) • Continuity beeper and diode check • Indicators of all functions and all ranges FINEST 183 MULTIMETER M0116 PLEASE CALL FEATURES • Display Hold mode • Hold and Low battery annunciators • Splash proof and dust proof case • 3½-digit, 2000 count digital display • DC voltage accuracy within 0.5% • 600V protection in ohms and diode test SPECIFICATIONS DC Voltage Range: AC Voltage Range: DC Current: 200mV to 1000V 200mV to 1000V 200µA to 10mA • Frequency measurement up to 40KHz • 10 readings per second conversion rate • Dimension: 162 x 80 x 30 (mm) • Weight: appro. 200g • Overflow indicators: steady "OF" • Polarity: Auto "-" sign on at minus input • Overflow indication: "OF" sign on • Measurement rate: appr. 10 readings per second • Displ ay area: 74.8 x 31.0 mm • Function: indicat ors: "MAX" "MIN" "HOLD" "BAT" "A'' "-fc:l-" "•tllJ " ".Q " "REI.'.' "M" "AT" "AC" 11 - " "K" "Hz" "m" "V" • Range selection: Auto, manual • Low battery: "BAT" sign on below operating voltage • Battery: 9V alkalin or carbon-zinc • Accessories: test leads, instruction manual, battery • Operating temperature: 0C to 40C (below 80% RH) • Storage temperature : - 20°c to 60°C *All Escort DMM comes with 3 year warranty. < INO-V 3NO-V 3NO-V 3NO-V 3NO-V /\-ONE A-ONE A-ONE kONE A-ONE HIGH QUALITY DIGITAL PANEL METERS 4½ DIGIT HI-PRECISION DPM S0406 $79.50 This precision digital meter is a standalone vo ltmet er - ammeter or can interface with a computer! 4½ digit 0.55" LED display. Tem perature compensated to 100 PPM/°C. Operating temperatu re range is 0°C t o +70°C. Outputs include BC D data , Busy and ,strobe. Panel read in g can be lat ched on hold. SPECIFICATIONS Ran ge: DC voltage: DC cu rrent: Stabi lity: Power requirements : Dim ensions: 3½ MULTIFUNCTIONAL LCD DPM (WITH HOLD FUNCTION) S0408 $59.50 S0408 Digital Panel Meter which employs high quality ND converter IC as a main device. The IC drives the 3½ digit of LCD digital display directly. By connecting one or two resistors to produce all range of voltmeter, ohmmeter and curren tmeter. Besides, this unit has detail circ uit diagram on temperature meter. Frequency meter.. .etc for reference. Being of high impedance due to FET input , and low bias current , the digital panel meter SM series is furnished with the automatic zero adjustment circuit and automatic polarity transfer, with 100 PPMl°C temperature compensated voltage reference, high reliable within 0°- 50°C. Input sensiti vity of S0408 Digital Panel Meter is DC± 199.9mV for full scale display. Input impedance: 100M ohm . Working voltage of S0408 is DC 9V, 1.8mA. In order to upset the meter's stability and accuracy, a 100ppm/°C temperature Compensated Vo ltage Reference Diode is employed, to make this meter work, in the best way within 0-50°C. SPECIFICATIONS DC Voltage Range: AC Voltage Range: Thermometer Range: DC Current Range: Capacitance Range: Frequency Counter: Display: 1mVto 1000V 1mVto 1000V 0°c to 100°c 1 microamp to 2 amps 1 pf to 2 microfarads 10 Hz to 20 KHz 3½ digit 15mm high LCD Maximum Ind icat ion : -1999 or +1999 Power Supply: DC9V ± 5% Power Consumption : 16mW Outline Dimensions: 3¾ " (W) x F /a " (H) x 4-1 / 16" (D). DIN standard This Case meets West German DI N standard. 3½ MULTIFUNCTIONAL LED DIGITAL PANEL METER S0405 $64.50 Th is is a high quality device with excellent 1mVto 2000V 1 microamp to 20 amp ± 0.025%± 2 digit s 5 to 6 vo lts DC at 200 ma 4-5/16" (W), 3¼ (D), 1¾ "(H) . specifications. Instructions are included to use this instrument as a voltmete r, ammeter, temperature meter, frequency meter and capacitance meter. The accuracy of this meter is ± 0.1 % , ± 1 digit. Input impedance is 100 megohms. It has high vibration resistance and so can be used in a mobile or portable environment. Resets to zero automatically. The meter is temperature compensated so that is can be used from Oto +150 degrees fahrenheit. SPECIFICATIONS DC Voltage Range: AC Voltage Range: Thermometer Range: DC Current Range: Capacitance Range: Frequency Counter: Display: Maximum Indication: Power Supply: Dim ensions: 1mVto 1000V 1mVto 1000V 0°c to 100°c 1 microamp to 2 amps 1 pf to 2 microfarads 10 Hz to 20 KHz 3½ digit 0.5" high LED -1999 or +1999 5 to 6 VDC , 200 ma 3¾ " (W) x F/a" (H) x 4-1 /6" (D). This Case meets Germany DIN standard . 4½ DIGIT HI-PRECISION DPM WITH DIN CASE S0407 $89.50 This is essentially our very popular S0406 digital panel meter but in a stand ard DIN case. Like the S0406, it has a large 0.55" LED readout. It is also temperature compensated to 100 PPMl°C. Operating temperatu re range is 0° to +70°C. A MEMORY SYSTEM can HOLD the input reading for comparison and monitor. Thi s is a sensitive unit. An input of 1.9999 volts results in full scale display. The unit operates on 5 VDC at 200ma. SPECIFICATIONS Rear outputs: Range: DC voltage: DC current: Accuracy: Power requirements: BCD data, Busy, Strobe 1mVto 2000V 1 microamp to 20 amps ± 0.025 %±2 digits 5 to 6 volts DC at 200 ma 3¾ "(W) x F/a"(H) Dimensions: 4-1/16" (D) . This Case meets Germany DIN standard . 3½ DIGITAL PANEL METER S0402 $49.50 S0404 $59.50 These meters use a Te ledyne ND co nverter integrated circu it. The display is a 0. 6" LED for high visibi lity. These kit s are eas to assemble and the instructions provide information on how to use the meter as a vo ltmeter, ammeter, ohmmeter, thermomet er, frequency co unter or capac itance meter. A red plastic face is provided to enhance viewing contrast. The S0404 has a HOLD FUNCTION, so the last readout can be held! SPECIFICATIONS DC Voltage Range: AC Voltage Range: Thermometer Range: DC Current Range: Capacitance Range : Frequency Counter: Display: Maximum Indication: Power Supply: Dimensions: 1mVto 100V 1mVto 1000V 0°c to 100°c 1 microamp to 2 amps 1 pf to 2 microfarads 10 Hz to 20 KHz 3½ digit 0.5'' high LED -1999 or +1999 5 to 6 VDC, 200 ma 4.75" (W) X 1.75" (H) x 1.56" (D) . >. ~ ~ 11NO-V 11NO-V 11NO-V 11NO-V 11NO-V +/· 0•50V &A REGULATED PSU +/· 0•35V 2,5A DUAL REGULATED PSU S0007 $48.00 S0010 $159,95 Output voltage: 0-32V 20AMAX Current: Overload Protection Ranges: CUSC Overload Induced Sharp Cutting Method (SC). Overload Induced Current Limiting Method (CL). Limiting Range: (Basic) 5A+5A+5A+5A Total 20A 18V-24Vx2/30A 24+24V/800VA Output voltage: +- 0-S0V DC (+- 0-35V SA RMS Regulated) Current: 2A, +2A=4A, +2+2=6A Overload Indicator: Current Limit Sharp cut out Output reset turn the selector to current limit point. I/P Transformer: 30-35Vx2 15A S00VA Recommended: 30+30V/S00VA (TO221) Output voltage: Current: Overload Indicator: Protection method: 1/P Transformer: Recommended : 0·20V 20A REGULATED PSU S0005 $134.00 6,5V TO 18V DC REGULATED PSU S0011 $149.00 0-20V Output voltage: Current: 20A Max Overload Protection Ranges: (CUSC) (Basic) 5A+5A+5A+5A Total 20A Switch Setting. 12V-18Vx2/30A 1/P Transformer: Recommended: 18+ 18V/SO OVA Output voltage: 6.5V to 18V DC (25V Max) Fully adjustable Output Current: 20A Max Current limit control:4 Steps (5A,10A,15A,20A) Ripple and noise: 15 mV Line Regulation : 0.08% + 20mV Load Regulation: 0.08% + 20mV Input Power: 18 to 20V AC 50-60HZ, 20-30A Recommended 18+18/S00VA Transformer: (T0238-Parallel Secondary) 100W CLASS 'A' MAIN AMPLIFIER (MONO) S0313 $79.00 120W MOSFET POWER AMP(MONO) S0329 $179.00 100W DYNAMIC CLAS 'N MAIN POWER AMP (MONO) S0310 $79.00 Power Output: Frequency Response: Input Impedance: Input Sensitivity: Supply Voltage: Current: Power Bandwidth: THD 1KHz 1W: Transformer: Recommended Transformer: Power Output: Frequency Response: Power Output: Recommended Transformer: 100W8 OHM 0-100KHz 22K. 0.8V DC+/-30 -42V(MAX) SA 5-50KHz 0.001% 28Vx2/5A 30+30V/ 160VA. (T0209) MONO 30+30V/300VA. (T0217) STEREO + 0-35V/0-70V 2.5A LED Current Limited 18-24Vx2/6-8A 22+22V/225VA 0·30V 20A HEAVY-DUTY REGULATED PSU SOOO& $149.00 120W RMS into 8 OHMS 8Hz to 20KHz, +0 to 0.4db Input Sensitivity: 1V RMS for 120W Output Power Requirement:+/- 45 to 55 VDC at 3A Mono 40Vx2/3A/160VA for MONO 40Vx2/6A/300VA for STERO Recommended Transformer: 40+40V/160VA. (T021 2) MONO 40+40V/300VA. (T0219) STEREO 0-50V 3A PRECISION PSU S0001 $42.00 Output voltage: 0-50V Current: 0.5 to 3A Overload Indicator: LED Protection method: Auto shut on overload , and short circuit I/ P Transformer: 22V-36Vx2/3A 50Vx2/3A for High O/P Recommended: 36+36V/160VA 45+45V/160VA High O/P Frequency Resp0nse: T.H.D.: TIO: Input Sen sitivity: S/N Ratio: Power Supply: Power Consumption: Recommended Transformer: Recommended Transformer: 100W RMS into 8 OHM .150W RMS into 4 OHM 10Hz to 20KHz Less than 0,008% Less than 0.008% 0.75V- 1V Better than 80db +/-35VTO +/-45V DC 3.5A per channel. 30+30V/160VA (T0209) Mono 30+30V/300VA (T0217) STER_fn A-ONE A-ONE A-ONE A-ONE A-ONJi >. ~~ >. ; DC FET SUPER CLASS 'A' PRE-AMP S0330 $145.00 FULL COMPLIMENTERY SYMMETRY FET STEREO PRE-AMP S0308 $159.00 300W HI-FI POWER AMP(MONO) S0331 $175.00 Frequency Response : Frequency Response: Power Output: T.H.D.: Input Sensitivity & Impedance: Phono: Output Level: Pre-AMP Output: Recording Output: Input Power: Recommended Transformer: Overall (AUX to pre output) (at rated ouput) 10 to 100,000HZ +0.5-1 db Overall (From AUX) Less than 0 .01% (1,000HZ for rated output) 47K OHMS.2mV Rated Output (0.01% THD) 1.3V (20V MAX. 0.1%THD) 130mV 36+36V/0.2A 30+30V/15VA. (T0231) 10 to 100KHz +0.5db -1db T.H.D. (From AUX): 0.005 % at/below rated O/P Channel Separation (at rated O/P 1 KHz) Better than 70db. Phono: HUM & Noise (IHF) Better than 70db. Phono: Better than 90db. AUX: Input Sensitivity & IMP. (1 KHz for rated Phono 47K OHM,2mV output) : Rated O/P(0.01 % THD). Output Level: Pre-AMP output 1.5V (0.1%THD) Max Output: Pre-AMP output 15V. Input Power Vol: AC 30V x 2 400mA Power 12W Consumption: Recommended 30+30V/15VA (T0231) Transfor_ mer: NF-CR BI-FET PREAMP/3-WAY TONE CONTROL S0307 $72,00 Frequency Response: T.H.D.: 1.M. Distortion: Power Requirements: Input Sensitivity: -DC to 100KHz +- 0.5dB 0.005% at/below rated O/P 0.005% at/below rated O/P +-15 VDC, 0.2A MAX Phono-2.5mV. Tuner, AUX and Tape- 100mV Input Impedance: Phono-47 K. Tuner, AUX and Tape-100K Output Voltage: 1V Tone Control Range: BASS, +-10 db at 50Hz MID, +-5db at 1 Hz TREBLE, +-10db at 15KHz RIAA Equalization : +-0.2db from 20Hz to 20KHz S/N Ratio: Phono,75db. Tuner, AUX and Tape, 90db. Frequency Response: T.H.D.: I.M. Distortion: Input Sensitivity: Power Requirement: Recommended Transformer: 300W RMS into 8OHMS 500W Music Power into 8OHMS 10Hz to 20KHz Less than 0 .05% Less than 0.05% 1VRMS at 47K +/- 60 to 75 VDC at BA Mono 48-53x2/6-8AMP AC 50+50V/500VA. (T0225) MONO A-ONE ELECTRONICS PTY LTD 432-434 Kent Street, Sydney NSW 2000. Phone: (02) 267 4819. Fax: (02) 267 4821. A.C N. 00-3 88? S13. MAIL ORDERS WELCOME: CHEQUE, MONEY ORDER, AMERICAN EXPRESS, BANKCARD,MASTERCARD AND VISA. Phone or write to us for a copy of your price list. Shop hours Mon-Fri 9-5 . . .- - - - - - - - - - - - - - - - - - - - - - - - - - - - - • Sat 9-1. All prices include sales tax . ~ >. ; ~ Special offer: 500 PC boards to give away A high intensity LED flasher for bicycles Have you joined the 2-wheel enthusiasts, cycling for fitness and enjoyment? If so, you'll want this high-intensity LED flasher to make sure you can be seen after dark. This one uses four high brightness LEDs and draws very little current. By DARREN YATES LED flashers for bicycles are a great idea. Because they flash and are so bright, they are much more visible than ordinary incandescent tail lamps. They also consume far less current than an incandescent lamp and so the batteries last a great deal longer maybe up to 100 times longer. Of course, a low-power high-brightness flasher such as this one need not be confined to use as a bicycle tail light. We're sure that our readers will come up with other applications. We are presenting this project as a cheap and brighter alternative to-units you can buy ready-made. With this unit, you have the option for going to super bright LEDs and bigger batteries. The circuit As you can see from Fig, 1, the circuit uses only one 8-pin IC, plus four high-brightness LEDs and a handful of other components. The IC is a National Semiconductor LM3909 LED flasher/oscillator which, as its name suggests, was specifically designed for The PC board fitted neatly inside a Basta No. 660 bicycle tail light case, which we obtained from K-Mart. We simply removed the standard 3V incandescent lamp & its reflector, & installed the flasher PC board instead. 40 SILICON CHIP the purpose of flashing LEDs. Normally, the LM3909 is used with a single 1.5V battery but our circuit runs off a 3V supply to provide extra light as well as longer battery life. The 2200µF and 470µF electrolytic capacitors are used to provide a charge reservoir and to provide the flash timing. The result is that the circuit only consumes an average of around 6mA yet the light from the four 2-candela (2000mCd) LEDs is bright enough to be clearly seen at night from a distance of several hundred metres. The four 18Q resistors provide current limiting and ensure that each LED only takes its share (one quarter) of the current. The circuit runs from two C cells, with alkaline types giving about 1000 hours of continuous operation. Nicad cells are not recommended for this application, as these should not be discharged below a certain voltage. Construction Before you begin soldering any components to the PC board, it's always a Fig.1 : the circuit uses an LM3909 flasher IC to drive four high brightness LEDs. 180ll 2200 + 16VW _ IC1 LM3909 3V ..%. KALEX The UV People ETCH TANKS • Bubble Etch • Circulating LIGHT BOXES • Portuvee 4 • Portuvee 6 • Dual Level 820ll TRIMMER BICYCLE TA IL FLASHER e ldeal PCB DRILL • Toyo HiSpeed MATERIALS • PC Board: Riston, Dynachem e 3M Label/Panel Stock • Dynamark: Metal, Plastic AUSTRALIA'S N0.1 STOCKIST * * 11111921 Fig.3: the PC board is coded 11112921 KALEX [Z & measures 47 x 33mm. good idea to check the copper side for any shorts or breaks in the tracks. You can do this by comparing your etched board with the published pattern. If you find any errors on the board, use a sharp utility knife to scrape away any shorts , or use your soldering iron and a small blob of solder to join any broken tracks together. Fig.2 shows the parts layout on the PC board. Begin the assembly by installing the resistors , then install the 470µF capacitor and the four LEDs. Note that the capacitor and LEDs are polarised devices, so take care with their orientation. It's easy to identify the LED leads, since the anode lead is always the longer of the two. Initially, the LEDs should be soldered at full lead length, since they will need to be adjusted later on. 40 Wallis Ave, East Ivanhoe 3079. Phone (03) 497 3422, Fax (03) 499 2381 Old Repr"nted Electrical Books The 2200µF capacitor is mounted proud of the board so that is can be bent over to clear the diffuser lens. The IC can n ow be installed on th e board, again taking care to ensure that it is correctly oriented . Don't take too long when soldering each pin , other- 500 Free PC Boards From RCS Radio In conjunction with our 5th birthday celebrations, RCS Radio Pty Ltd has kindly made available 500 free PC boards for this project. To obtain your free LED flasher PC board, send a stamped self-addressed envelope to RCS Radio Pty Ltd, 651 Forest Road , Bexley, NSW 2207. Only 500 boards are available free, so get your order in as soon as possible. Don't forget to put a 45 cent stamp on the self-addressed envelope. Build a 40,000 Volt Induction Coil .. .. ........ $9 Short Wave Radio Manual (1930) ........ $23 High Power Wireless Equipment (1911) $16 High FrequencyApparatus (1916) ........ $19 Build Short Wave Receivers (1932) ...... $13 Vision By Radio (1925) ...... ................... $16 1936 Radio Data Book .......................... $12 How to Become a Radio Amateur (1930) $6 All About Aerials ............. .......................... $5 Television (1938) ......................................$5 Shortwave Coil Data Book (1937) ........... $5 1928 Radio Trouble-Shooting ............... $24 101 Short Wave Hook-Ups (1935) ........ $14 Vacuum Tubes in Wireless's ....... .. .. ...... $21 Construction of Induction Coil ............... $21 Tesla: Man Out of Time (biography) ...... $22 Tesla Said, articles by Tesla 292pp ....... $74 My Inventions, by Nikola Tesla 111 pp ... $27 Dr. Nikola Tesla - Complete Patents .... . $93 Tesla Coil Secrets ................................. $13 How to Build a Solar Cell That Works ...... $9 191 4 Catalog Electro Importing Co ....... $14 Electric Arc Furnaces ............................... $6 Experimental Television ........................ $25 Allow 15 weeks for delivery of some items. Payment can be made by cheque made out to Plough Book Sales, PO Box 14, Belmont, Vic. 3216. Phone (052) 66 1262. ]ANUA R Y 1993 41 Protect your valuable issues . Silicon Chip Binders wise the heat will destroy the insides of the chip. Finally, install the 2200µF capacitor with its base about 10mm proud of the board, as shown in the photos. This is done so that the capacitor can later •be bent across the PC board, so that it clears the diffuser lens of the recommended case. Testing These beautifully-made binders will protect your copies of SILICON CHIP. They feature heavy-board covers & are made from a distinctive 2-tone green vinyl. They hold up to 14 issues & will look great on your bookshelf. · * Hold up to 14 issues * 80mm internal width * SILICON CHIP logo printed in gold-coloured lettering on spine & cover Price: $A 11.95 plus $3 p&p each (NZ $6 p&p) . Send your order to: Silicon Chip Publications PO Box 139 Collaroy Beach 2097 Or fax (02) 979 6503; or ring (02) 979 5644 & quote your credit card number. l ----------Enclosed is my cheque/money order for $_ __ or please debit my O Bankcard O Visa O Mastercard Card No : Card Expiry Date _ _/__ Signature _ _ __ _ _ _ _ __ Name _ _ __ _ _ _ _ _ __ Address_ _ _ _ _ __ __ _ . ___________ . _ _ _ _ __ _ P/code_ 42 SILICON CHIP Capacitors 1 2200µF 16VW PC electrolytic 1 470µF 16VW PC electrolytic Resistors (0.25W, 1%) 1 820Q 1180Q 418Q Housing * High quality Use this handy form Before switching on, go over the PC board carefully and check for possible wiring errors. When you are satisfied that the assembly is correct, connect a 3V DC supply to the board and switch on. Within a second or so (this is while the 2200µF capacitor charges up), the LEDs should all begin flashing in unison at a 2Hz rate (ie , twice per second). If they don't flash as expected, disconnect the battery and check that the LEDs are correctly oriented and that the supply polarity is correct. PARTS LIST 1 PC board, code 11112921 , 47 x33mm 1 LM3909 flasher/oscillator IC (I C1) 4 high-brightness LEDs, 2000mCd or better (LED1 -4) 1 miniature toggle switch (S1) 1 Basta No. 660 tail light with batteries (from K-Mart stores) _ _ If you are going to use this flasher on your bike, you will really want a case that is designed for just that purpose and fortunately there is at least one available. We obtained ours from the local K-Mart store. The unit in question is a Basta No. 660 bicycle tail light and at the time of writing it was available for $11.95 (includes two C-size cells). As supplied, the unit comes with a 3V incandescent lamp and red diffuser lens. To disassemble the unit, first slide off the battery compartment lid and then unclip the red diffuser lens. This reveals the lamp reflector and the lamp. To remove the reflector, unscrew the lamp. To make room for the PC board, we removed the integral lamp socket and the brass contacts associated with the integral on/off slide switch. We then mounted a miniature toggle switch on the back panel of the unit, as shown in one of the photos. The board itself was held in place using a suitable adhesive. You will need to run short hook-up wires between the battery contacts, the toggle switch and the PC board. As noted above, you will need to position the 2200µF capacitor so that it lays flat over the board. You will find that the PC board sits at an angle in the Basta tail light hous- The on/off switch was mounted on the rear panel, behind the diffuser lens. Make sure that the switch does not intrude into the mounting bracket are of the case. ing. Adjust the LEDs so that when the red diffuser lens is in place, they sit just behind its rear surface. Make sure that the LEDs are perpendicular to the diffuser lens, to obtain the best light transmission. Just as a matter of interest, we measured the current consumption of the supplied 3V lamp. It pulled about 215mA. Compare that with the under 6mA current of the LED flasher circuit. At that rate, the batteries will possibly last 100 times longer when powering the flasher circuit. SC I OFFERING 111 EXTRA SIZES II MORE ACCESSORIES II LOWER PRICES II NATURAL or BLACK ANODISED FRAMES fflll FOREST GREY or BLACK TEXTURE COVER FINISHES READER INFO NO. 6 SIMPLE,FAST & EFFECTIVE THATS ZIP-RACK THE UNIQUE ZIP-RACK DESIGN Twelve lengths of ZIP-RACK hollow section aluminium extrusion are interconnected using black ABS plastic corner connectors. This requires only a rubber mallet or similar tool. The assembly is self aligning and can be further strengthened by 'pop' riviting the overlapping flanges at each corner. RACK WIDTH 540mm. RACK DEPTH 460mm. 1U (RACK UNIT) =44.45mm OR 1 3/4". FOR EQUIPMENT/PANEL CAPACITY DEDUCT 90mm FROM TOTAL RACK HEIGHT TYPE 46 RACK DATA: ZIP-RACK FRAME sro'. 0 COVER SET ACCESOR IES TOTAL E~:1rrat1c.R J)1li1I GRE~ENT Nitie.ki ilf!]i H~~g~T 6101 PRICE$ M6 PACK 12 M6 Clip Nutsj 2 M6 Ph. Screws 12 Nyl Washers t As 6/01 in Black 100 M6 Clip Nuts 100 M6 Screws 100 M6 Screws Black 100 M6 Washers 100 M6 Washers Black Cantilever Tray 2U Cantilever Tray 3U Cantilever Tray 4U ZIP-RACK is made by "The ZIP-RACK Company" Factory 2, 7 Michellan Court, Bayswater Victoria 3153. Australia. Under licence to AUTOTRON AUSTRALIA P/L. The ZIP-RACK Designers Beware of illegitimate copies without the ZIP-RACK name. For product sales, wholesale pricing & product literature Phone: {03) 729 7255 or Fax: {03) 729 6017 SERVICEMAN'S LOG The customer is always right? In this business, one not only has to deal with technical malfunctions, which by themselves are bad enough, but with the customers as well. I sometimes wonder which are the worst. As I have mentioned before in these notes, one of my regular customers is a local motel owner who has about 30 Samsung TV sets spread amongst his guest rooms. Most of these sets are 50cm CB15F units and were purchased a little over three years ago. It is one of these sets that is the main subject of this story. At the time of purchase, the sets carried a 3-year warranty and the owner used to call me in whenever one gave trouble. There was no contract between us; each job was treated on its merits and the charge depended on the warranty situation. If the set was still under warranty, I simply made the necessary claim, Samsung re-imbursed me, and there was no charge to the customer If, on the other hand, it was a set FRACARRO DELIVERS... .. .best television antenna performance tor less cost. Peter C. Lacey Services Pty. Ltd. P.O. Box 678 (74Fulton Rd.) Mount Eliza 3930 Tel:03 787 2077 Fax:(03) 787 3460 ACN006893438 44 SILICON CHIP that was out of warranty, I charged the customer accordingly. I have presented this brief background because it does have a bearing on the sequence of events, although not in a technical sense. Basically, the story involves a complaint by the motel owner to Samsung, with yours truly as the meat in the sandwich. In greater detail, not long after these sets were originally installed, several of them developed the same fault. This fault involved several components in a front corner of the main board: inductor L401, capacitor C414 and resistor RH0l - the latter described as a safety resistor. Any or all of these components could have dry joints to the copper pattern and, as I later found out, this could cause arcing and damage to the board. And to digress here for a moment, the resistor type number (RH0l) caused a good deal of confusion. While it was so designated on the PC board, it did not appear at all on some early circuits and nor did its companion component, diode DHl. And when it eventually did appear, it was as RHl. It might be worth making a note of that. Anyway, after the first two or three encounters, I realised that this was something to watch out for on a routine basis. From then on, as other sets came in for attention over the next two years, I made a point ofresoldering all the connections in this area, regardless of their appearance. In fact, all but one, as I recall, appeared to be quite OK but I wanted to be sure. Eventually, the time came when there was only about six months of warranty period left. I had a full list of serial numbers for these sets and, on checking my own records, I realised that six sets had never been serviced, so this potential problem remained. More to the point, if Murphy had anything to do with it, there would be a faulty one in this group. At the first opportunity, I drew the owner's attention to this, emphasising that these sets should be checked now, while still under warranty. Furthermore, as this was an off-season for the motel, it would be a good time to take them out of service. He said, "Yeah, sure mate", but that was as far as it went. I subsequently prodded him a couple of times but again there was no result. I then went off on a few weeks holiday and by the time I returned, the warranty had virtually run out. I did make one final plea but nothing happened and so that was the end of it. Or so I thought until a couple of months later when the owner ap proached me to have the work done under warranty! Naturally, I had to knock him back. The warranty period had now expired and I was in no position to break the rules. Had I done so, I could have been left holding the financial baby. On the face of it, he seemed to accept the situation and went off to think about it. Call to Samsung What, in fact, he did do was ring Samsung and complain - not about me directly, but about the strictness imposed on the warranty period. To give Samsung their due, they didn't muck about. If this customer was dissatisfied then, regardless as to who might be at fault, they weren't going to haggle over a few weeks beyond the warranty period. I was instructed to go right through the system and make whatever repairs I considered necessary, all under warranty. At the same time, they made it clear aggravating what was already a delicate situation. In this situation, some diplomacy was called for. So, without showing any reaction to the implied aspersion, I simply asked what the problem was. This brought a more conciliatory response; apparently the set was drifting off channel after prolonged use and was also delivering a snowy picture. Well, one thing was certain; I wanted to see these faults in-situ. The snowy picture, at least, could be an antenna distribution problem, so that point had to be cleared first. s 'I,'< 1.0.WS. ~'S, ..,.etJ'f S, . ~e,tJ~"'o,JS 1 e"~•~t',,!1 ,-fllitr~!Q: Ill. f,A N 1111I, " ~~,a.,1111if'S, ,~-··· t-f('(SAALL wr>,Riv. & vott:> Back to the workshop 8E. f'JU~S1\CK'I I\OVl-~l'AA~WT~ t ~P,.W\l ~T"/~ Oil ~ ~,. ~ Well, he was right; it was snowy. A second set plugged into the same outlet cleared the antenna system, so it was back to the workshop with the set. I set it up on the bench, checked the adjustment of each channel, and let it run. This confirmed the snowy picture but I wanted to check out the drift problem first. If it was drifting, a new tuner would be quickest solution, and this might also sw eep away the snow, killing two birds with the one stone. I let it run for a couple of hours but there was no noticeable drift during that time. However, I wasn't going to be caught that easily; I'd been there before and a few comments by the owner had put me on alert. I switched to another channel, which I knew was correctly tuned, but the AFC wouldn't pull it in. I then switched back to the first channel - same thing, it wouldn't lock in. I don't know why it happens but it has caught me out before. The set can run OK on a particular channel for hours but, as soon it is switched to another channel, everything goes haywire. The only practical cure is to change the tuner. So I fitted a n ew tuner, set the channels up again and let it run. And that cured the drift problem; the tuner was now as steady as a rock. But it had done nothing for the snowy picture. Based on exp erience, I went first to VR151 , a 10kQ pot on pin 12 of IC101. This pot is the AGC delay adjustment and is a common offender. But not this time; my checks and adjustments achieved nothing. Next I checked the UHF reception against the VHF reception and established that it was just as noisy on either. So, with the tuner cleared, it - ~ ~11'1't ,':,o~Ai '"~-f 'l'y f:: 11-IE. WAR~N1'< HA~ EX? \RED & t WAS IN NO ~ Sl1",0N "'rt> ~RE.A..\<. °™e: ~\JL-E. S ... that this was a on e-off situation, so there could be no misunderstanding. It was not to establish a precedent and that was fair enough .. So I went to work. Apart from the aforementioned routine problem, most of the sets needed little or no attention . A few did, however, require minor adjustments and I did what was necessary to bring the whole system up to first class condition. It thus came as rather a shock when, a few weeks later, the motel owner was back on the phon e, complaining that, "The set in room so-and-so is still playing up". It was the word "still", spoken with some emphasis and with a bit of an edge to it, that upset me somewhat. It implied that I knew about a fault in the set and hadn't fixed it, whereas I could not recall that my attention had been drawn to any particular set or fault. I assumed that the most likely explanation was that it was an intermittent fault and I had no intention of J ANUARY 1993 45 TUOOI ER1U 2.-nc + EC104 .-----+-----,t--(JF 's.~" ED111 ll:2Ui 1N4141 1001( I R211 '-'" SQ10t-S0103 KSA 539 25A 1115 T1t1 PSF 11AT01 ,11:101 ... c,.. f ·" C1i1 1,11 C1H 1.01 1V "" '" iSv 1 l;zss:. '-+---+--.=,c.c.=_ _ _ _ ♦ 12'11-----------R\Di t - - - -- ---+--------+---+---'"""-'"-"'L----~TP-•7_,_,_ _ _ __ _ ____,<at> 11 :~1s10 ~ Fig.1: the tuner & IF circuitry of the Samsung CB15F. The IF output from the tuner (TU001) is fed to IF amplifier stage Q161 and this, in turn, drives SAW filter 2101 & the IF processing chip (IC101) at bottom right. had to be something further down the line. Signal tracing The signal from the tuner goes to the 1st IF amplifier (Q161, 2SC388), then to SAW filter Z101, and subsequently to pins 9 & 10 of IC101. So what to test next? From experience, my best suspect was the SAW filter, because I've had several faulty ones in the past. Fortunately, it is easy to change, involving only five soldered connections, and I had a spare on hand. A few minutes later I had the answer - it wasn't the SAW filter; it was still snowing. OK, so what about Q161? One of the weak points of these Samsung circuits is that they carry no voltage values. So I spent some time checking associated components around this stage, then measuring the voltages on the transistor, and doing some mental gyrations in an - effort to decide whether they were reasonable. In the event, I found no obviously faulty components and finally decided 46 SILICON CHIP that the voltages were reasonable. So, as a last resort I pulled the transistor out and fitted a replacement. Alas, no joy from that either; the picture remained snowy. So where did that leave me? I'd cleared the tuner, 1st IF amplifier and the SAW filter, all by replacement. So the next suspect was chip IC101. I (,4-~""\ \ \ \ \ I \ This photo shows the replacement component pack issued by Samsung for the CB515F/CB515Z TV receivers. The parts involved are C414, L401 & RH01. A detailed instruction sheet accompanies the component pack. didn't fancy replacing it if there was an easier way and so I resorted· to a trick that I have used in the past. As mentioned on a number of occasions, I have a self-contained tuner unit, made up from an old turret tuner and a small power supply assembled from junkbox parts. It has proved invaluable in tricky cases like this, because it delivers a known good IF signal. At this point, the reader should refer to the accompanying drawing, which the SILICON CHIP draughtsman has prepared from my rough sketch see Fig.2. It shows the copper side of the PC board around the tuner, the tuner itself being mounted on the component side. What we are looking at here are four tuner mounting lugs and eight tuner connection pins. For the sake of clarity, the top seven . pins are neither identified nor shown connected. The eighth pin, at the bottom of the drawing and hemmed in by the main copper pattern, is the IF OUT pin. This is connected to a small copper track which forms part of an inverted "T" pattern. Capacitor C161 then connects to the bottom of the inverted "T" and feeds the base of Q161. With me so far? Right. I fired up the substitute tuner and clipped its ouput lead onto C161's pigtail where it was soldered to the copper track. The result: a perfect picture, with not a snowflake in sight. This cleared the IF system, along with the following sections of the set. So what was going on? The external tuner gave a perfect picture whereas the set's internal tuner, which was known to be OK, gave a snowy picture. It just didn't make sense. As far as I could see, the only difference between to two setups was a 10mm length of copper track between the IF OUT pin of the set's tuner and the lead from C161 (which was fed directly by the substitute tuner). There was only one way to resolve the situation. I soldered a short length of wire to the IF OUT pin, clipped the substitute tuner lead to it, and tried again. Result: it was snowing again. So the fault was somewhere on that 10mm length of copper track. I fished out the jeweller's loupe, set EARTHY COPPER PATTERN 1111~----+ • I I \ • TUNER MOUNTING LUGS . . ~ < z :i a: . ~ a: w z ~ -TUNER • • 0161 C1~ 7 Fig.2: this drawing gives some idea of the layout around the tuner. It shows the copper side of the board, with the tuner (shown dotted) on the component side. Note that the connections to seven of the tuner terminals have been omitted for the sake of clarity. Electronics Workbench® up a good light, and moved in close. Sure enough, there it was - the finest of hairline cracks about halfway along the strip. And a continuity check confirmed what was now obvious - the track was open circuit. After that, the cure was simple; a run of solder along the strip put everything back to normal. So the set was returned to the motel owner, with my assurance that this latest fault had now been fixed - under warranty. By now, the atmosphere had thawed somewhat and the owner actually expressed his gratitude for my efforts, and his appreciation of Samsung's cooperation. So everything ended happily. But how did that hairline crack occur iif1cl. why did it show up after the seyhad been running for over three years? Well, I don't think that it was a recent happening. The set had not been dropped or otherwise abused and my bet is that the crack had always been there, from the time the board was made or while it was being fitted with parts. My theory is that, in spite of the crack, there was, initially, some bridge across it; a tiny area perhaps, but ad- EmonaLAB4 Four instruments in one package! The electronics lab in a computer! 0 ... <at>) [l! © t:l A simple, intuitive and very powerful teaching tool, Electronics Workbench lets students and hobbyists design and test both analog and digital electronic circuits, without the delays and expense of a laboratory . 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(002) 34 2233 The LAB4 has four full function test instruments: ■ DC POWER SUPPLY Triple output; 5V, 15V, 0-50V ■ with neatly laid out and labelled front panel controls. Also, the LAB4 is compact and only takes up a small space , compared to four bench-top instruments. DIGITAL MULTIMETER Full function, auto-ranging ■ FUNCTION GENERATOR 0.02Hz-2M Hz, with SWEEP ■ FREQUENCY COUNTER 1Hz-100MHz input range INDEPENDENT INSTRUMENTS Each instrument in the LAB4 is completely independent and can be switched ON or OFF as required. The LAB4 has only one 240V mains input, saving on multiple power points. Each instrument is clearly defined EMONA INSTRUMENTS NSW ......................... (02) 519 3933 VIC ................ ............ (03) 889 0427 OLD .......................... (07) 397 7427 DISTRIBUTORS Perth ............................ (09) 244 2777 Adelaide ..................... (08) 362 7548 Hobart .......... ............. ... (002) 34 2233 ]ANUARY 1993 47 TETIA TV TIP Samsung Model VB 711 VCR Symptom: machine will not record sound and a newly recorded pictu re shows flashes of the original ch roma . Any previous ly recorded tapes are unaffected. Cure: bias oscillator not working. This oscil lator not only provides the bias fo r record ing the sound but also powers the fu ll erase head to remove the original picture. The trouble is caused by an intermittent contact at the AC head and is cured by replaceme nt of the fau lty parts and a modification of the AC head connections . TETIA TV Tip is supplied by the Tasmanian branch of the Electronic Technician's Institute of Australia. Contact Jim Lawler, 16 Adina St, Geilston Bay 7015. -~ .•r.-- ~-c:::w~~...l. --'=r"'-~ .~ "-#ANO 'tl-\\S M\GH, P.,\...$0 ~W€EP A'WP.."1 1ltE: SNOW, KU..l.1"1G1WO 'B\~t>S W\1'\i ~ ONE. CS1'0~e:.... equate for a signal path. But copper, by its very nature, will eventually succumb to corrosion. So th e tiny contact area was eventually destroye d. Coincidentally, as I started to write these notes, Samsung issued a recall notice con cerning the dry join ts around C414 , 1401 and RHOl. Ap parently I wasn't the only one to rep ort this problem. As a result, I and oth er accredited service organisations have been issued w ith a detailed instruction sheet and kits containing replacements for all three compo nents . Samsung is not taking any chances. Computer repairs Now for a ch ange of scene. In the December 1992 issue, I detailed how I was conned into repairing a computer - or, more accurately, a computer monitor. As it turned out, the fault was relatively simple but , even so, I expressed the hope that it would be my last computer repair. 48 SILICON CHIP It was to be a forlorn h ope because it wasn't long before another customer, on e of my regulars , fronted up with another computer monitor. This time there was no image at all and the customer, rightly, thought that the monitor was at fault. This w as a different brand; an Acer, mo del MM211 , marketed by Dick Smith Electronics. This was a helpful aspect; it's always reassuring to know that there is someone to turn to for spare parts or technical advice , if n eeded. Undoing four screws released the p lastic cover and revealed a very neatly laid out board. It also revealed th e immediate cause of the failure; a blown fuse. And, significantly, there w as a second fuse nearby which was still intact. So where did they both fit in? By pulling off some plugs fitted to the board and removing some screws , I w as able to juggle the board clear and turn it over. This enabled me to make a qui ck assessment of the power supply circuit and even to make a rough draw ing of it. In many respects, the circuit w as very similar to that use d in the previously mentioned MAGIC model. It consisted of a transformer, w ith a fuse in the primary circuit, that delivered about ZOVAC to a bridge rectifier. This was then followed by another fus e, a filter capacitor, and a 12V voltage regulator - just about as ordinary as one could get. It was the fuses that pinpointed the culprit. The blown fuse was in the transformer primary circuit, while the one following the bridge rectifier was intact. That indicated that either the rectifier or the transformer was at fault. It took only a few minutes of checking with the ohmmeter to find a dead short across one of the 1N5401 bridge rectifier diodes; and only a few minutes more to clear the small capacitor across it. So that was it; whereas the MAGIC model had an open circuit diode , this unit had a diode that was shorted. As before, a new diode and fuse restored everything to normal. The biggest job had been getting things apart and finding my way around the innards. There's nothing to this computer business; so far, it's been-a snack. But don't tell anybody. SC SILICON CHIP AUSTRALIA'S BRIGHTEST ELECTRONICS MAGAZINE ENJOY THE WORLD OF ELECTRONICS & COMPUTERS EACH MONTH * Constructional Projects For The Enthusiast * The Serviceman's Log * Vintage Radio: Technology From The Past * Articles On Computers & Radio Remote Control * New Circuit Ideas & Techniques * Amateur Radio Projects & Features Subscribe today by phoning (02) 979 5644 & quoting your credit card number, or fill in the form below & fax it to (02) 979 6503. 0 New subscription - month to start._ _ _ _ _ _ _ __ RATES (please tick one) Australia Australia with binder(s)* Overseas airmail 2 years (24 issues) 0 $A84 0 $A105 0 $A240 0 Renewal - Sub. No.- - - - - 1 year (12 issues) Fax or mail coupon to: 0 $A42 0 $A53 0 $A120 Silicon Chip Publications Freepost 25 PO Box 139 Collaroy Beach 2097 *1 binder with 1-year subscription; 2 binders with 2-year subscription Your Name_ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Signature (PLEASE PRINT) Address_ _ _ _ _ __ _ __ _ __ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ Postcode_ __ Card No. I I II I I II I I Card expiry date_ __c/_ __ II I I I JANUARY 1993 57 A 2kW 24V/240VAC sinewave inverter; Pt.4 This month, we will begin construction of the 2kW inverter by presenting the· assembly details for the four main PC boards. Each PC board can be tested so that any faults can be fixed before they are wired into the chassis. By JOHN CLARKE Make no mistake, this is a major construction project and should not be attempted unless you are an experienced constructor. You will need access to a dual trace oscilloscope, a digital multimeter, an adjustable power supply capable of 24V at 1A, a crimping tool , plus light and heavy duty soldering irons. Also a small pro58 S1LICON CHIP pane torch will be necessary for soldering lugs to 150A cable unless an hydraulic crimping machine is available. We will begin by discussing the assembly of the four PC boards. These are the DC-DC Inverter Board, the HPack Board, the Sinewave Generator Board and the Rectifier Board. Check each PC board for shorted tracks, open circuit tracks and other faults which may be evident on a visual inspection. Repairs can be made to shorted tracks by cutting away copper with a sharp utility knife, while open circuit tracks can be repaired by soldering a length of tinned copper wire across the break. Look at the overlay diagrams and check that the holes in the PC boards are the correct size for mounting the components or hardware. Most of the component holes should be 1mm diameter while the PC board mounting and regulator tab mounting holes should be 3.5mm diameter. Holes for the 4mm screws (for the cable lug connections) should be 4mm in dia- *SOLDER 4mm NUT TO COPPER SIDE Fig.12: parts layout on the DC-DC Inverter Board. Install all the parts as shown except for the Mosfet transistors and the lMQ resistor marked "see text". This resistor is installed later only ifit is necessary to increase the "dead-time". meter. Drill or ream out any holes which need to be enlarged before you install any of the components. Most of the links and all low wattage resistors for these PC boards are spaced on 12.7mm (0.5 inch) centres and it may be expedient to make up a small jig so that the resistor leads and the link leads can be bent to match these centres. Do not use IC sockets We do not recommend using IC sockets for any of the ICs in this project. Apart from the fact that quality types can cost more than the ICs them selves, they can reduce the reliability of the circuit. Readers may notice from the photographs that we used a socket for IC23; ie, the OTP-ROM (One Time Programmable ROM. However, this was only so that we could easily remove and replace the OTPROM during the circuit development. DC-DC inverter board Let's now start with the DC-DC In- verter Board which is coded 11309921 and measures 204 x 15 7mm. The component overlay is shown in Fig.12. Note the 12 large pads, six on each side of the board. These are drilled to accept a 4mm machine screw. You will need to solder a brass nut to each of these large copper pads. This is best done by fitting all the screws and nuts in position on the board. Each nut is then soldered to the copper pad using a heavy duty iron. It is also a good idea at this stage to tin the Gate, Source and Drain pads for the Mosfets (Q5-Q16). Now insert the nine PC stakes and solder them in place. The 3-terminal regulator (REG1) is mounted flat on the PC board and secured with a screw and nut. Bend the leads first so that they fit precisely into the IN, GND and OUT pads when the regulator is secured in place. The links and low wattage resistors can now be soldered in place but omit the 1MQ resistor marked "see text" at this stage. This done, install the three ICs, taking care with their orientation. When soldering, check that adjacent pins are not bridged except where dictated by the copper pattern. This can easily happen with a medium size soldering iron tip. The capacitors can now be all installed, followed by trim pot VR1, transistors Q1-Q4, the diodes and zener diodes. Make sure that these components are all installed the right way around. The 82Q 5W wirewound resistor should be mounted so that its body is about 1mm above the PC board to allow the air to circulate beneath it for cooling. Finally, install the inductor (Ll). Do not insert the Mosfets at this stage - that step comes later. H-pack board Fig.13· shows the parts layout on the H-Pack Board. It measures 204 x 157mm and is coded 11309922. Assembly of the H-Pack Board begins in the same way as the previous board; ie, by soldering the brass nuts to the large pads on the copper side. There are 16 insulated links on the board and these are made using 15A mains-rated cable. These wires carry JANUARY 1993 59 CURVED LINKS 15A MAINS WIRE *SOLDER 4mm BRASS NUTS TO COPPER SIDE Fig.13: parts layout for the H-Pack Drive Board. Note that the 16 curved links must be run using 15A insulated mains wire. The four IGBTs & the four diodes are moun~ed on the underside of the PC board (see Fig.15). the heavy current from the IGBTs and diodes to the H-drive terminals (+365V, 0V, X and Y). Once these leads are in, the 14 PC stakes can be installed, followed by the links, resistors, ICs, diodes and zener diodes. The capacitors and varistors (the S14K275 devices) can then be installed, followed by the BOBBIN 12T CLOSEWOUND 10T CLOSEWOUND T2· H WINDINGS WRAP WITH INSULATING TAPE Fig.14: here are the winding details for transformers T2-T4. Use 0.125mm enamelled copper wire & make sure that there is at least 5mm clearance between the two windings'. 60 SILICON CHIP MOVs. The latter can be oriented either way but the electrolytic capacitors must be oriented as shown in Fig.13. Winding the transformers Transformers T2, T3 and T4 are wound using 0.125mm enamelled copper wire - see Fig.14. Each transformer bobbin is wound in the same way. The windings are 10 turns between pins 1 and 4 for the primary and 12 turns between pins 5 and 8 for the secondary, on a Philips EFD 15/8/ 5 bobbin. Wind the turns as close together as possible and solder the leads to the outside pins. The actual direction that each winding is wound is not critical but the completed bobbin should have at least a 5mm clearance between the primary and secondary windings to provide high voltage isolation. Complete the job by winding a couple of layers of insulation tape around the bobbin to keep the turns in place. Once the bobbins are wound, insert the two ferrite core halves and secure them in place with the spring clips. The three finished transformers can then be installed on the PC board, taking care to ensure correct pin orientation. The four IGBTs (Q17-Q20) and the four diodes (D10-D13) are mounted on the underside of the PC board as shown in the mounting detail diagram of Fig.15 (this diagram also applies to Mosfets Q5-Q16 on the DCDC Inverter Board). To install these devices, first bend their leads at right angles 3mm from their bodies as shown in Fig.15. This done, attach four 9mm standoffs to the PC board, then install and solder each device so that its face sits flat against the resting surface (ie, the workbench). Siiiewave generator board The Sinewave Generator Board measures 181 x 131mm and is coded 11309923. Its component overlay diagram is shown in Fig.16. You can begin this board by installing the 17 PC stakes, followed by the wire links. The remaining parts can then be installed. ~----3mm Note that the 7805 regulator (REG2) is fitted with a finned heatsink and is secured to the PC board with a screw and nut. Smear the metal tab of the regulator with heatsink compound before bolting the assembly together. The 150Q 5W resistor is mounted about 1mm above the PC board to allow the air to circulate beneath it for cooling. Rectifier PC board This board mainly functions as an assembly platform for the two high voltage capacitors (680µF 400VW & 25µF 370VAC), the three large toroids (12 , 13 & L4), and a terminating panel. Apart from that, it incorporates the fast rectifiers (D3-D6) and the optocoupled feedback circuitry for the DCDC inverter, involving IC4 and IC5. The board measures 214 x 162mm and is coded 11309924. The first step is to solder the seven 4mm brass nuts to the relevant pads on the copper side of the PC board. The heavy current links must be run using 15A mains-rated wire. Keep Fig.15: the IGBTs & diodes are installed on the underside of Hpack board as shown in this diagram. Make sure that the mounting face of each device is exactly 9mm below the bottom of the PC board. these links as short as practicable. Now install the fuse clips, the tinned copper wire links, the resistors and zener diode and, finally, the two ICs. The DC filter choke toroid, 12, is wound with six turns of 2mm enamelled copper wire spread evenly around the core. Strip the enamel insulation from the wire ends, tin them with solder and then solder them to the PC board. The finished toroid is anchored to the PC board using two small cable ties. Solder in the four fast recovery diodes (D3 -D6) but do not trim their leads under the board yet since their tabs have to be aligned with matching holes in chassis when the board is finally installed. Inductors 13 and 14 and the two high voltage capacitors are not installed at this stage. Testing DC-DC Inverter Board: to test the in- verter board, you will require a power supply capable of delivering 24V DC at 0.5A. You will also need a dual trace oscilloscope and a multimeter. Bridge the pins for the thermal cutouts and connect your DC power supply to the +24V and GND IN pins. Connect your scope probes to the 4. 7Q resistors at the emitters of Ql and Q2 and the emitters of Q3 and Q4 respectively. Now apply power; the oscilloscope should show two 20kHz square waves with an amplitude of 15V peak. The waveforms are as shown in Fig.9 which is on page 30 of the November 1992 issue. If no waveforms are present, you will have to backtrack through the circuit to find the malfunction. First check the outputs of inverter IC2 and then the outputs of ICl (pins 9 & 10). If nothing still, check that the 15V supply is present at the relevant pins of ICl and IC2. Now switch off the power and switch on again to observe the soft start feature. Each waveform should start off with a low duty cycle and increase to the maximum duty cycle of slightly less than 50% in about one second. Check the "dead time" between each waveform. This is measured as the time between the falling edge of one waveform and the rising edge of the other. It should be about 5µs. If the dead time is less than lµs, then the lMQ resistor between pins 4 & 14 of Fig.16: parts layout on the Sinewave Generator Board. Make sure that all polarised parts are correctly oriented & use PC stakes for the 17 external wiring connections. Don't use sockets for any of the I Cs. JANUARY 1993 61 CURVED LINKS ARE 15A MAINS WIRE *SOLDER 3mm BRASS NUTS TO COPPER SIDE Fig.17: parts layout for the Rectifier PC Board, minus L3, L4 & the two high voltage capacitors. As on the H-Pack Board, the curved links must be run using 15A mains-rated cable. ICl should be installed. This will increase the dead time. Test the under voltage cutout by winding down the power supply. At a voltage of around 20V from the power supply, the circuit should stop operating. The feedback control is tested by connecting a lOOkQ resistor between the "A" pin and the +15V pin. Adjust This close-up view shows the H-Pack Board. The tµF 500VAC filter capacitor that straddles the centre of the board will be added next month when the chassis wiring is described. 62 SILICON CHIP VRl slowly to check that the duty cycle can be varied from maximum to minimum. Note that maintaining a steady duty cycle with VRl is very difficult but this test will confirm that the control circuitry is operating. Finally, the Mosfets (Q5-Q16) can be installed. These are mounted at right angles on the underside of the PC board as shown in Fig.15. Sinewave Generator Board: connect a DC supply set to 15V between the GND and +15V pins on the PC board. Connect your oscilloscope probes to the A and B pins and check that these two waveforms are 180° out of phase and operating at about 1MHz. Similarly check that the E & F outputs-and the C & D outputs are also at 1MHz and 180° out of phase. If there is a fault here, check for correct supply voltages on IC14, IC15 and IC16. By the way, the supply rail for these three ICs was incorrectly shown as +5V on the circuit of page 70 in the December 1992 issue. It should be +15V. Disconnect the supply from the Fig.18: these 5V p-p waveforms should be present on the collectors ofQ21 (top) & Q23 (bottom). +15V pin and then bridge the G and H pins, the Kand L pins and the Mand N pins respectively. Now connect a 24V supply to the +24V pin and GND pins. Check that +5V is present on the relevant pins of ICl 7-IC23. To check the signals present on the collectors of QZl and Q23, you will need to trigger your oscilloscope externally using the 50Hz signal present at pin 1 of IC17. You should obtain signals similar to those shown in Fig.18. The top trace shows the signal at the collector ofQZl while the lower trace shows the signal at the collector ofQ23. A similar waveform should be seen at the collectors ofQ22 and Q24 when the external trigger is set to the opposite trigger polarity (see Fig.18) Note that these waveforms show only the active lOms half of the ZOms period. For the other lOms period, the collector ofQ21 is low and the collector of Q23 is high. The same remarks apply to QZZ and Q24. H-Pack Board: this board can only be tested when wired to the Sinewave Generator Board. You will need to cut 14 x 250mm lengths of hook-up wire and connect them between the A-N pins on the Sinewave Generator Board and the A-N pins on the H-Pack Board. An additional DC supply or the DCDC Inverter Board will be needed to provide +15V to the Sinewave Generator Board. Connect 24V to the DC-DC Inverter Board and to the Sinewave Generator Board and connect the +15 V rail from the Inverter Board to the + 15V pin of the Sinewave Generator Board. The GND pins should also be connected to Fig.19: check for these 15V p-p waveforms at the collectors of Q18 (top) & Q20 (bottom) the power supply (ignore the GND OUT on the DC-DC Inverter Board at this stage). Connect your scope's probes to the gates of Q18 and QZO, with the earth clips on the Y terminal and on the OV rail. Switch on the power. The waveforms should be as shown in Fig.19; ie, with an amplitude of 15V. Similar waveforms should be obtained on the gates of Ql 7 and Ql 9 with the earth clips on the OV rail and on the X terminal. If these waveforms are incorrect, check that there is a +15V supply across ZD7 and the supply pins (1 & 8) ofIC7, across ZD9 and the supply pins ofIC9, and across ZDl 1 and ICl 1 and the supply pins ofIC13. Unfortunately, the Rectifier PC Board is not easily tested until completely wired into the inverter chassis. After that, we can do some further tests to check that the circuits are functioning correctly before we finally switch on full power and drive 240VAC loads. Next month, we will describe the construction of the DC-DC transformer and the terminal board, and show how the PC boards and other components are wired into the chassis. SC J. The Rectifier PC Board serves mainly as an assembly platform for the two high voltage capacitors (680µF 400VW & 25µF 370VAC), the three large toroids (L2, L3 & L4), & a terminating panel. It also incorporates the fast rectifiers (D3-D6) and the optocoupled feedback circuitry (IC4 & IC5). JANUARY 1993 63 W 'ft ifiill iMI rt Brand new Hitachi LM215XB, 480 x 128 dot displays at a small fraction of their real Brand new 6 volt 1 watt value. amorphous solar panels. Two of these in series make a Item No. 0132 Controller IC (surface mount) great 12V battery maintainer/ $5. 28 pages of data $3. charger. Incredible pricing. t { $39 $10 ea for 10 for $85. Item No. 0130 Each one of these identical PCB filter assemblies contains six three terminal tuning fork filters (IN-GNDOUT), at different frequencies in the audio range : 1.8-3.1 Khz . These high quality dial fork filters have vary narrow bandwidths, and could be used as the basis of a selective call system, high stability oscillators etc. NATIONAL SEMICONDUCTOR seven segment, Common cathodl?, 12 digit, multiplexed, LED display with 12 decimal points. Overall size is 60 x 18mm and a pinout diagram is provided. ONLY $2.50 A very small but complete IR tele- scope which only needs an EHT power supply, which is provided in kit fo rm. Brand new large precision TV projection lenses: 117mm diameter, 107mm long, has adjustable focussing. Will project bright images at close proximity onto walls/screens. The whole assembly can be easily unscrewed to obtain three large lenses: Two plastic and one glass. Use it for projection , magnification, or a very low light lens fo r night viewers! Experimenters delight at ONLY $279 Item No. 01 21A Includes a "Free" 75mm IA filter. Brand new 5mW-670nM laser diode, plus a collimating lens, plus driver kit, plus, hardware, plus instructions. $30 $89 ea.or5for $10. Used air cooled ARGON laser' heads, that produce a BLUE beam! Power output is in the 30-100mW range. Limited stock, at a fraction of their real value: $600-800 ... For the Argon head only. We also provide a circuit fo r a simple power supply. Item No. 0109 Use them to activate door strikers for entering buildin gs, car alarms, central locking, the most secure key ever (See E.A. July 92) : ON SPECIAL <at> For two keys, and on e decoder kit. Cat. No. GK138. $49.90 Item No. 0137 Item No. 01 64 ~ ! Two used 3mW Siemens HeNe visible red laser tubes, and one of our efficient 12V universal laser supply kits. $129 $99 Item No. 00105 X The second tube is a Bonus till end of January 1993 only . A high quality military grade deep infra red (IR) filter. Used to filter the IR spectrum from medium and high power incandescent spotlights and flood lights. It's glass base makes it capable of withstanding high temperatures. Approx. 130m diameter and 6mm thick. Can be used in conjunction infra red night viewers and IR responsive CCD cameras: Many colour video cameras and most monochrome video cameras have good IR response: Check by viewing the LED's in an TV or VCR infra red remote control. Excellent for night surveillance equipment! At a FRACTION OF THEIR REAL PRICE. ON SPECIAL AT ONLY: $45 These industrial quality detectors will detect ferrous and non-ferrous metals at close proximity. Some are DC powered (10-30VO, some are AC powered (Mains), and all will switch loads di rectly. All have a th ree wire fo r con necting into circu itry: Two fo r the supply, and one fo r switching the load. LIMITED QUANTITIES at a small fraction of th eir real price: $28 Corning soon is our new 12 channel UHF remote control channel that is easily expandable to 16 channels. T~e system features a SAW resonator locked transmitter, prealigned and assembled receiver "front end" which solders onto the main receiver PCB, and a very compact 2 channel relay driver PCB which can be used in rnuttiples: Up to eight units. As a price indicator, we will be offering a package deal consisting of 2 transmitter kits, plus one receiver kit, plus three relay driver kits, for a total cost of $200 Based on an IC with 20dB of gain, a bandwidth of 2Ghz and a noise figure of 2,8db this amplifier kit out performs many other IC's, and is a fraction of their cost. The complete kit of parts for the masthead amplifier PCB and components, and the power and signal combine r PCB and components, is priced at an incredible: $19.90 Fore more information see a , novel, extremely popular, and an effective active antenna design which employs this amplifier: MIRACLE TV ANTENNA - E.A. May 1992. 1 Coming soon is our easy to construct electric fence kit. It features very low power consumption , a solar charging/regulating and indicating circu it, and it can be easily solar powered. The PCB (Screened and solder masked) and all components kit will cost under Based on a brand new, very compact modern EHT flyback transformer which includes an EHT diode rectifier. We supply the transformer, a very simple circu it, and the components to suit. All you need to make a very simple EHT, DC or pulsed AC supply. Powered from 12V DC supply. . Great for EHT experiments, EHT ,,, testing, plasma displays, etc. Total price for the transformer and the components is ONLY: A 5mW gunsight at an unbeatable price . $50 $279 Item No. 0108 Includes one "Free" rifle or pistol mount. Small PCB Assembly based on a ULN2232IC. Th is device has a built in light detector, filters, timer, . narrow angle lens, and even a siren driver circuit that can drive an external speaker. Will detect humans crossing a narrow corridor at distances up to 3 metres. Much higher ranges are possible if the detector is illuminated by a remote visible or IR light source. Can be used at very low light levels, and even in total darkness. With IR LED. Full information provided. The IC only , is worth $16! OUR PRICE FOR THE ASSEMBLY IS: $6EA,OR 5 FOR $25 Item No. 0163 Brand new uriits. Diameter 58mm, height 25mm, 5V operation, simple to drive (Two phase - 6 wires) , 7.5 egree steps, coil resistance 6.6 ohm: $12 Item No . 0140 . Driver IC 9UCN5804B) plus circuit $9. '• ..)\~l \i\1' '•• $20 Item No. 0161 The first generation (XX1080) passive IR night viewer tube features excell ent gain, and when used with a very low light objective lens, it can produce , useful images under almost as little as sub-moon light illumination. Cal also be IR assisted. We will supply a XX1080 tube, plus a suitable Lens, plus a kit of parts fo r an EHT power supply (PCB and components only) fo r a total price of High quality pen sized 5mW laser diode pointer for teachers , doctors, etc. On Special Cl:199 It~ No. 0101 REMOTE CONTROL BY BOB YOUNG Installing & adjusting the low-cost speed controller; Pt.3 Installing the speed controller is a matter of connecting it to the motor & receiver, & wiring the all-important suppression components across the motor. The speed controller must then be fine-tuned to match the transmitter & receiver. Last month, we ended by saying that the spark suppression components must be mounted directly on the motor terminals despite the fact that this is usually not very convenient, due to space restrictions in the model. Also, soldering three or four leads to each motor terminal can be difficult and frustrating at times, so why do it when some commercial speed controllers have these components built right into the speed control module? The laws of physics were written by a much higher authority than Bob Young and these laws state that the radiation from a spark gap transmitter (commutator) must be killed at the source. If this radiation is allowed to reach the motor interwiring, then it is all over. Marconi transmitted across the Atlantic with a spark gap transmitter and remember, you have a receiver antenna within just a few centimetres of this spark source. Much of the commotion over opto- coupling in speed controllers is largely a result of poor installation practices regarding this point. There is no need for optocoupling if the installation is carried out correctly. Antenna range tests carried out with diodes fitted in various places in the installation, and with the varistor fitted and deleted, all indicated quite clearly the importance of fitting these items directly at the motor terminals. The range decreased as the varistor was moved further away from the motor terminals. Leaving the diode off results in the FETs running extremely hot very quickly and some or all of the FETs being damaged. Make sure that the diode is installed with its banded end towards the positive battery lead. The varistor and capacitor are non-polarised. Ifby chance the motor spins in the wrong direction for your prop or application, reverse the wiring at the motor terminals and don't forget to reverse the diode! Finally, keep all of these component leads as short as possible. One point not mentioned so far is that the suppression diode must be a fast recovery type capable of operation at the full motor current. A Schottky MU810 or similar will do the job nicely. Fine tuning One of the test beds used for the SpeedlB has been this twin engined model. The controllers were mounted as close as possible to the motors, while still being housed in the main fuselage. 66 SILICON CHIP We now come to the interesting bit: fine tuning the motor/speed control/ radio combination using VRl, VR2 and VR3. You will need a tachometer (eg, the optical tachometer described in the May 1988 issue), a moving coil ammeter and a voltmeter (multimeter). It is also desirable although not essential to have access to an oscilloscope and a frequency counter. (Editor's note: you cannot use a digital multimeter to monitor the current unless you know that it has a response which is flat to 3kHz or more on the DC current range. Nor will a moving iron ammeter do the job since its response tapers off quite rapidly above 100Hz. That leaves a conventional moving coil meter as the only choice. Such a meter will respond to the average value of the current and not the RMS value but, for the purpose of this test, this should not be a problem. You can distinguish a moving iron meter from a moving coil meter by the fact that it does not have a linear scale - ie, it is cramped towards zero - and it has no polarity markings). Due to the fact that not all radios use a standard pulse neutral, pulse width variation or pulse frame rate, some adjustment must be made in the speed control to match these factors. For example, the old Futaba 2-channel sets used a 1.3ms neutral, 0.71.9ms pulse width variation, and a 14ms frame rate. The new Futaba and J. R. PPM sets use a 1.5ms neutral, 12ms pulse width variation and a 20ms frame rate. The standard unit as delivered is set to 1.5ms neutral, with variation between 1-2ms. The frame (repetition) rate will often va:r: with the number of channels and some sets use swinging frame rates which keep the sync pause constant and thus deliver the fastest possible system response time. All of these factors influence the speed controller performance to some extent. For example, the frame rate will have some affect on the voltage tripler. 1 Throttle settings That said, let us proceed. First, the travel direction and the 0V DC condition must be set with the throttle stick at the low throttle position. This is usually done with the trim lever in the mid position to allow for small variations over time. Switch on the transmitter and set the throttle to low, with the trim lever in the mid point. The usual convention in Australia is for full throttle to be applied by pushing the throttle stick forward (to the top of the Tx case). If you have an old transmitter with no servo reversing switch, the flexible wire jumpers between JlA, JlB, J2A and J2B need to be correctly connected. If your radio gives an increasing pulse length with increasing throttle, connectJlA to JlB This photo shows the test setup used to measure the change in efficiency at part throttle for various switchmode frequencies. No definitive answer emerged to give a best frequency for all conditions. Instead, there tends to a broad range of frequencies that will best suit a particular motor. and J2A to J2B as shown in Fig.2 (p.41, Dec. 1992). If your radio gives a decreasing pulse length with increasing throttle, connect JlA to J2B and JlB to J2A. If you haven't the slightest idea what your radio does, jumper the pins as shown in Fig.2 or use it as deliveredyou'll have a 50-50 chance that this is correct. If the throttle works backwards, you've got it wrong and the leads should be swapped over. With the speed control connected, restrain the model and switch on the Rx, making sure that you are well clear of the propeller. If the motor leaps into life, check to see if moving the throttle to full power slows the motor. If this is the case, reverse the direction of the throttle with the Tx switch or the PC board jumpers Jl and J2. All being well, the motor will sit quietly, eagerly awaiting your first command. Adjust VRl until the motor begins to emit a tone and then back offVRl slightly, until no noise is heard. If your scope is hooked up to the common gate line (ie, emitter of Q2), very narrow voltage spikes will appear just before the motor noise is heard. Set VRl to deliver a dead flat trace, with no sign of switching. As the throttle lever is gradually advanced, the gate pulses will become wider and current will begin to flow. At some point, depending on the number of poles in the motor, the resistance of the windings, motor loading and a host of other factors, the motor will start to turn slowly. From that point on, the throttle response is very smooth and linear, giving excellent control over motor revs. Throttle sensitivity Now push the throttle all the way forward, listening to the prop noise or observing the instruments to ensure that after about 7/8ths of the stick travel, there is no further increase in motor RPM or voltage at the gates. If a scope is being used, the gate pulse width should increase to the point where it is pure DC (about 14V) by 7/8th throttle. If this is not the case, and full stick travel still leaves the gate voltage in the switching mode, VR3 must be adjusted to increase the sensitivity of the throttle range control. Alternatively, if the throttle range control is too sensitive, VR3 must be adjusted to soften the range control. By the way, while VR3 is shown on the overlay diagram in last month's issue, it did not appear on the circuit diagram in the November 1992 issue. This was_a late change, made in response to requests from a number of enthusiasts, and has been included to give optimum throttle response. The change has been made by altering the value ofR2 to lOkQ and then connecting VR3 (50kQ) in series with it. The smoothest results are obtained by using the full stick travel to achieve full throttle. Using VRl and VR3 in JANUARY 1993 67 Another view of the twin-engine model (shown here partially completed) that was used as a test bed for the Speed 1B speed controller. A critical function in twin-engine models is that the prop speeds must be matched over a wide range. conjunction with each other will give end point adjustment. Switchmode frequency Having completed the above, we are now ready .for the fine tuning of the speed control switching rate. This is the most important part of the whole project. As you may recall, the rationale behind the design of Speed 1B was to allow it to be matched to the motor parameters. It was my belief that maximum efficiency would be obtained at a particular switching rate, depending on a myriad of variables in the motor design and application requirements. Such factors as winding inductan"Ce, motor capacitance and commutatio.g speed (which in turn is influenced by prop or gearbox loading) all contribµte to a complex and highly interactive chain that determines system efficiency. At the time, this was only a hunch and I had seen nothing in previously published work to confirm this feeling. After extensive testing, I can now publish the results confirming this premise. In this regard I owe a very large debt of gratitude to Barry Younger who worked flat out to provide the test facilities and who did much of the actual testing and tabulation of the final results. Put briefly, improvements of up to 25% in efficiency can be obtained by careful selection of the operating RPM and switching rate. This result will vary from motor to motor and with RPM on any one motor. The process of selecting a switching rate is divided into two distinct phases: (1) full throttle (DC mode); and (2) partial throttle (switchmode). The first step is to push the throttle to full power and monitor the RPM while swinging VR2 through its full range. According to theory, the RPM should not vary over the full range of VR2, as at full throttle the Mosfet gates are being fed pure DC. However some Table 1 68 FETType Switching R,ate Gate Peak Volts Gate DC BUK455-60A 540Hz 9.5V 13.SV J3UK455-60A 825Hz 9.5V 13.SV BUK455-60A 1.1kHz 9.5V 13.SV BUK455-60A 2.7kHz 6.8V 13.2V BUK455-60A 12.6kHz 3.1V 12.8V SILICON CHIP speed control/motor/radio combinations we have tested have exhibited a best switching rate at full throttle and this is a puzzle. The only explanation I can offer is that the voltage tripler is peaking in output at some frequency, yet the gate voltage does not appear to vary to any appreciable level that I can detect. As stated many times in this series of articles, the subtlety of the various interactions between system components is quite confusing. The second and more understandable phase is tuning the mid-throttle ranges. Here the switching rate, at least according to theory, will have a very definite effect. There is a trap to be careful to avoid in the partial throttle test and it threw me off-track for some time during early testing. Part of the reason for the long delay in this project was that I could not decide what was the best frequency to use and even now I still cannot give a definitive answer to this question, for the simple reason that there is no best frequency for all applications. Each application has its own ideal rate, hence the need for a variable switching rate. What we are trying to establish here is the point of maximum efficiency of the motor/speed control/radio combination in the mid-throttle ranges; ie, in the switching mode. Once again I must point out that once the throttle is fully advanced, the whole argument about switching rates becomes academic, because the speed controller moves out of switching mode and into DC mode. The switching rate then has absolutely no bearing, or at least it should have no bearing, on gate voltage :-- apart from the anomaly noted above. For those who missed the earlier articles, there is a long-standing argument in electric power modelling circles over the merits of 50Hz or 2.5kHz switching rates. The argument runs that controllers using the 2.5kHz switching rates are less damaging to the motor magnets, use less current and run cooler. They are also much smoother in use and the 50Hz controllers are disparagingly referred to as "rattlers". The main problem with the 2.5kHz controller is the component count. This is much higher than in a 50Hz controller which uses the receiver input pulse as the master clock. Thus, a Kit prices & availability Kits for the Speed1 B Speed Controller are available in a number of configurations and prices, as follows: (1 ). Surface mount PC board with all components installed, including trimpots but without Mosfets, together with an' unpunched case ..... $69.50 (2). Complete unit, assembled and tested, includes servo lead, punched case and with 8 SMP60N06-18 FETs fitted .. ................................. $175.00 (3) . Complete unit, assembled and tested, includes servo lead, punched case and with 4 BUK456-60A FETs fitted ... ................................. $129.00. Servo lead (depending upon brand) .................................................. $5-7. SMP60N06-18 FETs ................................... ........ .. ...... .. ... .. .. ............. $9.50 BUK456-60A FETs ................ .. ................................ ............... .. ......... $6.50 Graupner ECO 600 non ball-race motors .. ..................................... $28.00 Graupner ECO 600 88 ball-race motors .......... .. ... .. ...... .. ............... $49.00 Post and packing for all the above kits is $2.50. Payment may be made by Bankcard authorisation of by cheque or money order payable to Silvertone Electronics. Post orders to Silivertone Electronics, PO Box 580, Riverwood, NSW 2210. 2.5kHz controller is more bulky and more expensive and so the argument rages on, with both schools quite vocal about their point of view. To complicate matters, the microprocessor controller arrived, reducing the component count but introducing software and service problems. After months of testing in the early days of researching this project, I became more and more confused as I went deeper and deeper into the argument. To make matters worse, I could never seem to obtain a repeatable set of results. What I did find was that the inter- $ 5 99 For many years you have probably looked at satellite TV systems and thought "one day". You can now purchase the following K-band system for only: actions between the switching rates, FET gate input capacitance, motor commutation rate, motor loads and a host of other factors were so complicated that a logical analysis was almost impossible. In the end, I decided that the answer was a variable switching rate design which would allow the user to fine tune the unit to his combination. Table 1 gives some idea of the parameters of the Speed 1B with various switching rates. Notice that the peak gate voltage is starting to roll off at 2.2kHz with this particular set of FETs. By 12.6kHz, the gate input waveform was a virtual Here's what you get: • A 1.6 metre prime focus dish antenna, complete with all the mounting hardware. • One super low-noise LNB (1.4dB or better). • One Ku-band feedhorn and a magnetic signal polariser. • 30 metres of low-loss coaxial cable with a single pair control line. • lnfrared remote control pre programmed satellite receiver with selectable IF & audio bandwidth, polarity & digital readout. Your receiver is pre-programmed to the popular OPTUS transponders via the internal memory. triangle of 3.1 V and the FETs were starting to heat badly at 3/4 throttle they weren't being turned on hard enough. Interestingly enough, the unit still worked well, with a very smooth throttle response. There was no heating in the tests conducted up to 3.5kHz, despite the fact that the peak gate volts had dropped below 6V at this point. To return now to the trap mentioned above, it involves the method of testing. If we regard the real measure of efficiency as the ability to move a given load with th8 minimum of energy, then testing should proceed as follows. Set the throttle at some given point (half way, for example) and measure the RPM and note this figure. Now, while monitoring RPM , tune VR2 through its complete range, looking for the lowest possible source/drain current that will deliver this RPM. In fact, at some point the RPM may increase at the same current draw, and this is what makes this test so confusing. In this case, back off the throttle until the target RPM is once again obtained and note the new current, which will of course be lower due to the reduction in duty cycle. On one unit tested, this point occurred at about 1200Hz. Most units tested exhibited a minimum 5% increase in efficiency at the best frequency, a useful figure. Finally, do a range test before flying the plane. The radio should not be significantly affected by running the motor at any speed. SC AV-COMM Pty Ltd, PO Box 225, Balgowlah NSW 2093. Pb: (02) 949 7417. Fax: (02) 949 7095. All items are available separately. Ask about our C-band LNBs, NTSC-to-PAL 9onverters, video time date generators, FM2 & EPAL & Pay TV hardware. r,--------------~ I YES GARRY, please send me more information on K-band I satellite systems. I Name: _ _ _ __ _ _ _ _ _ _ __ I Address: _ _ _ _ _ _ _ _ _ _ _ __ : _ _ _ _ _ _ _ _ _ P'code: _ _ __ I Phone: _ _ _ _ _ _ _ _ _ _ _ __ 10/91 I ACN 002 174 478 ]ANUARY 1993 69 I PRODUCT SHOWCASE I Intelligent nicad battery charger Using a microprocessor-based smart algorithm, the System 90 range of battery chargers, analyse, discharge, charge & condition nicad batteries at the press of a button. The System 90 is suited for batteries used in 2-way radio equipment, cellular phones or video equipment. A liquid crystal display gives information on the capacity and voltage of the pack under test. The System 90 allows testing of up to six batteries at the same time, either of the same type or all different types. Unlike dedicated chargers which can become obsolete as models change, the plug-in adaptor modules of the System 90 will enable new battery models to be charged. New modems have 16-bit processors Netcomm has announced a new range of SmartModems which have 16-bit processing and a surface mount board. This has enabled more features to be included while maintaining the present size. The new design combines V.42 er- Mercury-free batteries from Panasonic Panasonic now has a range of cells which are guaranteed to be free of mercury and thus won't release this noxious metal into the environment at the end of their life. The range comprises heavy duty, extra heavy duty and alkaline batteries in 9V, D, C, AA & AAA sizes. The batteries are easy to re~ognise with their green packaging, apple symbol, and "0% mercury" label. They are on sale at supermarkets, department stores and electrical parts retailers. 70 SILICON CHIP The unit is available in single, three or 6-unit modules and can analyse any nicad battery in the range from 4.8V to 14.4V (up to 7Ah). A universal clip lead adaptor is also available to connect unusual batteries. For further information, contact Premier Batteries Pty Ltd, 9/15 Childs Road, Chipping Norton, NSW 2170. Phone (02) 755 1845. ror correction and V.42 data compression as specified in CCITT standards, thus allowing effective data throughput rates of up to 57,600 bps. Netcomm is offering hardware upgrades to existing users of SmartModem models. For further information, contact Netcomm (Australia) Pty Ltd, Block A, 25 Paul St North, North Ryde, NSW 2113. Phone (02) 888 5533. New FET has high avalanche rating Motorola has released the MTP50N05E N-channel enhancement mode Mosfet which is designed to withstand high energy in the avalanche and commutation modes. The MTP50N05E is designed for low voltage high speed switching applications in power supplies, converters and PWM motor controls. Since the new FET has a drain-tosource diode with a fast recovery time, it is well suited to bridge circuits where diode speed and commutating safe operating areas are critical. For more information, contact David Segal at VSI Promark Electronics Pty Ltd, 16 Dickson Ave, Artarmon, NSW 2064. Phone (02) 439 4655. Digital insulation tester has bargraph display Yokogawa has announced the release of the 2426 digital insulation tester which has digital and analog bargraph displays and "one touch" measurement with an audible indicator to allow fast repetitive testing. The bargraph display circuitry has Jamo Concert. wmrung~am a sampling rate of 20 times/second to provide a rapid response, while a moving average filter technique is used to reduce flicker on the last digit of the 3½-digit display. Two models are available, covering voltages from lO0V to 1000V and resistance ranges from 20MQ to 2000MQ full scale. Standard accessories include ground and line probes and a soft carrying case. For further information, contact Yokogawa Australia Pty Ltd, Unit D3 Centrecourt, 25-27 Paul St North, North Ryde, NSW 2113. Phone (02) 805 0699. 128Mb removable optical disc drive Viva Computer Products has released a new disc drive based on the 3.5-inch ISO rewritable optical format. Providing an on-line capacity of 128Mb from its compact disc cartridge, the Matsushita LF-3000E employs split optics and very thin actuators to allow the complete drive to be contained within a standard PC case. The LF-3000E can be easily incorporated into an existing PC or PS-2 enclosure, allowing for simple upgrades, or it can stand alone as an external drive. With the disc spinning at 3000 RPM, very fast data transfer rates are available. A sustained rate of 640Kb per second is routine across the disc and a built-in SCSI-2 interface provides burst transfers of up to 4Mb/s in synchronous mode. Average seek time is less than 48ms, with an average latency of only lOms. It also reads OROM (Optical Read Only Memory) discs. The LF-3000E is priced from $2,500 It runs in the family. Hear what the First Concert VII voted test panel had to say 'Loudspeaker of The say about Concert II: "On audition it didn 't Year'. Now the smaller model Concert II take long to establish winning hands down that the Jamo was in a group test with 8 something special. other loudspeakers The-speaker simply in the UK magazine sounded more trans"High Fidelity". parent and revealing The conclusion of than the other speakthe test was: "The ers in the test.... They speaker that resolved imaged better.... A the problem was the deep, tangible bass dark horse Jamo. Very and crystalline mid much an unknown and treble clarity.... quantity in the UK, it Imaging was virtually was nothing less than a holographic... " revelation when put to With 24 years exThe test winner the test. It was the one perience having prospeaker here with duced more than 10 genuine grip and grace million loudspeakers, 2-way bass reflex and, as such, ended up System: Jamo is today Woofer: 170mm Polypropylene the overall winner." Europe's preferred Tweeter: 25mm soft dome When a Danish loudspeaker brand. Power Handling: 80 watts RM$ loudspeaker is the Timber Finishes: Walnut and Mahogany To experience RRP: (Timber finish) $1190 pair preferred choice in why Jamo is winning (Black Ltd. Edition) $ 990 pair the UK over such time and time again, brands as B&W, Mission, Heybrook, call into your nearest authorized Castle and Tannoy, it must be of Jamo specialist or contact Scan outstanding design. And this is Audio for more information and exactly what Jamo's Concert II is. the name of your nearest dealer. CONCERT II uamo AWARD WINNING LOUDSPE AK E R S SCAN AUDIO, 52 Crown St, Richmond VIC 3121. Phone: (03)429 2199. Fax (03)429 9309 for the internal drive. For further information, contact Viva Computer Products Pty Ltd, 144 Pacific Highway, North Sydney, NSW 2060. Phone (02) 954 0622. Large screen colour monitor Trace Technology has released the Barco "Megagraphics", a large screen colour monitor. Covering the sweep frequency range between 30kHz and 80kHz, the unit has a resolution of up to 1600 x 1200 dots and allows the full display of two A4 pages. The Megagraphics is also available in a chassi&:version and can easily be integrated into an industrial console. An Inv'ar shadow mask guarantees the purity of the image and also improves contrast by using a 52% lo w transmission filter. This m eans the Megagraphics will display bright and readable pictures, even under harsh lighting conditions. A flat square tube equipped with dynamic focus , together with access to a nine-zone convergence control, ensures picture ]ANUARY 1993 71 1K x 512 using the DT3851 and to 1K x 1K using the DT3852. The DT3851 series hardware supports image placement and scaling anywhere on the screen, within a window. The Windows 3.1 interface is fully implemented to increase flexibility for programmers and non-programmers. For further information, contact TCG, 30 Balfour St, Chippendale, NSW 2008. Phone (02) 699 8300. 24-bit handheld colour scanner Power capacitors with plastic dielectric Siemens Matsushita Components has released a new range of "dry" plastic power capacitors offering a 15% weight saving over equivalent types. The new capacitors are intended for use in traction systems, as in mainline and subway trains, or in stationary converters. Their capacitance range is from 3 70µF to 10,500µF, with a voltage range from 900-2900V DC. Their life expect- sharpness over the entire screen area. An "Ambient Light Controller" adapts the output of the Megagraphics automatically as surrounding lighting conditions change. This provides more comfort and better readability for the operator and may increase the life of the CRT by up to 30% . For further information, contact Trace Technology Pty Ltd, Unit 4, 265 Williamstown Road, Port Melbourne, Vic 3207. Phone (03) 646 5833. Flexible image processors A new range of image proces~ors from Data Translation has just been released. The DT3851 and DT3852 are software compatible PC AT boards which combine a precision frame grabber, processor, and display circuitry to acquire, digitise and display standard and non-standard video signals 72 SILICON CHIP ancy at full load is at least 100,000 hours. Internally, the capacitors consist of metallised plastic windings with no oil impregnant. They incorporate self healing and over voltage protection. As well, the capacitors incorporate an internal over-pressure disconnector which operates in the event of a fault. For further details, contact Malcolm Evans, Electronic Components Department, Siemens Ltd, 544 Church St, Richmond, Vic 3121. Phone (03) 420 7716. on a high resolution VGA monitor. Windows graphics can be mixed with images and images can be acquired while non-interlaced video is being displayed. The boards' dual buffers allow images to be scaled and placed anywhere in the display without corrupting the image data, thus providing true single monitor operation. Both the Windows graphics and the processing ofimages, including frame averaging, convolutions and morphological operations, are accelerated by the on-board Texas Instruments TMS34020 Graphics System Processor. DT-connect ports add 32-bit floating point digital signal processing when connected to the optional DT2878 Advanced Processor board. Input and display resolution, acquire and display rates are controlled through software. Input (spatial) resolution is software programmable to Logitech Inc has introduced the ScanMan Color, a 24-bit handhold scanner for the Microsoft Windows environment. ScanMan Color's hardware captures up to 16.8 million colours and features a proprietary white fluorescent light that permits consistent scanning brightness without a warm-up period. With its 24-bit capacity, ScanMan Colour is able to capture true 256-step greyscale data without the need to convert colour information, a process necessary with all 12 and 18-bit models. ScanMan Color comes bundled with FotoTouch colour image editing software, an expanded version of Logitech's FotoTouch application. A key component ofFotoTouch is Logitech's "AutoStitch" capability, which allows the user to easily merge multiple scans. Additional features include slider controls for adjusting brightness, contrast and tone, and software control of colour balance and transparency effects. The suggested retail price for the ScanMan is $1 ,323.00. For more information, contact B. J.E. Enterprises, 124 Rowe St, Eastwood, NSW 2122. Phone (02) 858 5611. ► SerialTest PC-based Protocol Analyser & Data Line Monitor c,j Q; 23 ~ u::. a ~ 1£ l: (.) The new version of Serialtest turns ANY PC into a full-featured serial data protocol analyzer- even laptop and notebook computers for both synchronous and async data. Serial/est unleashes the power ofyour PC for data communications testing with a simple, user-friendly interface! ThenewComProbeplugs in to yourp_rinterport. With Sena/test and your PC, there is no longer any need to buy or rent expensive, dedicated protocol analyzers. Th e Serialtest package includes Serialtest software and Frontline 's RS-232 ComProbe"' adapter. The ComProbe connects to your computer via the parallel printer port (no need for plug-in cards) and allows Serialtest towork with both synchronous and asynchronous devices. Serialtest's monitor mode shows you exactly what information is flowing between any two serial devices - both data bytes and control signals. Source mode allows you to interactively simulate either the DTE side or DCE ·side of the commun ications link. Serialtest Async is similar to Serialtest, but is limited to asynconly testing. Anyone who works with serial data communication needs Serialtest Field service engineers and system integrato rs wi ll appreciate the portability and easeof-use. Communication specialists and network supervisors wi ll enjoy the power and flexibility. No matter what the industry, Serialtest will prove to be an indispensable tool. SerialTest Sync/Async with Comprobe $2480.00 (ex tax) $2536.00(inc tax). Allow$15 P&P. Plug Pack$24.95. SerialTestAsync is still $480.00. Demo disk $10.00 refu ndable on purchase [t ~ a ~ (f.) 9:: 23[t ~ a ~ c,j 9:: 23 [t ~ 2mm Test Leads HCK-MS101 HCK-MS102 2mm Blk 1.0m Lead 2mm Red 1 Orn Lead 2mm Test Fittings HCK-8234-1 HCK-82342-2 HCK-9217-1 HCK-9217-2 HCK-9225-1 HCK-9225-2 HCK-9229-1 HCK-9229-2 2mm 2mm 2mm 2mm 2mm 2mm 2mm 2mm Blk Hook Grip Red Hook Grip Blk Stackable Plug Red Stackable Plug Blk Test Prod Red Test Prod Blk Test Tweezers Red Test Tweezers 4mm Blk Sight 1.0m Lead 4mm Red Sight 1.0m Lead 4mm Blu Sight 1.0m Lead 4mm Yel Sight 1.0m Lead 4mm Blk R/A 1.0m Lead 4mm Red R/A 1.0m Lead 4mm Blk Sight 1.0m Lead 4mm Red Stght 1.0m Lead 4mm Blk R/A 1.0m Lead 4mm Red R/A 1.0m Lead 4mm Blk Sfty 1.0m Lead 4mm Red Sfty 1.0m Lead 4mm Blk Sfty R/A 1.0m 4mm Red Sfty R/A 1.0m 4mmBlk16A 0.5M Lead 4mm Red 16A 0.5M Lead 4mm Blu 16A 0.5M Lead 4mmYel 16A 0.5M Lead 4mm Gm 16A 0.5M Lead 4mm Via 16A 0.5M Lead 4mm Blk 16A 1.0m Lead Electronic Workbench Analog Module includes • Comprehensive parts bin includes op-amps, zeners, transistors etc • Function Generator with sine, square, triangle etc • Bode Plotter for frequency responses and phase shift $4 .20 $4. 20 $1.60 $1.60 $3.25 $3.25 $14 .05 $14.05 4mm Test Leads HCK-9014-1 HCK-9014-2 HCK-9014-3 HCK-9014-4 HCK-9016-1 HCK-9016-2 HCK-9024-1 HCK-9024-2 HCK-9026-1 HCK-9026-2 HCK-9023-1 HCK-9023-2 HCK-9025-1 HCK-9025-2 HCK-S051 HCK-S052 HCK-S053 HCK-S054 HCK-S055 HCK-S056 HCK-S101 The Electronics lab you keep in your PC! YES you can now build, simulate and test Analog and Digital Circuits without layingyour hands on asingle co mpo nent with Electronics Workbench®. Do it all with the mouse - drag new parts from the parts bin, drop them onto the breadboard and click to run wires. Editing circuits is easy as wires are re-routed automatically. It's much faster than building real circu its. No faulty parts! $10.20 $10 .20 • Dual Trace Oscilloscope • SPICE, transient and steady-state simulation $12 .95 $12.95 $1 2.95 $1 2.95 $13 .80 $1 3.80 $14 .20 $14. 20 $14.65 $14. 65 $11.80 $11 .80 $12.25 $1 2.25 $9.80 $9. 55 $9.80 $9 .80 $9 .80 $9 .80 $1 0. 60 2mm to 4mm Adaptors HCK-9227-1 HCK-9227-2 4mm/2mm Blk Adaptor 4mm/2mm Red Adaptor 8 $2 .65 $2 .65 CJ (i 4mm Test Fittings HCK-9120-1 HCK-9120-2 HCK-9123-1 HCK-91 23-2 HCK-9295-1 HCK-9295-2 HCK-9209-1 HCK-9209-2 HCK-9206-1 HCK-9206-2 HCK-9112-1 HCK-91 12-2 HCK-9113-1 HCK-9113-2 HCK-9116-1 HCK-9116-2 HCK-9119-1 HCK-9119-2 HCK-9124-1 HCK-9124-2 HCK-9214-1 HCK-9214-2 HCK-9132-1 HCK-91 32-2 HCK-9205-1 HCK-9205-2 HCK-9203-1 HCK-9203-2 HCK-9230-1 HCK-9230-2 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm 4mm Blk Clamp Grip 50mm $14.30 Red Clamp Grip 50mm $14.30 Blk Coupling XHK $2.20 Red Coupling XHK $2.20 Blk Crocodile 34A $5.05 Red Crocodile 34A $5.05 Blk Crocodile 2A $2.80 Red Crocodile 2A $2.80 Blk Hexagonal Probe $3.60 Red Hexagonal Probe $3.60 High Voltage Prod $4.95 Red High Volt Prod $4.95 Blk High Volt Prod $5.55 Red High Vo lt Prod $5.55 Blk Hook Grip $12 .85 Red Hook Grip $12.85 Blk Jaw Grip $19.95 Red Jaw Grip $19 .95 Blk Adaptor XSA $4 .45 Red Adaptor XSA $4.45 Blk Panel Mount Socket $4.35 Red Panel Mount Socket $4.35 Blk Panel Twin Socket $4.70 Red Panel Twin Socket $4 .70 Blk Square Probe $3.20 Red Square Probe $3 .20 Blk Stackable Phg $3 .25 Red Stackable Plug $3.25 Blk Test Tweezers $13.70 Red Test Tweezers $13 .70 DIC SC-7000 DeSoldering Tool ESD* Protected • Now with 100W ceramic heater • Work on up • Sensor feedback digital Digital Module includes to 12 layer temperature control • Comprehensive parts bin with • • Special antistatic housing and boards gates, flip-flops , half adders, zero crossover switching to • Optional displays etc surface protect sensitive components • Word Generator up to 16x8-bits • Sucti on/Hot air blow switch mount kit • s eh. Logic Analyser suck for desoldering , blow for • Logic qonverter .__s_M_D_re_mo_va_1- - - ~ ex tax Professional version has inhanced Personal Plus Version is $579 inc tax monochrome. Requires PC/XT/ colour interface, supports maths AT or PS/2 , 2 floppies or hard co-processor. Requires IBM AT disk, 512kB RAM,,, Microsoft or PS/2 with 286 or greater, hard mouse, CGA/EGANuA/Hercules disk, 640kB RAM , Microsoft graphics ad aptor and DOS 3.0 or mouse, EGANGA and DOS 3.0. greater. $299.20 $429 .00 $482. 50 Check our range of Hako Irons for great value! ::0 () ;i;; ~ 8 CJ (i ::0 ~ • Extra tough for industrial users • High energy fuse and PTC protection against overloading • 0-ring sealed case, switch and jacks against dirt and moisture • Protective holster and tilt stand with lead storage • Test probes have finger shields and sleeved plugs • Thick walled ABS case and shock mounted LCD withstands 2m drop on to concrete floor • Unique rotary switch with berylium copper contacts and gold plated pcb Model 103 & 105 • 4000 count • Digital update twice/second , analog 20 times/sec • 8 Functions - Vdc, Vac, Ade, Aac, Ohms , Diod e, Continuit y, Frequency, Capacitance • Data hold & Relative function s • 0.5% de accuracy $298 .80 $249 .00 ex tax Ranges Vdc 400mV, 4V, 40V, 400V, 1OOOV Vac 4V, 40V, 400V, 750V Ade 4-400mA, 1OA Aac 4-400mA, 1OA Ohms 400Q, 4kn, 40kQ, 400kQ, 4MQ, 40MQ Freque ncy 1OOHz, 1kHz, 1Ok Hz, 1OOkHz, 1MHz Capacitance 4nF, 40nF, 400nF, 4µF, 40µF Model 105 has similar specs but with improved accuracy of 0.1% typ on Vdc and 0.5% at 50Hz $358.80 $299.00 ex :ax a ~ 8.30am to 5.00pm Mon to Fri. 8.00am to 12 noon Saturday. s 1£ 5: o ~ u::. § s:: Mail Orders add $5.00 min to cover postal charges. Next day delivery in Sydney add $8.00. All prices include Sales tax unless stated otherwise_ Tax exemption certificates accepted if the line value exceeds $10.00. BANKCARD, MASTERCARD, VISA, CHEQUES or CASH cheerfully accep.ted. ~ ., 4't'\ Ji1~ ~ ~ ~ E\.f,~ Geoff Wood Electronics Pty Ltd and Semtech Ns W) (inc in 229 Burns Bay Road, Lane Cove West N S W 2066 (Corr.er Beatrice Street) Telephone: (02) 428 411 1 Fax : (02) 428 5198 ~ 8 CJ (i ::0 ~ ~ 8 \) (i ::0 () ;i;; r ~ § ·:n ~ ~ ~ 8 CJ (i ::0 ~ 8 CJ (i ::0 () ;i;; ~ 8 CJ kit. This includes the soldering and accessory tips, including a hot air tip for heat shrinking, and a small stand. All this goes for $64.95 which is a very good price. Both packages are available from your nearest Jaycar Electronics store. Butane soldering irons at a low price Jaycar has two new butane soldering irons which are selling at an attractive price. If you have not used a butane soldering iron before, you will find that they are very useful and convenient. For example, if you working in the back of a TV set or other confined space where you don't want trailing power cords, they are a boon. For service technicians working on airconditioning control panels or security panels, they are great. They are also very handy to use if you are working on your car - no need to have trailing leads from the battery. By the way, although they use bu- tane (ie, cigarette lighter fluid) as the fuel, they do not have a flame. Instead, the tip itself has a catalytic burner which produces the heat. The iron is adjustable so that you can have the equivalent of an iron rated anywhere between 10W and 60W and a tip temperature up to 400°C - equally handy for those delicate or heavy duty soldering jobs. You can buy this new soldering iron in two packages. First, there is the iron by itself which has a 2.4mm tip and a built-in gas lighter (in the cap). The case is transparent so you can see how much fuel is available and you can refill it quite simply. This unit is priced at just $38.95. Better still, you can go the whole hog and buy the complete carry case Compact soldering station from DSE This new temperature controlled soldering station represents a big saving on conventional soldering stations. It is quite small and is intended mainly for soldering components on PC boards. The soldering iron tip temperature is fixed at 310°C and the power consumption is low - 6W at idle and 12W when the element is continuously energised (eg, during temperature recovery after soldering). The soldering tip has an iron cladding which stops erosion (due to copper being dissolved in the hot solder), so you should seldom need to dress the tip. There is one small point that we think should be fixed and that relates to the exit point of the mains cord ANTRIM TOROIDAL TRANSFORMERS New range of thermistors for transformer protection • Now made in Australia. • Standard range 15VA to 2kVA. • Large ex-stock quantities available. • Competitive pricing available for OEMs & resellers. • Simply the best transformers all round. HARBUCH ELECTRONICS PTY LTD 90 George Street, Hornsby NSW 2077. Telephone (02) 476 5854. Fax (02) 476 3231. 74 SrucoN CmP Siemens Matsushita Components has developed a new range of ther:µiistors for protecting transformers. Designated th e C1831 to C1871 series, they provide primary protection up to a rated load oflO0VA. Their maximum operating voltage is 265V and, depending on their type, they are suitable for a rated current of 120-47OmA and for switched currents from 250-990mA. Their diameter varies between 9mm and 22mm. A suggested application is for the protection of transformers for halogen lamps. For further information, contact Malcolm Evans, Electronic Components Department, Siemens Ltd, 544 Church St, Richmond, Vic 3121. Phone (03) 420 7716. First High-Speed IEEE 488.2 Controller for Notebook PCs from the case. This is a little close to the integral soldering iron holder which will normally be quite hot. We suggest that the mains cord be strapped away from this point, for long term safety. Apart from that point, this new soldering station is selling at the very low price of just $49.95. It is available from all Dick Smith stores. Mitsubishi training seminar to be held at Wrest Point The Electronic Technicians Institute of Australia (TETIA) has arranged with Mitsubishi Electric AWA to hold a training seminar at the Wrest Point Hotel Casino. To be held on the 13th and 14th March 1993, the seminar will include sessions on servicing CD players, fax machine theory and servicing, TV and VCR servicing, microwave ovens, and cellular phone theory and practice. Normally, this seminar would only be open to TETIA members from Tasmania but on this occasion it is open to service technicians from all states. According to the organisers , an enquiry to the Taxation Department has indicated that attendance at the seminar is tax deductible as a training expense, including travel, accommodation , meals and registration fees. You will need to check with your accountant on this aspect. For further information on registration and travel arrangements, contact Cliff Townsend, 27 Alma Rd, Orford, Tasmania 7190. Phone (002) 571 266. SC IOtech The Personal488/NB is a compact external IEEE 488.2 interface that enables 170 Kbyte/s IEEE 488.22 control of up to fourteen IEEE instruments from a notebook PC via its parallel port. A virtual PC plug-in board in terms of speed and performance, the Personal488/NB is compatible with both IOtech 's DLL driver for Microsoft Windows and with its DOS subroutinestyle and device driver software. The Personal488/NB also supports third-party data acquisition software packages, such as DADiSP and Labtech Notebook. The Personal488/NB uses FPGA (field programmable gate array) technology to permit simultaneous instrument-control and printer transactions via its connection to a notebook PC's parallel port. The unit can draw power from a notebook PC's keyboard port, a 7 to 15 VDC voltage source, or a standard A/ C voltage source via an included power supply. Portable and Remote Applications. As notebook PCs decrease in price and increase in functionality and power, many engineers are finding them practical, easily transportable alternatives to cumbersome desktop PCs. The Personal488/NB enables engineers to use notebook PCs in IEEE instrument control and data acquisition. It is well suited for vehicle testing, such as aircraft and automobile testing, where physical space is at a premium, and is also ideal for users who require a portable computer, such as test-instrument sales engineers, who can now use notebook PCs to demonstrate IEEE 488 instruments on customer calls. The Personal488/NB is also useful for engineers who need to analyse acquired data away from the test site because it enables the same notebook PC to be used both on-site for data acquisition, and in the lab for subsequent data analysis. This eliminates the time-consuming data transfer processes and cross-platform incompatibility problems sometimes associated with using one desktop PC for testing and another for analysis. ::;CIE TIFIC DEVICES AUSTRALIA PTY LTD ~ Melbourne (03) 579 3622 Fax (03) 579 0971 Sydney (02) 344 5200 Fax (02) 349 2602 Adelaide (08) 281 3788 Fax (08) 281 4194 Product names listed are trademarks of their respective manufacturers' company. ]ANUARY 1993 75 e ALTR. ~ ~ I C ~ e A US TRALIA JL,,, -'-'""'JJ' L,vv WIDE Yet another year has passed us and now it is 1993. Once again we all at ALTRON ICS thank you - our valued customer for your continuous support throughout 1992. Already this new year is promising to be bigger and better with the arrival of many new products in the coming weeks ahead. February marks the arrival of ALTRONIC 'S 1993 catalogue which is su pplied FREE inside this magazine, so be sure to get your copy. COMPONENTS Multi-Station Headset Intercom Kit Mini Home Telephone Exchange Kit This great unit allows you to place calls on hold, intercom other extensions, answer calls from any extension and transfer calls. It is expandable up to 10 extensions, and is com- patible with all DTMF (touch tone) telephones. Operation is as simple as pressing to place a call on hold and press the extension number (0.9) and the respective station rings. Once answered you have a two way intercom w ith which you can announced. call. To pick up the incoming call from hold press #. A neat feature is that all extensions will ring w hen an incoming call is placed on hold for 30 seconds so·that it won' t be forgotten. The basic kit is complete with power supply, case and facilities for 3 extensions. Extra extension boards allow expansion in multiples of 3. Fantastic for home or small office. No more shouting from room to room. Not Austel approved. 0 K 1430 Basic Kit K 1435 Expansion Board '*' $79·95 $189· ° This multi-station headset intercom is designed to provide clear communication in high noise environments such as at race tracks and rock concerts. It is designed to operate with a head phone and mic combination. Each headset requires a station module. Stations are simply connected in a daisychain fashion. Up to 12 units (stations) can operate from the powe~ supply. Features low noise circuity and compares equivalents. Mics can be switched on continuously at one time for hands free operation of all stations. Also includes visual and audio call function. Ideally suited to our C 9055 headset mic and the C 9070 noise attenuating Aviation Headset. K5250 Station Module $74·95 K5255 Power Supply $64·95 1----------------....----------------Beat Triggered Strobe Drill Speed K6010 $39·95 Kit K 5790 $79·0° Controller Kit --,-,-,,-;......-,---:---------==- -.,.,r:-- ?Orr-- - -~ : - - --i Flashes in time with the 2 Way Active K557o$19· 95 Disco Ite aser & Crossover Kit Colour Organ Kit This great new kit enables you to customise your sound system in your car or at home. The Variable speed conmusicor canrun on own oscillator (variable troller for 240V power speed).Output canbe increased with two tube tools includ option. ing drills, _____ _ _ __ _ _ _ _ _ _ ___.power saws, LED Digit Tacho engravers etc suitable for brush type tools up to SA N ot suitable for globes or radiator heaters. Flexible Loudspeaker Protection Circuit Kit Kit (SC Nov '87) Simply plugs into your multimeter. Two ranges of .0022µF and 2.2µF. Ideal addition to power supplies, voltage zoom in to 6 ,.,,..----,,-...,.--,-,-- ----==....--I meters, cursegments of rent, meters interest then etc. It can be save them to disc. The unit has 32K of storage A fun gift for calibrated to memory and a sampling rate of over 600K Christrnas. Wi th accurately read samples per second. Input level of up to 2.5 this project you 2mV, 2V, 200V. Requires 9 volt power supply. Volt. Full sampling rate between 15K s /s to remove the Programmable decimal point. over 600K s/ s. Input impedance of IM ohm. can lead vocals from 1 t 50 K2520 $24·95 'Karaoke' A Designed to rid your nicad batteries of the memory effect and regain full recharge potential. It discharges your nicads correctly to enable a full recharge. Suits most battery packs. Great for mobile phones, battery drills, toys etc. I-Am ___B___d_ ________,,jK1640$24·95 P fi gmg 1--- ..,...------,--------K.2806 PC Software to Suit $19· way to liven up Module for Stereo Sub-Woofer Adaptor ..,..-=,....- .---,. - - - - - - - - - - - - i p a r t y. ·e i,;,K;;,,::1.:.;.1,.;;.;o=-,~~-- -- --'!Amps Kit Kit K 5560 $ 29·95 With this circuit it is possible to quadruple the Get an amazing bass Do output of your stereo amplifier by turning it improvement froi_n your K 2805 $63· lrliiliWiill 95 This great kit is ideal for security applications such as an ignition killer for cars. With an add itional really it easily connects up to either a fuel solenoid . or your car coll. A good way to protect your K1925$44·50 BuyBothfoT :e:~~i~;yGrea This device easily connects up to the combo lock kit giving securi ty a nd keyless easy access to your room. Comes supplied with two facial plates. Requires 12v DC. $75·00 54390$39·95 into one high powered mono amplifier. It uses one J.C. and is easily connected to any existing two channel amplifier. Harmonic distortion. Less than 0.001% <at> 8V RMS. K5565 $1fr80 ster~ system. ~1s fantastlc adaptor srmply "samples" your stereo amp output and provides a single channel output to feed a separate sub-woofer amp. Requires 12V AC or M 9020 plugpack. PHONE ORDER - FREECALL 008 999 007 e A US TRALIA WIDE Electronic Controlled Soldering Station This Month Only T2446 NORMALLY$49 This Month Only COMPONENTS An excellent companion to any of our irons. If you need to de-solder you need one of these. 00 95 $39· PfflffflZiifP'/P Switches * SPST chassis mount. With built in 240VAC Neon light. ea S 3218 .99( T124o$11· 95 Tuning Meters$ Panel Mount 345 · Q0600 Just Arrived - Multi-Purpose Electrical Tester $3· Solder 200g rolls. Mullicore: $7-oo 00 T 1202 0.7mm $8· T 1200 1.0mm Fans Fantastic computer type fans for replacement or additions for extra cooling of power supplies, amps etc. F 1020 240V 80mm' $25·50 F 1030 240V 120mm' $25·" F 1040 24VDC 120mm' $23·"' F 1050 12VOC 80mm' $17· 50 * .ALTRO ~ I C The next best thing to our soldering station is our temperature adjustable handheld soldering iron. Temperature is Self cleaning plunger. regulated via a screw driver adjustment on the handle. Long life teflon tip. Double (Range 250"C to 450"C). Ask about our range of tips to suit. diaphragm $139·95 2 sizes available. All one low price. T1232 4mm T1234 3mm 5 Both 0 e Tl25o$45·00 00 De-soldering Braid L..J""'JJ' vvv Variable Temperature Soldering Iron The micro T 2440 Soldering Station offers the ultimate in controlled hand soldering with a range of pre-selected temperatures. Zero crossing switching protects your components with a 24V element. Excellent soldering results with our earthed chrome plated iron clad tip. T2440NORMALLY $159. ~ Jv,., * This fantastic gadget will test a myriad of electrical and electronic components. It is simple to operate and is sure to amaze you with it's uses. Best of all, it's priced to make it a must for every technician, electrician and enthusiast. It is not much larger than a fat pen and fits easily into your pocket. It tests continuity/resistance (with JO0MQ, S0MQ and SMO: ranges), with buzzer and/ or LED indication. Ingenious design uses your hands and body to check continuity - by a metal tab imbedded into the handle (for one point of body contact), placing the probe tip onto the component being tested and touching the other side of the component with your other hand! Dead easy to use. Will check fuses, light bulbs, wiring, elements, speakers, diodes / LEDS, transistors, transformers and the list is endless. Add to this a high voltage AC test (by touching the contact with the probe tip) and a noncontact high voltage test (check for wires etc. behind or inside a wall/ cable etc etc.) this would have to be one of the most versatile and value for money electronic tester available! 95 Q 1250 Amazing Low Price portable gas soldering irons would have to be this iron.This great new model is excel- lent value Uses standard butane gas as fuel. Easy to use. Easy to refill. Replacement Tips T 2481 1mm Tip $5.95 T 2482 2mm Tip $5. 95 T 2483 3mm Tip $5.95 T 2484 4mm Tip $5.95 T 2485 Tip Wrench $3.50 T 2486 Cutter Tip $5.95 T 2487 Hot Blower $5.95 T 2488 Blow Torch Head $5.95 T 2448 Gas Refill $6.95 $17' T248o$34·95 Famous Labtech 20MHz i:~l°t'U:~ei::t:r:;,ic:e~~:~~tts~~:z~:::;:;:~;~"It:J,!~;:;rs High-Tech Remote Car Alarm 0 Dual Trace Oscilloscope This model is a dual trace 20MHz oscilloscope using high brightness CRT. The vertical amplifiers have high sensitivity of SmV/ div and a frequency characteristic response with smooth roll off exceeding 20MHz. The TV sync. signal operator circuit is provided to ensure stable observation of video signals. Triggering is obtained by sampling the AC power waveform, external waveform or internally generated trigger. Requires Probes. Q 0156 $649·00 Cro Probes Ideally Suited to Q 0156 (2 required). Superb quality DC to 80MHz. Max 600 volts DC. Lead length approx. l.Sm. 95 Q 0175 ea $49· AM/FM PLL Tuner ,--,--..--------, This amazing model features just about everything you could imagine! Multi-function keyring remote control will arm and disarm alarm (and activate central locking if fitted), chirp the horn, tum on the car headlights, panic and even open the boot (if actuator fitted). One remote can control two alarms (in two cars). Other features include starter inhibit, valet mode, central locking interface, . - - - - - - - - - - - - I flashes car indicators when tripped, auto reset, user programmable options plus much more. S 5230 With this simple device you can monitor any door in your house. This two piece alarm consists of a control box and a magnet. The magnet simply onto the door frame while the compact unit can deliver control box is mounted on the a mass·ive 120dB. It condoor, so that they are opposite nects via 3 wires to any when the door is closed. Easy alarm system that has cin to use on/off switch. Built-in output which is normally beeping buzzer sounds w hen negative. Will sound if tripped. Requires 9V battery. the wires are cut. $249·00 Satellite Siren ~~~Yi:$~~~"r : : : ] , L:-';-5•_:~_:_N_:-:-~-:-:-~Y-!'-:-~-9-n_•'_O.t~.:.':;n;Y;"=z=~i:ag==:=;J·:,:::: ~~~:•~ -------------------1 Auto-Ranging Digital Multimeter This neat digital multimeter has all the most used ranges. • Extra large LCD display • Auto ranging • Continuity check • Diode test • Overload beeper indication • Range annunciation • High impact case • One easy to use control• Low battery indication • DC Voltage • AC Voltage 00 Q 1072 $89· Q 1065 Carry Case to Suit $12.50 • t M u ltime er . A great meter just for basic use. No fancy bits and pieces that you won't use. Includes: DC Volts • AC Volts • DC Amps • Resistance • Diode Check • Load test on battery check etc. etc. Q 1056 NORMALLY $53.45 This Month Only $49· verts 12 Volts output. Works well with most electrical equipment. M 8120 NORMALLY $249 00 95 This Month Only $229·00 PHONE ORDER - FREECALL 008 999 007 A US TRALIA e WIDE ~ l..,vv Jl.," ~.AJJ' e A. L TR C> NI C COMPONENTS Palm-Grip Series Hand Tools Uni-Directional Microphone A must for all toll boxes. ALL NORMALLY $9 95 ea T 2710 Flat Nose Pliers 95 T 2720 Needle Nose Pliers This Month Only ea T 2730 Curved Needle Nose Pliers $7· Great general purpose and enter~UY ALL FOR Bargain P, teed! tainment mic.600Q. Fitted with 6.Smmplug. Designed to house amplifiers, inverters, power supplies micro-processor equipment etc. (Mic holder ~ - -- - - ~ ~ -- ~, Built-in mounting posts for PCB's, transformers not included) etc. Ventilated for efficient air-flow cooling. C 0360 NORMALLY $39 50 Extra tough, Super finish front and rear panels. 3 colours available 95 This Month Only $29· H 0490 Grey Case All NORMALLY H 0491 Black Case H 0492 Blue Case $3995 $18] Super Large Instrument Cases * Auto Wire Strippers This Month Only $29· Automatically adjusts to insulation and wire diame- This Month Only This multiple-function l0Hz to 1GHz counter model features 8 digit LED readout, small size, light weight and highly stabilised crystal oscillator for accurate measurement. Q 1535NORMALLY $499 00 CD Cleaner This Month Only $449· We_ are clearing out our CD Cleaners. These cleaners use the corrt'ct motion for removing small surface scrdtches and general dirt and grime. A 9220 NORMALLY This Month Only 8" PECC Woofer Wllh tJ11s Prod11c! You won't believe this one. As we have moved out of the Vila speakers, we have limited stocks of the SA 100 Speaker and cabinet kit sets. Once these kits have gone that is it. No more stocks, You will need to move fast at this price. This - - -- ---------lported two way system now offers even better value for money. C 3270 NORMALLY $799 00 00 This Month Oniy$599· .5" Carbon F oofer $19 50 A high grade speaker with fibre impregnated paper cone, aluminium voice coil and vented magnets. This Month Only A lightweight cone helps to produce a more accurate reproduction of the signal. These drivers also use a kapton voice coil which disap1 - - - - - - - - - - - - - - - - - ' - -- - - -- - - -- ------lpears heat faster than conventional speakers. RatedPower ..... 30WRMS The new power line series of motorola 2I<Hz horn speakers incorporates protection circuitry Impedance ....... .8 ohm which allows them to be used safely with amplifiers rated as high as 400 watts. This results RES Frequency .65Hz Sensitivity ......... 97dB/W (0.Sm) in a product that is a practically blow out proof. QMS .... ....... 3.99 Frequency Response ....... l.8KHz - 30KHz QES .................... 0.43 Average Sensitivity .........92dB <at> 1m/ 2.83V QTS ....................0.39 Max Power Capacity ....... 400W VAS...... .... .... .6.00 Max Tt"mperature ............ 80,C $10·00 This Month Only $10·00 Motorola Power Line Series Rated Power ... 60W RMS Impedance ....... 8 ohm RES Frequency60Hz Sensitivity ........ 98dB QMS ........ .. ......1.81 QES ........ ...........0.38 QTS.... .....0.31 VAS (L) ... ........ 27.8 C 3034 NORMALLY $82 55 95 This Month Oniy$59· Horn Size ......................... 367mrn x 112mm $69 00 . Month Only $54·95 This ifa 100W Speaker · A11 str11lw its f1t't' frt'1ght ,11 95.3mm in diameter Piezo Speaker with a frequency response of 3KHz to 40KHz. Great Value C 6100 NORMALLY $7-95 C 3024 NORMALLY 00 1 - - - - - - - - - - -- -- - - -r- -- $17-95 T 2360 NORMALLY $9700 30mm. 00 This Month Only $69· 95 1 GHz Frequency Counter $8 .95 Cuts holes in metal up to 1.6mm (16 gauge). Set of 5 punches and tapered reamer. Punch sizes, 16mm, 18mm, 20mm, 25mm and * ·cm5$89·95 ·1I111t·~ I oe t. er .A. HEAVY HEAVY SERVICE-All orders of l0kgs or more must travel Express Road-Please Phone (09) 328 J 599, Fax (09) 328 4459 MAIL ORDERS C /- P.O: Box 8350 allow 7 days for delivery. $12.00 to lOkgs. $15.00 over JOkgs. Stirlin Street, PERTHW.A.6849 INSURANCE-As w ith virtually every other Australian supplier, we send goods at con4 STANDARD DELIVERY 6; PACKING CHARGE $3.50 to 500gms, $5.50 500gms _1 kg, $8 signee's risk. Should you require comprehensive insurance cover against loss or damage lkg-5kg AUSTRALIA WIDE-We process your order the day received and despatch via. please add $1.00 per $100 of order value (minimum charge $1). When phone ordering please Australia Post. Allow approx 9 days from day you post order to when you receive goods. request "Insurance"• OVERNIGHT JE'l'SERVICE Up to 3kg is $10.00, 3kg to 5kg is $23.00-We try to process TOLL FREE PHONE ORDER-Bankcard, Visa, Mastercard Holders can phone order toll free your order the day received and despatch via. Overnight Jetservice Courier for deli very up to 4pm Eastern Standard Time. Remember with our Overnight Jetservice we deliver next next day Country areas please allow additional 24-48 hours. day. ALTRONICS RESELLERS Chances are there is an Altronic Reseller right near you-check this list or phone us fo r d etails of the nearest dealer. Blue Ribbon Dealers are highlighted with a • These d ealers generally carry a comprehensive range of Altronic products and kits or will order any required item for you. · * · t.,, :.,.. ~ b ~ _.,· WA - COUNTRY ALBANY ~[;~ttfe~~~~~; .. 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(066) 525684 ::::Jg~; ~llij~ SA - CITY BRIGHTON CHRJSTIES BEACH FINDON HOLDEN HILL LONSDALE Force Electronics• ........ ........ (0 8) 2125505 Force Electronics e ................ (OS) 3770512 Force Electronics e .. ...... (08) 3823366 Force Electronics e ................(08) 3471188 Force Electronics• .............. ..(08) 2617088 Force Ek>ctronics e .. ............. (08) 3260901 NEWCASTLE WARNERS BAY WINDSOR WOLLONGONG WOY WOY Novocastrian Elect.Supplies.(049) 621358 Vilec Distributors ...................(049) 566792 M & E Elect. and Comm ........ (045) 775935 Newtek Electronics e ........... (042) 271620 Vimcom Electronics .............. (042) 284400 Alphatran Electronics ........... (043) 434919 PHONE ORDER-FREECALL 008 999 007 Panasonic's super-quiet dot-matrix·printer If you thought dot-matrix printers were aHnoisy, then think again. Panasonic's newly released KXP2624 dot matrix printer is a great deal quieter than its competitors & rivals the noise levels of many ink-jet & laser printers. By DARREN YATES With the inroads that laser and ink jet printers have made into the market, you could be forgiven for thinking that the humble old dot matrix printer was in its last days. But there is plenty of life left in dot matrix technology. Not only is the dot matrix printer generally cheaper to run then other printers, it can also be faster to print out a single page than most laser models. When it comes to printing out multipart forms such as invoices , statements, delivery dockets and any other application where duplicates or triplicates are required, the dot matrix printer is still the only choice. Other applications where the dot matrix printer is the first choice would be for the printing of adhesive address labels with tractor feed backing, for fixed layout forms or where forms larger than the A4 format are required. However, dot matrix printers have always been noisy. So much so that in most offices large dot matrix printers are generally installed in a separate room or underneath a sound reducing hood. This new model from Panasonic is so quiet that it can sit right next to the computer, just like a laser or ink jet model. The Panasonic KX-P2624 is a wide carriage 24-pin printer which has multiple fonts and flexible paper JANUARY 1993 79 One big benefit of a dot matrix printer is low running cost. The only part that needs to be replaced on a regular basis is the ribbon cartridge, pictured here. This one is rated for three million characters. ing features of the KX-P2624 are sehandling. The improvement in noise level comes from the new diamond lected from menus displayed on a 16shaped print head and the way in character LCD screen on the front panel. This forms part of the Easy Set which the pins print each character. With conventional 24-pin print Operator Panel which enables conheads, each character is printed as a trol of all printer functions. The front panel has seven memmatrix of dots which is produced a column at a time. The 24 pins are brane switches, most of which peractually arranged in a zigzag column form dual functions. The first three and the characters are produced as a are "Super Quiet", "P.Cut", and "TOF SET". These are manual control number of columns of dots. For example, a 24-pin dot matrix switches which set the printer into Super Quiet mode, advance the paper printer operating in draft mode may produce characters as a 12 x 24 dot to the perforation cut mark, and set matrix with the print head taking four the Top of Form mark on the page. The other four membrane switches or five sequential hits. Now while are the standard 'On Line', 'Form Feed' this process of hitting the paper four and 'Line Feed' controls. The final or five times for every character is not as noisy as with daisy wheel printers, switch is the FUNCTION control. it is still very noisy. And when the When this is pressed, the printer then printer is running at 300 characters enters its menu selection mode. per second or more, it amounts to Three LEDs in the centre of the quite a racket. · panel are used to indicate the status of the printer. The top green LED The difference with the KX-P2624 shows the printer's ON LINE status is that the 24 pins of its print head are not arranged as a staggered column and flashes when it is in function but as a diamond array. This means mode. The second green LED indicates when the Super Quiet mode is that instead of having groups of pins on, and the third red LED indicates hitting the paper four or five times, the pins hit the paper in a wave like · power and when the printer is out of sequence as the print head moves paper. along the carriage. The result is a lot Function mode less noise. This mode allows you to set up all Operating features the printer's parameters before you So what else does it do? As with start printing. The first message that many printers these days, the operat- appears on the LCD is MACRO MODE. 80 SILICON CHIP In this menu, you can save the current settings in one of four memories and select any one of these four to be loaded when the printer is turned on. To thumb your way through a submenu, the P.Cut switch doubles as the ITEM switch. Pressing this allows you to go down a sub-menu step by step. The FF and LF switches also permit this but in both directions; ie, down (LF) and up (FF) the menu. Making a selection in any one of the sub menus is done by pressing the TOF SET/SELECTION switch. This takes you through the possible choices with an' =' sign appearing next to the current selection. To make a new selection, go through the selection choices until you get to the one you want and then press the ON LINE/SET menu. The printer will then beep to acknowledge that the selection has been made. Printer emulation The second of the main menus is Emulation. The KX-P2624 can emulate either an Epson LQ-1050 or an IBM Proprinter XL24E. This allows you to work with either printer's command (ESC sequence) set. The default setting is Epson emulation but to change this you simply hit the ITEM switch and then change the selection by pressing the SELECTION switch. You then press the SET switch and the new selection has been made. Print styles This menu controls the font and the pitch of the type. You can choose from Draft, Bold PS, Courier, Orator, Prestige, Roman, Sans Serif, Script and Super LQ (Letter Quality) ranging from 5 to 20 cpi (characters per inch). Text enhancement can be added to any font, including bold, double high, double strike, double wide, italics, outline, shadow and zero slash. Print mode This menu controls such functions as the print direction for both graphics and text, as well as the print width, which can be set to either 8 or 13.6 inches (ie, 136 columns at 10 cpi). There is also a PANEL LOCK sub-menu. This determines whether or not the Function mode settings for pitch, font and other functions override software derived settings. This is useful when you wish to print from a word processing package in say, SLQ mode, and Panasonic KX-P2624 Dot Matrix Printer: Sound Levels Mode Draft Super Letter Quality Standard 47dBA 45.1dBA Super Quiet 43.?dBA 43.2dBA quite a problem if you are printing out an invoice run, for example. Single sheet paper and envelopes are accommodated by raising the paper bail and setting the paper feed selector to the friction position. Paper parking the package doesn't support it with software controls. Page parameters such as lines/inch, page length and top, bottom, right and left margins are controlled using the Page Format menu. The number of lines per inch can be varied from 1 to 12 in steps of0.5 in most positions. Page length is variable from 0.1 to 14.9-inches in 0.1-inch steps, the top margin from O to 2.5-inches in 0.5inch steps, bottom margin from O to 4.9-inches in 0.05-inch steps, left hand margin from 0-134 cpi in 1 cpi steps, and the right hand margin from 2-136 cpi in 1 cpi steps. You can also select the centre position for the print head from 10 to 80. The Character Set menu allows you to select one of 14 mainly European language character sets, as well as from the three resident special sets (Italics, GRAPH1 and GRAPH2). Install menu The Install menu sets up initial parameters including: (1) alternative graphics mode for IBM emulation, on or off; (2) auto carriage return for IBM mode, on or off and (3) auto line feed, on or off. You can turn the internal beeper on or off, while other parameters include setting the data length to either 7 or 8 bits, turning off the paper out detector, quiet mode and reverse line feed in pull mode, on or off. The paper's perforation can also be made to move to the tear-off position manually or automatically and there are options for a sheet feeder and a 32K RAM package. Like all impact printers, the KXP2624 has a manual print head gap adjuster lever which allows you to vary the gap between head and platen (roller) for different paper thicknesses paper, up to the 0.013-inch maximum. This is important if you are printing in duplicate or triplicate. Using the macro mode So what if you wanted the printer to come up in your own defined mode with margins, fonts and other selec- tions in place ready to go. How do you do it? This is actually quite simple. You simply set up the printer as you wish, going through the various menus and their selections. Once you've done that, you go back to the MACRO MODE menu and select the SAVE MACRO option. This will store the current settings in one of four memories. You then go to the POWER ON MACRO selection and cycle through until you get to the memory where your setup parameters are stored and then press the SET button. The printer will now come up with these options each time it is turned on from now on until you change the POWER ON MACRO. Paper feeding The KX-P2624 has a number of ways of feeding in paper. You can feed paper from the rear using the tractor push option or from the front using the tractor pull option. Push tractor feed is usually used where the paper is single sheet. It also gives you the option of auto tear-off. This allows you to feed the paper through to the perforation mark at the finish of printing, tear off the page, and then feed back the paper to the top of form mark. This is great for minimising waste but when multipart forms are being printed it is often better to use pull mode to reduce the possibility of a paper jam (this can be One very useful feature is automatic paper loading and parking. This does away with the need to unload tractor feed paper when you want to print a single sheet using friction feed. Upon setting the paper bail release lever to park/load, the printer reverses the tractor feed paper back to the park position. If you then set the paper feed lever to friction feed, the tractor feed is disabled and a single sheet of paper can be loading in for printing. Once the page has been printed, the paper feed selection lever is returned to tractor feed and the paper bail lever returned to load/park. The tractor feed paper then returns to the previously set top of form. While not unique to the Panasonic KX-P2624, this feature is very handy. The instruction manual is well laid out and describes all operations of the printer and the IBM and Epson escape sequences. Conclusions In summary, the Panasonic KXP2624 is proof that there is a great deal of life yet in dot matrix printers. As well as being a highly flexible printer, it is very quiet in operation what more recommendation could you want? Its recommended retail price is $1299.00. For more information on the KXP2624 or any of the range of Panasonic printers, contact Panasonic Australia on (02) 986 7629. SC VIDEO & T.V. SERVICE PERSONNEL TV & VIDEO FAULT LIBRARIES AVAILABLE AS PRINTED MANUALS $85 +P/H BOTH MANUALS T.V. & VIDEO $145 +P/H OR AS A PROGRAM FOR IBM COMPATIBLES OR AS AN APPLICATION PROGRAM FORD-BASE Ill PLUS FOR MORE INFO. CONTACT TECHNICAL APPLICATIONS PO BOX 137 KENMORE 4069 OR FAX/PHONE (07) 3781064 JANUARY 1993 81 . 1:.... ' ." ' : . ,, ,~ The Story Of Electrical Energy, Pt.22 While Sydney Council generated its own power from 1904, the Railways & Balmain power station provided a big share of the load in years to come~ The privately owned Balmain station was particularly innovative & continued to run until 1973. By BRYAN MAHER Sydney Council's electricity supply undertaking got off to an au.spicious start in 1904, but' it soon had a battle on its hands. The first real expansion into suburbia took place in 1910. The councils of Annandale in the west, Mascot to the south and Woollahra and Randwick in the east all agreed to supply electricity to 82 SILICON CHIP streets, homes and businesses. Long distance transmission to Long Bay Gaol prompted the council's first rise in transmission voltage to 1 lkV and this was completed in 1911. So busy was the Council Electricity Department with suburban extensions that the work ofreplacing the remaining city gaslights lagged and was still incomplete in 1913. This prompted calls for a slowing-down of suburban work. In the midst of these delays, the long-established Redfern Municipality Electric Supply undertaking was actively pursuing business. But then came an entirely new challenge. In 1908, a brand new private enterprise, the Balmain Company, was formed, with the full title of "The Electric Light and Power Supply Corporation". This was no small amateur competitor but was a large, professional engineering organisation, a fierce commercial adversary. Newtown Council rejected Sydney City Council's overtures and opted to buy electricity from Balmain. In quick succession, Leichhardt, Ashfield and Petersham municipalities gave the Left: a classic photo of Ultimo power station taken in 1915. Six turboalternators are pictured here but the original 1.9MW Parsons turbine is out of the picture. Balmain Company exclusive rights to electrify their suburbs. At the same time, the North Shore councils sought to set up their own power stations. Sydney Council's dream of a huge electricity system was in grave danger of being boxed in by competitors! Fast expansion or extinction seemed the only choices. By 1913 the Redfern Electricity enterprise and the remaining city generating company sold out to the City Council. But the Balmain Company was to remain in the picture for years to come. Tungsten filament lamps The original incandescent lamps of Swan and Edison used carbon fibre filaments operating at bright red heat. These were very wasteful, giving mostly heat and little light. The advent of tungsten wire filaments iii 1910 allowed a much higher operating temper::iture, giving more light output per watt. 8ne candlepower per watt of electricity was achieved. This was 13 times more efficient than the old carbon filament lamps. Despite the reduction in electricity consumption per lamp, the load on the council power station continued to increase. By 1914, Pyrmont's output had increased fifteenfold to over 22MW and 10,000 customers. World War I The war years created grave problems for the council's electricity undertaking. In June 1914, a new German-made turboalternator of SMW capacity failed after just three months service. The A.E.G. turbine suffered damage to one blade wheel, requiring replacement parts from Germany but war broke out before they could be shipped. Therefore a replacement turbine was ordered from the British Westinghouse Company and delivery promised within a year. In the meantime the spare blades for the German machine turned up in Sydney Harbour aboard a Swedish ship, Sweden being neutral in the conflict. The Westinghouse order was This was the scene at Ultimo in 1950. A turbine attendant reads the recording instrument panel and logs the steam pressure, condenser vacuum, cooling water temperature & bearing oil temperature & pressure. Turbine attendants worked 8-hour shifts and did not leave their machines during this time. promptly cancelled by agreement. But the new German turbine blades ran for only 10 days and again failed, the rotor blades hitting the stator blades when on load. Desperate to keep the system going, the council engineers took an unusual step. They simply removed the offending blade wheel and let the turbine run with one less set of blades. Though 15% less efficient, it worked. No new generators were installed at Pyrmont until 1921. Railways to the rescue So critical was the power shortage that in 1916 the City Council asked the Railway Commissioner to supply electricity from the Ultimo power station. A 2-year contract was eventually signed for the supply ofup to 4MW of power. Initially, a 6.6kV 25Hz cable was run from the tramway substation in Jamison Street to the City Council's substation almost next door at Lang Park. To make use of this railway power, the City Council purchased transformers and two rotary converters from the USA. These changed the railway's 3-p hase 25Hz AC supply to 480/240V DC for use in city shops and apartments. By April 1919 increasing quantities of 25Hz AC power fro m the railways power stations was supplied to a new City Council substation in Castlereagh Street. The city and suburbs were becoming increasingly dependent on electricity generated at the Ultimo railway power station. Indeed, the then minister for local governm ent preferred th e railway department to supply bulk electricity to outlying suburban councils, who in return would reticul ate power to homes and industries. The reasoning was logical - tramway current load occurred mostly in the morning and evening peak hours. During the day an d at night, the railway power station at Ultimo was only lightly loaded, just when domestic and industrial load was at its peak. Sharing power seemed sensible. Steam turbines introduced Fortunately, when one technology reaches its limit, it sometimes coincides with the practical realisati on of the next. This situation occurred in 1904, with steam reciprocating engines reaching their zenith and steam turbines app earing on the scene. Because of their much higher speed, steam turbines coul d produce much more power at greater efficiency than their reciprocating counterpart. Also JANUARY 1993 83 were purchased, designed to run at 50% overload during peak hours. Running at 750 RPM, they were directcoupled to 4-pole 25Hz alternators. Both were running by 1909, though one machine had to survive a shipwreck on the way out from England. Continued demand for both tramway and city power led to a further 5MW turboalternator being installed in October 1911. This WillanRobinson turbine was called a "disc and drum" type, being a combined impulse and reaction machine. The 4-pole alternator was manufactured by Dick Kerr and Co. The installation of these three turboalternator sets more than trebled the output of the station, from 7MW in 1903 to over 23MW by 1911, making Ultimo the most powerful electricity generating station in the southern hemisphere. These turboalternators at Ultimo power station were made by Standard Waygood Ltd & were commissioned in 1923. Each machine produced 2.5MW 3-phase power at 50Hz for signals, lighting and bulk supply. Taken in 1905, this photo shows the first Parsons turbine installed in Australia, at the Ultimo power station. It was a great deal smaller but much more powerful than the huge reciprocating steam engines which preceded it. because of the higher revolutions, the alternator produced more megawatts for a given size machine. The Parsons works at Newcasth: on Tyne, England, produced the first steam turbine used for electricity generation in the southern hemisphere. This 3000hp (2.24MW) turboalternator set was installed in Ultimo power station in 1904 and was in service by 9th January, 1905. This unit ran at 84 SILICON CHIP 1500 RPM to drive a 2-pole 25Hz alternator, producing 1.875MW of electricity at 6.6kV. It became the precursor of all future designs in power stations. Never again would engineers think in terms of reciprocating engines. The continuing rapid expansion of Sydney's tramway system led to more Parsons turboalternator sets being installed at Ultimo. Two 5MW machines First Sydney Harbour Tunnel The idea of tunnels under Sydney Harbour is not new and you may be surprised to learn that the recently opened traffic tunnel is not the first tunnel under the harbour. So fast did the North Shore tramway system expand between 1902 and the following decade, that difficulties were soon encountered in keeping enough 6.6kV submarine cables in service. The cables originally laid on the floor of the harbour were of 3-core construction, each core having 3 7 strands of 16SWG copper. The lead and jute sheathing was not entirely successful in preventing the ingress of sea water and a few cables were also destroyed by ship's anchors. Therefore, the Railways Department dug a cable tunnel under the harbour, from Longnose Point to Greenwich. The construction of the tunnel was commenced from a point near Louisa Road in Birchgrove, close to Snail's Bay. Simultaneously, a complementary dig was begun on the north side of the harbour at Greenwich near Manns Park. The two digging teams met in the middle below the harbour. Leaky tunnel An expensive construction, this tunnel was large enough for a few men to walk abreast and was lined throughout its length. The walls were fitted with racks in which rested many 3-phase 6.6kV cables. By this means, AC high tension supply was provided for all tramway substations on the north shore. The under harbour passage was electrically lit but electricians who worked down in the depths found it a foreboding place. The sound of boats' propellers in the water above could be clearly heard as could the shuddering thud of a ship's anchor being dropped. Many more 6.6kV cables were laid in this tunnel between 1924 and 1925 to supply the new 1500V DC substations at St Leonards and Gordon for the electrification of the north shore railway. However, water seepage in the tunnel was always a problem and so it needed to be continuously pumped to prevent flooding. Once the Harbour Bridge was opened, the underwater cable crossing· was no longer needed. Eventually, the Railways Department abandoned the tunnel to the invading seawater. 50Hz generation at Ultimo The 25Hz current used by the tramway rotary converters and induction motors was unsuitable for lighting, due to the obvious low frequency flicker. By 1915, the Sydney tramway system was so complex that electric lamp signals were necessary. In that year, a Bellis-Norcom 75kW turboalternator was installed at Ultimo. This generated a 2.2kV 50Hz 3-phase supply, coming on line on 15th July 1916. At vital points in the city and inner suburbs, small transformers reduced this to 120VAC single phase for lighting signals and waiting sheds. Further 50Hz generators were quickly added, one of120kW and two of ZZ0kW capacity. So fast did the system grow that by 1921 those four machines were scrapped, to be replaced by four turboalternators each of 2.5MW 50Hz rating, including two units made in Sydney by Standard Waygood Ltd. Later, between 1925 and 1928, White Bay power station had installed four much larger 50Hz 1 lkV generators, taking over the bulk supply role to Sydney City Council, municipal councils and outlying towns. Thus, high frequency generation at Ultimo was no longer needed and all four 50Hz machines were removed. White Bay power station had been opened by the Railways Department in 1913, initially as a 25Hz supply r. Ultimo power station included an AC/DC substation with five lMW rotary converters. This converted the 25Hz AC supply to 600V DC for trams in the Ultimo area. source. The Standard Waygood works also turned out larger steam turbines and alternators for that plant. The No.4 and No.5 turboalternators for White Bay, both 18.75MWunits, were under construction during 1925/27. These machines were designed by English Electric through their Australian counterpart, Associated General Electric Industries. The heavy casting and machining was shared between Standard Waygood Ltd and Cockatoo Island Dockyard. The alternators were also wound in Sydney. Both were 6.6kV 25Hz units, the largest low frequency machines ever installed at White Bay. Independent Balmain The Electric Light and Power Corporation, an independent private company, secured the franchise to supply the borough ofBalmain in 1906. Consequently, two small reciprocating steam engine driven generators were installed on the eastern bank of Iron Cove. Operation commenced in 1908, beginning one of the longest-lived private generating concerns in Australia. The service area was soon extended to include Newtown, Petersham, Ashfield and Leichhardt and so the generating system was quickly enlarged to become the Balmain A power station. By 1923, Balmain A was a well engineered 10MW system of turboalternators and boiler equipment. Situated immediately north of the Iron Cove bridge on Victoria Road, between Terry Street and the water, the station buildings soon became a well-known landmark. Later Balmain supplied power as far afield as the Parramatta, Granville and Dundas areas, taking over from an earlier generating station at Parramatta. Risky shipping Because Balmain's service area included many industrial and shipping facilities, continuity of supply during World War 2 was vital. Coal and coke were burned, originally supplied by ship from the Newcastle coal fields. Throughout the war years of 1942-45, little colliers such as the William Macarther and Hexham Bank dodged attacks by Japanese submarines. The technique was for the coal ships to ply between Newcastle and Sydney so close inshore that enemy submarines were not game to follow. The smallest of these colliers had such low freeboard that they were almost impossible to spot. The view through an enemy periscope was confused by the background hills of the shoreline, preventing a clear silhouette for torpedo aiming at the slow moving col~ liers. By 1942, Balmain was running turbines rated at 18.75MW, 12MW and 9MW. All of these turbines were driven by steam at 225psi (1550kPa) and 3 70°C. The total installed turboalternator capacity was 39. 75MW but boiler capacity totalled only 27MW. JANUARY 1993 85 L " 1J1! I ::i 2 ·9 Balmain power station was Australia's largest privately owned electricity generating station. It began operations in 1906 in the building at extreme left & progressively expanded to lOOMW capacity. It ceased operation in 1973. tor. Instead, the secondhand unit was transferred to one of the railway's smaller power stations to extend its service life. The inevitable result was that Newcastle used mostly secondhand generators, rotary converters and so on. From 1928 onwards, Ultimo power station only had 25Hz alternators. To provide a standby systeip, a frequency changer was installed at Ultimo in 1937. This 2MW unit consisted of a 6.6kV 25Hz synchronous motor directly coupled to an 1 lkV 50Hz alternator. A belt-driven DC generator supplied the rotor fields of both units. This frequency changer was also secondhand. It had previously served to link the 25Hz and 50Hz systems at Zarra Street power station from 1922 to 1936, until replaced there by a much larger 7.5MW machine. The ultimate Ultimo Clearly more boilers were needed but the company took an approach new to Australia for that time. In a bold step, Balmain installed the highest pressure boiler then seen in Australia, generating steam at 1250 psi (8600kPa) and 490°C. The huge boiler towered 26 metres high, with the 25-tonne drum of forged chrome molybdenum steel mounted 16 metres above the firing floor. The first new 9.375MW turboalternator went into service in 1946, the first "back pressure" machine ever installed in Australia. This machine received steam at 1250psi from the high-pressure boiler and exhausted spent steam at 225psi and a temperature of 370°C. The exhaust steam, the so-called back pressure, was used to drive one or two of the old turbine sets. High efficiency The efficiency of any steam engine depends on the difference in temperature between inlet and exhaust. In the multiple turbine scheme, the inlet to outlet temperature difference is measured right across the high and low pressure machines. Thus, the efficiency of both machines is quite l\igh. Taken together, the 9.375MW high pressure and 18. 750MW low pressure units generated a total of 25.5MW. The condensate water from the low pressure machine condenser was then pumped back into the high pressure boiler to be converted to steam. 86 SILICON CHIP The purpose of the Balmain scheme was twofold: to increase plant capacity and to improve efficiency by enabling old steam turbines to operate within a higher temperature steam cycle. The combined high and low temperature turbines achieved a 50% increase in power output using only 8 % more fuel. Three more 25MW high pressure turboalternator sets and more boilers were later installed at Balmain. The total capacity in 1956 was just over lO0MW and it continued supplying electricity until 1973. Railway alternator swaps Meanwhile, back at the railway's power stations, further modernisation was in progress. Of the four 50Hz generators running at Ultimo since 1921/23, the two Willan-RobinsonDick Kerr units were scrapped in 1928 but the two Australian-made alternators were reinstalled elsewhere. No.1 went to Zarra Street power station in Newcastle in November 1925, where it helped supply that city until 1930. After that, the turbine was removed and reinstalled at Lithgow power station. The No.2 machine became the inaugural generator at the new Lithgow power station which was opened in 1928. These are examples of the musical chairs played by the Railways Department. Their philosophy was not to scrap an old machine when it was to be replaced by a new, larger genera- By 1950, Ultimo had reached its greatest output of 83MW, generated by just four turboalternators. They occupied the large turbine hall which had originally been built to house six huge low-speed vertical reciprocating steam engines and alternators. These would have generated a total of only 9MW. Ultimo was closed by the newly formed Electricity Commission in 1963 at the same time as trams were phased out, leaving White Bay to carry the railways and the bulk supply load. The 65-year history of Ultimo was an accurate reflection of the development of electric power generation. At various stages, Ultimo included nearly every type and class of electricity generation equipment. And on many occasions, it lead the way in size, capacity and technology. Thus, it is fitting for this station to now be the Powerhouse Museum. Sadly, little of the equipment remains today. Acknowledgements Grateful thanks to the SRA Archives and the Trustees of the Sydney Museum of Applied Arts and Sciences for the photographs used in this article. Acknowledgements also to Don Godden et al in "Ultimo Power House; Report on its History and Technology"; also to Victor Poljanski, Arthur Perry, W. H. Myers, G. F. Anderson, P. Smythe, P. Tweedie, J. Brearley, Pacific Power and the Public Works Department of NSW. SC IAN J. TRUSCOTT'S ELECTRONIC WORLD 30 Lacey Street, Croydon, 3136. Phone (03) 723 3344; Fax: (03) 725 9443. Now also at: 200 Smith Street, Collingwood. Phone (03) 419 8208 Mail & Credit Card Orders Welcome We now have a range of 5,6,8,9 & 10 pin Ask about our range of E.A.O. precision resistor networks and a comprehensive push button switches, motor start range of micro's and eproms at ridiculous capacitors and Beckman Industrial prices. Quote this ad and receive another multimeters. 5% discount. $16.80ea. 27C010-15 1 meg eprom 150ns...... .$8.I0ea. SAB8031 P Romless Micro ........$2.S0ea. MAB8049H Rom less Micro ...... .$2.S0ea. 62256-LP S-Ram ..................... $9.75ea. 41256 D-Ram ................................. $2.60ea. 27C020-15 2 meg eprom 150ns... . ·, $1•19 NQYEMIERSPECIAL: . BECKMANDM15XL Multimeter . ·.. $10.00 ea. 3mw Laser Tube & inverter $99.00 ea. 6 volt 1 watt Solar Panels Infra Red Night Viewing Monocular (kit) $269.00. COMPONENT PHONE ORDER HOTLINE (03) 723 3344 ON SALE NOW First edition Vintage Radio Calendar, in full colour. Featuring a selection of ' Australia's most photogenic radios. Ideal Christmas gift for friends and collectors overseas. Available from Resurrection Radi CREDIT CARDS ACCEPTED 51 CHAPEL STREET, WINDSOR, VIC. 3181. PHONE (03) 529 5639. ]ANUARY 1993 87 AMATEUR RADIO BY GARRY CRATT, VK2YBX Radio signal monitoring from all over the .world Imagine this scenario: you are the manager of Radio Australia and you want to monitor your signal in Tokyo or any other designated target area. Now with a new remote monitoring system developed in Australia, you can do this task merely by picking up the phone. One of the major problems experienced by HF commercial and amateur users alike, located in a typical high density urban environment, is overcoming the massive amount of man-made noise masking HF reception. Apart from aligning antennas to minimise this effect (often reducing the optimum signal level), there appears little the HF operator can do to eliminate this problem, other than move the location of the receiving station, a rather inconvenient proposition. If the problem is difficult for amateur radio operators, consider it from the point of view of an operator such as Radio Australia, the BBC or Voice of America. them to develop the Radphone 2000DX, the latest in a series of intelligent interconnect units. It is capable of being located in any area offering good RF reception and provides dial up access via a telephone line. This unit allows radio receivers (or transceivers) to be located in a rural environment, free of RF interference and chosen to provide optimum service area coverage. The Radphone 2000 interconnect can be configured with a variety of software options and interface boards to suit various commercial transceiv- System operator The Radphone 2000 Recently, after several years of development, a practical answer to this problem was devised by Philip Collins and Associates Pty Ltd, a Sydney based electronics engineering group having a close association with Codan, one of Australia's prominent manufacturers of HF radio equipment. The considerable RF experience they had gained from the development of earlier generations of intelligent telephone interconnects for the RFDS (Royal Flying Doctor service) and outback business users allowed 88 SILICON CHIP ers and amateur receivers, including Yaesu, Kenwood and Icom models. The communications equipment is connected to the Radphone 2000, which in turn is connected to the telephone line. Users are then able to phone into the Radphone 2000 and control receiver or transceiver functions using the keypad of any DTMF telephone. A typical station consists of one or two LF, MF, HF, VHF or UHF communications receivers, together with the appropriate antennas, installed at a suitable site and connected via a Radphone 2000 to a telephone line. Access to the system is restricted to authorised users with a 7-digit PIN. It is possible to select between two receivers, enter a receive frequency and mode, and then step the frequency up or down in various increments, change IF bandwidth, change sideband, etc. A digital speech synthesiser advises the user of the current frequency, mode, signal level and so on. Fig.I: the Radphone 2000 is controlled using a standard DTMF telephone keypad. This diagram shows the functions of the various buttons. A digital speech synthesiser advises the user of the current frequency, mode, signal level & so on. One local user is designated as a sysop (system operator) and has full access to all the system features. The sysop can change the system configuration, add or remove user PIN numbers, and change system default values. This can all be done from a remote Jocation using a DTMF telephone and voice synthesiser prompts. No PC or modem is required. For on-site parameter verification, the Radphone 2000 is equipped with a 40-character, 2-line LCD and a 16button keypad. A logging printer can also be connected to record system use. In addition, the on-board microprocessor provides the necessary This photo shows the Radphone 2000DX/f in a typical monitoring setup with two receivers. The Radphone can .be called up by phone from any part of the world for a report on signal reception & can be used to remotely control a local transmitter. housekeeping functions for auto ring detection for call connection, detection of loss of telephone line current, and detection of service tones for call disconnection. There are two important functions to which the Radphone 2000 can be put, which are not immediately obvious. Firstly, the unit can be used to provide real-time signal evaluation of shortwave broadcasts directly from the target country, allowing international broadcasters to immediately assess reception or interference on existing or proposed frequencies. Secondly, in the "electronic news gathering" role, users can listen to a local broadcast station from a remote location to obtain instant local news on current events. There are other applications, such as use of the system by law enforcement agencies as an RF surveillance aid, and remote spectrum monitoring by statutory authorities. The system has already been purchased by various overseas broadcasters such as the BBC and Voice of America, foreign embassies, and RF monitoring organisations. Typical scenario For those still not convinced, imagine the following scenario: a user dials the phone number for the Rad- phone 2000 service. The system answers the call and announces "enter identification number". Our user enters his personal 7-digit PIN, using his DTMF keypad. The Radphone 2000 announces "Welcome to Radphone 2000, receiver one, eight decimal eight six seven megahertz, upper sideband". At this point, the user hears several transPacific airliners advising Hawaii air control of their positions, mid-Pacific, between Australia, and Los Angeles. This default frequency has been programmed by the sysop. Our user wants to listen to Radio Australia on 11,800kHz, so he keys in "11800". The Radphone reads back the frequency as "one one decimal eight zero zero megahertz, upper sideband". In order to select AM, our user presses the "2" digit repeatedly, to cycle. through AM, SSB and FM modes. Following each key depression, the speech synthesiser advises the receiver mode. Having selected AM, our user depresses the "3" key to toggle from wide to narrow IF bandwidth. Reception is good and our user listens to Radio Australia for several minutes. Our user then decides to scan the 20-metre band, to check ori any activity. Having selected 14.100MHz USB as his starting point, he repeatedly presses the "4" key, incrementing the receiver frequency by 1kHz. Scanning his preferred segment, and hearing a group of familiar stations, our user keys "O", then"*" , activating the transmitter VOX circuit. Announcing his callsign, he converses with several stations during the next 10 minutes. Signing off, our user then decides to check for UHF activity. By depressing the "1" key, he commands the Radphone 2000 to select receiver 2, a Yaesu FRG9600. Knowing the output frequency of his local UHF CB repeater, he listens to several truckies discussing weather conditions as they pass through his home town on the Hume Highway. After monitoring the frequency for several minutes, our user arrives at Los Angeles airport, terminates the call to Australia, switches off his cellular mobile phone, and walks to the Qantas check-in for his return flight home. Despite 6ur fictitious situation, the Radphone 2000 is capable of all the functions described above and more. For further information on this amazing system, call Philip ColliI1 s and Associates, phone (02) 416 8799 or fax (02) 416 8761. The company operates several remote sites in Australia and can arrange on-air demonstrations to interested parties. SC ]ANUAR Y 1993 89 iG ELECTR0N1cs ROD IRvING ELECTR0NIcs ROD IRvING ELECTRoNics Fioo iiivioo ELECTRONics Fioo IRvING ELECTRONICS ROD IRvING ROD IRvING ELECTRONICS ROD IRvING ELECTRONICS 1G ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROO IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING IG ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROO IRVING ELECTRONICS ROD IRVING 1G ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROO'IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING JG ELECTRr . ........................ ,,....,, .. ,.... ,..., ,...,....,..., ...... ,,,.."' ..,,..."' 1nH1a. 1,.. r-1 r-,..Tnn a. 11r~ nnn 1nu1.. ,n c1 crTon~ll"C onn 10\1111.1n c1 crTon 11.11rc onn ID\lltJ~ c1 crT ~ 1ll"c DfV"I 1D\11t..an q ()Q IRVING c1 cr-TOntJ V"" C., PACK & POST FOR MAILORDERS OVER $25.00 & UNDER 5 KG. OFFER EXPIRES MIDNIGHT 31/1/93. IGELECTRI FREE IOOIRVING 1G ELEc· ,·'·" ··· " "·" · ... , .. ,.·. · · ··•····.. · · · · · · · · · · · · · · · · · · · · · · · .. · · · · · · · · · · · · · · · .... · · · · · .. · · ·..... ... .. · · ·· · · · .. · · c·~ ~ · · .. ., .. --- -· ·· · ·- · ,. . .. · ·.. · ... ·•·· · ............ ... . · .... ... ·,. ....... · .. · .. ., •· ..... , .. ,. · ··• .. ··· ·· · ... .... ..... ··· .. ·, ,. ..... ,....,,,.,·.,·, ,., ": .... .. ..... ,·, ... .. ..., ')Q IRVING J!mr RITRON QUALITY 4 year warranty! 1i1~1~; :~~~~IVE IG ELEC. .. ,..--, E~~~~~. . "<;=aa==o! . :! it!g:*8~B~~s~l o 1 b~ :::l!IJ/ IG ELEc·· 80386SX 25M CPU /.;!~ 1G ELEC" 2 MEG RAM EXP TO 8 MEG '----;;;..;;..=:, G ELEC" 31Mhz LANDMARK SPEED TEST r------, .G ELEC" 1.2MJAPF.D.D. 512KVGACARD NOW ,G ELEc· 40M HARD DISK DRIVE, WITH . 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IG ELEc· IN AUSTRALIA. 3 ELECl Add $40 for a 386SX-33/41$1099 TAX EX Mt:G RAM 2 $ 3 9 1 1 ..,.,,.,,,,,,,,,,..,.,.,.....,.,,,,,...,.,....,,,,.,_ ~ Ill ~§e!§~ w ~.c.,. r =~tt~~E~ ',;==-;:,/ · •• 1~ . 80386-33 CPU •• ~~:t:g ~o~:;~ $1 '3 99 126M HD add $210 105M HD •• $175 170M HD.. $ 275 } lM add $89 2M add $138 4M add $278 SOUND CARDS ( ··· =-z"""-"-=-_,.......,......., / SOUND COMMANDER FX •.••.••••••••••••.•••••• $159 \ SOUNDBLASTER U with lpeakers........... $149 ) SOUNDBLASTER PRO ••••••••••••••••••••••••••••• $369 \ 21 FI.OPTICAL J?RIVE add ••••••••••••••••••••••••••• $849 M/BYTE DISC TO SUIT•••••••••••••••••••••• $4 9 ~===::::::::::::::::::::::::::::::::::::::::::z:: "'r============:;::::;§#:Z::; ~~t~g~ RITRON • ·• RITRON • , 3 ELECl EXECUTIVE 3 ELECl .,:; EXECUTIVE '==""' /~ NO~. 3 ELECl BOARD 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl ~ ~L~Ci ~E t Egl 3 ELECl 3 ELECl 3 ELECl 2 2 MEG RAM EXP TO 16 MEG WITH 65 Mhz LANDMARK SPEED TEST OF 40 MEG HARD DISK 12ms ACCESS TIME 1.2MJAPANESE BRANDF.O.D ------' 101 EXTENDED "CLICK" KEYBOARD MINI CASE & 200W POWER SUPPLY SERIAL, PARALLEL, GAMES PORTS 512K VGA CARDSUPA VGA COLOUR MONITOR (1024 x 768 Res) 0.28" 4 YEAR PARTS & LABOUR WARRANTY SPEADSHEET, WORDPROCESSOR & DATABASE SOFTWARE INCLUDED. •SHAREWARE SOFTWARE MEG RAM $1 ,44 $1,210 9 TAX WITH INC. • • ., •: i ,. •• j • •: CD ROM SOUND BLASTER PACK. ••••••••••• $949 .· $1,585 TAX EX. NOW 2 MEG RAM $1 469 "!:! ' • $1 , 225 Wl$TH129001M9EGORIVE I TAX INC. $1,6QQ TAX EX. TAX EX. 3 ELECl .....,................................................................................~ . '-'........,.........,.,....,....,....,............,....,.....,.....,.....,....,....,.....,.~ 3 ELECl ..·.·•... . ;---------------------------------------------........., ~~t~gi l!t!!i RITRON EXECUTIVE l ELECl _.,,.,...,,.....,......,,,.....,,.....,,.....,,.,,.,,,,.,,,. 3 ELECl 3 ELECl 3 ELECl 3 ELECl 3 ELECl ..__....,......_........._....._..........._......._ l!!Jil RITRON EXECUTIVE - - - -- -- - -- -- - - - - IEIi ~itm ~1.§.§r~e.~ :.=--~~~-,,..._,....~·•~D§t2•ag;••1~ G ~t~g g $3 099 ' $2 579 I TAXINC. SOFTWARE. ASSEMBLED&TESTED IN AUSTRAUA. TAX INC. IDEAL CAO MACHINE! -.,,,,..-.,-.,-.,..,,,--,---,-- $3495 $2915 -. TAXINC. ~l1i186~U;§/i\i!~ i )D IRVING )D IRVING goD1 RRvv1 NNGG I ,,PD IIRVING DD IRVING !!! i ~! /O~JWI • 80486-33 CPU ,. 256K ON BOARD CACHE. 2 MEG OF RAM • 157Mhz LANDMARK SPEED TEST NOW WITH 2 MEG OF RAM )0 IRVING )D IRVING )D IRVING •' 40 MEG HARD DISK )0 IRVING •• 1.2M JAPANESE BRAND F.D.D )0 IRVING 101 EXTENDED"CLICK" KEYBOARD )0 IRVING :• SERIAL, PARALLEL, GAMES PORTS .___ _ ____. )D IRVING · 512K VGA CARD. IBM' COMPATIBLE )D IRVING SVGA COLOUR MONITOR (1024 x 768 Resolution) 0.28"DP )D IRVING MIN1 CASE & 200W POWER SUPPLY ,D IRVING 4 YEAR PARTS & LABOUR WARRANTY )D IRVING SPREADSHEET, WORDPROCESSOR • DATABASE SOFTWARE. )D IRVING .•• ,. ••• $2 249 ' WITH TAXINC. $1,870 200 MEG DRIVE )DIRVING 5g:~~:~g $2,699 TAXINC $ 2 1 245 TAX EX TAX EX. JD IRVING ) 0 IRVING ) D IRVING CID IRVING DD IRVING . ..... .. .. .. ... g:=~:~~ g:::::g Jg:=~:~~ RITRON EXECUTIVE _.._....,_____ D IRVING _I) IRVING _____ ·-=~· OD IRVING 80486•EISA CPU 256K ON BOARD CACHE. 4 MEG OF RAM OD IRVING 167 Mhz LANDMARK SPEED TEST OD IRVING 2 QQM 200 MEG HARD DISK 12ms ACCESS OD IRVING TIME 1.2M JAPANESE BRAND F.D.D HARD OD IRVING 3.5" 1.44M JAPANESE BRAND F.D.D DRIVE OD IRVING 101 EXTENDED"CLICK" KEYBOARD OD IRVING SERIAL, PARALLEL, GAMES PORTS & TOWER OD IRVING 1 MEG VGA CARD. IBM' COMPATIBLE CASE OD IRVING TOWER CASE & 220W POWER SUPPLY _ _ _ _ _ oo IRVING SUPA VGA COLOUR MONITOR (1024 x 768 Res) 0.28" DP 00 IRVING 4 YEAR PARTS & LABOUR WARRANTY OD IRVING SPEADSHEET, WORDPRCESSOR & DATABASE OD IRVING SOFTWARE. ASSEMBLED&TESTED IN AUSTRALIA. TAX EX. . .. 1-= ..__.___.....__...__....._....___._. G ~ ELEc· SPEADSHEET, ;::ELEc· WORDPRCESSOR& ., . DATABASE SOFTWARE. G ELEC ASSEMBLED & TESTED G ELEC. IN AUSTRAUA. I■ RITRON EXECUTIVE ~•1:§§i•E•i•s•~• •: """"-'""""-'=""--"'-"~"'-""""-..., 80486-33 CPU 256K ON BOARD CACHE. 4 MEG OF RAM 80486•50 CPU 25~K ON BOARD CACHE. 4 MEG OF RAM 157Mhz LANDMARK SPEED TEST 200+Mhz LANDMARK SPEED TEST 2QQM 2QQM 200 MEG HARD DISK 200 MEG HARD DISK 12ms ACCESS 12ms ACCESS TIME HARD TIME 1.2M JAPANESE BRAND F.D.D HARD , ELECl 1.2M JAPANESE BRAND F.D.D DRIVE 3.5" 1.44M JAPANESE BRAND F.D.D DRIVE ELEc· 3.5" 1.44M JAPANESE BRAND F.D.D 101 EXTENDED "CLICK" KEYBOARD G ELEC 101 EXTENDED "CLICK" KEYBOARD & TOWER SERIAL, PARALLEL, GAMES PORTS & TOWER ~ ELEc· SERIAL, PARALLEL, GAMES PORTS CASE 1 MEG VGA CARD. IBM' COMPATIBLE CASE ELEc· 1 MEG VGA CARO. IBM' COMPATIBLE -----4:':ITOWER CASE & 220W POWER SUPPLY ,___ _ ___. . TOWER CASE & 220W POWER SUPPLY SUPA VGA COLOUR MONITOR (1024 x 768 Ree) 0.28" DP ~ SUPA VGA COLOUR MONITOR (1024 x 768 Res) 0.28'' DP 4 YEAR PARTS & LABOUR WARRANTY , ELEC 4 YEAR PARTS & LABOUR WARRANTY SPEADSHEET, WORDPRCESSOR & DATABASE 6g :~~:~~ ,. 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TAX EX. ~t1il§§Z§1I )0 IRVING ) D IRVING ) D IRVING ) D IRVING )D IRVING ) 0 IRVING JO IRVING )0 IRVING po IRVING )0 JRVING )0 IRVING )DIRVING •) D IRVING ) D IIWING JD IRVING JO IRVING i 200m HD add $450 EXTRA RAM ._.._,.._.,..._....,..,_=.,..,. ,••, 3 ELECl 3 ELECl i"" lit!~! . ,!~~8~f~,~~, gg i~~i~i ~g: !·~~ws·s:·i·:~:g~~ i 85M HD add $100 ., $1,165 TAX EX IN AUSTRALIA. )D IRVING • lM VGA CARD................. $lOO.OO •• TO CHANGE A 40M HARD DRIVE TO A 2 MEG RAM ~11E DR DOS 8.0 ADD ............ $ 7 5 ~ • :: :::.IW 64K CACHE ON /pllfil\\\~ •• BOARD MEMORY •• 2 MEG RAM EXP TO 16 MEG NOW ., S7MhzLANDMARKSPEEDTEST WITH 40 MEG HARD DISK •: 1.2M JAPANESE BRAND F.D.D OF ·• 101 EXTENDED "CLICK" KEYBOARD ' SERIAL PARALLEL GAMES PORT MINI CASE & 200w POWER SUPPLY .___ _ ____. SUPA VGA COLOUR MONITOR (1024 x 768 Rea) 0.28" DP 512K VGA CARD (256 COLOURS) IBM' COMPATIBLE 4 YEAR PARTS & LABOUR WARRANTY SPEADSHEET, WORDPROCESSOR & DATABASE SOFTWARE INCLUDED. A~ . TAX INC. ,. . ~l~~l~ J ,,, , IDEAL CAO MACHINE! $4999 $4150 OD IRVING ODIRVING TAXINC • OD IRVING TAX EX OD IRVING IRVING ~~~g , - - - - --.R:r:; - o~ · D~- ' iR~ - r: v r:: iN"G ::- -=e~L-=ei-::c::.f=-:R::-::0~- N" ·7.: ict; •st'= e '=' st:-:'19 .:".: :7::7~- -----,r,fO&:Rii!E'ir.fG;llHTFi"'i"cHO'.Ai,';Rii'G1i=Ei'ie.rnsErlo>io:;'lNl"'35iiir.KG?.i'T11'!". ,/ "' ,}~ :;:.,.~ ::}'° :)'° X '°?~O~U':':R~P~ ..,O::-.l.:-:.,:-:C~.Y."' i :::"' >= "'···•"' :•.·.·"' ······" '···'•~ ' :•.··. OD IRVING I!!! G ELEC ;!1!!t!!l!I~,i!!!~i; ~~iiii~jt~·ltJ!~!~IIHiti -- . . . .. . . PACK & POST FOR MAILORDERS OVER $25.00 & UNDER 5 KG. OFFER EXPIRES MIDNIGHT 31 /1/93. ! 00 IRVING G ELEC F R EE ROD G ELECTRONICS ROD IRVING ELECTRUNl(.;:S HUU IHVIN\:a tLtvl MV""-" nvu ,nvu= L<Lv" , v , . , - ,, __ " • · " • - - - - - .. • - .. ·• • - • > ROD G ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING RECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROO ,G §L§C!RONICS i~VIN~ ~LECTRONICS ROD IRVING ELECTRONICS ~OD I~yING ELECTRONICS ROD IRVING EL~CTR_9NICS ~OD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD ~Ot:> IRVING IRVING IRVING jfl_VING G ELECTRONICS G ELECTRONICS G ELECTRONICS G ELECTRONICS G ELECTRONICS G ELECTRON G ELECTRON G ELECTRON ROD ROD ROD ROD ROD IRVING ELECTRONICS IRVING ELECTRONICS IRVING ELECTRONICS IRVING ELECTRONICS IAVING ELECTRONICS ,G ELECTRON ~~~~gi=g~: ~ ~ IGELECTRONI IG ELECTRON! IG ELECTRON! XENON/STROBE IG ELECTRON! TUBES 1G ELECTRON! As used in projects or IG ELECTRON! as replacement. IG ELECTRON! 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IG EL!oCTI O IG ELECTI ~ z :~ ~t~gi:(/)UJCJ: G ELECTR G ELECTR G ELECTR G EL!oCTR >( G ELECTR UJ O: ~ ~t~gi~ 0: G EL!oCTA UJ G ELECTA G ELECTR O G ELECTA G ELECTA • G ELECTR Cl G ELECTA ~ G ELECTR It) G ELECTA 0: GELECTA UJ G ELECTR C G ELECTR, Z G ELECTA, :::) G ELECTA, G ELECTRi all G ELECTAr O G ELECTRr O G ELECTAr G ELECTA• N G ELECTAI 0G ELECTRI 0: G EL!oCTR• UJ G ELECTRt 'G EL!oCTR• 0 R1 G ELECT (/) G ELECTRt 0: ·G ELECTAI UJ 'G ELECTAI O IG ELECTRI 0: IG ELECTAI Q I IG ELi:;CTR tt 10 > 9 mm hole, available 3 colours S14030 Rad ......... $1.20 S14032 Graan ..... $1.45 s14034 Yellow ....$ 1.45 . . ,, ; ~ GREY FLAT RIBBON CABLE ~! ;6~·4 W12616 W12620 W12624 W12625 w12626 w12634 W 12636 Wl 2640 W12650 W12660 14way 16way 20way 24way 25way 26way way 34 way 36 40way 50way 60way 4 _,,f! .· .·- •. . 10 TURN WIRE WOUND POTENTIOMETER Spactrol Model 534114 ,. shaft. Equivalent (Bourns 3540S Backman 7256) Dials to suit 16·1·11, 18-1-11, 21·1·11. R14050 SOR A14055 lOOR R14060 200R ..J R14070 SOOA R140~92K :~mg=:<( :;~•~ $2.20 $2.50 $2.90 $3.20 $3.60 $ . 3 90 $ . 3 90 $4.90 $5.90 $6.90 R14100 A14110 A14120 R14080 SK 10K 20K 1K ROD ROD ROD ROD ROD IAVING ELECTRONICS IRVING ELECTRONICS IAVING ELECTRONICS IAVING ELECTRONICS IAVING ELECTRONICS D ROD IAVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IAVING ELECTRONICS ROD IAVING ELECTRONICS ,----,---,--::::::;:::;:::::,-------. • • DIE CAST BOXES Diecaat boxes are excellent for RF aheildlngand strength. Screws are provided with each box. 4 Hll Sl ~~:s~ x 25mm. .......$8. 9S DIODES· BUYINBULK&SAVE! •F==== Cat No. 210135 210105' 210107 2 10110 210115 210119 1000+ $0.03 $0.04 $0.05 $0.06 $0.13 $0.15 IN4148 IN4002 IN4004 IN4007 IN5404 IN5408 10+ $0 .05 $0.06 $0.08 $0.10 $0.18 $0.20 100+· $0.04 $0.05 $0.06 $0.07 $0.14 $0.16 10K $0.02 $0.03 $0.04 $0.05 $0.11 $0.14 i'ii'iiSii""";;-;;;aii'ii...,.. •====~~=~ ••••••• ~~~:sS: x 30mm ........$9.50 120 x 65 x 40mm....... $10.50 H11461 120 x 94 x 53mm. ..... $13.95 H11462 188x120x78mm.... $15.95 H11464 188 x 188 x 64mm.... $29.50 ~~ ~ GENERAL PURPOSE PN100 REPLACES : PN2221, PN2222, PN2222A, PN3585, PN3568, PN3569, PN3643, PN5133, 2N2219A, 2N2222A, 2N3414, 2N3415, 2N3416, 2N3417, 2N3700, 2N3704, 2N3904, 2N4123, 2N4124, 2N4401, 2N5088, 2N521 0. PN200 REPLACES: PN2907, PN2907A, PN3638, PN3638A, PN364D, PN3644, PN4121, PN4143, PN4248, PN4~49, PN4250, PN4355, PN49i6, PN4917, PN5910, 2N2905A, 2N3467, 2N3702, 2N3906, 2N4125, 2N4126, 2N4291, 2N4402, 2N4403, 2N5086, 2N5087, 2N5447. oo.. , .. PN1 T90001 PN200 ......T90002 l0+ lOO+ 1_9 =: $0.20 a: • :~ti.\:fw1R......... $l 39 .oo ~fT~~iR..........$l 49.oo !!~t::::::::::::::g~: I I ,--------, J~!,~ ;~;!~e~~roi purpose medium power amp and ■witch with continuous collector current up to SOOmA. PN200: a PNP general purpose amp at collector currents to 1 AMP. Both are TO..a2 plaatic package. $0.18 $0.15 ........... LOW PROFiLE IC SOCKETS Savo I small lortuno on thoso "Direct Import" tow profllolCsockets!PCB mounting solder tall. All tin plated phosphor bronze or borrylllum and dual wlpo for POWER SUPPLIES SLIMLINE BABY AT P.S. 200W................$89.00 IGELECTAt:i= $ .95 $ 1~~;0 12 K iG ELECTR< s . .......IG ELECTAI O R14130 50 ..............$16.9 14140 IG ELECTRI R lOOK............ $lS.BS IG ELECTRI LI. 1-'-"""""""-!.J SUPER BRIGHT IG ELECTAI t[D 0 <at>J LEDS 1G ELECTA, (/) 0 (I) [II , RED .................210146 IGEL!ocmO r,i,.,-., GREEN 210147 t.:..1 •'G ELECTR, Q. 0 (£)<at>) YELLOW 210148 ffiELECTA' oll • • • l-9 ......... l0+ 1G ELECm ~ NUMERIC KEYPAD ffiELECTA ..._ $1.00 $0.90 1G ELECTA O Un4:ncoded keypad, 1_0. 1G ELECTA ,et d191t ke_y• plus ~o utility . Q. keya. Light grey in colour. ffi ELECTA OUTPUT ARRANGEMENT: liG EL!oCTR UJ Output Pin No. Symbol IG ELECTA ~ 1....................... N.A. 1G ELECTR LL 2.......................Shleld plate ~~~~~~ .iG ELECTA 3.......................Column 2 1G ElloCTAON 4....................... Row 1 CARD EDGE 1G ELECTAONI s....................... Column 3 CONNECTORS 1G ELECTRON! 6....................... Aow 1 11G ELECTRON! 7.......................Column 1 ,1" SPACING t - 'i I of .iG ELECTRON! 8...................... Row 2 P12060 10pin $3.95 $3.50 1G ELECTRON! 9....................... Row 3 P12062 20pin $4.25 $3.75 liGEL!oCTRONI 10..................... N.A. P12064 26pin $4.50 $3.95 .iG EL!oCTAON Cal C19030 P12066 34pin $4.95 $3.95 1 9 .iG ELECTRON I • lO+ lOO+ P12068 40pln $5.95 $4.95 m ELECTRON! $2.95 $2.50 $1.95 P12070 50pin $6.95 $5.95 .iG ELECTRON! 11G ELECTRONICS ROD IAVING ELECTRONICS ROD IAVING ELECTRONICS «, ELECTRONICS ROD IAVING ELECTRONICS ROD IRVING ELECTRONICS m EL!oCTAONICS ROO IRVING ELECTRONICS ROD IAVING ELECTRONICS ao c , ccYQOIJrr<> ACYl iAViNG c I CCIROllllCS RCXl iRVING ELECIBQ~ICS == AOC IAVING ELECTRONICS ROD IRVING ELECTRONICS AOC IRVING ELECTRONICS AOO IAVING ELECTRONICS AOO IAVING ELECTRONICS ~~°; P10550 8 :~•;;~ty~;; P1056014pin 20c 18C 15' P1056516pin 20C 18C 16e P1056718pin 30c 25c 22C P10568 20pin 35c 30c 25' P10569 22pin 35c 30C 2se .! ~~~~~ ~~~ !~: ~s!: · - • BREAD BOARDS lhia Inexpensive range of modular interlocking unite enables a quick easy way of experimenting with new circluta and ideaa. There are two main unite conalatingofltermlnlll atrip or distribution and a central plug In unll 'lOO ho lea. P11000 ................$2.75 •840 + 100 holes P11007 ............... $14.95 • 1280 +100 holes • P11010 ............$26.95 •2560 + 700 holes p 11 0 18 $69 9 5 • ............. • ~ _; . COMPUTER CABLES •Slxconductorlhlokl1d computodntorf1coc1blo. W12670 • CIC& 6 con. $;::M $11.~M $~'.:M W12672•CIC9 9con. 1•BM 10M• 100M. $1.60M $1 .SOM $1.20M W12674 • cIc12 12 con. 1·BM 10M+ 100M+ $2.SOM $2·20 M $l.90M Wl2676 'CICl 6 16 con. $3150,BMM $31200MM+ $2.10050MM♦ · /i~i~~::t_ Thost quality 3I ,v,I wlro wrap sockets are tin platod phosphorbronzo. P10579 Spin $1.50 $1.40 P10580 14pin $1.85 $1 .70 P1058516pin $US $1.80 P1osa11apin $1.95 $1 .80 P10590 20pin $2.95 $2.75 P10592 22pin $2.95 $2.70 Pl05 94 24 pin $3.95 $3.50 95 28 5 3 50 Plos pin $3.9 $ . 95 Pl05ll8 40pin $4. $4.50 NICADS ~ · ---·--- - - - . TRANSFORMERS 2155 2cov r,.1;:1A 10+ M12155 $895 $795 • 2156 240V.. ;.'uv A2 M12156 ........$13.95 $12.95 12-eYCT 25 DmA 285 12 12851 95 .. $4.50 M .........$4. 6672 240V 15 lOvc 1"' tapped M16612 ........$12.95 $11.95 D TYPE1~ c ~~u~~ •DE&P&plnplug p121s6 $1 .50 $1.20 $1.00 • DA15P 15pln plug , 12168 $l .50 $l.20 $l .OO ~~:.~: :!:sl:?~~~95 $3.50 OTYPE IDC SOCKETS 1·1 10+ 100+ DEBS 8 pin eockot P12167 $1 .50 $1.20 $1 .00 • DA15S 15 pin eocket P1216e $1.50 $1.20 s.1.00 ~~:,~s $~~~ $3.50 t:.~ . , .. .. . . ---IOC CENTRONICS 36 WAY PLUG & SOCKET 10+ 1.a 100+ 'Plug Pl 2200 , sa!~-~S p f ~ $2,95 n IAVING ELECTRONICS IAVING ELECTRONICS IAVING ELECTRONICS IAVING ELECTRONICS so.oa so.12 so.12 so.12 :!: :::!: ::: ::~ --- ~. A_ . ~ ~~~EN ~i;~,v.:[~:~~u\:r hotspot cooling etc. Anywhere you need plenty ol air. 240V 4 518" T12461..$16.95 11sv 4 518" T12463 ..S16.95 : ROOIRVING ROD IAVING AOC IRVING ROD IRVING ROD IAVING ROD IAVING ROD IAVING "TI O IAVING lJ O IAVING m O IAVING m ,o IAVING "tl O IAVING )> 0 IRVING 0 0 IAVING ~~. ~!: :~ ~3: g :=~:~~ g:~~:~~ 2°' 1ss· 12C 1<>s YELLOW )> - 1:!(11; diib DU ~~:; ~ :,~: ;:::;:::::::: :,st> r 1 .• · 0 D IAVING . D IAVING D IAVING ~ g:~~:~~ DB2;~~~l~~ TOR lO+ 100• m D IAVING 1.a P10880 DUP $1.00 $0.80 $0.60 lJ D IAVING P10885 DE9S $1 .00 $0.70 $0.60 (/) D IAVING P10881 DA15S$1.00 $0.70 $0.60 Q D IAVING P10882 DA15C$1.00 $0.90 $0.60 J IAVING P10885 DA15S$1.00 $0.80 $0.60 m J IAVING P10802 DB25C$1.00 $0.80 $0.60 lJ J IAVING P10804 DB25P $1.00 $0.80 $0.60 ) IAVING P10805 D8259 $1.00 $0.80 $0.60 ~ J IRVING ~ · UI J IAVING IRVING O ) IAVING . · go J IAVING MOSFET SPECIALS J IAVING 1-9 10+ 100+ C ) IAVING 2SJ49 $9.50 $8.00 $7.00 Z J IAVING 2SJ58 $10.00 $9.50 $8.50 C ) IRVING 2SK134 $8.50 $8.00 $7.00 m J IRVING 2SK178 $9.50 $8.90 $6.90 lJ ) IAVING 2SJ50 $9.50 $8.50 7.oo (11 ) IAVING 2SKl:1_5 s9.50 $8.50 s7.oo ,;; ) IAVING ELECTRET G') :, IAVING . . MIC INSERTS • ) IRVING ~ wI111 pi•• 1-e,,,,bo1n1 ) IAVING ·- Q ) IRVING ln..,,.on. c 1o170 "TI ) IAVING 1 1 1000 .a lO.ll8 0G+ • "TI ) IRV G $l.20 $l.OO $0.90 $0.70 m ) Rv:NNG -.. I IRVING -· IRVING >( ) IAVING , .. < TOGGLE SWITCHES 1-9 10+ s11010 S.P.D.T$1.20 $1.10 S11020 D.P.D.T$1 .3D $1.20 O) ~,.:, ~ ( s M/ f!! TRANSISTORS BUY IN BULK &SAVEi • ·=. ,, ) _ ' - - -- - - ~ 1.. 10. 100. BC 547 $0.15 $0.10 $0.07 BC 548 $0.15 $0.10 $0.07 BC 549 $0.15 $0.10 $0.07 BC 557 $0.1 5 $0. 10 $0.07 BC 558 $0.15·$0.10 $0.07 BC559$0.15$0.10$0.07 BC 327 $0.20 $0.15 $0.12 BC 337 $0.20$0.l5$0.l2 BO 139 $0.75 $0.60 $0.50 BD140$0.75$0.60$0.50 9 PIN D SWITCH BOXES 2 WAY...............$59.95 4 WAY................$69.95 MONITOR & KEYBOARD SWITCHBOXES$69.50 ffl • Lever operated auction base grip for Instant ! :,':," :n:~:;::~g "J:ity. 0 non-porous aurlocea , ldealfor holding & other amall objecta. 124A 58R ...D .....~ ..........$6•95 r:g I.I HOLDER . ~1 Better than-. ~ •ofhanda,., Amiiiiior all PCB work. T12444 ..............$9.95 • PCB MOUNTING SCREW TERMINALS (INTERLOCKING ENDS) These terminal• feature Interlock:::•~• to lo~ 0 connect ona. any 1111111 st rd anda 5mm spacing pina. PlOS20 2way lOO+ . l-t lO_ 7 Pl:;: $0. 0 $0.60 3 $l 00 way . $0.90 $0.ao nvu ; ROD ROD ROD ROD ~:=~:: FLASHING LE.OS ,;; 0 IRVING RED 5mm 1-9 10+ 100+ go O IAVING Z10159 $1 .10 $1.00 $0.80 D IRVING - -. "tl D JRVING - - · 0 DIRVING ~ D IAVING RECTANGULAR D IAVING LEOS "TI D IAVING 12V DC FANS aoxaox25.4mm . 12V DC. 1.7 Watt 0.14 Amp. T12469................$18.95 10+ fans, only $17.95 • 1K QUALITY 5mm LEDS ~::~~:: Z10152(Y).. S0.25 so.20 so.11 so.12 ---- '°" · - QUALITY 3mm LEDS 1.a 1 - 10G+ ~~~Rl so. 15 so.12 so. 10 z1ow(o~. so.20 so.11 so.15 z101'3(Y~. so.20 so.11 so.15 10145(0).. S0.20 so.11 S0.15 ECONOMY , ROD IRVING ROD IRVING ROD IAVING AOO IAVING ROD IRVING ROD IAVING AOC IAVING ROD IAVING AOO IAVING ICB VOLTAGE REGULATORS WOW! BARGAINS OncripUon 1·1 10+ 100+ WHAT PRICES! 1aosuc $0.50 $0.45 $0.40 .__ _ _ _ _ _ _.,.. 7812UC $0.50 $0.45 $0.40 IDC PLUGS & . 7815UC $0.50 $0.45 $0.40 7905UC $0.60 $0.55 $0.50 SOCKETS 7912UC $0.60 $0.55 $0.50 WOW I FROM $1 .00 7915UC $0.60 $0.55 $0.50 78L05 $0.40 $0.30 $0.28 78L12 $0.40 $0.30 $0.28 LM324 $1 OO $0 90 $0 80 • · • •••• 555 $0.40 $0.38 $0.33 741 $0.50 $0.45 $0.39 . Save a fortune on expensive throw away batteriea with these quality Nicada and Rechargeral Sia AA 450mAH 1·8 10+ 100+ $2.95 $2.75 $2.50 srzec 1 2AH $9.95 $9•50 $8. 95 12 Sim D 95 AH 9 50 $&. $ • $8. 95 ttuu Ittvn,u t: "~ ROD li:IVING ELECTRONICS ROD IAVING ELECTRONICS ROD IAVING ELECTRONICS AOO IRVINIG ELECTRONICS ROD IRVING ELECTRONICS ROD IRVlNG ELECTRONICS AOO IAVING ELECTRONICS ROD IAVING ELECTRONICS ROD ·IAVING ELECTRONICS . WlflE WRAP IC SOCKETS · W12678 • CIC25 25 con. 1.eM 10M+ 100M+ $3.90M $3.40M $3.00M ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS AOO IAVING ELECTRONICS ROD IAVING ELECTRONICS AOO IAVING ELECTRONICS ROD IAVING ELECTRONICS ROO IAVING ELECTRONICS ROD IAVING ELECTRONICS ROD IAVING ELECTRONICS AOO IRVING ELECTRONICS AOO IRVING ELECTRONICS ROD IRVING ELECTRONICS AOO IRVING ELECTRONICS .m,., )) ~; en ) :=~:~~ m ) IRVING iRvING :::,, ) IAVING ;:a, ) IAVING IAVING IAVING ;::;: ) IAVING ... , )I AVING ::C ) IAVING -i )IAVING c., ) IAVING ~ ) IRVING IRVING. IRVING c., ) IAVING , nw IAVING ROD IRVING ROD IRVING ROD IRVING ROD IRVING ROD IAVING ROD 1RVING ROD IRVING AOO IRVING ROD IAVING ROOIRVING ROD IAVING ROD IAVING ROD IRVING ROD IRVING ROD IRVING ROD IRVING ROD IAVING ROD IRVING 0) z ) _., ) CD ) Silicon Chip May 1989: Electronic Pools/Lotto Selector; Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference; LED Message Board, Pt.3~ Electronics For Everyone - All About Electrolytic Capacitors. BACK ISSUES June 1989: Touch-Lamp Dimmer (uses Siemens SLB0586); Passive Loop Antenna For AM Radios; Universal Temperature Controller; Understanding CRO Probes; LED Message Board, Pt.3. July 1989: Exhaust Gas Monitor (Uses TGS812 Gas Sensor); Extension For The Touch-Lamp Dimmer; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; NSW 86 Class Electric Locomotives. July 1988: Stereo Control Preamplifier, Pt.2; Fitting A Fuel Cut-Off Solenoid To Your Car; Booster For TV & FM Signals; The Discolight Light Show, Pt.1; Tone Burst Source For Amplifier Headroom Testing;What Is Negative Feedback, Pt.3. December 1988: 120W PA Amplifier (With Balanced Inputs), Pt.1; Diesel Sound Generator; Car Antenna/Demister Adaptor; SSB Adaptor For Shortwave Receivers; Why Diesel Electrics Killed Off Steam; Index to Volume 1. August 1988: Building A Plasma Display; Universal Power Supply Board; Remote Chime/Doorbell; High Performance AC Millivoltmeter, Pt.1; Discolight Light Show, Pt.2; Getting The Most Out Of Nicad Batteries; Data On Insulated Tab T riacs. January 1989: Line Filter For Computers; Ultrasonic Proximity Detector For Cars; 120W PA Amplifier (With Balanced Inputs) Pt.1; How To Service Car Cassette Players; Massive Diesel Electrics In The USA; Marantz LD50 Loudspeakers. September 1989: 2-Chip Portable AM Stereo Radio (Uses MC13024 and TX7376P) Pt.1; AlarmTriggered Telephone Dialler; High Or Low Fluid Level Detector; Simple DTMF Encoder; Studio Series 20-Band Stereo Equaliser, Pt.2; Auto-Zero Module for Audio Amplifiers (Uses LMC669). September 1988: Hands-Free Speakerphone; Electronic Fish Bite Detector; High Performance AC Millivoltmeter, Pt.2; Build The Vader Voice; Motorola MC34018 Speakerphone IC Data; What Is Negative Feedback, Pt.4. February 1989: Transistor Beta Tester: Minstrel 2-30 Loudspeaker System; LED Flasher For Model Railways; Build A Simple VHF FM Monitor (uses MC3362), Pt.1; Lightning & Electronic Appliances; Using Comparators to Detect & Measure. October 1989: Introducing Remote Control; FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 1Mb Printer Buffer; 2-Chip Portable AM Stereo Radio, Pt.2; Installing A Hard Disc In The PC. October 1988: Stereo FM Transmitter (Uses Rohm BA1404); High Performance FM Antenna; Matchbox Crystal Set; Electronic House Number; Converting A CB Radio To The 28MHz Band; Queensland's Powerful Electric Locomotives. March 1989: LED Message Board, Pt.1; 32-Band Graphic Equaliser, Pt.1; Stereo Compressor For CD Players; Amateur VHF FM Monitor, Pt.2; Signetics NE572 Compandor IC Data; Map reader For Trip Calculations; Electronics For Everyone Resistors. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); Sensitive FM Wireless Microphone; FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disc Drive Formats & Options; The Pilbara Iron Ore Railways. April 1989: Auxiliary Brake Light Flasher; Electronics For Everyone: What You Need to Know About Capacitors; Telephone Bell Monitor/Transmitter; 32-Band Graphic Equaliser, Pt.2; LED Message Board, Pt.2. December 1989: Digital Voice Board (Records Up To Four Separate Messages); UHF Remote Switch; Balanced Input & Output Stages; Data For The LM831 Low Voltage Amplifier IC; Install A Clock Card In Your PC; Index to Volume 2. November 1988: 120W PA Amplifier Module (Uses Mosfets); Poor Man's Plasma Display; Automotive Night Safety Light; Adding A Headset To The Speakerphone; How To Quieten The Fan In Your Computer; Screws & Screwdrivers, What You Need To Know; Diesel Electric Locomotives. l. r----------------------------------- ---, Use this handy form to order your back issues Please send me a back issue for: O October 1988 o November 1988 O March 1989 O April 1989 0 September 1989 0 October 1989 O February 1990 O March 1990 O July 1990 o August 1990 O December 1990 O January 1991 O May 1991 O June 1991 0 October 1991 O November 1991 o March 1992 O April 1992 O August 1992 O September 1992 0 July 1988 December 1988 0 May 1989 0 November 1989 0 April 1990 o September 1990 o February 1991 · 0 July 1991 O December 1991 0 May 1992 O October 1992 o Enclosed is my cheque/money order for $__._or please debit my: O August 1988 O January 1989 o June 1989 0 December 1989 0 May 1990 O October 1990 O March 1991 o August 1991 O January 1992 O June 1992 O November 1992 O Bankcard Card No. Signature _ _ _ __ _ _ _ _ _ _ _ _ Card expiry date_ _ /_ _ O Visa Card O O 0 0 O O 0 0 O 0 0 September 1988 February 1989 July 1989 January 1990 June 1990 November 1990 April 1991 September 1991 February 1992 July 1992 December 1992 O Master Card $5.00 each (includes p&p). Overseas orders add .$1 each for postage. NZ orders are sent air mail. Street _ _ _ _ _ _ _ __ __ _ _ _ _ _ _ _ _ _ _ __ _ _ Detach and mail to: SILICON CHIP PUBLICATIONS PO BOX 139 COLLAROV BEACH NSW 2097 Suburb/town _ _ _ _ __ _ _ __ __ __ Postcode _ _ _ _ __ Or call (02) 979 5644 & quote your credit card details. Fax (02) 979 6503. Name _ _ ______________ __________ _ L------------------------~--------------J--96 SILICON CHIP January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Speeding Up Your PC; Phone Patch For Radio Amateurs; Active Antenna Kit; Speed Controller For Ceiling Fans; Designing UHF Transmitter Stages. ' February 1990: 16-Channel Mixing Desk; High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2; PC Program Calculates Great Circle Bearings. Cost Sinewave Oscillator; Fast Charger For Nicad Batteries, Pt.2; How To Design Amplifier Output Stages; Tasmania's Hydroelectric Power System. March 1991: Remote Controller For Garage Doors, Pt.1; Transistor Beta Tester Mk.2; Synthesised AM Stereo Tuner, Pt.2; Multi-Purpose 1/0 Board For PC-Compatibles; Universal Wideband RF Preamplifier For Amateurs & TV; A Look At The Config.Sys & Ansi.Sys Files. March 1990: 6/12V Charger For Sealed LeadAcid Batteries; Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. April 1991: Steam Sound Simulator For Model Railroads; Remote Controller For Garage Doors, Pt.2; Simple 12/24V Light Chaser; Synthesised AM Stereo Tuner, Pt.3; A Practical Approach To Amplifier Design, Pt.2; Playing With The Ansi.Sys File; FSK Indicator For HF Transmissions. April 1990: Dual Tracking ±50V Power Supply; VOX With Delayed Audio; Relative Field Strength Meter; 16-Channel Mixing Desk, Pt.3; Active CW Filter For Weak Signal Reception; How To Find Vintage Radio Receivers From The 1920s. May 1991: Build A DTMF Decoder; 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1; Setting Screen Colours On Your PC. May 1990: Build A 4-Digit Capacitance Meter; High Energy Ignition For Cars With Reluctor Distributors; The Mozzie CWT ransceiver; Waveform Generation Using A PC, Pt.3; 16-Chan.nel Mixing Desk, Pt.4. June 1991: A Corner Reflector Antenna For UHF TV; 4-Channel Lighting Desk, Pt.1; 13.5V 25A Power Supply For Transceivers; Active Filter For CW Reception; Electric Vehicle Transmission Options; Tuning In To Satellite TV, Pt.1. June 1990: Multi-Sector Home Burglar Alarm ; Low-Noise Universal Stereo Preamplifier; Load Protection Switch For Power Supplies; A Speed Alarm For Your Car; Design Factors For Model Aircraft; Fitting A Fax Card To A Computer. July 1991: Battery Discharge Pacer For Electric Vehicles; Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2; Tuning In To Satellite TV, Pt.2; PEP Monitor For Transceivers. July 1990: Digital Sine/Square Generator, Pt.1 (Covers 0-500kHz); Burglar Alarm Keypad & Combination Lock; Simple Electronic Die; Low-Cost Dual Power Supply; Inside A Coal Burning Power Station; Weather Fax Frequencies. August 1991: Build A Digital Tachometer; Masthead Amplifier For TV & FM; PC Voice Recorder; Tuning In To Satellite TV, Pt.3; Installing Windows On Your PC; Step-By-Step Vintage Radio Repairs. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Wave Generator, Pt.2. September 1991: Studio 3-55L 3-Way Loudspeaker System; Digital Altimeter For Gliders & Ultralights, Pt.1; Build A Fax/Modem For Your Computer; The Basics Of AID & DIA Conversion; Windows 3 Swapfiles, Program Groups & Icons. September 1990: Music On Hold For Your Telephone; Remote Control Extender For VCRs; Power Supply For Burglar Alarms; Low-Cost 3Digit Counter Module; Simple Shortwave Converter For The 2-Metre Band. October 1990: Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; The Dangers of Polychlorinated Biphenyls; Using The NE602 In Home-Brew Converter Circuits. November 1990: How To Connect Two TV Sets To One VCR; A Really Snazzy Egg Timer; LowCost Model Train Controller; Battery Powered Laser Pointer; 1.5V To 9V DC Converter; Introduction To Digital Electronics; Simple 6-Metre Amateur Transmitter. December 1990: DC-DC Converter For Car Amplifiers; The Big Escape -A Game Of Skill; Wiper Pulser For Rear Windows; Versatile 4-Digit Combination Lock; 5W Power Amplifier For The 6Metre Amateur Transmitter; Index To Volume 3. January 1991: Fast Charger For Nicad Batteries, Pt.1; The Fruit Machine; Two-Tone Alarm Module; Laser Power Supply; LCD Readout For The Capacitance Meter; How Quartz Crystals Work; The Dangers When Servicing Microwave Ovens. February 1991: Synthesised Stereo AM Tuner, Pt.1; Three Inverters For Fluorescent Lights; Low- October 1991: Build A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator Mk.11; Magnetic Field Strength Meter; Digital Altimeter For Gliders & Ultralights, Pt.2; Getting To Know The Windows PIF Editor. November 1991: Colour TV Pattern Generator, Pt.1 ; Battery Charger For Solar Panels; Flashing Alarm Light For Cars; Digital Altimeter For Gliders & Ultralights, Pt.3; Build A Talking Voltmeter For Your PC, Pt.2; Error Analyser For CD Players Pt.3; Modifying The Windows INI Files. December 1991: ·TV Transmitter For VCRs With UHF Modulators; lnfrared Light Beam Relay; SolidState Laser Pointer; Colour TV Pattern Generator, Pt.2; Windows 3 & The Dreaded Unrecoverable Application Error; Index To Volume 4. January 1992: 4-Channel Guitar Mixer; Adjustable 0-45V 8A Power Supply, Pt.1 ; Baby Room Monitor/FM Transmitter; Automatic Controller For Car Headlights; Experiments For Your Games Card; The GPS Satellite Navigation System; Restoring An AWA Radiolette Receiver. · February 1992: Compact Digital Voice Recorder; SO-Watt/Channel Stereo Power Amplifier; 12VDC/ 240VAC 40-Watt Inverter; Adjustable 0-45V 8A Power Supply, Pt.2; The Mobile Telephone Revolution; Designing A Speed Controller For Electric Models. March 1992: TV Transmitter For VHF VCRs; Studio Twin Fifty Stereo Amplifier, Pt.1 ; Thermostatic Switch For Car Radiator Fans; Telephone Call Timer; Updating The Resistor/Capacitor Scene; Coping With Damaged Computer Directories; Valve Substitution In Vintage Radios. April 1992: lnfrared Remote Control For Model Railroads; Differential Input Buffer For CROs; Studio Twin Fifty Stereo Amplifier, Pt.2; Understanding Computer Memory; Switching Frequencies in Model Speed Controllers; Aligning Vintage Radio Receivers, Pt.1. May 1992: Build A Telephone Intercom; LowCost Electronic• Doorbell; Battery Eliminator For Personal Players; lnfrared Remote Control For Model Railroads, Pt.2; A Look At Large Screen High Resolution Monitors; OS2 Is Really Here; AliQning Vintage Radio Receivers, Pt.2. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; lnfrared Remote Control For Model Railroads, Pt.3; 15Watt 12-240V Inverter; What's New In Oscilloscopes?; A Look At Hard Disc Drives. July 1992: Build A Nicad Battery Discharger; 8Station Automatic Sprinkler Timer; Portable 12V SLA Battery Charger; Off-Hook Timer For Telephones; Multi-Station Headset Intercom, Pt.2; Understanding The World Of CB Radio; Electronics Workbench For Home Or Lab. August 1992: Build An Automatic SLA Battery Charger; Miniature 1.5V To 9V DC Converter; The lnterphone Digital Telephone Exchange, Pt.1; Dummy Load Box For Large Audio Amplifiers; Internal Combustion Engines For Model Aircraft; Troubleshooting Vintage Radio Receivers. September 1992: Multi-Sector Home Burglar Alarm; The lnterphone Digital Telephone Exchange, Pt.2; General-Purpose 3½-Digit LCD Panel Meter; Track Tester For Model Railroads; Build A Relative Field Strength Meter; Internal Combustion Engines For Model Aircraft, Pt.2. October 1992: 2kW 24VDC To 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm, Pt.2; Mini Amplifier For Personal Stereos; Electronically Regulated Battery Charger (Charges 6V, 12V & 24V lead-acid batteries); Internal Combustion Engines For Model Aircraft, Pt.2. November 1992: MAL-4 Microcontroller Board, Pt.1 (Uses 68HC705C8); Simple FM Radio Receiver; lnfrared Night Viewer; Speed Controller For Electric Models, Pt.1 ; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.2; Automatic Nicad Battery Discharger; Modifications To The Drill Speed Controller. December 1992: Diesel Sound Simulator For Model Railroads; Easy-To-Build UHF Remote Switch; MAL-4 Microcontroller Board, Pt.2; Speed Controller For Electric Models, Pt.2; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.3; High Voltage Probes - Beware The Dangers; Index To Volume 5. PLEASE NOTE: All issues from November 1987 to June 1988 plus the August 1989 issue are now sold out. All other issues are presently in stock. For readers wanting articles from sold-out issues, we can supply photostat copies (or tearsheets) at $5.00 per article, including postage. When supplying photostat articles or back copies, we automatically supply any relevant Notes & Errata at no extra charge. /ANUARY 1993 97 ASK SILICON CHIP Got a technical problem? Can't understand a piece of jargon or some technical principle? Drop us a line and we'll answer your question. Write to: Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097. 3-phase power from a single phase supply I refer to your reply to P. L. in the October issue regarding the possibility of generating 3-phase power from a single phase supply. The humble 3phase induction motor has other uses: (1) as a synchronous alternator; and (2) as a rotary transformer. In the latter mode, a star connected 3-phase motor driven at synchronous speed, with one winding excited from the single phase supply, will generate 3-phase power from its windings. This arrangement was used in French trains supplied from one phase of the National Electricity Grid, to provide 3phase power for auxiliaries such as air-conditioning, fans, etc. I used a similar set up about 30 years ago to provide 3-phase power for a small workshop. Strictly speaking, the motor should have unequal windings to allow for losses but I found that putting power factor capacitors across the other windings provided adequate balance. (B. J., Hahndorf, SA). • Thank you for your comments regarding the running of 3-phase motors from a single phase supply. A number of readers have written in Noise cancelling for microphones I am looking for a noise cancelling circuit for a microphone. It is to be used inside a motorcycle helmet and must cope with the very high noise levels from the motor and wind roar. Can you help me? (M. K., Richmond , Vic). • Any noise cancelling system for a microphone must employ two microphones, one to pick up the wanted signal plus noise and the other to pick up noise alone. When the two signals are electrically subtracted, most of the noise should 98 SILICON CHIP with further information on this subject and some of the schemes are really quite crude, such as one documented from Simpson Pope whereby a 415V delta 3-phase motor was connected with one winding across 480V single phase. However, the scheme must have worked otherwise it would not have been documented. Plugpack supply for SLAcharger I have been following your articles on SLA battery chargers which have been very good. For my use, the charger described in the July 1992 issue would be suitable. What I would like to know is what size battery could be used with the portable charger? You say to use a 9V DC plugpack but what would be wrong with using the Eliminator circuit described in the May 1992 issue of SILICON CHIP?. It could be set to provide a 12V output and thereby overcome the high open circuit voltage of a 12V DC plugpack. You also note that the peak current through the inductor is about 650mA so why specify a 2A fuse? Do you have any up to date chargers for lead-acid and nicad batteries? Also what is the largest size available disappear. At least, that is the theory. In practice, the gain levels of the two microphones must be carefully adjusted to suit the particular situation, otherwise feedback is likely to occur. Actually, we h ave probably produced a circuit which will meet your needs exactly. It is the "FM Radio Intercom For Motorbikes", as published in the October and November 1989 issues of SILICON CHIP. This used two electret microphones in each helmet and the gain for each electret w as adjustable. We have stocks of these issues at $5 each, including postage. in AA nicads above 600mAh? (G. 0., Berriedale, Tas). • The portable SLA battery charger circuit can be used with any 12V SLA battery with a rating of 1.2Ah or more. The charge time will be proportionately longer for the larger batteries. In the testing procedure, we cautioned against using a 12V DC plugpack because its unloaded output voltage of about 17V will be more than enough to cause the 15V zener diode (ZDl) to conduct and maybe blow it or the fuse. If you want to permanently power the charger circuit from a 12V DC lA plugpack, all you need do is to remove the 15V zener from the circuit. . You could also use the Eliminator project from May 1992 provided you make the necessary modifications to change its output voltage to 12VDC. You can not use it with a battery on the charger though, as this will be too heavy a load for a 12VDC 300mA plugpack. The fuse can be lA or 2A; it is not critical. We have not published any nicad chargers recently but have featured a lead acid battery charger in the October 1992 issue. To our knowledge, the largest capacity AA nicads currently available are 600mAh. Instability in the Twin Fifty Amplifier My most recent project was the power amplifier section of your Studio Twin Fifty Stereo Amplifier, as described in the March and April 1992 issues of SILICON CHIP. The assembly was not a problem and the voltages appear to be normal during testing. The quiescent current was set to just below 22V across the 560Q test resistors; if I tried to get any closer, it would jump to 36V. Initially, I did not consider this a major problem as one channel worked perfectly when tested with music. However, the other has a diabolical problem - it does not work. When put back into test mode, with Speed controller gate drive modifications I would like to present what I believe to be ari improvement for the MOSFET gate drive in the Speed Controller circuit in the November 1992 issue. As you know, to turn a MOSFET off quickly,' charge must be extracted from the gate to bring the gate-source voltage to zero. This requires a negative current from the gate and there are no gate-source resistors to allow VGS to fall exponentially. My suggested changes are: (1). Reduce the lO0kQ pull up resistor at pin 2 of IC2a to lOkQ. The extra current of l.5mA is well within capability of the LM339 and speeds up the turn-on transition; (2). Add a current buffer with source/sink capability. The BD139 and BD140 are ideal for this duty. My suggested drive circuit has a 0. lµF ceramic capacitor close to the buffer. For best speed, the entire gate current path length and enclosed area must be minimised. (3). I also suggest the addition of a '!.QkQ resistor between the gate and :,ource of each MOSFET. This speeds turn -off and should be placed as close as physically possible to the MOSFETs. Then, in the event of a wire or track break, the MOSFETs will revert to a failsafe off state. (4). Adequate supply filtering should be placed across the motor supply, and the loop comprising the MOSFETs, DB and the supply capacitors must be minimised. The all inputs and outputs disconnected, it was found thatthe faulty channel suffers from high frequency oscillation, as seen on a scope. Being a feedback type circuit, I cannot isolate its source. I have replaced transistors Ql, Q2, Q4, Q5 & Q6 without success. Can you suggest possible causes and/ or remedies for this problem? (A. H., Falcon, WA). • It is true that the quiescent current adjustment is quite critical but you should be able to go beyond 22V across the 560Q resistors without suddenly r - - - - - - - loop containing the motor does not need to be minimised, as the motor has so much inductance as to swap any stray lead inductance. (5). Capacitor C9 should not be connected directly across the MOSFET drain-source connections. This simply leads to excessive stress at turn -on. High frequency ringing in the VDs waveform can be damped by either reducing the gate-drive speed (increasing gate resistance) or by placing an RC snubber across the paralleled MOSFETs. (F. B., Kensington, NSW). • Your modified gate drive circuit for the Speed Controller would be considerably better; there is no argument there. However, the voltage tripler could not supply the extra current drain required by the improved circuit and therefore the improvement in switching would probably be marginal. In addition, the extra components required would increase the size of the board quite a bit and that would not be desirable. The author, Bob Young, is quite aware that the gate drive circuit is less than ideal but going all the way to 36V. It is unlikely that replacing any of the transistors will solve the problem of supersonic instability. The components which should be checked are the 68pF capacitor between the base and emitter ofQ5, the 2.2pF capacitor between the base and collector of Q2, the components in the output Zobel network (ie, Ll, etc), and the 0.22µF supply bypass capacitors. The most critical of these is components is the 68pF capacitor. You should also check that the 0V TO R22-R28 it is a good compromise considering the relatively low component count. C9 , the capacitor across the MOSFETs, should be omitted as you point out. It is covered by the notes & errata in this issue. We disagree with your comments regarding the bypassing of the motor supply. Diode DB, capacitor C14 and varistor Vl must be placed directly across the motor to minimise the motor loop. The reason is that the leads from the motor will otherwise radiate commutator hash and this will cause interference to the receiver. Nor is extra filtering required across the motor supply. The battery leads should be as short as possible and have a high current rating, as discussed at some length in the articles. The resulting very low impedance source presented by the battery and its heavy duty connecting leads will not be improved by any practical combination ofbypass capacitors since their internal impedance is likely to be higher. and supply connections to that side of the board have been properly soldered. A poor 0V connection could lead to instability. Equaliser thumping the speakers I have built my music system from SILICON CHIP kits, consisting of the Studio 200 Control Unit, Studio Series Half Octave Equaliser, 140W + 140W MOSFET Power Amplifier and Studio 3-551 Loudspeaker System. JANUARY 1993 99 lar problems? I would like to get Ford Telstar ignition the circuit working just in case my loses its spark replacement secondhand ignition I have recently had the misfor- module ($90 and many phone tune of having my car's factory calls) fails sometime in the future. fitted ignition module fail. My car (G. L., Emerald, Vic). is a 1983 AR Ford Telstar that is • We suggest that you set up your fitted with a Mitsubishi reluctor · ignition system on the bench, todistributor as standard. After gether with the reluctor distribuchecking the price of a new mod- tor and HT coil. Place a bent paper ule ($265 plus tax), I decided to clip in the HT electrode of the coil replace the old module with the and bend it so that there is a small reluctor based high energy igni- gap between the paper clip and tion system in the May 1990 issue one of the primary terminals of the of SILICON CHIP. coil - that then works as a spark I assembled and installed the gap. kit in accordance with the instrucRotate the distributor shaft by tions supplied. Unfortunately, the hand and note that a spark is gencar does not run properly. The en- erated each time a reluctor tooth gine runs well for a minute but passes the pickup coil. Now, with then stalls. The Darlington tran- the reluctor stationary and the LED sistor gets very hot and even with on, measure the voltage between just the ignition on it gets hot in a collector and emitter of the few minutes. Also, the light inten- Darlington transistor. This voltage sity of my timing light reduces should be around 2V or less. If it is when the transistor is hot. more, then either the Darlington The Telstar's ignition does not transistor or ICl is malfunctioning have a ballast resistor so I was able and that is why the Darlington gets to connect the circuit to the +12V hot. By the way, the voltage at the side of the coil. The reluctor polar- base of the Darlington should be ity is correct (the LED blinks off) about 1.8V. and the engine timing was correct Normally, the Darlington tranbefore the circuit failed. I have had sistor should run warm to the touch the circuit checked a couple of although the coil itself can be extimes to make sure the components pected to run hot. are in the right positions and are We have had very little correconnected the right way around. spondence from readers regarding Can you please give me some this project and certainly none advice on what to look ·for and have listed the problem you have check? Has anyone else had simi- experienced. They give excellent performance, when they behave. The first problem I noticed is a big "thump" while turning on and off the power of the equaliser. Turning off fluorescent lights in the house also makes a big thump. I suspected the problem was in the power supply of the unit. I tried connecting a .047µF capacitor across the mains switch but it didn't help. I also checked, the voltages of power rails and to pins of ICs. They all showed OK. The second problem is intermittent. Sometimes the output from the left channel of the equaliser drops to a level that is nearly inaudible. I checked the voltages to the !Cs and 100 SILICON CHIP these are OK. Is it likely to be a thermal problem when I stack the preamp on the equaliser, then on the power amplifier? I would appreciate it if you can help me to solve these two problems. (T. T., Sydney, NSW). • It seems likely that the problems are all involved in the equaliser unit. We suggest that you first remove the unit from the hifi system and check that the system operates properly without it. There should be no thump from the equaliser when it is turned on. The fact that you appear to have a thermal problem in the equaliser points to a fault either in its power supply or in one of the op amps. Do the supply voltages in the equaliser change when the cabinet becomes warm. If so, suspect the power supply. If not, we would suspect the LM833s. As a general rule , we advise against stacking equipment on top of big power amplifiers. It may reduce the ventilation to the amplifier and may also cause hum induction from the large power transformer. This can happen even if the power transformer is a toroidal type which generally have low flux leakage. Notes & Errata Automatic Nicad Battery Discharger, November 1992: the circuit on page 41 shows a lµF capacitor across Dl and a lOµF capacitor across LED 1 while the component overlay on page 42 shows these capacitors swapped. The circuit is correct. Low-Cost Speed Controller, November 1992: two changes have been made to the circuit and these will be implemented on the PC board supplied with the kit. First, C9, across the sourcedrain connections of the paralleled FETs, will be omitted. Second, VR3, a 50kQ trimpot has been added in series with R2 which is now changed from 47kQ to lOkQ Also, the text of the article on page 43 of the December 1992 issue makes reforence to the Rns figures for several FETs as being 18MW, 15MW and 23MW. These figure should be 18mW, 15mW and 23mW; ie, milliohms not megohms. High-current 0-20V power supply, December 1992: the circuit on page 35 shows the bridge rectifier, BRl, connected the wrong way around. Stereo AM Tuner; Feb-April 1991: a small piece of PC track may be miss ing from some boards. This missing track is in the right channel twin-T filter and causes two symptoms: (1) the notch in the right channel cannot be adjusted; and (2) this channel will burst into high frequency oscillation. The missing track is to the left of the 'K' ground connection pin on the PC board, as viewed on the wiring diagram (Fig.1) in March 1991. Find the second 270pF capacitor to the left of this 'K' pin and join the copper pad on the side which runs to a 100pF capacitor to the adjacent 68kQ and 1.8MQ resistors. A blob of solder between these two points will be sufficient since the gap is small. SC ... --;1. ~ .., ~ J1 _ _ /.1_ 1~1 I ~ I -; ~ 1 I . I 7' I ,~,--,, II ~ ... 1_ 7 II II 'f I I/ I' ORDER FORM /. i A /2 } a.._ __/..A. BACK ISSUES* ·MONTH VEAR MONTH VEAR MONTH VEAR MONTH VEAR *Back issues are $A5 each (incl. postage) . Overseas orders add $A1 per issue for postage. BINDERS Please send me _ _ SILICON CHIP binder(s) at $A 14.95 each (incl. postage). Overseas orders please add $A3.00 each for postage. TOTAL PRICE $A SUBSCRIPTIONS 0 New subscription - month to start 0 Renewal - Sub. 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Please have your credit card details ready Fax the coupon with your credit card details 24 hours 7 days a week Card expiry date I Mail coupon to: Freepost 25 Silicon Chip Publications PO Box 139, Collaroy Beach 2097 No postage stamp required in Australia JANUARY 1993 101 ......TCENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. r-------------------------, CLASSIFIED ADVERTISING RATES ANTIQUE RADIO Advertising rates for this page: Classified ads: $10.00 for up to 15 words plus 40 cents for each additional word. Display ads (casual rate) : $20 per column centimetre (Max. 10cm). Closing date: five weeks prior to month of sale. To run your classified ad, print it clearly in the space below or on a separate sheet of paper & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy Beach, NSW 2097. Or fax the details to (02) 979 6503. ANTIQUE RADIO restorations . Your one-stop radio repair shop. Specialising in restoring vintage radios, including chassis rewiring, re-condensing, quality new parts, valves, valve sockets, speakers, power & audio transformers. Second hand radio dials & parts for most brands & models. About 400 radios in stock for sale, restoration & parts. Every restored wireless is covered by a 2year warranty on parts & labour. We restore damaged woodwork & cabinets & French polish (approx. 40 coats). Vintage car radios available for sale or restoration. Repairs done on tape decks. Open Sat. 10am-5pm; Sun. 12.30-5pm. 109 Cann St, Bass Hill, NSW 2197. Phone (02) 645 3173 BH or (02) 726 1613AH. FOR SALE FRANCHISED TV VCR REPAIR CENTRE with small TV/VCR hire and antenna installations. Central North Brisbane location. 1991 /92 turnover $212,000 (tax returns and trading statements available). Currently operated by two technicians. Premises available for sale or long lease. Room for expansion; eg, computer repair, fax, mobile phones, etc, etc. Forced sale for family reasons. Enjoy the benefits of successful Old trades and services franchise. Get settled in before pay TV arrives. Enquiries to Fixzit, PO Box 672, Lutwyche 4030. Phone (07) 857 6296. Enclosed is my cheque/money order for $_ _ _ _ or please debit my O Bankcard 0 Visa Card O Master Card XI I I Sign ature_ __ _ _ _ __ ____ Card expiry date_ _~/_ __ I I Name _ _ _ _ _ _ __ __ _ _ _ _ __ _ _ __ _ _ __ I I Street _ _ _ _ _ _ __ __ _ _ _ _ __ _ _ __ _ _ __ I I Suburb/town _ _ _ _ _ _ _ _ _ _ __ Postcode_ _ _ _ __ I L _________________________ J Card No. 102 SILICON CHIP WEATHER FAX programs for IBM XT/ ATs *** "RADFAX2" $35 is a high resolution, shortwave fax, Morse & RTTY receiving program. Suitable for CGA, EGA, VGA and Hercules cards (state which): Needs SSB HF rad io & Radfax decoder. *** "SATFAX" $45 is a NOAA, Meteor & GMS weather satellite picture receiving program. Needs EGA or VGA plus "WEATHER FAX" PC card. *** "MAXISAT" $75 is similar to SATFAX but needs 2Mb expanded n. •mory (EMS 3.6 or 4.0) and 1024 x 768 SVGA card. All programs are on 5.25-inch or 3.5-inch disks (state which) & include documentation. Add $3 postage. Only from M. Delahunty, 42 Villiers St, New Farm, Old 4005. Phone (07) 358 2785. NEW ZBO SINGLE BOARD COMPUTER: designed for the 1990s. Also modern kits. Local SAE for details. DIY Electronics, GPO Box 904, Hong Kong. NEW NOTEPAD Computer by Amstrad as advertised on TV. Z80B micro, Builtin Standard Parallel, Serial, Basic, Word Processor, Dictionary, Calendar, Diary, Address/Telephone book, World time clock/alarms, Calculator, PC File transfer. $390 inc post & ins. For more info send a 45c stamp to Don McKenzie, 29 Ellesmere Crescent, Tullamarine 3043. Phone (03) 338 6286. PAY ASIAN PRICES for common electronic components. No minimum. Ask about hard to get items. Local SAE for details. DIY Electronics, GPO Box 904, Hong Kong. FOR SALE: we have a number of Plessey 2001 B-MAC satellite receivers for sale. This model is currently retailing at over $2200.00. These are in good going condition and complete with remote controls and handbooks. If interested, please make a cash or Bankcard offer to: Langridge Electronics, PO Box 290, Norfolk Island 2899, or fax to (0011) 6723 22833. THE HOMEBUILT DYNAMO: (plans) brushless, 1000 watt at 740 revs. $A85 postpaid airmail from Al Forbes, PO Box 3919 - SC, Auckland, New Zealand. Phone Auckland (09) 818 8967 anytime. ON SALE NOW: First Edition Vintage Radio Calendar, in full colour. Featuring a selection of Australia's most photogenic radios. Ideal Christmas gift for friends and collectors overseas. Available from Resurrection Radio, 51 Chapel Street, Windsor, Victoria, Australia 3181. Phone (03) 529 5639. $18.95 plus $2 postage. COMPONENT PACKS, 30 trimpots, Bourns, Beckman etc, mixed values and types including multiturn. 400 metal film ¼W resistors, most are 1% or 2% Beyschlag, mixed values including some E96 and E192 series. 200 carbon film ½W and 1W resistors, most are Beyschlag 1% or 2%. All compo- MEMORY EXPANSION PRICES AT OCTOBER 19TH,·1992 SIMM 1Mbx9 1Mbx3 1Mbx8 4Mbx9 4Mbx8 70ns 70ns 100ns 70ns 80ns $46 $42 $37 $160 $150 DRAM DIP 1 x 1Mb 256 X 4 41256 1Mb x 4 70ns 70ns 80ns (slat) $5 $5 $2 $23 DRIVES SEAG 89Mb SEAG 107Mb SEAG 130Mb SEAG 245Mb 14M 15M 12M 12M $320 $350 $430 $780 IBM PS.2 50/55(70 70/35 90/95 2Mb 4Mb 4Mb $115 $180 $190 TOSHIBA T2000SXe T3200SX T44/6400 T5200 4Mb 2Mb 4Mb 2Mb $260 $135 $345 $135 MAC 2MbSI & LG 4Mb P'Book $83 $260 BOARDS & PTRS 8MbAT W2MB $232 8Mb PS2 W2MB $234 4Mb HP Laser W2MB $155 1MbTI W1MB $80 Sales 1ax 20%. Overnight delivery. Credit cards welcome. Ring for Latest Prices Plans Kits and PCBs 100W Valve Amp PCB............... .. ......... $30 Valve Amp PSU PCB........................ .. ..................... $25 Universal PSU (±5/±12V) Dual Supply ................... $10 Digi 125 100W amp/pair ... .. ...... ___ $1 0 ETI 1623 PIA for PCs ............................... .. ............. $40 Max 1/0 Board .. .. . .. .................................... $40 Max Ki1 ................................................................. $169 LM380 3.5 amp PCB ..... ........................ .. ..... $7 AEM 35W amp kit ............................... .. .................. $20 ETI Audio Toolkit PCB........................... .. ...... $10 AGC Amp PCB . .. ....... $7 Z-80 Miniprocessor PCB... .. ............. $50 6502 Miniprocessor PCB ...................... .. ................. $50 6809 Miniprocessor PCB ....................... .. ...... $50 8048/8049 Developers board complete B&T ......... $199 IBM PC Prototype PCB..................... .. ........... $50 EPROM Programmer .......................... .. ................ $299 ESL-1 Electrostatic speaker kiUpair inc manual ...... $899 ESL· 1 Assembly Manual . .. .................... $50 P.C. Computers (08) 332 6513 36 Regent St, Kensington SA. 1st Floor, 100 Yarrara Rd, PO Box 382, Pennant Hills, 2120. Tel: (02) 980 6988 Fax: (02) 980 6991 PELHAM FIX-A-KIT KIT REPAIR & CONSTRUCTION TRANSFORMER REWINDS 3 MONTHS WARRANTY ON REPAIRS 12 MONTHS WARRANTY ON CONSTRUCTION TECHNICAL ASSISTANCE ALL TYPES OF TRANSFORMER REWINDS HVCAL ELECTRONICS TRANSFORMER REWINDS Design, Manufacture & Repair of Electronic Equipment Reply Paid No.2, PO Box 438, Singleton, NSW 2330. Ph: (065) 761291. Fax: (065) 761003. (02) 633 5477 nent packs $12 ea plus $5 p&p. Japanese transistor pack with two each of 2SA1069, 2SC923, 2SC1826, 2SC3157, 2SD381, 2SD667, $15 per pack. Electronic component pack, 400 items including ICs, transistors, diodes, resistors, trimpots, capacitors, relays, fuses etc. All new components, $25 per pack, plus $8 p&p. Valves, CV3998, 12AX7, 12AY7, 12BY7A, 3A4, 6AM5, 6J7G, all $8 each or 10 for $70 (can be mixed). Open Thursday, Friday 4pm8pm, Saturday 9am-4pm, 143 Grays Rd, Enoggera, Old. Ph (07) 355 1314 or (07) 855 1880 AH. Fax (07) 855 1014. Visa, Bankcard, Mastercard available for fax or phone orders over $20. Secontronics, PO Box 2215, Brookside, Old 4053. 16-CHANNEL UHF REMOTE CONTROL: EA Nov 88-Jan 89. One transmitter kit, one receiver kit, & one 4channel relay driver kit, priced to clear at a total price of $99. Ref XXJAN9401. * 1-INCH CRO TUBE: new 1-inch CRO tube, plus a connecting diagram, plus a simple experimental circuit. Very limited quantities: $30. Ref XXJAN9402. * FIBRE OPTIC CABLE: high quality fibre optic cable, single fibre <at> $2/ metre or 10 metres for $15, dual fibre <at> $4/metre or 10 metres for $30. Ref XXJAN9403. * SWITCHED MODE POWER SUPPLIES: compact enclosed ex-Telecom supplies. Dimensions: 300 x 90 x 180mm. Unregulated input 3050V, regulated output of 12V <at> 6A or 5V <at> 40A. Two different units. Limited stocks <at> $28 ea. P&P $7 (heavy!) . Specify type when ordering. Ref XXJAN9404. * SOLAR POWERED MOTOR KIT: a 6V 50mA solar panel with terminating clips, a very efficient motor to suit, and instructions. Great for education and experimenting. Only $7 per set, or 5 sets for $28. Ref XXJAN93101. * SOLAR LIGHTING BARGAIN: (EA Nov 92) this kit has RC§ RADI[O PTY LTD ~•~1,~Ill D1°1i~I RCS Radio Pty Ltd is the only com- ;=J I 0 pany that manufactures and sells every PC board and front panel published in SILICON CHIP, ETI and EA. RCS Radio Pty Ltd, 651 Forest Rd, Bexley 2207. Phone (02) 587 3491 ]ANUARY 1993 103 JV Tuners - Repairs * Tuner repairs for TVs & VCRs * • • • • Shorted Turns Tester High Voltage Probe _Degaussing Wand Remote Control Tester (02) 7741154 Fax (02) 7741154 Transfonner Rewinds Advertising Index Altronics ................................ 76-78 For all types of transformer re\\ inds. Antique Radio Restorations ..... 102 (065) 761291 Fax (065) 761003 Autotron Australia ...................... 43 A-One Electronics ................ 36-39 Av-Comm ................................... 69 Breakthrough Computers .......... 27 Ian J Truscott's Electronic World EEM Electronics David Reid Electronics ....... ......... 5 Dick Smith Electronics .......... 10-15 \lail or credit card facilities Printed circuit board assembly, s,,itchmode po\\er supplies repaired. Design work from start to finish. Ring anytime 9am-9pm \Ion-Sun. (03) 7233344 Fax (03) 4192808 (03) 4011393 For senice & repair work EEM Electronics ...................... 104 Electronic World ................. 87,104 Emona Instruments ................... 47 Ford Motor Company ............ OBC Geoff Wood Electronics ............. 73 T.A. Mowles Silicon Chip Harbuch Electronics .................. 74 Hycal Instruments .................... 103 Printed circuit boards for the hobbyist. For senice & enquiries contact: To ad,ertise your JJroducts or sen ices. please call Sharon on (08) 3265590 (02)9795644(018)285532 Jaycar Electronics ......... 49-56,IBC JV Tuners ................................ 104 Kalex ......................................... 41 Oatley Electronics ......... 64-65, 103 PC Computers ......................... 103 Pelham ........... .. .. ..... ..... ...... 25,103 three separate sections that are contained on one PCB, but can be separated: (1) a crystal locked ultrasonic movement detector; (2) a fluorescent tube inverter (4-20W) with logic circuitry; (3) a solar battery charging regulator and an incandescent lamp switcherpulser which employs a Mosfet switch. As a package special we are offering the complete kit for the three sections plus six 6V/1 W solar panels for a total cost of only $99! Ref XXJAN93104. * SWITCHES: high quality miniature enclosed, Italian (FEME) 1, 2, 3 and 5pole, 12-position switches: $2.80 ea or 10 for $20. Ref XXJAN93105. * MYSTERY LASER: includes a 12V univer- sal power supply kit, plus a very small, modern, brand new 0.5mW laser tube to suit. To top the bargain, we will include a diverging lens (holography etc) with the deal, for a total price of $79! Ref XXJAN93106. Major cards accepted with phone and fax orders. Total cost of certified p&p: Australia $5, NZ (airmail) $10. Oatley Electronics, PO Box 89, Oatley, NSW 2223. Phone (02) 579 4985. Fax (02) 570 791. SILICON CHIP BINDERS These beautifully-made binders will protect your copies of SILICON CHIP. They feature heavy-board covers, are made from a distinctive 2-tone green vinyl & have the SILICON CHIP logo printed in gold-coloured lettering .on the spine & cover. To order, just fill in & mail the form on page 101, or phone or fax your order to: I I I Silicon Chip Publications, PO Box 139, Collaroy Beach, 2097. Phone (02) 979 5644. Fax: (02) 979 6503. I I I I I I I I I I I ·------------------------~ 104 SILICON CHIP Philips Test & Measurement ...... 31 Plough Book Sales .................... 41 RCS Radio .............................. 104 Resurrection Radio .................... 87 Rod Irving Electronics .......... 90-95 Scan Audio ..........,. ................. 7,71 Scientific Devices ...................... 75 Silicon Chip Binders ........... 42,104 MAGAZINES: approx. 300 various electronics magazines for sale from 75c each plus postage. SILICON CHIP Nov. 1987 & Dec. 1987, $10 ea incl. p&p. Phone Terry on (08) 326 5590. r------------------------• I I I I I I I I Peter C. Lacey Services ............ 44 Silicon Chip Back Issues ...... 96-97 T. A. Mowles ............................ 104 Technical Applications ............... 81 Transformer Rewinds .............. 104 PC Boards Printed circuit boards for SILICON CHIP projects are made by: • Jemal Products, 5 Forge St, Welshpool, WA 6106. Phone (09) 350 5555. • Marday Services, PO Box 19-189, Avondale, Auckland, NZ. Phone 88 5730. • RCS Radio Pty Ltd, 651 Forest Rd, Bexley, NSW 2207. Phone (02) 587 3491. NEW FROM JAYCAR HOT-SOL GAS SOLDERING IRONS Jaycar Electronics proudly announce a new force in gas soldering irons. The Hot-Sol needs no cords or gas bottles. Al I you need is standard Butane cigarette Iighter gas which is available everywhere. The Hot-Sol has adjustable temperature control , you can vary it from the equivalent of 10 to 60 watts. Features include: • Built in gas igniter. • Totally see through case - see how much gas you have left at a glance. • Supplied with protective cap with Pocket Clip. • Fu lly portable, always ready to use. • Heavy duty, tip temperature up to 400°C. • Hard working, one fill will last over an ho • Refills in seconds. • Low cost. ::< • No leakage current to sensitive circuits. J..~ A v. • Spare tips available, and they are not expensive. • Hot blow tip available. Supplied with 2.4mm tip. • 1 year warranty on unit. Hot-Sol Gas Soldering Iron ONLY $ HOT-SOL SERVICE KIT Th is kit includes the same soldering iron , but comes with a range of accessori es, and its all housed in its own case. Includes: • Hot-Sol Butane Gas Tool. • Protective cap and pocket clip. • Non slip stand with sponge. • Torch Tip which gives a flame. • 2.4mm Soldering Tip. • Hot blow tip for shrinking heatshrink tubing. • Scoop for feeding tub ing to hot blow tip. • Hot knife tip. • Roll solder. • Case which holds everything. MAIL ORDER VIA ~ FREE CALL FOR OROERS ONLY (008) 022 888 HOTLINE (02) 743 6144. ·-......_\ ~"' ■ VISA Optional Extras: • 1mm Soldering tip with catalyst. Cat. TS1704. $9.95. • 2.4mm Soldering tip with catalyst. Cat. TS1705. $9.95. • Hot air tip for heatshrink. Cat. TS1708 $9.95. • Sma ll stand to suit so ldering iron. Cat. TS1720 $3.95. Flame Torch Tip Cat TS1710 $3.95. $64 95 ■ i~'P.if1rn r;.:~ t::~ :~:~~~;~: :.~i:fi~~1f IN OVER $100 $8.00 AUSTRALIA (up to 20kg) $13.50 4~~~~i Fax (02) 743 2066. 138 i;-yl!J <.;~ ~-- ;'ll ._ 1~- - ADELAIDE SA 190 Wr ight St (Cnr Selby SI) (08) 231 7355. Mon- Fri 9-5.30 Fri 8.30-Sal 9- 12. BURANDA QLD 144 Logan Rd (07) 393 0777 Mon -Fri 9-5.30 Thurs 8.30-Sat 9-4. COBURG VIC 266 Sydney Rd (03) 384 1811. Mon-Fri 9-5.30. Fri 8.30-Sal 9-4. MELBOURNE CITY Shop 2, 45 A'Becketl St City (03) 663 2030. Mon-Fri 9-5.30 Fri 8.30-Sat 9- 2. SPRINGVALE VIC 887-889 Springvale Rd Mulgrave (03) 547 1022. Nr Cnr. Dandenong Rd. Mon-Fri 9-5.30 Fri 8.30 - Sal 9-2. SYDNEY CITY 129 York SL (02) 267 1614. Mon-Fri 8.30-5.30 Thurs 8 30pm - Sat 9-4. BANKSTOWN 363 Hume Hwy Cnr Meredi th SI (02) 709 2822. Mon-Fri 9-5.30 Thurs 8. 30pm - Sal 9-4 - Sun 10-4pm GORE HILL 188 Pacific Hwy (Cnr. Bellevue Ave) (02) 439 4799. Mon-Fri 9-5.30 Thurs 8.30 - Sat 9-4pm PARRAMATTA 355 Church St (Cnr Victoria Rd) (02) 683 3377. Mon -Fri 9-5.30 Thurs 8 30prn - Sal 9-4pm Sund ay 10am-4pm PENRITH 199 High SL (047) 21 8337 Mon-Fri 9-5.30 Thurs 8.30 - Sal 9- 4pm Sun 10-4pm. RHODES 6 Leeds SL (02) 74 3 5222. Mon-Fri 9-5.30 - - -- - - -- -- - -- -- -- - - - - - - - - - - - - -- - - - - ~