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www.siliconchip.com.au April 2002  1 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Contents www.siliconchip.com.au Vol.15, No.4; April 2002 FEATURES 7 How To Get Into Avionics Working with aircraft electronics is a fascinating career but how do you get started in it? – by Daniel Field 14 At Last – An Easy Way To Make Pro Panels One-off panels and labels have been a problem for years. Now a new process makes it easy – by Ross Tester 19 Better Cooling Systems For Car Engines New thermal management systems will replace traditional radiators and coolant pumps 25 Volvo’s Integrated Starter Generator It pumps power back into a 42V battery when you slow down and promises fuel savings of up to 20% PROJECTS TO BUILD Automatic Single-Channel Light Dimmer – Page 26. 26 Automatic Single-Channel Light Dimmer It’s fully automatic, has a host of features and will drive incandescent lamp loads up to 2400W – by John Clarke 34 Build A Water Level Indicator Low-cost circuit lights a LED bargraph to indicate the level in a rainwater tank – by Allan March 48 Easy-To-Build Bench Power Supply It runs from a 9VAC plugpack and offers six fixed dual-polarity DC voltages from ±3V to ±15V – by Jim Rowe 60 Versatile Multi-Mode Timer Versatile timer is based on an Atmel microcontroller and has seven different operating modes – by Frank Crivelli & Peter Crowcroft Water Level Indicator For Tanks – Page 34. 70 6-Channel IR Remote Volume Control, Pt.2 Second article completes the construction – by John Clarke COMPUTERS 58 Computer Tips More FAQs on our MP3 Jukebox player – by Peter Smith SPECIAL COLUMNS 40 Serviceman’s Log Who said servicing was dying? – by the TV Serviceman 78 Vintage Radio Multi-Output Bench Power Supply – Page 48. The AWA 719C 7-band console; Pt.2 – by Rodney Champness DEPARTMENTS 2 4 45 69 84 Publisher’s Letter Mailbag Circuit Notebook Subscriptions Form Product Showcase www.siliconchip.com.au 90 93 94 96 Ask Silicon Chip Notes & Errata Market Centre Advertising Index Versatile Multi-Mode Timer – Page 60. April 2002  1 PUBLISHER’S LETTER www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Rick Walters Reader Services Ann Jenkinson Advertising Enquiries David Polkinghorne Phone (02) 9979 5644 Fax (02) 9979 6503 Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Julian Edgar, Dip.T.(Sec.), B.Ed Mike Sheriff, B.Sc, VK2YFK Philip Watson, MIREE, VK2ZPW Bob Young SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $69.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: Unit 8, 101 Darley St, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silchip<at>siliconchip.com.au ISSN 1030-2662 Electronics in cars: the improvements keep on coming This month, we have two short stories concerning continued developments in cars. Both involve the application of electronics and both aim to improve fuel economy, passenger comfort and so on. The Volvo development, involving the replacement of the starter motor and alternator with the “integrated starter genera­tor” is particularly interesting, in that it is another approach to a hybrid motor vehicle like the Toyota Prius or the Honda Insight which were featured in our December 2001 issue. In general, hybrid vehicles gain most of their fuel economy improvements because the internal combustion motor only runs when needed and does not run when the vehicle is stationary (ie, otherwise at idle) or running downhill. However, when you look at the whole thing dispassionately, it is all “fiddling around the edges”, isn’t it? Few people are really concerned about fuel economy or “saving the environment”. If we were, very few large 4-wheel drive recreational vehicles would be sold. Nor for that matter, would most of the large six and 8-cylinder cars be sold. Most people would contentedly drive around in small 4-cylinder cars which are perfectly capable of keeping up in today’s traffic. Or they’d take public transport. Or walk! Perish the thought. To take matters further, if there was a real drive to obtain seriously better fuel economy, there would have been a much bigger effort to eliminate the internal combustion engine from cars. Until that happens, the internal combustion engine and our continuing love affair with ever-more powerful cars will continue to be the limiting factors in “saving the environment”. Do we really care? Not really. I must own up myself. I like a big car – I don’t like driving a little four-banger. And if in the future, all-electric vehicles become readily available, I still don’t see myself driving something small and slow. I want space and I want some “oomph” when I push the pedal down. Most people are the same. So is there any hope? Of course there is. Electric cars with heaps of performance will eventually become available. They will be silent, economical and they will be attractive to drive. But it is also a fair bet that they won’t be battery-driven. They will still run on petrol, LPG or some other hydrocarbon fuel and they will have fuel cells to drive the electric motor. Ultimately this is the only practical solution, short of governments making conventional cars illegal. That’s not likely though, in democratic countries at least. So is the fuel cell coming? Is it just a pipe dream? Indeed, it is not. Fuel cells are coming, although it might be 10 years before they become really practical in motor vehicles. Until that time, try to drive a little more economically. And we will bring you the stories on fuel cells in the months to come. Leo Simpson * Recommended and maximum price only. 2  Silicon Chip www.siliconchip.com.au Video Signal Conditioner/ Stabiliser USB Manual Data Switch The 4 port USB manual switch allows up to four PC’s and/or Macs to share the use of a single USB peripheral device (printer, scanner, modem, etc), on a one-at-a-time basis. Cat 12049-7 $33 Improve results when recording DVD’s. This simple device installs between the program source and the recording device to remove the jitters that frequently mar your backup copies. Cat 3431-7 $135 Ethernet (Network Interface) Card PCI Intel 21143 10/100 Mbps. Designed for file server applications, the Intel 21143 chipset (formerly known as the DEC 143), will deliver high networking performance. The 21143 features a high-bandwidth PCI interface and extended PCI commands to maximize data throughput and device utilization. It incorporates a powerful on-chip DMA capability to minimize CPU overhead and also features interrupt mitigation on transmit and receive; this batching mechanism can increase Windows NT* server performance by lowering the CPU overhead. Cat 11332-7 $109 USB Macro Switch Close a switch and run a Macro-USB Interface. Store multiple keystrokes or complex commands and send them to your computer by simply closing a switch. There are 12 switch inputs which can share over 900 keystrokes. The inputs consist of 3.5mm mono phono sockets. Software supports Win 98/ME and Mac OS 8.5+. Cat 8936-7 $319 Get Rid of the PS2 Octopus!!! 2 or 4 Computers, but only 1 keyboard, mouse and monitor. USB technology does away with the tangle of cables normally accompanying KVM switches. Huge space and ergonomic benefits! Cat 11658-7 2 way USB - KVM Switch $219 Cat 11659-7 4 way USB - KVM Switch $449 Cat. 11519 LAN Testers Test a range of Modular cables including 10Base-T (Categories 3 to 5), as well as AT&T 258A, EIA/TIA and Token Ring. Includes remote terminator (8 wire tester). Cat 11516-7 $124 Cat 11512-7 $149 Cat 11515-7 $187 Cat 11519-7 with LCD Display $227 fibre solutions Fibre optic converters allow RS232 or RS422 signals to be converted to fibre optic for long distance, high speed & high quality communication. Cat 15073-7 $609 Cat 15074-7 $665 Cat. 11326 Ethernet 100BaseTX to Fibre SC/ST Converter. Convert fibre optic to UTP or vice versa in minutes without replacing equipment, re-configuring existing equipment or re-wiring your network. Cat 11325-7 $365 Cat 11326-7 $402 Cat. 11328 Ethernet MII to 100Mbps Fibre ST/SC Converter. These 100Mbps Fast Ethernet transceiver provides one MII (media independent interface) connector and one 100BaseFX port (ST/SC connector) that can connect to a multi-mode fibre optic cable. Cat 11327-7 $435 Cat 11328-7 $354 Cat. 12052 USB Sharing Switch 2 or 4 PCs Share 1 USB Device or Share one USB device between 2 or 4 computers. Easily share USB printers, IRDA adapters, Zip drives etc. Computer uses the peripheral on a first come first served basis. Cat 12053-7 2 PCs/1 USB device $89 Cat 12054-7 4 PCs/1 USB device $139 Cat 12052-7 4 PCs/3 USB devices $189 Memory Card Reader/Writer CF SM MMC SD MS&MD - USB. Six in 1. Will read and write Compact Flash, Smart Media, Multimedia, Secure Digital and Memory Stick & IBM MicroDrive memory cards via a USB connection. Will operate with Win 98 or later, & Mac OS 8.6. Cat 6678-7 $229 USB Four-in-one Reader Four in 1 - Will read and write Compact Flash, Smart Media, Multimedia & Secure Digital memory cards via a USB connection. It will operate with Win 98 or later and Mac OS 8.6. Cat 6658-7 $199 USB 2.5” (Notebook) External Drive Case Thin Client Terminal This Colour TCP/IP terminal is the replacement of choice for critical applications. Providing support for a broad range of popular operating environments and most WYSE emulations. If you need your network replacements up and running quickly, and reliably, these terminals are the answer, especially in harsh environments. Cat 1134-7 $579 Imagine.. Plug n Play, 40Gb or so in your pocket (easy to install your own drive). Also available in a Firewire version for really serious speed. Cat 6653-7 USB Cat 6659-7 FireWire Cat. 6653 $139 $289 Satellite/Cable TV to every room This compact unit pumps your favorite Video (or audio) program to any room without wires. The quality remains excellent. Send the same signal to every room if you like (with additional receivers). Cat 11808-7 $299 Australia wide express courier $15 (3kg max) Dealer Enquiries Welcome! Vamtest Pty Ltd trading as MicroGram Computers ABN 60 003 062 100, Phone: (02) 4389 8444 FreeFax: 1 800 625 777 Unit 1, 14 Bon Mace Close, Berkeley Vale NSW 2261 sales<at>mgram.com.au All prices subject to change without notice. Pictures are illustrative only. info<at>mgram.com.au SHOREAD/MGRM0402 Ground plane antenna works well I have recently completed the “Elevated Ground Plane Anten­na” from the February 2001 edition of SILICON CHIP. Reception has improved greatly, compared with the “rubber duckie” and will soon be mounted up in the roof, mainly for use on the club’s Sunday net. There’s a small trap for the unwary, myself included. Half-inch copper pipe in NZ has an internal diameter of 0.5-inch while the Australian counterpart has an external diameter of 0.5-inch. Calcula­tions showed that the radiator would need to be 0.3-inch diameter, an unlikely purchase other than in copper pipe which would be from a coil and tricky to straighten. A friend was holidaying in Mel­bourne and brought back a piece of pipe which made things a lot easier. I couldn’t buy a 110mm square of 1mm brass sheet (the minimum sale was half a sheet), so a piece of single-sided fibre­glass PC board was used. Otherwise, it’s made strictly to your design. The demountable radials are a great idea, particularly when accessing the roof space. I used the club’s MFJ antenna analyser to check the antenna. With the analyser connected directly to the PL259, the following frequency/SWR/Z (resistance) readings were noted: 144MHz-1.7/35; 145-1.4/35; 145.5-1.2/33; 146-1.03/32; 146.61:1/30; 147-1:1/30 and 148-1.2/25. These figures were obtained after the radiator had been shortened by 10mm. There’s still a mismatch of 30-50 ohms but our net frequency is 146.575MHz 4  Silicon Chip and I’ve decided to leave things as they are. On a general note, I’m pleased to see projects coming through where things have to be made but how popular they will be, only time will tell. I taught metalwork, woodwork and techni­cal drawing for some years but the formal teaching of the practi­cal subjects has all but gone here and, I believe, to some extent in Australia. A recent editor in “House and Home” magazine sug­ gested people should go to night classes to retrain in these subjects. I was sorry to see “Electronics Australia” fall by the wayside but you’re doing a great job at SILICON CHIP. Keep up the good work. The antenna is a very good design and I enjoyed making it. B. Toomey, Bucklands Beach, NZ. nents seems rather superfluous to me. Unless there is some necessity to obtain very close track layouts or component pack­ ing, Veroboard is quite adequate for most circuits. When constructing a circuit on Veroboard, I find it very helpful to draw a diagram of the component layout on a grid of dots which matches the holes in the Veroboard and then glue this on the top side of the board. To locate the position of each break in the tracks, I push a pair of map pins through the paper and the Veroboard holes underneath on either side of the required break. When the board is turned over, the location of the break is obvious and mistakes are virtually eliminated. A photocopy of a layout published in a magazine of course makes it even easier! R. Hancock, Port Elliot, SA. Comments on Veroboard Electric power history wanted Your remarks concerning the use of Veroboard in the Motor­cycle Alarm project, January 2002, to the effect that you “don’t like it much” seem a little enigmatic. I assume the reason is that some constructors have difficulty in correctly locating the components and track breaks. Personally, I prefer to use Veroboard for relatively simple circuits and would be delighted if electronics mag­ azines produced a Veroboard version of all their projects where complex PC boards are not required. Producing a special PC board for something with less than a couple of dozen compo- I was quite taken with the letter from Dick Smith in the January 2002 issue in which he suggested an article on the Aus­tralian 3-pin mains plug/ socket. I wouldn’t mind seeing an article about our AC mains in general. Why do we have 240 volts and why do the Americans have 110? What scientific reason is there for either voltage? (Prob­ably none.) Why do the American also have two-pin plugs/sockets and no earth wire? Why do the British Isles have about three different plugs/sockets for their 240VAC mains? Wouldn’t one do? I also believe Western Austral- www.siliconchip.com.au ia has a slightly different voltage from the rest of the country. Do we know why this is? I seem to recall that one of the electronics magazines did something along the above lines some years ago. It may have been in SILICON CHIP – I can’t remember exactly. Perhaps you may consider an article on the AC mains around the world for the future. I, for one, would be interested in it. B. Freeman, Morphett Vale, SA. More on Australian mains plugs Following on the letter in March issue on how the Austra­lian mains plug came about, it’s an interesting question as to what happened to the original 3-pin design in the USA. I’ve only seen reference to it in US wiring and DIY books up until the 1950s. It was used only for 240V applications like ranges, dri­ers, etc. Obviously it was meant to be incompatible with their conventional 120V 2-pin design (although as we know a slight twist to the pins with a pair of pliers will overcome that). I should also point out that our/ their 3-pin design was not the only one in use. There was, and still seems to be, an assort­ment of pin shapes and patterns for 240V use in the USA, without any standardisation. For example, the (240V) DEC PDP11 etc, computer equipment I’ve worked with has what looks like a modern US 3-pin plug but the blades are at right angles. As for the US 3-pin 120V plug, it seems that this didn’t become popular until the 1950s and then only for things like power tools. In fact, I can’t recall having seen it at all in any of the old literature I’ve read prior to this time. Things like washing machines were earthed directly to the closest water pipe. You could also purchase (and I have such one example) an adaptor to convert a 2-pin outlet to take a 3-pin www.siliconchip.com.au plug. It’s a Bakelite moulding with a 2-pin plug one side and the 3-pin socket on the other, with a short wire protruding, intended to be screwed under the cover plate screw of the outlet, the idea being that the earth return is via the metal outlet box and earthed conduit. John Hunter, via email. Endorsement of editorial content Keep up the great work on SILICON CHIP! Please don’t change anything. However, as a suggestion, why not ask readers to submit a photo of their SILICON CHIP project in use, or maybe have a featured reader with all the SILICON CHIP projects that he or she has constructed? I liked the item in the January 2002 issue, on how a reader submitted a picture of his video scope. It is good to see the high standard quality of work pro­duced by the readers. In many instances, producing the case and the front panels can take almost twice as much time to make as the inner working parts of the project. Recently I made the ±18V 1A power supply (SILICON CHIP, January 1988) from scratch, making the PC board, sourcing the parts, then making the front panel out of aluminium, powder-coating it, then using Letraset (rub on lettering) for all labelling and finally spraying on lacquer to prevent the letters from coming off. It looks as though it has just come off a production line, with the difference being that it took almost 4 weeks to build as opposed to a production line making it in a few hours! Attila Palotas, via email. Electronics Australia Congratulations on picking up the EA flag. I first read “Radio and Hobbies” about 50 years ago and picked up much of my electronics know­­ ledge from its articles. I was disap- pointed to see EA become a lifestyle magazine and SILICON CHIP has been the only thing to keep the electronics enthusiast satisfied. The fact that you have elected to maintain the EA back issues, web page, etc is to be lauded. Others may have just cast the whole lot of history out with the rubbish. I appreciate the SILICON CHIP stance and hope that the SC/EA combination has a long and fruitful future. Doug Rickard, Coomera, Qld. Deja vu with Diason vintage set Well, was I delighted when I opened my February 2002 issue of SILICON CHIP? There it was, my Diason radio of 32V country lighting plant fame. I dusted off the one I have and had a good look and rattled my memory banks – it is not quite the same as in the article. I believe this one has 6SK7 RF; 6A8 converter; 6SK7 first IF; 6SK7 2nd IF; 6AR7(?) detector/first audio; and a single 32L6 audio output – yes 32L6! An easy heater string arrangement and lots of selec­tivity. In mine, there is another IF can above the 32V sticker in your photo on page 83. The cabinet and chassis is otherwise identical and I note a Rola 8H speaker, stamped 21 Nov 1951. Unfortunately, during my RMIT & amateur radio days in the late 1960s I rebuilt it with miniature valves for 240V; boy was it wild! It was used here near Corryong up until FM became avail­able. However, I distinctly remember how few components were present underneath in its 32V form. It was an excellent perform­er. As a kid, I used to listen to the Argonauts on 2CO (Corowa) our nearest station, but later go to 2GB Sydney for Hop Harrigan and other kids radio. The family would often turn to 3AR or 3LO Melbourne during the day for news, etc from Victoria. Yes, its audio output was dismal – but distortion was only really April 2002  5 noticeable when the batteries were down and I remember my father going to lots of effort to suppress the generator. The residual whine was OK and used to follow the beat of the old “Hit & Miss” engine on the generator, as did the dial lights. I must restore it to its original 32V form; the mechanicals and speaker are fine, ply lifting here and there. Hugh Paton, via email. More on the Diason vintage set Following Rodney Champness’s excellent article on the Diason PP 32/6 DC receiver in your February 2002 issue, here are some facts that I have discovered about this firm. It was founded in 1947 by Mr Colin Leason, a former toolmaker, to manufacture radios and sound systems. These activities were first performed in a flat at 5 The Avenue, Balaclava, and later at 10 College Street, Gardenvale (both Melbourne suburbs), where Mr Lea­son’s parents lived. With his wife Myrtle as a partner and Mr Kevin Peterson, he continued until 1978, at that time concentrating on guitar ampli­fiers and pickups. As mentioned in my article in the October 2001 issue of HRSA Radio Waves, the name “Diason” was coined from the first and last syllables of his daughter’s name – DIAnne LeaSON. Diason was one of a number of small but not insignificant firms in Austra­ lia’s postwar radio history. Bill Smith, Editor, HRSA Radio Waves. PC infrared transceiver appreciated Thanks for the “PC Infrared Transceiver” project featured in the December 2001 issue. I had a need for such a device for the last year and this one fits the bill perfectly. For over a year I have been writing SIR and FIR drivers for a Linux hand­ held computer project, along with 6  Silicon Chip some core applica­tions that used those drivers. The IR software stack evolved into a data transfer medium that could transfer true Internet Protocol (TCP/ IP) through it. If I were to draw the whole stack in picture form it would be higher than “Princess and the Pea” mattress stack. Your project arrived at a time where I could apply it imme­diately. Needless to say, it is a real buzz to see it all working. Now I, and a few colleagues, will be able to attach our Linux based handheld computers straight onto the Net via this IR pro­ject. Have you thought of a project that uses low-power short-range radio transceiver modules to do a similar job? Kevin Bertram, via email. Wright Audio Developments AM tuner Does anyone remember the Wright Audio Developments AM tuner produced around 1974? It was said to outperform the contemporary Quad tuner. The designer now lives in Germany and tells me he lost all his circuits. Does anyone have a circuit for this? It had a FET bandpass front end, autodyne mixer (I think), manual IF gain and Aegis coils. David Collier, GPO Box 1755, Canberra, ACT 2600. Shutdown for “no keyboard” computer Here is a suggestion for a small addition to your very useful “No Keyboard” project in the February 2002 issue. In not having a keyboard on a computer you can sometimes get stuck by not being able to reset or shut down the computer cleanly. By adding a switch which shorts the necessary lines into the keyboard controller to simulate a “Crtl-Alt-Del” key press, one will be able to reboot the computer. To find the lines to short, trace the tracks on the key matrix membrane or PC board. “Crtl-Alt-Del” is especially useful for Linux since this performs a clean shutdown and reboot of the system. If other keys are needed (F1, for example), these could be added as well. A useful addition would be one of the function keys as­signed as a shortcut to cleanly shut down Windows. Karl Gramp, Athelstone, SA. Vintage Radio on the Internet People interested in Vintage Radio can find plenty of information on the internet. Below are some sample links. Historical Radio Society of Australia http://goanna.cs.rmit.edu.au/~dnl/ hrsa.html South East Qld Group of the HRSA http://seqg.tripod.com/ OZ-Wireless Email Chat Group http://www.clarion.org.au/wireless/ SEQG Crystal Set Competition 2000 http://www.clarion.org.au/crystalset/ SEQG One Tube Radio Competition 2001 http://seqg.tripod.com/onetube/ onetube.html How to build the mystery Crystal Set, A Great Aussie Crystal Set. http://www.clarion.org.au/crystalset/ mystery.html Antique Radio Forum http://antiqueradios.com/cgi-bin/ forums/ Rap ‘n Tap Crystal Set Chat site. http://www.midnightscience.com/ rapntap/ Ray Creighton, Everton Hills, Qld. Manual wanted for video monitor I have a badly behaving monitor belonging to my son. It is a KTX model CAD 415S – does anyone have a circuit diagram and overlay? Or know where I can obtain same. Kathy Gluyas, 14 William St, Donvale, Vic 3111. www.siliconchip.com.au HOW TO GET INTO AVIONICS Ever wondered how to get into Avionics? That’s short for Aviation Electronics, a field that can be very challenging and satisfying. This article looks at the work of a typical avionics maintenance engineer and tells you how to proceed if you want a career in this area. By Daniel Field O utside my window the engine shut down. It had been running for barely a minute. Curious, I walked onto the tarmac to see what the problem was. The pilot looked at me with the slightly bewildered gaze of someone whose detailed planning has suddenly become worthless. “The radios don’t work,” he said, without any emotion. “I can hear, but no-one’s responding to my calls.” It was the same on both the VHF radios, he told me, and he hadn’t tried the HF yet. I started checking the standard causes. First, I gave his microphone plug a firm push to make sure it was in properly. “Click”. Ah, that might be it. I flicked the power back on and called the control tower. No worries. I tried the second VHF radio. That’s good too. www.siliconchip.com.au Thanking me profusely, the pilot said it was a good thing, because he had left his lunch box in his car and he would have left without it. I went back inside, shaking my head. Just another minor occurrence in another very busy day in the life of an Avionics maintenance engineer. Avionics is an abbreviation of “Aviation Electronics”. In the aircraft maintenance industry, an Aircraft Maintenance Engineer (AME) in avionics looks after all the electrical, instrument and radio systems. This may include installing, maintaining, troubleshooting and repairing avionics systems and components. If you want to get into avionics, you need to know which avenues to try. Do you want to cut your teeth on the big stuff? Are you strictly a hi-tech person? Are you willing April 2002  7 Cessna 208B Grand Caravan with some instruments out. Top: engine instruments with warning panel in front of pilot. Left: flight & navigation instruments. Centre: (“right” in the picture): radios, radar, autopilot and GPS. to work your way up from the bottom? I hope this article will help answer these questions. First, let’s introduce the three main branches of Aviation: Military The Army, Airforce and Navy provide excellent training in Avionics. You can join from 17 to 48 years old. You will be trained initially in Wagga Wagga, NSW, then on-the-job in Oakey, Qld. The training gives you the same qualifications as a civilian course. After getting your trade you will be posted to a base in a location such as Townsville or Darwin. Your initial enlistment will be for six years. In the military, your job description will be broader than most civilian aviation jobs. In addition to the standard work on aircraft you will learn to service the ground and test equipment while also being a soldier. Pros: Consistently high quality training. A system that gives you room for advancement. Respect from the industry. Cons: Military experience does not automatically transfer to an avionics licence in “civvy street.” While your training itself is recognised, it can be very difficult to get any official recognition for your experience. The basic reason for this is that military aircraft are not on the civil register. Therefore the Civil Aviation Safety Authority (Australia’s aviation regulatory body, generally known as “CASA”), does not have any authority over military aircraft nor the work done on them. At the same time, CASA is responsible for issuing avionics licences in civil aviation. 8  Silicon Chip I should explain that: without a CASA licence, you can work on civil aircraft but you won’t get paid very much. People with military experience outside of CASA’s authority find that their experience may not count towards a licence. Some of the military trained people I know have had frustrating experiences trying to get civilian licences without effectively going back to the end of their apprenticeships. But it can be done and once you go through the process you should find that the industry generally accepts and respects military experience. To find out more, try www.defencejobs.gov.au or contact the Australian Defence Force Recruiting Centre on 13 19 01. Airlines This is the “heavy metal” side of aviation. Airlines fly anything from 19 seaters and smaller to the massive Boeing 747-400 series and the planned full length double-decker Airbus A380. In the airlines you will generally work on advanced, complex avionics systems built for reliability. You may not realise that there are several significant airlines in Australia; not just Qantas and Virgin Blue. The regional and subsidiary airline market with 30 to 100-seat aircraft is seen as the growth sector within the airline industry worldwide. If you want to fly between, say, Albury and Canberra, or Brisbane and Rockhampton, you could book a ticket through Qantas but you would actually fly on one of Qantas’s subsidiary airlines such as Airlink, Eastern Australia www.siliconchip.com.au A Sunair HF power amp with one valve missing. (Yes, valve!). Trying to find the cause of intermittent transmit on this twenty-something-year-old Cessna radio. Airlines, Southern Australia Airlines, Sunstate Airlines or Airconnex. (and I mean actually work on them), do yourself a favor and do not put a degree at the top of your list of options. That leaves us with Apprenticeships. Apprenticeships have two outstanding advantages: 1. You get paid while you learn. 2. You work as you learn, so you get to touch, break, smell, see, repair and play with the things you are learning about. When you come out of an apprenticeship you are fully ready to do the work. Perhaps I should introduce myself. I am a fourth year apprentice in General Aviation. I work on mail planes, charter planes, trainers, small freighters, some small regional airliners and the Royal Flying Doctor Service aircraft. I install, maintain and repair all sorts of electrical, instrument and radio systems and components. When you look at apprenticeships, it’s worth thinking about the differences between the airlines and General Aviation. In the airlines you will work on more advanced avionics in larger aircraft. The large airlines train you to work in a specific area: Line Maintenance, Heavy Maintenance or Component Overhaul. Line Maintenance means “turnaround” checks and trying to quickly solve problems that have recently come up. This usually involves “box swapping” until you find the box that is faulty and then send it away for repair. Heavy maintenance means checking and repairing avionics systems while the aircraft is in the hangar for several days or weeks for a major routine inspection. This is also a box swapping job, as well as checking and repairing the several kilometres of wiring running all over the aircraft. Component Overhaul is the benchwork side of aviation: testing and repairing the “boxes” – generators, instruments, etc, that have been removed by the line or heavy maintenance techs. The bench techs may overhaul electric motors, repair and calibrate instruments or test and repair electronics to board or component level. The great thing about General Aviation is that you can do it all! I spend about 50% of my time doing “line maintenance” (including 100 hourly checks), about 30% doing “heavy maintenance” such as modifying systems, installing new equipment and chasing faults that have not been solved General Aviation GA is the “everything else” of civil aviation. This includes private owners, charter operators, corporate aircraft and some freighters. The majority of GA is single-piston- engine aircraft; some new, some old. At the glamour end you have twin-jet aircraft from tiny six-seaters to multi-office-and-boardroom jets designed for productive long-haul flights. So how do you get into Civilian Avionics? There are two main approaches: 1. An apprenticeship. 2. Tertiary study. Tertiary study probably sounds like a great idea. It is, as long as you keep in mind that people with degrees generally don’t get to work on aircraft. For example, you could do a Bachelor of Engineering in Aerospace Avionics at Queensland University of Technology. This course “...prepares students for careers in the expanding field of aircraft and spacecraft instrumentation and in associated ground equipment.” You would find that the course is quite deep mathematically and also covers management considerations. By the end of the course you will know more about Avionics than the best tradesman. But with only three months of work experience you probably won’t be able to remove a gyroscopic instrument from a Cessna single without breaking something. Compare that to a certificate IV in Aeroskills (Avionics) at Kangan Batman TAFE, also known as the trade course. It prepares students for “...employment with international and domestic airlines, in aircraft production and refurbishment, and corporate and general aviation.” This course is light on theory compared to the degree (though you still learn a lot). Students will generally be working in the industry for about eight or nine months per year and will be fully ready to work as Aircraft Maintenance Engineers the day they finish. If you want to get into design then yes, get a Bachelor of Engineering, or perhaps an Advanced Diploma in Avionics. But if you want to work on aircraft avionics systems www.siliconchip.com.au April 2002  9 Cessna Grand Caravan battery, standby instrument vacuum system and high energy ignition units. Our 2nd year apprentice getting access to a Cessna P210 instrument. by box swapping and about 20% of my time doing “component overhaul” in our radio workshop. Practically every GA outfit does line and heavy and a large percentage also do component overhaul. In the airlines you may work on three or four different aircraft types, or possibly specialise in only one or two, for example, Boeing 737-300 and 737-400. In GA, you will work on more types than you can remember. A sample of my own list is: Cessna 172, 182, 206, 207, 210, 402, 404, Beech Bonanza, Baron, Piper Seneca, Cherokee, Lance, Navajo, Chieftain, Shrike Aero Commander, Parten-avia (all single and twin piston engine aircraft, up to ten seats), plus Cessna 208B Grand Caravan, Pilatus PC12, Beech Kingair 200, Fairchild Metro 23, Embraer Brasilia (all single and twin turboprop aircraft from 10 to 30 seats), plus Robinson R22, R44, Bell 206 Jetranger (helicopters). These are just the ones I had worked on at least a few times within my first two years of avionics. Any work that is done on an aircraft or its components must be certified. To certify work you must have an Aircraft Maintenance Engineer’s Licence. These licences are issued by CASA. How to get a licence is another story altogether. For now, you should know that only a select few in the airlines ever get a CASA licence. In General Aviation almost the reverse is true, with nearly everyone encouraged to get at least one licence. Having or not having a CASA licence is one of the biggest single factors effecting your income in civil aircraft maintenance. In the airlines, unlicenced workers are paid more than in GA. The basic reasons are that the aircraft are in a different legal classification because they carry fare-paying passengers on regular routes and they are over 5,700kg which puts them in a different category for CASA licences. An airline apprentice generally has a higher base wage than a GA apprentice. Table 1 shows the wages for both Qantas and GA apprentices. When you finish your apprenticeship with Qantas your wage would be about $610.00 per week if you don’t work on aircraft and about $640.00 per week if you do. It is very important to realise that most of Qantas’s finishing apprentices will not work on aircraft: they do component overhaul in workshops. If you do component overhaul it is unlikely that you will ever get a CASA licence. Qantas only fills licenced positions as they become vacant and they choose people based on performance and qualifications. Qantas also offers a Graduate Trainee Program so you can follow your apprenticeship with an engineering degree. For those who get neither a licence nor a degree, your prospects are to progress through the Qantas ranks to Maintenance Supervisor or a job in management. Alternatively you could move “sideways” into another related industry such as industrial motor overhaul, consumer electronics, etc. On the other hand, when you finish your apprenticeship in General Aviation your base wage would be about $480.00 per week (minimum). The major and very important difference is that you will almost certainly be very close to getting your first CASA licence. All it requires is some aptitude and effort. Once you have your first licence your wage will jump to around $530.00, depending on which licence it is. Within a year of your apprenticeship ending, if you put in the effort, you could have Electrical, Instrument and Radio licences in multiple categories. This would set your minimum wage around $750.00 per week. Depending on which licences you have, you could be highly sought after. If all you want is the money then you can get certain hard-to-find licences (certain helicopters, or the latest bizjets, for example.) Typical wages in this niche of GA are around $50,000 to $65,000 per year in Australia and possibly that much in US dollars if you are willing to work in God-forsaken countries of the world at all hours. Airlines generally advertise their apprenticeships in major newspapers. However, if you really want to get an 10  Silicon Chip Table 1: Weekly Rates of Pay for Avionics Apprentices Qantas General Aviation 1st year $269.00 $171.40 (minimum) 2nd year $352.50 $224.50 (minimum) 3rd year $480.40 $306.10 (minimum) 4th year $563.70 $359.10 (minimum) www.siliconchip.com.au Replacing a lighting dimmer pot in a Super Kingair used for charter work. airline apprenticeship then you should contact every airline you can think of, get their application forms, and apply. Remember to contact every regional and subsidiary airline that you can, not just Qantas. During my apprenticeship I studied with two Ansett avionics apprentices. The word on the street was that about 2,000 people applied for Ansett apprenticeships that year. About 60 were taken. Of those 60, only two were put on as avionics apprentices. That’s two out of two thousand applicants. It is only fair that I tell you at the time Ansett ceased operations, both those apprentices felt that they would most likely end up in component overhaul, even though they both wanted to do line maintenance and they were entirely capable of it. My best advice for getting into the airlines is to keep trying, be proactive, and make sure you always show them that you really want to work for them. By proactive I mean you should try to make your own Changing the altitude alert selector in a Fairchild Metro. Notice it mounts from the front: much easier than rearmounted, as used in smaller aircraft. Notice the sections of the panel. Across the top: radios, audio and warnings. In front of pilot: flight instruments (electro-mechanical). Then: two columns of engine instruments: Left & Right. Centre: radar, GPS, fire warning/extinguish, standby and auxiliary instruments. www.siliconchip.com.au April 2002  11 A combination of analog and digital circuits is found in this VHF communications transceiver/navigation receiver, typical of Cessna aircraft from the ’70s and early ’80s. Crimping a connector for de-ice wiring: windscreen replacement on a Pilatus PC-12, used for regional mail runs, charter and carriage of goods and people for the Aboriginal corporate owners. opportunities: don’t just wait for a newspaper advert to appear. Apply for apprenticeships everywhere, even if you are told there is nothing available. Be prepared for a lot of “No” answers and also be prepared to keep trying for every opening you see. There is no set procedure for getting into General Aviation. Most of the avionics workshops are genuine small businesses with around two to ten employees. The business owners and workshop managers are flesh-and-blood people with concerns about the fickle nature of the aviation industry. Some of them may have been laid off by various airlines up to three or four times over their careers. In this setting you will understand that some GA avionics businesses may consider putting on an apprentice for several months or even years without ever taking the step of advertising for one. If you can find one of these businesses and show that you are both able and interested, chances are you will get a week’s work experience with a view to becoming an apprentice. I personally decided to seriously try for an apprenticeship in October 1998. I wrote a letter, included written references from my employer at the time (a mobile phone shop) and my previous employer (a Retravision store). I included all my school results, science and maths competition results and details of an unrelated qualification from my retail work. I emphasised my strong maths and science background and the positive comments of my previous employers. I sent all of this to an Avionics workshop in Mackay that had advertised for an Avionics apprentice. I didn’t get the apprenticeship. Still enthusiastic, I rang another organisation that I knew had avionics engineers. They told me to send my information but there was not really anything available. I sent them my package. A week later, they sent the same information to a related company in Alice Springs. After some discussions they decided to take me on, provided I worked in the hangar for a year before starting on Avionics. Now I am in my fourth year and I should be able to get several CASA licences as soon as my apprenticeship finishes. So my advice for getting into General Aviation is really the same as for the airlines, only there are a lot more places to try. Keep trying, be proactive, show your enthusiasm. Be prepared to do a week of work experience as part of the process. My only word of caution is that you must make sure you know what you are being offered before you accept anything. With such diversity in GA there is no guarantee that your prospective employer will help you get CASA licences, or that you will work on any more than one or two aircraft types. It is in your interests to know what sort of work you will do and how far the employer will encourage you to go, right from the start. My last bit of advice is for older people who want to work with avionics but cannot live on apprentice wages. Remember that all the GA wages I have quoted are minimum wages, set out in the Aircraft Engineers (General Aviation) award. As a mature-aged person your job is to convince a potential employer that it’s worth taking you on instead of a 17-year-old. Part of taking you on is to pay reasonable adult wages. The main thing is to be (surprise, surprise) proactive and positive. List all the reasons why you are better, convince yourself, then set out contacting every place you can. It’s also worth thinking “outside the box”. At the moment it is still possible to gain your CASA licences without doing an apprenticeship. You need to pass all your exams and fulfil the experience requirements but it’s possible to do your experience as a trades assistant or (really outside the box now) an accountant or taxi driver who works on aircraft 20 hours a week, etc. Please take me seriously when I say that this door is almost closed now. New legislation currently being introduced will effectively make it impossible to sit the licencing exams without attending an approved course. So if you want to get into Avionics without doing an apprenticeship, DO IT NOW! I hope that’s enough to get you started. Anyone who likes aircraft and enjoys electronics would agree that Avionics is the greatest industry in the world. Keep trying and maybe we’ll meet at a trade fair or in SC the tail of an aircraft one day. 12  Silicon Chip www.siliconchip.com.au N O I T N E ATT s t is y b b o H d n a s r e n ig Project Des n w o ir e h t e k a m w o can n f f o e n o , y t li a u q l a profession s n ig s d n a ls e b la , panels When a SILICON CHIP project is released as a kit by one of the major suppliers, almost invariably it includes a front panel to make the project look professional. But what happens when there is no kit – or when you want a panel for one of your own projects? And what do R&D labs do? I t has long been one of the stumbling blocks in building your own projects: how to make them look as good as they work! Hobbyists are not alone in this – professional designers – even here at SILICON CHIP – have had similar problems in making a prototype look “professional”. There have been various commercial systems available over the years: perhaps the best known was the self-adhesive aluminium “Scotchcal” (and later “Dynamark”) labels from 3M. However, these were withdrawn from sale some time ago. Back in February 1999 we told you how we did it for many of our projects: by laminating a laser print or inkjet print with self-adhesive plastic and glueing that to the case. While that method works and looks pretty good, it certainly isn’t as permanent or hard-wearing as a proper silk-screened or engraved panel. But as far as the projects we publish are 14  Silicon Chip concerned, that isn’t a major problem. We just need them to look good long enough to photograph them – it’s up to the kit suppliers to include “proper” panels. But there are many times when we build a project which we DO want to keep for a long time and use, just as our readers would be doing. What we usually do in that case is make the temporary (printed) panel and then when the kits are released, beg, borrow or buy one from the suppliers to replace ours. Then (as often happens) something caught our eyes: a press release from Perth-based Computronics Corporation (www.computronics.com.au) promoting their new “Quick-Mark” system of producing self-adhesive labels, signs and front panels. Front panels? What was that again? By Ross Tester Computronics is not new to us. Readers may recall a little over a year ago (March 2001 issue, to be precise) we described an easy way to produce your own PC boards using Compu-tronics’ “Kinsten” photo-resist board blanks and nothing more than a photo-copied or laser printed PC board pattern on ordinary bond paper. We’ve made countless PC boards over the past year or so using this method and have achieved exceptional results. It’s relatively simple to achieve very high resolution (for example, two or three point type in board markings, too small to read with the naked eye but which can be read with a magnifying glass). If the Quick-Mark system was anywhere near as good as the Kinsten system, the panel problem could be solved. So we asked Computronics’ Kevin Dare for a few samples and some inwww.siliconchip.com.au structions – and set about proving it one way or the other. You be the judge! The Quick-Mark system There are two (or three) parts to the Quick-Mark system. First is a range of exposure films which set the letter colouring of the panel. This film is available in a range of colours: black, dark blue, red, green, light blue, brown, white and grey/silver. Second is a range of base sheets, which set the background colour of the panel – most are a plastic but there are also aluminium base sheets. Again, these come in a range of colours: the plastic are white, yellow, silver, transparent, red, gold, orange, beige and blue. There are plain and gold aluminium and also premium white and aluminium sheets. These have a thick, premium 3M adhesive, particularly good for sticking panels to rough, non- smooth surfaces and low energy materials such as polypropylene and polyethylene. They are also significantly more expensive. Third (and not usually needed) are the over-laminating films, available in transparent, matt and Lexan. For reasons which we will go into shortly, if the emulsion side of the exposure film is towards the inside, the film itself obviates the need for an over-laminating film. You can mix’n’match the colours of the exposure films and base sheets to your heart’s content. If you want a dark blue label on a yellow background, simply choose the appropriate (dark blue) exposure film and (yellow) base sheets. Like PC boards, the Quick-Mark system depends on exposing the pre-sensitized exposure film to UV light through a suitable image. But that’s where the similarity ends. Where the PC board is then developed, dried and etched, the QuickMark system can take a couple of different routes. That’s because the exposure film produces, at the same time, positive and a negative images of the original artwork. Which you use depends on whether your artwork is a positive (ie, black lettering/images on a white or clear background) or a negative (clear/white images on a black background). Once exposed, the two parts are separated using a special “Peeling Board” and the required piece of film is then www.siliconchip.com.au Here’s a selection of the colours available in Quick-Mark. The “Roman Road” sign also gives a good idea of the resolution possible with a good (high contrast) original artwork with dense blacks and clear/translucent whites. secured to the base sheet (which has self-adhesive on both sides). We’ll look at the actual mechanics of this shortly. The top piece of film is higher gloss than the bottom – this may also influence which one you use. If necessary, a piece of over-laminating film is also secured at this time. Finally, the panel/label is cut to size and secured to the project. Emulsion-to-emulsion We’ve already looked at the difference between positives and negatives but before we get into the nitty-gritty of producing a label or two, a word on a long (hyphenated) word: “emulsion-to-emulsion”, and also on “wrong-reading” and “right-reading”. What emulsion-to-emulsion simply means is that the emulsion, or toner image on the film (or paper) being used for exposure is in direct contact with the UV-sensitive emulsion on the imaging film. Basically, what you are doing is avoiding any UV light scatter or “bending” which can occur when you pass the light through a sheet of film or paper after the image. Especially in paper but also in the types of film used for laser printing, the light path can be interrupted by fibres and even defects in the material. If the light passes through the material first, then the image, what you get is a more faithful reproduction of the image. You’ll also hear the expressions “emulsion up”, “emulsion down”, “right-reading” and “wrong reading”, probably used in conjunction with each other. “Emulsion down” for all intents and purposes means the same as “emulsion to emulsion”. “Emulsion up” means the emulsion is on the side of the film closest to you (ie, away from the material being exposed). “Right reading” means that as you look at the exposing film, you can read the words normally. “Wrong reading” means that the words are back-to-front or mirror image. (Hold a sheet of normal laser-printed paper up to the light, unprinted side towards you. Notice how everything is back-to-front? That’s wrong reading!) Negative acting A short time ago we said that QuickMark produced both a positive and a negative at the same time. And so it does. But Quick-Mark should be April 2002  15 SIX EASY STEPS TO A PRO-QUALITY L 1: The better quality your artwork, the better your final result. Blacks should be as dense as possible regarded as a negative-acting process in order to get the final emulsion of the label or panel on the right side, thus avoiding the use of an over-laminating film. Of course, if you WANT to use an over-laminating film anyway (perhaps to create a matt finish or to use the super-strong Lexan film), it doesn’t matter which way around you go. Normally, though, you would use a right-reading, emulsion-down negative artwork to produce a positive label. Producing your artwork The first step in producing a professional-quality label or panel (using any system) involves its design. With today’s computer software, this task has been made relatively simple but there are some traps for young players! (1) Avoid too many fonts. Most panels/labels look best with at most two fonts – and often one of those is a variation of the other (eg, bold and normal weight). (2) Also avoid fancy fonts. For some reason, many people go straight to “Old English” styles of typefaces, which have to be amongst the most difficult to read faces ever invented. You might think Helvetica is boring – but you can read it instantly. And that’s what a good panel is all about! (3) Faces with serifs (the little strokes at the top and bottom of letters), swashes (flowing artistic flourishes), etc, are best avoided on panels. 16  Silicon Chip 2: Expose the imaging film to UV light through your artwork film. Test strips can be used to determine time. 3: Use the peeling board to separate the positive and negative exposures. Either/both can be used, as required. (4) Large logos might give the manufacturer a warm and fuzzy feeling but do nothing for the end user. Keep logo sizes down! (5) Linework should be neither too bold nor too fine. Bold lines might detract from an otherwise great design; fine lines can be difficult to reproduce. (6) If you are making a one-off panel for your own use, consider what is going to be near the device. Reversed panels (ie, white lettering on a black background) have tended to be out of fashion in recent years (some notable manufacturers excepted!). But if most of your hifi gear, for example, is white on black, a new black-on-white device (or a different colour) could stick out like a sore thumb! (7) When you’ve come up with your design, print it out on a laser or inkjet printer and ask other people what they think of it. Don’t be hurt by criticism! (8) Above all, keep type straight and on the same horizontal and vertical lines where appropriate. Nothing looks worse than higgledy-piggledy type! made for the production of high resolution, dense PCB artworks directly from any Laser printer. It will also accept copier toner enabling usable artwork to be produced from pre-printed originals. We understand Computronics will be stocking this material soon but at the time of writing, it was not available in Australia. So for the moment, we’re stuck with using ordinary laser/photocopy paper. By the way, don’t even think about using overhead projector transparency film. Its blacks are usually anything but! (Hold a printed sheet up to the light and you’ll see what we mean). As we found with Kinsten PC boards, a good quality laser print or photocopy works fine – as long as you get the UV exposure right. But more on this shortly. What you are looking for in your print is very dense blacks (you should not see any variation in darkness when you hold the page up to the light) and no tone scatter or scumming in the whites. Many laser printers are fully automatic, not offering an exposure (or “darkness”) control. But if yours has, experiment until you get the best possible blacks without affecting the whites. Photocopiers almost always have an exposure control. The same rule applies if you are copying a PC board pattern from SILICON CHIP (or an overseas magazine, for that matter). Here’s a tip for photocopying: Printing your artwork The instructions for Quick-Mark refer to transparent or translucent film for the artwork – they don’t mention using bond paper. But then again, neither did the Kinsten PC board instructions – and we’re achieving great results with that and bond paper. They do mention a proprietary film called “LaserStar”, a translucent film www.siliconchip.com.au LABEL, SIGN OR PANEL 4: Stick the film to the self-adhesive base sheet using a wetting agent for slip. Squeegee out air bubbles. 5: Add extra lamination if required; allow to dry then guillotine (or cut) the sign/panel/label to size. 6: And it’s finished. Remove the cover from the adhesive on the back and secure in its final position. always place a piece of black paper against the other side of the leaf you are photocopying. This will tend to mask the print and illustrations on that page, allowing you to adjust the exposure for best possible results. Don’t know where to get a sheet of black paper in a hurry? Raise the lid of your photocopier and press the print button . . . Ideally, if a positive label is required, a right-reading, emulsion-side down negative artwork should be used. Quick-Mark should be considered as a negative-working system. However, as we said before, Quick-Mark produces simultaneous positive and negative film. The difficulty about producing a positive from a positive is that the emulsion in the final label ends up on the outside, requiring extra lamination. If you want to make a positive label from a positive artwork, it should be wrong-reading, emulsion down. A piece of imaging film of the required colour (ie, the lettering and markings on the panel) is cut slightly larger than the finished panel size. Remember that this film is UV sensitive so should not be exposed to room light (especially fluorescent) light for any longer than is necessary. Put it back in the lightproof container as soon as possible. It must never be exposed to sunlight (direct or reflected). The film is placed in a UV exposure box (or frame) with the shiny (emulsion) side towards the UV source with the artwork between the film and the source. Exposure There are a couple of minor wrinkles here. First of all, the exposure time needs to be determined and that can be affected by the age of the material and the type of paper you are printing on. The second thing to watch is something we have already talked about: type of original (negative or positive) and emulsion side/reading. These factors determine how the film will be exposed relative to your original. Masking The film is masked to aid later peeling. Once you have laid the artwork on top of the imaging film you should apply two masking strips along two joining sides. For masking strips you can use offcuts of the black imaging film. This means you have two joining sides and one corner that have not been exposed to UV light. The top layer is peeled from the unexposed corner. Having this unexposed corner makes the peeling process much easier. If you do not mask as above, lifting K&W HEATSINK EXTRUSION. SEE OUR WEBSITE FOR THE COMPLETE OFF THE SHELF RANGE. www.siliconchip.com.au April 2002  17 an initial corner and the peeling itself is much more difficult. By definition, if you are using a big negative artwork with plenty of black opaque areas along the edges then masking may not be necessary as the negative is doing the masking for you. But if using a positive, masking will be required. Exposure The film is then exposed to UV for the required time. We cut several small test strips and exposed these for various periods to determine our optimum exposure time – somewhere between 15 and 25 minutes or so for our setup. We were using the Kinsten UV exposure unit; if you are using another UV source, your exposure times may be different. Just experiment until you get an acceptable result. Exposure time is a compromise between ensuring sufficient UV light gets through the white paper to the sensitized film underneath but not enough to start “punching through” the black (toner) areas of the artwork. Exposure time using high contrast film is dramatically less: seconds, rather than minutes. Peeling the image An adhesive-coated “peeling board” is used to help separate the film once exposed. Lay the film onto the peeling board with its glossy side up (the side which was exposed to UV) and smooth out the film. Peeling is a bit tricky. First you need to separate the two layers of film with your finger nail at one corner, then grasp that raised section with your thumb and forefinger and peel it (away from the corner) without raising the film up. In other words, peel it back on itself – as you would do in trying to remove an adhesive bandage from your skin: do it quickly in one movement and it doesn’t hurt as much! It is also vital that this be done in one, smooth, continuous motion – if you stop or hesitate, the panel could be ruined by lines or imperfections. When the two pieces of film are separated, you’ll find the top piece is a reversed image of the original artwork with the coloured emulsion side underneath (in other words, if you used a negative, you’ll now have a positive, right reading, emulsion side down). 18  Silicon Chip The other piece of film, still stuck to the peeling board, will have an exact duplicate of the original artwork with the coloured emulsion on top. You can use either piece of film as your panel, depending on which way around you want it to look. Now you should start to understand why we made such a fuss of positives, negatives, emulsion sides, etc before; if you only had positive artwork and wanted a positive panel, a positive artwork, right reading emulsion side up is produced, (the same as an ordinary letter is produced). This is then turned over (wrong reading emulsion down) placed on a piece of imaging film and an exposure made. The image is then peeled and the bottom piece of film is used. On the peeling board this is wrong reading emulsion side up but when removed and turned over and stuck to a base sheet produces a right reading, protected emulsion panel. Laminating Now comes the easiest part: laminating the piece of film to the base sheet. The base sheet is not UV-sensitive so you don’t need to take such precautions with it. Cut a piece of base sheet just larger than your label and place both it and the label film, in a plastic tray (or perhaps on a large newspaper). Peel away the protective coating from the coloured (top) side of the base sheet and spray both it, and the label film, with a fine mist water spray into which you have added a couple of drops of concentrated household detergent. Don’t use enzyme-based detergent: it will damage the adhesive. The “slippery” water allows you to place the film on the base sheet without the “sudden death” of most contact adhesives. You should be able to slide the film around a little should that be necessary. Once you are happy with the position, “squeegee” the water out from under the label. Computronics have an applicator pad for the purpose which you might consider if you are doing regular labels – otherwise, squeegee it using a soft cloth. Some small milky blotches may appear between the layers of the label: don’t worry, these are quite normal and usually disappear after a day or so as the water dries out. Squeegeeing as much liquid out as possible tends to minimise this effect. Extra lamination If your image is on the upper side of the film and/or if you want to change the shiny label to matt or cover it with the tougher Lexan, you do this by using over-laminating film. Otherwise, you don’t need to do this because the emulsion will be “sandwiched” between the imaging film and the base sheet. Finally . . . Now’s the time to cut your panel to size (preferably with a guillotine, but scissors can be used) and fix it to the object required. The same type of acrylic adhesive is on both sides of the base sheet so again, a fine spray of slippery water (water/detergent mix as above) can give you a bit of movement. Acrylic adhesive normally takes some hours to finally cure but when it does, the panel will be very tightly stuck on, by gum! Cost The Quick-Mark components are not cheap. However, when alternative methods may be non-existent or much more expensive, it all becomes relative. The imaging film costs around $50 per sheet or about $35 per sheet in a pack of five. Each sheet measures 305 x 508mm, so you should get many projects out of a single sheet. Likewise, the base sheets are 305 x 508mm. The normal sheets cost about $30 each or about $21 each in a 5-pack. The “premium” sheets are about $44 each or $31 in a 5-pack. Large peeling boards are about $50, small about $38. They also have application fluid to help enable accurate positioning of the film on the base sheet. Personally, I would take their tip and substitute ordinary water with a couple of drops of concentrated washing-up liquid in a sprayer bottle (cost about two dollars compared to about $40!). Where do you get it? For additional information, refer to the Computronics website at www. computronics.com.au or call (08) 9470 SC 1177, fax (08) 9470 2844. www.siliconchip.com.au Better cooling systems for car engines Up ’til now, engine cooling systems have all been based on a mechanical thermostatic valve, a belt-driven water pump and cooling fan which is now usually electric. Now that is all about to change. E lectronics has brought about great changes in motor vehicles, especially in regard to fuel consumption, emissions, safety and comfort. Almost all functions today are controlled and monitored electronically. The cooling system in the engine has been the exception. The German company Bosch is now developing electronically controlled thermal management for the engine. This is expected to reduce fuel consumption by up to five percent and also raise the heating comfort within the vehicle by controlling the temperature in the passenger area faster and more evenly. Electronic engine thermal management aims to optimise the heat balance in the engine and transmission. Depending on the operating conditions and load requirements of the engine, the system controls the coolant tem- www.siliconchip.com.au perature and coolant flow in a highly dynamic way. As a result, the engine reaches its operating temperature faster after a cold start and this helps reduce the emission of unwanted pollutants. At engine idle and in the part throttle range, electronic thermal management permits a higher engine temperature. The resulting lower oil viscosity reduces engine losses and leads to further fuel savings compared to traditional engines. In contrast, at high engine load the coolant temperature drops faster and even with sudden full power (open throttle), temperature spikes do not occur. This is easier on the engine and may contribute to a longer lubricant life. Thermal management therefore could also enable longer service intervals. Finally, the heating of cars will ben- efit from electronic thermal management. Constant heating, independent of engine load, raises passenger comfort and saves the step of subsequent frequent temperature control, which is usual for conventional vehicle heating systems. The key components of a thermal management system have continuous electronic control and include: • A cooling fan driven by an electric motor • One or several electrically-actuated proportionate water valves as replacement for the traditional thermostat valve • A primary water pump, driven by a 14V or 42V electrical supply. Variable speed cooling fans are already in production. Bosch is developing the other key components with the first applications in series-produced passenger vehicles scheduled SC for 2004. April 2002  19 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au .. AS AS In fact, SILICON CHIP is now the ONLY truly electronics-oriented magazine published in Australia. But if you want SILICON CHIP to continue to thrive; to continue as YOUR magazine, we need YOUR support. WE NEED YOU TO JOIN US – AS A SUBSCRIBER! You’ll not only save money, you’ll get your copy earlier than the newsstands, you’ll never miss an issue because it’s sold out . . . and if you’re in the electronics industry, it could be 100% tax deductible. CALL SILICON CHIP NOW ON (02) 9979 5644 OR TURN TO P38! 24  Silicon Chip Volvo’s ISG cuts fuel consumption by 20% Reducing fuel consumption is one of the top-priority environmental goals at Volvo Cars and one of the most promising projects in this sphere is the Integrated Starter Generator (ISG) which was demonstrated at the 2001 Frankfurt Motor Show. H ans Gustavsson, who heads the Research, Development and Purchasing unit at Volvo Cars states: “In urban driving with its many stops and starts, ISG can cut fuel consumption by as much as 20% and also reduce the emissions.” The ISG unit is installed between the engine and gearbox, linked directly to the crankshaft and it replaces both the conventional starter motor and alternator. The ISG system runs from 42V and has a separate battery placed in the spare wheel bay in the luggage compartment. “There is no need to develop a new car model or significantly modify an existing car – ISG can be integrated with most of our current models. It’s a very cost-efficient system compared with other solutions such as hybrid cars,” says Hans Gustavsson. He adds: “A Volvo with ISG behaves pretty much like today’s Volvos. The only noticeable differences are that the engine stops as soon as the car comes to a standstill and there are longer intervals between visits to the petrol station.” Instead of continuing to use fuel at idling – for instance when waiting at traffic lights, the engine of a car with ISG switches off completely when the vehicle is no longer in motion. When the traffic lights turn green and the driver presses the accelerator to move off, the ISG car starts instantly and almost noiselessly. ISG supplies the engine with power at the moment the car moves off and also during accelerwww.siliconchip.com.au ation – when the car would otherwise require extra fuel to be injected into the engine. ISG remains active throughout the driving process, for example during overtaking or at other times when extra power is needed. “In certain situations, the ISGequipped car feels even more responsive than a corresponding car with conventional motor. For instance, you can drive at low revs in a high gear. The basic principle behind ISG is that the combustion engine should work as little as possible, in order to cut fuel consumption and exhaust emissions,” says Hans Gustavsson. “Free” energy to the battery When you lift off the accelerator pedal to slow down, the car’s forward movement powers the ISG unit, which in turn recharges the 42V battery with free energy. The Integrated Starter Generator is therefore far more efficient than a conventional alternator and this is another contributory factor to the low fuel consumption. This also means that systems such as power steering and air conditioning, which are normally powered by the combustion engine can be powered by the 42V battery instead. The air-conditioning system thus continues to remain active even when the engine switches off. This is a benefit that many of Volvo’s competitors cannot offer in their own ISG projects. SC April 2002  25 . . . dimming with the power of a PIC Pt.1: By JOHN CLARKE This single-channel fully automatic high-power light dimmer has a host of control features because it is driven by a PIC microcontroller. It will drive incandescent lamp loads up to a total of 2400 watts. 26  Silicon Chip www.siliconchip.com.au T HE SILICON CHIP Touch/Remote Controlled Dimmer, described in the January and February 2002 issues, was a low power device, suitable for lamp loads up to 250W. That’s OK for dimming the lights in your lounge room or bedroom but useless for dimming high power stage lights or a bank of lights in a hall or church. For that purpose you need a high power dimmer and that is the reason for this completely new design. It is specially de­signed to drive the high power lamps used in stage lighting, up to a total of 2400W. It has all sorts of control features such as preset brightness levels, dimming rates, flash on and off buttons and so on. Our last high power dimmer, featured in the August 1994 issue, was a fairly basic design with just a slider knob to control the brightness. This new design has no slider knob but can dim up or down manually or automatically and has LED bar­graphs to indicate the brightness levels, dimming rates and more. Features The SILICON CHIP Automatic Light Dimmer is housed in a rugged diecast metal case measuring 170 x 120 x 55mm. We used a diecast metal box for two reasons: first because stage light dimmers often have a rugged life and second, the case provides heat­sinking for the Triac which is the power control device at the heart of the circuit. At one end of the case is the 240VAC mains cord, a 3-pin mains socket for the lamp, a power switch and a fuse holder. On the front panel are two LED bargraphs, a large LED brightness indicator and no less than eight switches of various sorts. Along the bottom edge of the control are three rocker switches, two of which are spring-loaded centre-off types. Want to dim the lights up or down? Use the DIM switch in the lefthand corner. Push it up to go brighter; down for dimmer. Want to flash the lights to full brilliance? Push the FLASH switch on. Want to flash them off? Push the FLASH switch off. This can be done at any time, regardless of other settings or modes. Dimming can be manual or automatic, depending on the set­ting of the Automatic/Manual Dimming switch www.siliconchip.com.au SPECIFICATIONS Maximum lamp power ��������������������2400W Minimum lamp power ���������������������60W (lower power lamps may flicker) Phase angles ���������������������������������5.8° for maximum brightness and 174° for minimum brightness Auto Dimming rates ������������������������0, 0.5s, 1s, 1.5s, 2s, etc in 39 steps up to 40s maximum Dimming steps �������������������������������102 typical beyond initial preheat setting up to full brightness Dimming display �����������������������������39 levels Triac gate drive period ��������������������80µs in the right-hand corner. When dimming automatically, pushing the DIM switch UP lets the lamp(s) brighten up to the preset brilliance. Pushing the DIM button DOWN, dims the lamp(s) back down to zero. Brightness can be preset to one of 39 brightness levels with the LEVEL UP/DOWN rocker switch. Brightness levels are indicated on a 20-LED bargraph. Yes, we know we said there are 39 brightness levels? So how do you indicate 39 levels with 20 LEDs? The trick is that we use 20 LEDs to indicate 20 levels from maximum to minimum but the intermediate brightness levels are indicated with two adjacent LEDs – its harder to describe than to use. So as the level is increased, we get one LED, then two adjacent LEDs, then the top one of that adjacent pair, then the next adjacent pair and so on. This one-two-one LED sequence indicates 39 levels. The same 20-LED bargraph can also show the Flash brightness setting which is preset using the DIM/FLASH switch, in conjunc­tion with the up/ down rocker switch to the left of the bargraph. Filament preheat When high power lamps are initially switched on, their cold filaments have a very low resistance and so they have very high surge currents. This is bad enough at switch-on but if a lamp is to be repeatedly flashed on, as it can be with this dimmer, then the repetitive surge currents can destroy the Triac and also blow out the filament of the lamp itself. To reduce this problem, the lamp filament is always run with a low value of “preheat” cur­rent, typically with the filament glowing a dim red. Preheat setting is done by pressing the DIM UP, LEVEL UP and Store Settings switches all together. We will discuss this later in this article. The actual lamp brightness is indicated in two ways on the display. Firstly, there is a large 10mm LED which glows according to the lamp brightness. Second, the 20-LED bar- MAIN FEATURES • • • • • • • • • • High power lamp control Maximum lamp brightness preset Minimum lamp brightness preset for filament preheating Automatic or manual dimming between brightness presets Separate flash on and flash off Flash brightness preset Dimming rate programmable from instant through to 40 seconds A and B dimming rate selection Lamp brightness indication Automatic dim up and dim down indication April 2002  27 in the two bargraphs are in “dot” mode – ie, single LEDs glowing – rather than “bar” mode. When dimming automatically, dimming can be stopped at any time by momentarily pressing the DIM UP/ DOWN switch in the op­posite direction to the dimming. So if the lamp is in the process of dimming up, dimming can be stopped by momentarily pressing the DIM DOWN switch. If this switch is held down or pressed again, then the dimmer will begin dimming down. Similarly, if dimming down in auto mode, dimming can be stopped by momentarily pressing the DIM UP switch. Dimming rate Scope 1: this somewhat distorted mains sinewave is straight out of a power point. While nominally 240V AC, 50Hz, in this case it’s actually 250V AC and the frequency is just a tad low (neither of which is unusual). Scope 2: this scope shot shows the power being made available to the load very late in the half cycle so that it effectively receives just under 40V. In this case, the lamp would be barely glowing. graph indicates actual brightness and preset brightness levels. Actual lamp brightness is shown with a flashing LED in the bargraph, while the DIM or FLASH preset levels are shown by a constant LED. If the two levels are the same, the indicating LED will shimmer rather than glow constantly. By the way, all the LED indications 28  Silicon Chip PLEASE NOTE! The scope waveforms in this article are shown to explain the operation of the circuit. DO NOT try to reproduce these waveforms yourself – it is much too dangerous. Automatic and manual dimming occurs at a preset RATE. You can set two dimming rates (A and B) with each one ranging from instantaneous to 40 seconds, in 0.5s increments, as displayed on the right-hand bargraph. The topmost LED indi­cates the longest dimming time and therefore the slowest rate. When automatic dimming is in progress, the topmost LED in the Rate 20-LED bargraph display flashes for dimming up while the lowest LED flashes when dimming down. Some controls cannot be used when dimming is in process. These are the Level Up/Down, Rate Up/Down and Store Settings switches. These switch­ es are locked out of service during dimming to prevent any possible lamp flickering which may happen if there is any attempt to operate several functions at the one time. The A and B dimming rate settings, the Dim and Flash pre­ sets and the minimum level preheat setting can be stored so that these settings will be remembered when the dimmer is used next time, after being switched off. This is done by pressing the “Store Settings” switch. In fact, it is important to press this switch after the minimum level filament preheat has been set so that this will always be set correctly.During this time, the LED bargraph dis­play momentarily goes off as an acknowledgement that storage has taken place. When ever the dimmer is first switched on, the lamp bright­ness is set to fully off and no filament pre­heating is applied. This means that no power is supplied to the lamp. The dimmer will begin to provide power to the lamp www.siliconchip.com.au Fig.1 the block diagram of the Auto Dimmer circuit. The key device is the PIC16F84A-20/P microcontroller. It accepts inputs from the transformer and switches and provides outputs to switch a Triac and drive the LED displays. as soon as the Flash or Dim switches are pressed. Phase-controlled Triac As with any light dimmer, the circuit uses a phase-controlled Triac to set the lamp brightness. The principle is virtually the same as outlined in the January 2002 article on the Touch-controlled Dimmer. For those readers who did not see that article, we will go through the details again. Our mains electricity supply is a 240VAC 50Hz sinewave which goes positive for 10ms, back through zero and then negative for 10ms. This returns to zero and again goes positive. Normally a lamp is connected across this supply whenever it is switched on. In a dimmer circuit, we delay apwww.siliconchip.com.au plying power to the lamp during each half-cycle of the mains waveform and switch it off each time the voltage goes through zero to effectively provide less power and so dim the lamp. This timed switching of the power is performed by a Triac which can be triggered on by a short pulse at its gate. The Triac will then only turn off when the current through it drops below a certain threshold value. In practice, when driving a resistive load this means that the Triac switches off when the mains vol­tage is near 0V. The accompanying oscilloscope waveforms, repeated from the January 2002 issue, show how it works. The first oscilloscope waveform (Scope 1) is the mains sinusoidal voltage measured on the Active output of a power point. Note that the mains voltage shown here is closer to 250VAC and it is by no means unusual to have such a high voltage. The second oscilloscope waveform (Scope 2) shows the waveform applied to the lamp when it is dimmed to a low brightness. In this case, the lamp is powered about 150° from the start of each mains half-cycle and is switched off at 0V. Note that the lamp voltage is applied for both positive and negative excursions of the mains active and the RMS voltage is around 39V. The third oscilloscope waveform (Scope 3) shows the lamp voltage when the dimmer is set for close to maximum brightness. Now the voltage is switched on early in each mains half-cycle so that almost the full mains waveform is applied. Again the lamp is switched off at 0V. The RMS voltage is now a lot higher, at 242V. The circuit for the lamp dimmer obtains this phase control by dividing April 2002  29 Scope 3: this waveform shows triggering very much earlier in the cycle, so that the lamp receives almost all the available power. In this case, the lamp would be at virtually full brilliance. up each half cycle (180°) of the mains waveform into 250 discrete sections. Thus, each discrete section is equiv­ alent to 0.72° (180/250). The overall range of phase control in the dimmer circuit is restricted to a minimum count of 8 (5.8°) and a maximum count of 241 (174°). Block diagram Fig.1 shows the general arrangement of the dimmer circuit. The key device is the PIC16F84A-20/P microcontroller. It accepts inputs from the transformer and switches and provides an output to switch the Triac. Its other outputs drive the LED displays. IC1 operates from a 20MHz timebase and this clocks a timer which counts up until it reaches 40µs. The output then clocks the brightness counter which counts from 0 through to 250 for each 10ms half-cycle of the mains voltage. This is locked to the mains waveform via the zero voltage negative edge detector which resets the brightness counter to zero each time the mains voltage drops to zero. An important part of this circuit is the feedback from the brightness counter back to the internal timer. This is required to lock the internal timer rate to the brightness counter and adjusts so that the counter is just on the verge of counting to 250 at the occurrence of the zero voltage signal from the 30  Silicon Chip mains. Any deviation from this locked arrangement will pro­duce flickering in the phase controlled lamp. The current required lamp brightness is stored in the brightness level register and this value is compared with the brightness counter value using an exclusive comparator. The exclusive comparator output drives the optocoupled Triac driver (IC4) when both the brightness counter and the brightness level register are the same value. Input signals from switches S1-S8 provide the controls to set the dimming brightness, flash brightness, dimming rate and so on, as described above. Input response logic decides what action to take when one of these switches are pressed. Circuit diagram The circuit for the Automatic Dimmer is shown in Fig.2. As already noted, IC1, the PIC16F84A-20/P microcontroller, is the heart of the circuit. This IC runs at 20MHz, by virtue of the 20MHz crystal (X1) connected to pins 15 & 16. It needs to run at this speed in order to perform all the necessary functions of driving the LED displays and monitoring the switches without this interfering with providing the trigger pulses to the Triac. The two bargraphs, comprising LEDs 1 to 40, are driven via IC2, IC3 and transistors Q1-Q5. However, while the LEDs are physically arranged as two 20-LED bargraphs, they are connected in a matrix of five rows and eight columns. They are driven in multiplex fashion, under the control of IC1, IC2 and IC3. Each of the five transistors drives the commoned anodes of its row of LEDs via a 47Ω resistor. The eight columns are each driven via a Darlington transistor in the cathode driver (IC3). Each of the eight base inputs in IC3 is driven by 4017 coun­ter IC2 which is clocked by IC1. Only one column is driven at a time and the required LEDs in that column are driven by the row drivers, Q1-Q5. Each time IC2 is clocked by IC1, one of its eight outputs goes high to drive IC3 to display the next column. After the last column is lit, IC2 is clocked again so that the “8” output goes high. This output is not connected to the circuit and so all the columns (and all LEDs) are off. Next, IC1 checks switches S1-S4 to see if they have been operated. It does this by pulling the RB3-RB7 lines (pins 9-13) low in turn, to check if its pin 18 is pulled low via a switch and diodes D1-D5. So for example, if RB7 is brought low and S1 is open, pin 18 of IC1 will remain high via the 10kΩ pullup resistor. If the switch is closed, the low RB7 output will pull pin 18 low via diode D1. The diodes ensure that the RB7RB3 outputs are not shorted together if more than one switch is closed. Note that bringing the RB7-RB3 lines low will also drive transistors Q1-Q5, so it is important that the columns are off. This is why IC1 can only check these switches when the (unused) “8” output of IC2 is high. After this switch test, IC2 is reset via a high RB1 signal from IC1. Now the “0” output is high to drive column 1 again. Switches S5 to S8 are tested for closure using the high outputs from IC2 and the RA0 input, pin 17, of IC1. Normally pin 17 is held low via a 10kΩ resistor. If the “0” output (pin Fig.2 (right): the full circuit details of the Auto Dimmer. Microcontroller IC1 controls optoisolator IC4 which in turn controls Triac1 to vary the lamp brightness. It also drives transistors Q1-Q5 and IC2 to switch the LED displays. www.siliconchip.com.au www.siliconchip.com.au April 2002  31 This is the view inside the prototype with the wiring almost completed. The full assembly details will be published in Pt.2 next month. 3) of IC2 is high and switch S5 is closed, then RA0 will be pulled high via diode D6. If the switch is open then RA0 will remain low. Diodes D6-D12 ensure that IC2’s outputs are not shorted together if more than one switch is closed. Triac drive The RA3 and RA4 outputs of IC1 drive IC4, the MOC3021 opto­coupled Triac driver, via a 220Ω resistor. When these outputs are high, the LED inside IC4 is off. When these pins go low, the LED is driven and this activates the internal Triac between pins 4 and 6 to drive the gate of Triac1, a BTA41600B. The gate drive current comes via 360Ω and 470Ω resistors from the 240VAC mains Active line The .047µF capacitor is included as a “snubber” to prevent false switching of the Triac by transients on the mains Active. The gate drive pulse to Triac1 is set at 80µs which is sufficient time to ensure that it latches on for the duration of the mains half cycle. 32  Silicon Chip Triac1 is a BTA41-600B, a 600V 40A device which has been specified to cope with the very high surge currents which occur when switching a 2400W incandescent lamp load. Typically, the surge current at switch-on can be 10-15 times the normal load current; ie, the surge current could be 100150 amps and could last for several milliseconds. WARNING! Part of the circuitry used in this Automatic Light Dimmer operates at 240VAC (see Fig.2) and is potentially lethal. Do not touch any part of this circuit while the unit is plugged into the mains and do not operate the circuit outside its earthed metal case. This project is for experienced constructors only. Do not build it unless you are entirely familiar with mains wiring practices and construction techniques. The Triac must also be able to cope with the very high fault currents that occur when high power lamps blow their fila­ments. When this happens, the broken sections of the filament can establish an arc between the stem supports and this arc current continues until the stem fuse blows. Considering that this arc current can be many hundreds of amps, the Triac has to be very rugged. EMC filtering The rapid switching of the Triac, combined with high cur­rents, means that this circuit can generate a lot of interfer­ence. So we have included a two-stage filter network comprising L1 & C1 and L2 & C2. The 4.7MΩ resistor across the Active and Neutral output discharges the capacitors when power is off to prevent these from being left charged. The first stage in the filtering uses an powdered iron toroid for the 40µH inductor L1. This type of inductor is quite lossy for frequencies above about 1MHz and so in conjunction with the 0.1µF capacitor, it attenuates much of the electromagnetic interference www.siliconchip.com.au Fig.3: this simple circuit is used to derive the low-voltage AC and DC supply rails for the dimmer. (EMI) caused by the rapid switching of the Triac. However, it is not a good filter below 1MHz, particularly for frequencies between 10kHz and 100kHz which must also be attenuat­ed to prevent EMI above the allowable limits. This is where the second filter comes into play. It com­prises a toroidal core with two windings. The core has a high permeability ferrite material so that we can obtain a much higher value of inductance without an excessive number of turns on the toroid. However, the combination of high inductance and high load current means that the core is easily saturated by the magnetic flux generated when current flows through the wind­ings. This is why we have two windings on the core; so that any flux generated by one winding is opposed by the second winding. This means the net magnetic flux in the core adds up to zero and so saturation does not occur. However, if we say that the flux generated by one winding is cancelled by the flux in the second, then how does the filter work? Clearly, flux cancellation does occur for the low frequency part of the load current but for the high frequencies, which are bypassed by C2, flux cancellation does not take place and so the twin windings give a high effective inductance for the interfer­ence frequencies we are trying to get rid of. LED brightness indication As mentioned previously, we use a large LED on the front panel to mimic the lamp brightness. This is driven by the RA2 output of IC1 which goes low when the Triac is driven to light the LED via a 470Ω resistor. It is then switched off at the end of each mains half-cycle. Note that the drive to LED41 does not occur for the filament preheat period, where the lamps are effec­tively off. Low voltage power for the circuit comes from transformer T1, as shown on the circuit of Fig.3. Its centre-tapped secondary feeds diodes D13 and D14 and the 470µF capacitor filters the DC which is fed to the 7805 3-terminal regulator, REG1. This provides the +5V rail for the ICs and the LEDs. Most of the circuitry is isolated from the mains by trans­former and the optocoupler IC4. The portion of the circuit in the top right-hand corner of Fig.2 is at 240VAC mains and is poten­tially lethal. Zero crossing detection Because IC1 must provide precisely timed trigger pulses to the Triac, it needs be synchronised to the 240VAC mains waveform. To do this, IC1 monitors the 15VAC waveform from the transformer at its RB0 input, pin 6. This is used to detect the zero crossing point of the mains voltage. The 15VAC signal is filtered with a two-stage RC filter comprising 220Ω & 2.2kΩ resistors and 1µF & 0.1µF capacitors. This rolls of frequencies above about 700Hz to remove transients from the mains. The 100kΩ resistor to the RB0 input is included because there is a diode within IC1 which clamps the voltage when it goes 0.7V below ground. The resistor limits current in the clamping diode. That’s all for this month. Next month we will conclude with all the construction and setting up details. SC UM66 SERIES TO-92 SOUND GENERATOR. THESE LOW COST IC’S ARE USED IN MANY TOYS, DOORBELLS AND NOVELTY APPLICATIONS 1-9 $1.10 10-24 $0.99 25+ $0.88 www.siliconchip.com.au April 2002  33 This simple circuit lights a string of LEDs to quickly indicate the level in a rainwater tank. It’s easy to build and can be powered from an AC or DC plugpack supply. By ALLAN MARCH There are two traditional methods for finding the level of water in a tank: (1) tapping down the side of the tank until the sound suddenly changes; and (2) removing the tank cover and dipping in a measuring stick. The first method is notoriously unreliable, while the second method can be awkward and time-consuming. 34  Silicon Chip After all, who wants to clamber up on top of a tank each time you want to find out how much water is inside it? That’s where this simple circuit comes in. It uses five green LEDs arranged in a bargraph display to give a clear indica­tion of how the water supply is holding up. The more LEDs that light, the higher the water in the tank. A sixth red LED lights when the tank level drops below a critical threshold. There are no fancy microcontrollers or digital displays used in this project. Instead, it uses just a handful of common parts to keep the cost as low as possible. Circuit description Fig.1 shows the circuit details. It’s based on an LM3914 linear LED dot/ bar display driver (IC1) which drives five green LEDs (LEDs 1-5). Pin 9 of the LM3914 is tied high so that the display is in bargraph mode and the height of the green LED column indicates the level of the water in the tank. The full-scale range of the bargraph depends on the voltage on pin 6. This voltage can be varied using VR1 from www.siliconchip.com.au Fig.1: the circuit is based on an LM3914 dot/bar display driver (IC1) which drives LEDs 1-5. Its output depends on the number of sensors covered by water – the more covered, the higher the voltage on Q1’s collector and the greater the voltage on pin 5 (SIG) of IC1. LED6 provides the critical level warning. about 1.61V to 2.36V. After taking into account the voltage across the 390Ω resistor on pin 4, this gives a full-scale range that can be varied (using VR1) between about 1.1V (VR1 set to 0Ω) and 2V (VR1 set to 470Ω). By the way, if you’re wondering where all the above voltag­ es came from, just remember that IC1 has an internal voltage reference that maintains 1.25V between pins 7 & 8. This lets us calculate the current through VR1 and its series 1kΩ resistor and since this same current also flows through the series 1.5kΩ and 390Ω resistors, we can calculate the voltages on pins 6 and 4. As well as setting the full-scale www.siliconchip.com.au range of the bargraph, VR1 also adjusts the brightness of LEDs 1-5 over a small range. However, this is only a secondary effect – it’s the full-scale range that’s important here. IC1’s outputs directly drive LEDs 1-5 via 1kΩ current limiting resistors. Note, however, that an LM3914 has 10 compara­tor outputs but we only need five steps for this application. That’s done by wiring the outputs of successive comparator pairs in parallel – ie, pins 1 & 18 are wired together, as are pins 17 & 16 and so on. Water level sensor The input signal for IC1 is provided by an assembly con­sisting of six sensors located in the water tank and connected to the indicator unit via light-duty figure-8 cable. This sensor assembly relies on the fact that there is a fairly low (and constant) resistance between a pair of electrodes in a tank of water, regardless of the distance between them. As shown in Fig.1, sensor 1 is connected to ground, while sensors 2-5 are connected in parallel to the base of PNP transis­tor Q1 via resistors R5-R1. Q1 functions as an inverting buffer stage and its collector voltage varies according to how many sensor resistors are in-circuit (ie, how many sensors are covered by water). When the water level is below sensor 2, resistors R5-R1 are out of circuit and so Q1’s base is pulled high by an 82kΩ resistor. As a result, Q1 is off and no signal is applied to April 2002  35 Fig.2: follow this diagram when installing the parts on the PC board. Note that some parts have to be omitted for 12V battery operation – see text. IC1 (ie, LEDs 1-5 are off). However, if the water covers sensor 2, the sensor end of resistor R5 is essentially connected to ground. This resistor and the 82kΩ resistor now form a voltage divider and so about 9.6V is applied to Q1’s base. As a result, Q1’s emitter is now at about 10.2V which means that 0.8mA of current flows through the 2.2kΩ emitter resistor. Because this same current also flows through the two 1kΩ collec­tor load resistors, we now get about 0.8V DC applied to pin 5 (SIG) of IC1. This causes pins 1 & 18 of IC1 to switch low and so the first green LED (LED5) in the bargraph lights. As each successive sensor is covered by water, additional resistors are switched in parallel with R5 and Q1’s base is pulled lower and lower. As a result, Q1 turns on “harder” with each step (ie, its collector current increases) and so the signal voltage on pin 5 of IC1 increases accordingly. IC1 thus progres­sively switches more outputs Fig.3: this is the full-size etching pattern for the PC board. Check your board carefully before installing any of the parts. low to light additional LEDs. Note that Q1 is necessary to provide a reasonably low-im­ pedance drive into pin 5 (SIG) of IC1, while keeping the current through the water sensors below the level at which electrolysis becomes a problem. of IC2 is high and LED6 is off. However, if the water level falls below sensor 2, LED5 turns off and the anode of LED5 “jumps” to +12V. This voltage exceeds the upper threshold voltage of IC2 and so pin 3 switches low and LED6 turns on to give the critical low-level warning. Note that the control pin (pin 5) of IC2 is tied to the positive supply rail via a 1kΩ resistor. This causes IC2 to switch at thresholds of 0.46Vcc (5.5V) and 0.92Vcc (11V) instead of the usual 1/ Vcc and 2/ Vcc and is necessary to 3 3 ensure that IC2 switches correctly to control LED6. Power for the unit is derived from a 12-18VAC plugpack supply. This drives a bridge rectifier D1-D4 and its output is then filtered using a 100µF electrolytic capacitor and applied to a 12V 3-terminal regulator (REG1). The output from REG1 is then filtered using a 10µF electrolytic capacitor and used to power the circuitry. Note that a regulated supply rail is necessary to ensure that the water Critical level indication IC2 is a 555 timer IC and it drives LED6 (red) to provide a warning when the water level falls below the lowest sensing point; ie, when all the green LEDs are extinguished. However, in this role, IC2 isn’t used as a timer. Instead, it’s wired as a threshold detector and simply switches its output at pin 3 high or low in response to a signal on its threshold and trigger inputs (pins 6 & 2). It works like this: normally, when there is water in the tank, LED5 is on and its anode is at about 2V. This “low” voltage pulls pins 6 & 2 of IC2 low via a 100kΩ resistor, so that these two pins sit below the lower threshold voltage. As a result, the pin 3 output Table 1: Resistor Colour Codes  No.   1   1   1   1   1   1   1   2   1   9   1 36  Silicon Chip Value 820kΩ 680kΩ 560kΩ 330kΩ 220kΩ 100kΩ 82kΩ 2.2kΩ 1.5kΩ 1kΩ 390Ω 4-Band Code (1%) grey red yellow brown blue grey yellow brown green blue yellow brown orange orange yellow brown red red yellow brown brown black yellow brown grey red orange brown red red red brown brown green red brown brown black red brown orange white brown brown 5-Band Code (1%) grey red black orange brown blue grey black orange brown green blue black orange brown orange orange black orange brow red red black orange brown brown black black orange brow grey red black red brown red red black brown brown brown green black brown brown brown black black brown brown orange white black black brown www.siliconchip.com.au level indication doesn’t change due to supply variations. Construction Construction is straightforward, with all the parts in­stalled on a PC board coded 05104021 and measuring 80 x 50mm. This is installed in a standard plastic case, with the LEDs all protruding through the lid. Fig.2 shows the parts layout on the PC board. Begin the assembly by installing the resistors, diodes and capacitors, then install the ICs, transistor Q1 and the 3-terminal regulator (REG1). Make sure that the diodes and ICs are installed the right way around. The same applies to the electrolytic capacitors – be sure to install each one with its positive lead oriented as shown on Fig.2. Trimpot VR1 can now be installed, followed by the RCA socket and the 2.5mm power socket. The two sockets are both PC-mounting types and mount directly on the board. The LEDs are fitted last and must be installed so that the top of each LED is 33mm above the PC board. This ensures that the LEDs all just protrude through the lid when the board is mounted in the case on 10mm spacers. Make sure that all LEDs are correct­ly oriented – the anode lead is the longer of the two. The power socket and RCA connector are both mounted directly on the PC board. Make sure that all parts are correctly oriented and that they are in the correct locations. Dot operation You can easily convert the LM3914 (IC1) from bar to dot operation if that’s what you prefer. All you have to do is cut the thinned section of track immediately to the left of the 0.1µF capacitor and install a wire link between the two vacant holes at the top of the board near IC1. Alternatively, the link can be omitted (ie, pin 9 can be either pulled low or left open circuit). Battery operation If the unit is intended for 12V battery operation in a mobile home or caravan, regulator REG1 and diodes D2, D3 & D4 are omitted. Both D4 and REG1 are then replaced by wire links – ie, install a link instead of D4 and install a link between the IN & OUT terminals of REG1. D1 remains in circuit to protect against reverse battery connection. Metal tanks If the tank is of made of metal, you can dispense with Sensor 1 and conwww.siliconchip.com.au The PC board in secured to the bottom of the case using two 10mm standoffs at one end, while the RCA socket provides the support at the other end. nect the tank directly to the circuit ground. You must also ensure sensors 2-6 do not touch the walls of the tank. This can be done by slipping a length of 25mm-OD clear PVC tubing over the completed probe, securing it at the top so that the water inside can follow the level in the tank. Final assembly The PC board is mounted in the bottom of the case on two 10mm standoffs and is secured using 3mm machine screws, nuts and washers. Note that the corners at one end of the PC board must be removed to clear the pillars inside the case. You will have to remove these corners yourself using a small hacksaw and rat-tile file if this hasn’t already been done. Fig.6 shows the locations of the two board mounting holes in the bottom of the case. You will also have to drill two holes in one end of the case, so that they line up with the RCA socket and the power socket when the board is in­stalled (see Fig.6). The front-panel artwork (Fig.5) can be used as a template for drilling the front panel. There are six holes to be drilled here – one for each LED – and these are all 5mm-dia. It’s a good idea to countersink these holes from the underside of the lid using a 6mm drill, so that the LEDs slip easily into position when the lid is fitted. Sensor assembly The sensor assembly is made by threading six lengths of 1mm enamelled copper wire through 8mm OD April 2002  37 Fig.4: the water level sensor is made by threading six lengths of 1mm enamelled copper wire through 8mm OD clear PVC tubing (see text). The six sensors should be evenly spaced down the tube. clear PVC tubing – see Fig.4. This tubing should be long enough to reach the bottom of the tank, with sufficient left over to fasten the top end securely. The reason for using 1mm wire is primarily to make it easy to thread it through the plastic tube. Parts List 1 PC board, code 05104021, 80 x 50mm 1 plastic case, 130 x 67 x 44mm 1 PC-mount RCA socket 1 RCA plug 1 2.5mm PC-mount power socket 1 12V AC 500mA plugpack 1 100gm spool 1.0mm enamelled copper wire 1 length 8mm-OD clear PVC tubing to match height of tank plus 200mm 2 3mm x 20mm screws and nuts 2 10mm spacers The top sensor (S6) is placed about 100-150mm below the overflow outlet at the top of the tank, while the other sensors are spaced evenly down the tube. Begin by using a 1.0mm drill to drill holes through the tube wall at the appropriate points, including a hole for the bottom sensor (S1) to hold it in place securely. That done, you can thread the wires through by pushing them through the drilled holes and then up the tube. You will find that the wire goes in more easily if the PVC tube is bent at an angle so that the drilled hole is in line with the bore of the tube. The end of each wire should also be smoothed before pushing it into the tube, to avoid scratching the enamel of the wires already in the tube. Leave about 150mm of wire on the outside of the tube at each point. It’s a good idea to trim each successive wire so that it protrudes 20mm further out of the top of the tube than its prede­cessor. This will allow you to later identify the individual wires when attaching the resistors. When all six wires have been installed, the next step is to solder the wire for S1 to the “earthy” side of the figure-8 lead, cover it with insulating sleeving and pull the covered joint down about 50mm into the 8mm tube. This done, the resistors can be soldered to their appropriate wires. Push about 15mm of 2.5mm sleeving over each wire before attaching its resistor. This sleeving should then pulled up over the joint and the bottom end of each resistor after it is soldered. Once all the resistors have been soldered, the wires should be pulled down so that the joints are just inside the 8mm tube, as shown in the photo. When this process is complete, there will be five resistors protruding from the top of the 8mm tube. Their Semiconductors 1 LM3914 linear dot/bar driver (IC1) 1 NE555 timer (IC2) 1 BC558 PNP transistor (Q1) 1 78L12 12V regulator (REG1) 4 1N4004 diodes (D1-D4) 5 5mm green LEDs (LEDs1-5) 1 5mm red LED (LED6) Capacitors 1 100µF 35VW PC electrolytic 1 47µF 16VW PC electrolytic 1 10µF 16VW PC electrolytic 1 0.1µF greencap Resistors (0.25W, 1%) 1 820kΩ 1 82kΩ 1 680kΩ 2 2.2kΩ 1 560kΩ 1 1.5kΩ 1 330kΩ 9 1kΩ 1 220kΩ 1 390Ω 1 100kΩ 1 470Ω trimpot Miscellaneous Light-duty figure-8 cable, 2.5mm PVC sleeving, heatshrink tubing. 38  Silicon Chip This is the author’s completed water level sensor. A weight can be attached to the bottom end to keep the plastic tube straight when it is immersed in the tank. www.siliconchip.com.au Fig.5: this full-size artwork can be used as a drilling template for the front panel. Improved Water-Level Sensor For a long-life water level sensor, Bob Barnes of RCS Radio suggests that the probe be made out of 19mm plastic conduit fitted with stainless-steel radiator or fuel pump hose-clamps for the sensors. Suitably sleeved nichrome or stainless steel wire (“up the spout”) can then be used to make the connections between the clamps and the resistors. You will need to use Multicore Arax cored solder or Litton Arax cored solder (available from Mitre-10) when soldering nichrome or stainless steel wire (ie, a corrosive flux is needed). You can buy ni­ chrome wire from Dick Smith Electronics or from Jaycar, while stainless steel wire should be available from boating suppliers. remaining leads are then twisted together, soldered to the other side of the figure-8 cable and covered with heatshrink tubing. The other end of the figure-8 cable is fitted with an RCA plug, with the resis­tor lead going to the centre pin and the sensor 1 lead going to the earth side of the connector. The next step is to scrape away the enamel from the 150mm wire lengths at each sensor point and wind them firmly around the outside of the tube. A 30mm length of 12.5mm copper water pipe can be pushed over sensor 1 to add weight and increase the surface area if desired. Note: on no account should solder be used on the submersible part bewww.siliconchip.com.au The top of the water level sensor can be secured to the tank using a suitable bracket. cause corrosion will result from galvanic action. Finally, the end of the plastic tube and the holes can be sealed with neutral-cure silicone sealant. However, don’t get any silicone sealant on the coiled sensor wires, as this will reduce the contact area (and perhaps render them ineffective). Switching on Fig.6: this diagram shows the drilling details for the plastic case. Now for the big test. Apply power to the unit and check that the red LED comes on and that there is +12V on pin 3 of IC1. If all is well, the unit can now be tested by connecting the sensor assembly and progressively immersing it (starting with sensor 1) in a plastic dish that’s full of water. When sensor 1 and sensor 2 are immersed, LED6 should extinguish and LED5 should come on. Similarly, when sensors 1, 2 & 3 are immersed, LEDs 5 & 4 should be on and so on until all five green LEDs are lit. Finally, trimpot VR1 must be set so that the appropriate LEDs light as the sensors are progressively immersed in water. In practice, you should find the two extremes of the pot range over which the circuit functions correctly, then set the pot midway between these SC two settings. April 2002  39 SERVICEMAN'S LOG Who said servicing was dying? Well, maybe it is but my bench is still full. In fact, I have quite a collection of stories this month for no less than 10 different models. Fortunately, several were short and fairly straightforward. I have a full house this month, starting with a 1999 Pana­sonic TC14S15A (MX5 chassis). It was dead and the horizontal output transistor Q551 (2SD2499) was short circuit. A new one was fitted but it became extremely hot. The horizontal output trans­former T501 was also replaced and all the components around the horizontal output stage were checked thoroughly. Nothing amiss was found but it was still blowing the transistor. The only clue was a some ringing around the positive horizontal pulse on the collector of the horizontal output tran­sistor. This problem was solved only when a sister set was brought in and the two compared. A smart pair of eyes noticed that there were four ferrite beads fitted on the good set – L552 in the emitter, L558 in the base and L551 & L557 in the collector. In the crook set, someone in the factory had left out L551 and L552 and fitted only links. The question is, how did it last for so long before it reached this stage, because the transistor was very hot? Anyway, the ferrite beads fixed it quick smart and the transistor now runs quite cool. Another Panasonic At about the same time, a similarly aged (1999) Panasonic TV set also came in with a similar fault; ie, it was dead with the horizontal output transistor short circuit. This model was a more upmarket TAU set, model TX-79P100Z with an MD2 chassis, and advanced features such as computer and DVD inputs (B-Y & R-Y), etc, which one might expect at $4700. 40  Silicon Chip The cause of the failure was unusual, as the frequency of the horizontal drive was far too high. In fact, it was double the correct frequency. Surprisingly, it wasn’t the jungle IC that was the culprit. Rather, it was the Digibox that had somehow become stuck in the 100Hz mode. This module is non-serviceable and was replaced under warranty which fixed the problem. A mysterious customer Mr Armstrong was a rather mysterious customer. He was a single man in his late thirties and spent a lot of time travelling overseas. And he was on his way to another overseas trip so there was no forwarding address – just a mobile telephone number. He brought in an Hitachi 5-inch LCD/Video Cassette Recorder VTLC50EM (AU) which was completely dead. This is a rather nice little toy, consisting of a truly portable battery Items Covered This Month • Panasonic TC-14S1SA TV set (MX5 chassis) • Panasonic TX-79P100Z TV set (MD2 chassis) • Hitachi 5-inch VT-LC50EM (AU) • Sony KV-XF29M35 TV set • Panasonic NV-FS90A TV set • Sony KV-XF29M35 TV set • Philips 28CE1965 TV set • Philips 28GR6775/75R TV set • Sony KV-1415AS TV set • NEC N-3452 VCR operated miniature multi-system TV receiver and VHS video system, all in a neat 370 x 90 x 220mm case. It was a set I had never seen before. Mr Armstrong was convinced that it was just a fuse or switch and left it with me after I had checked the external AC adaptor/charger (VMAC600­EM) was delivering a healthy 9.6V DC from a rather frayed cord. I knew immediately that this wasn’t going to be simple; it was far too compact and it would be like a notebook computer – all surface mounted components and tricky access. I shot around to my mate who is an Hitachi agent and borrowed his service manu­ al(s) – and that’s when I started having second thoughts. Maybe I had been too courageous in taking on this repair? Mr Armstrong had given me the impression that the unit was only a few years old and so I was rather disillusioned when I found out that it was in fact nearly 12 years old. The first thing I did was to confirm that the 2Ah 9.6V nicad battery, VMBP63, was completely shot and that a new one was rather expensive and obtainable only from Hitachi. A tape was also stuck inside but the video cassette was unable to eject it or even show any signs of life. I removed the bottom cover by undoing seven screws to reveal just what I had expected – a fair whack of miniature electronics in a small box. After a little careful reconnaissance and surfing the service manual, I discovered that there are two main boards on the left looking from underneath – ie, PC boards JAS and TTS – plus a further board (SWS) on the right under the video deck. The TTS board could be unclipped and folded upwards to give access to the JAS board below. Of course, the boards were double-sided with surface-mount components – but the thing I noticed most, which filled me with fear, was the vast number of subminiature electrowww.siliconchip.com.au lytic capaci­tors, many of which were leaking electrolyte on all the boards. At this stage, all I was intending to do was to diagnose the fault(s) so that I could give Mr Armstrong a quote for the repair cost. I already had a good idea what had happened but I was determined to cross a few “t”s and dot a few “i”s. And I needed to know where the power came in and where it went, which I thought was going to be fairly simple. It wasn’t. The circuit was very complex and it took a long time to work out that the AC adaptor came in via JK1501. The battery came in via PG502 and the line then went via fuses FU1501 and FU501. These are 2A picofuses and both had blown. The fuses, which look like resistors, were located some distance away from the DC jack and battery input. Unfortunately, it was too difficult to trace the path, not only because the board was double-sided but also because the parts were tightly packed. Even with the fuses blown, there were voltages that could be measured at random on all the boards at places that were accessible. Unfortunately, replacing the fuses had no positive effect – the unit was still as dead as a doornail. Next, I followed one rail from the fuses to the TTS board and then to another switchmode power supply. In the process, I checked a lot of other fuses but I was getting nowhere. By now, I was feeling rather frustrated. All I had achieved so far was www.siliconchip.com.au to find two open circuit fuses and determine that there was no 5.1V where it should have been. Nor was the 9.6V reaching pin 11 of IC581, the switching regulator. What’s more, there were a lot of electrolytic capacitors to replace. I then checked some of the IC regulators that fed the microcontrollers, to find they were OK (eg, IC1902 that fed IC1901 on the TTS board; and IC906 to IC901 on the SWS board which controls the power-on function). By now, I could see that a lot of work was needed to replace the electros and possibly fix the corroded tracks under­ neath them. Then there was the NiCad battery, plus the memory back-up lithium battery. After adding 10% GST, I thought it hardly worth continuing with what was essentially a toy. Anyway, I had to wait a few months before I could finally contact Mr Arm­ strong, when he resurfaced back in Australia. I was agreeably surprised when he accepted my expensive estimate. I guess he is one of those blokes who doesn’t have many other interests and this was one of the luxuries he felt he had to have. While waiting for his verdict, I had been planning my cam­paign of attack and now I was ready to go. First, I removed his jammed video tape by unplugging the loading motor (CN904) and connecting a 9V battery to it to release the tape. That done, I concentrated on changing the worst of the electrolytic capacitors. There were 10 brown electrolytics, eight of which were 47µF 16V (C584, C587, C588, C589, C597, C1855, C1857 & C1939) and there were also two at 100µF (C585 and C586). C1855 and C1857 had corroded the tracks badly underneath and it took a lot of effort to work out which “micro-thin” tracks were which. The main one was VDET from PG1902-6 to pin 22 of IC1901 via R1958 and pin 1 of D1901. Unfortunately, I wasn’t having much luck and still couldn’t get the power switch to work – or even get the poweron LED to light. I have to confess that much of my work was done with the unit upside down and I was operating the power switch by toggling it with my fingers under the half-opened LCD screen lid. After changing a few more electros, it was getting late so I thought I would clear the bench and partially reassemble the unit, ready for the next day. That done, I turned the unit over, opened the lid fully and was staring at it hatefully while I again hopelessly pushed the power switch. To my total amazement, the whole lot came on – even the video system was working. I tuned in a channel (when I worked out how to do it!) and the picture and sound were perfect. When I came in the next day, I couldn’t help feeling that it had all been a mirage – but it was still working! What I hadn’t realised before was that the set would only work when April 2002  41 Serviceman’s Log – continued While a new one was on order, I decided to chase the ABL circuit and see if there was anything untoward there. It turned out to be a fairly involved circuit but my hunch was correct in the end – several surface mount components on the A board, in­cluding Q312 (2SA1162-G), D315 (ISS3565) and D316 (a 6.8V zener diode), were faulty. This was rather surprising because I would have expected Q512 to have been destroyed as well but it was OK. The new horizontal output transformer finally restored the set until the next onshore sea breeze. And the customer was happy. The SAMPO chassis the screen was fully opened. There is another panel switch (S2801) – not mentioned in the manual – on the LCD board that controls pin 17 of IC1901. So I’m no too sure just when the set had actually been fixed as I worked on it. There was no question that the screen was fully open at the start and the set was definitely “no go” then! The problem was that the power switch doesn’t just switch the power straight on. The power switch (S017, FSW board) con­trols IC1901-18 on the TTS board which, if everything is OK, will somehow talk to IC901. IC1901-61 then “wakes up” Q904 and acti­vates IC901-49 on the SWS board. And that in turn switches on Q581, Q585, Q582 and IC581 on the JAS board which then switches on regulator transistors Q588-Q591 Of course, that’s all assuming that nothing is wrong and that the protection circuits don’t switch on! In the future, jobs like this are definitely for the birds. Seaside problems Disasters can happen to everyone 42  Silicon Chip and to every type and make of set. Mr Byron had one such experience with a newish (1999) Sony KV-XF29M35, which lived with him in a stylish mansion by the sea. I guess one can have too much of a good thing, because the humid salty sea breeze plays havoc with anything containing metal and electricity. Inevitably, his set died prematurely and ended up on my bench. The power supply was dead and blowing IC601 (STR-F6656) repeatedly. I checked for shorts on the secondary of the chopper transformer and found the horizontal output transistor, Q511 (2SC­4927-01), was short circuit also but this didn’t stop the switchmode control IC from destroying itself. It was only after I had committed the third IC to the bin that I woke up to the fact that the sensor amplifier, SE135N (IC602), was giving incorrect feedback information. However, I wasn’t completely out of the woods. The picture was extremely dark, with no contrast. And the horizontal output transformer, T503, was looking particularly dodgy, as it was hissing and spluttering. The Philips Group has produced over 5000 different models of colour TV sets in the last 30 years. Almost all have been designed and made by the company but there are a few that have been made outside. Two that come to mind are made in Taiwan – the SAMPO-1 and SAMPO-2 chassis (Models 26CE1991 and 28CE­ 1965). Anyway, Mr Ten­nant phoned for a home service call on his Philips set, a 28CE1965, complaining that when it was cold it was hard to start. And he was convinced that it was the on/off switch. Well, of course – if it isn’t the fuse, the switch or the tube – it can’t be anything else! When I arrived, he had the set on and so it was switching on and off perfectly every time. I just couldn’t accept that the switch was faulty only when it was cold, so I told him that I suspected the power supply and probably the electrolytic capacitors in it and that it would have to go to the workshop. Back at the workshop with the back off, I could see the set was very well made and that it used a Toshiba IC chip set. There is no master power switch – the set is controlled by a subminiature push switch going to a microprocessor and then a relay. I found and replaced capacitors C713, C714, C717, C735 in the power supply which were dried out. I then put it back into operation and left it to soak test on the bench but with back off just in case I had to do any further work. After a few days, it was still working correctly and so I put the back on. However, with the back on, I found it difficult to turn the set off with the www.siliconchip.com.au remote control. I didn’t discover this until it had run all day and it was time to turn it off, so I wondered whether this new problem might be caused by additional heat affecting something. I tried it for another day, before opening it again. And with the back off, I couldn’t fault it, so I was even more suspicious of the heat factor and replaced even more capacitors – C740, C741, C744 & C745 – in the auxiliary power supply for the relay and microprocessor. Well, I still couldn’t fault it with the back off but once back in its case, the set intermittently wouldn’t switch off with the remote control, even when it was cold. However, it did re­spond to the switch on the set. Consistent with my old age, it took a while for the cause to sink in. The chassis slides in from the back, on plastic rails, until the escutcheon mounted pushbutton controls just touch the push switches. However, the combination of the chassis being pushed too far forward and a slightly distorted power knob meant that the microswitch was permanently switch­ ed on. So, when the remote control was used, it could only mute the sound but not turn the relay off. However, when the switch itself was pressed, it released itself properly. So Mr Tennant was right; or at least partially – there was a problem with the switch assembly. Another Philips I had a Philips 28GR6775/75R G110-S chassis in for repair at about the same time. This model was very popular in Australia and there are a lot of them about. Mr Brady brought this one in and, originally, it had inter­mittent vertical deflection and linearity but the fault was now permanent. I replaced capacitors C2813 and C8214 (both 1500µF 40V electrolytics), which were leaking badly and thought that that would fix it. However, before replacing them, I had to clean off the excess electrolyte on the board. It had even leaked under­neath the chassis but no visual damage to anything was apparent. Unfortunately, having done all this, the fault was still there. I measured everything in sight with the ohmmeter but could find nothing wrong. I then spotted a surface mount component link (4815) under C2813 and C2814. This had 000 printed on it, denot­ing zero ohms, and connects C2813 and C2814 together. Anyway, when I measured this, it did indeed measure zero ohms but when I hit it with freezer, while the set was on, the vertical timebase began to scan. I felt that it was telling lies and linked it out with a fair dinkum wire link. This fixed the fault completely and when I measured the surface-mount link again, I found it was high resistance. I can only assume that the corrosion from the electrolyte had damaged it in a manner such that it failed under load. Dark NEC A Thai-built NEC portable 34cm remote control TV set was brought with a dull dark picture. It was an N-3452 model with PWT-101A chassis. The voltage on TP91 was only 85V when on but shot up to 143V on stand-by. It should have been 116.5V so something was very wrong. The power supply uses an STK 730-80 (IC601) and I noticed that it raised the voltage when hit with freezer. The voltage input across capacitor C604 was a very healthy 320V. I then started looking for any electros in the primary or control section of the power supply and at first didn’t see any. But then I spied C610 (10µF, 50V) on the circuit although I couldn’t see it on the board. I finally found it tucked up tight behind IC601 and replaced it. This was indeed lucky as it was the culprit and not the expensive IC I was about to order and replace. A crook guess I don’t appear to be very good at guessing which jobs look easy and which don’t. Mrs Lyon’s Sony KV1415AS (SCC-F35A, G3E chassis) had a very small dark picture and for all the world it looked like the main HT was low, which would be relatively easy to repair. However, after I had taken the back off, I measured the HT and it was spot on at 115V, on the cathode of D608. So my main theory was quickly dissolved. I moved to my fall-back position – when in doubt, measure all the power rails. This I did, and realised fairly quickly that all the secondaries of the horizontal output transformer were low and the EHT was down to about 15kV. There are three main voltages from the transformer: 200V for the CRT video outputs, 26V for the vertical output and 15V for all the ancillary circuits. I started with the latter by disconnecting the output of IC851, a 9V IC regulator, to see if the rail would come up when the load was removed. I was back on track again! Disconnecting the 9V rail brought all the secondaries up to normal – but what was loading it? There were no shorts on the 9V rail but when it was recon­ nected, the 9V dropped to 6V. PARALLAX BS2-IC BASIC STAMP $112.00 INC GST WE STOCK THE COMPLETE DEVELOPMENT SYSTEM www.siliconchip.com.au April 2002  43 cant dis­count but she still thought it was too expensive! Panasonic VCR Unfortunately for me, the 9V rail goes everywhere in the set. So in the absence of any other brainwave, there was nothing for it but to progressively disconnect the devices being fed by the 9V rail and keep track of its value. Much later, I found that desoldering the links to Q851 (2SA1162), a surface-mount PNP regulator, made a significant difference, even though the device itself was perfectly OK. I then found that disconnecting diode D251 (ISS119) in series with the collector of this transistor restored everything. That surprised me, as both these devices are minute and yet were holding this rail down by one third! I measured D251 to find it too was perfect – so where to now? D251 fed the bases of the two transistors, Q251 and Q252, which apply audio muting to IC251 (the audio output IC). Once again, I had to disconnect 44  Silicon Chip components to find out where the current was going. I desoldered Q251 and Q252 in turn but found that it was D250, another ISS119, that was causing the problem. It was leaky and replacing it fixed the set completely. So what was the significance of D250? As already stated, its cathode (along with D251) fed the two muting transistors. The anode goes to the emitter of Q2004, which is in the power on/standby circuit and feeds horizontal drive transistor Q801 via R057 (1kΩ). Not being a circuit designer, my hypothesis is that a leaky diode reduced the drive to the horizontal output stage. And it was this that was causing the low output rather than a current overload problem. It was an interesting case but unfinancial as far as I was concerned. Mrs Lyons’ set had been fixed at a signifi- With the low cost of VCRs, I am getting less and less to repair, the exception being the more expensive hifi and SVHS machines. Recently, I had a Panasonic NV-FS90A with no TV reception – the tape would play OK and all the other functions were fine. Unlike most similarly dated SVHS machines from Panasonic, this model selected AV via the program selector in sequential order, or it could be selected on the remote control. Other models have a switch on the front panel offering Tuner, Simulcast or Auxiliary inputs. This set was stuck in the AV mode and wouldn’t switch to TV at all. I took a long time studying the service manual and in the course of tracing the circuit, discovered that C1003, the memory back-up capacitor, had leaked electrolyte onto the main board, corroding at least three tracks. I thought that linking the broken tracks would fix the problem but it wasn’t to be. The critical point was pin 4 of the microprocessor (IC6001, MN188166VDU) which should have 5V on it for the TV function. It took a long time to realise that the corroded tracks were not the only problem. IC6001 itself was also faulty but only on pin 4. But why had such a complex microprocessor failed only on one pin. The reason, I suspect, was because the electrolyte from the leaking capacitor had shorted the nearby -20V to pin 4. I worked out a fix by shorting Q607’s base and collector, to hold this rail at 5V. But this fix was incomplete – it fixed the TV problem but only at the expense of the AV function. Basically, of course, the answer was to replace IC6001. But I hesitated. It was a large and fairly expensive unit and, with labour costs, would make a costly exercise. And I sensed that the customer was worried about further costs. As an alternative, I suggested that I could fit a toggle switch so that he could switch between the AV and TV inputs. However, he ultimately decided that he really had no further use of the AV inputs and that a switch would look out of place. So we left it at that. The customer was happy and I was happy. What SC more could one want? www.siliconchip.com.au 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. Solar battery protector prevents excessive discharge This circuit prevents the battery in a solar lighting system from being excessively discharged. It’s for small systems with less than 100W of lighting, such as several fluorescent lights, although with a higher rated Mosfet at the output, it could switch larger loads. The circuit has two comparators based on an LM393 dual op amp. One monitors the ambient light so that lamps cannot be turned on during the day. The second monitors the battery voltage, to prevent it from being exces­sively discharged. IC1b monitors the ambient light by virtue of the light depend­ent resistor connected to its non-inverting Radio controlled electronic flash A radio controlled electronic flash is a useful item in any photographer’s kit. Professionals use them all the time. For example, a wedding photographer would put one behind the bride to back-light her gown and veil. You don’t want wires showing in a shot like that. www.siliconchip.com.au input. When exposed to light, the resistance of the LDR is low and so the output at pin 7 is low. IC1a monitors the battery voltage via a voltage divider connected to its non-inverting input. Its inverting input is connected to a reference voltage provided by ZD1. Trimpot VR1 is set so that when the battery is charged, the output at pin 1 is high and so Mosfet Q1 turns on to operate the lights. The two comparator outputs are connected together in OR gate fashion, which is permissible because they are open-collec­ tor outputs. Therefore, if either comparator output is low (ie, the internal output To build this control you will need an old R/C car (the simplest sort) in which the car runs in reverse at switch-on and goes ahead only when the remote is operated. They can be picked up cheaply as school fetes and garage sales. A typical car will run from 3V (two cells) and use 9V in the transmitter. Before proceeding, make sure that the electronics in the car are operat- transistor is on) then the Mosfet Michael (Q1) is prevent­ is this mon Moore th’s wined from turning ner of the Wavetek M eterman 85XT on. true RMS digita In practice, l multimeter. VR1 would be set to turn off the Mosfet if the battery voltage falls below 12V. The suggested LDR is a NORP12, a weather resistant type available from Farnell Electronic Components Pty Ltd. Michael Moore, Beecroft, NSW. ing. It doesn’t matter if the wheels are broken or the motor is dead. You need to gain access to the leads to the motor. Normally (ie, without the remote operating), one is posi­ tive with respect to the other. Label them accordingly. On press­ing the remote button, the polarity of the motor leads should swap. You will also need a flash excontinued on page 46 April 2002  45 Circuit Notebook – continued Radio controlled electronic flash: continued from page 45 tension cord you can cut into two sections. At the transmitter, the camera end of the extension cord is fed into the case and soldered to the control button contacts, as shown in Fig.1. The contacts are in series with the battery supply, so if you don’t want to open the transmitter, just cut one of the battery leads and connect the flash extension cord into the gap so created. You will then need to tape down the remote button so that it is permanently operated (ie, closed). All that needs to be done at the receiver end is to connect the normally negative motor lead to the gate circuit of an SCR, as shown in Fig.2, while the normally positive lead goes to the cathode of the SCR. Now, when the transmitter is operated by the camera’s contacts, the lead polarity is reversed and the SCR acts as a switch to fire a portable electronic flash via the other half of the flash extension cord. The transmitter can be attached to the camera via a flash bracket or a screw into the tripod socket, depending on what is the most convenient arrangement. The added components in the receiver can be mounted on Veroboard and housed in the space where the electric motor was. If appearance is a primary consideration, the receiver and the added components could be mounted in a standard jiffy box. Finally, a note of caution: when connecting the flash end half of the extension cord to the SCR, make sure that it is the positive wire which goes to the anode of the SCR. Flash cords do not always have the centre wire connected to the centre pin of the plug. The centre pin of the lead on the flash unit will be posi­tive and this must connect to the anode of the SCR via the lead connected to the R/C receiver. A. J. Lowe, Bardon, Qld. ($40) Luminescent generator When spun rapidly between the fingers, a bipolar stepper motor will generate around 10VAC. If this is stepped up with a small 240V to 6-0-6V transformer in reverse (with series connect­ ed secondaries), a small bipolar stepper motor is capable of powering a standard 5cm by 6cm luminescent sheet at full bright­ness. These are designed to be powered from 20V to 200VAC (typically 115VAC), producing 1.5 candelas of light – which will dimly light the average room, or adequat­ely light a camp table. They are manufactured by Seikosha (RS Components Cat. 267-8726). 46  Silicon Chip The transformer should be a small one (around 100mA or so), otherwise efficiency is compromised. The wires of the motor’s two phases are usually paired white & yellow and red & blue. Just one of these phases is employed in the circuit. If a small bipolar stepper motor from a discarded 3.5-inch disk drive is used, the Luminescent Generator may be built into a very small enclosure. To sustain rapid, smooth spinning of the motor, a geared handle may be added. Thomas Scarborough, Cape Town, SA. ($30) www.siliconchip.com.au The Tiger comes to Australia Neon flasher runs from 3V supply A neon indicator typically requires at least 70V to fire it and normally would not be contemplated in a battery circuit. However, this little switch­mode circuit from the Linear Tech­nolo­gy website (www.linear-tech. com) steps up the 3V battery supply to around 95V or so, to drive a neon with ease. The circuit has two parts: IC1 operating as step-up converter at around 75kHz and a diode pump, consisting of three 1N4148 diodes and associated .022µF capacitors. The 3.3MΩ resistor and the 0.68µF capacitor set the flashing rate to about once every two seconds. The average DC level from the diode pump is set to about 95V by the 100MΩ feedback resistor to pin 8. The circuit could also use an LT1111 (RS Components Cat 217-0448) which would run at about 20kHz so L1 could be reduced to 100µH and use a powdered iron toroid core from Neosid or Jaycar. SILICON CHIP. www.siliconchip.com.au Tigers are modules running true compiled multitasking BASIC in a 16/32 bit core, with typically 512K bytes of FLASH (program and data) memory and 32/128/512 K bytes of RAM. The Tiny Tiger has four, 10 bit analog ins, lots of 2 digital I/O, two UARTs, SPI, I C, 1-wire, RTC and has low cost W98/NT compile, debug and download software. JED makes four Australian boards with up to 64 screw-terminal I/O, more UARTs & LCD/keyboard support. See JED's www site for data. TIG505 Single Board Computer The TIG505 is an Australian SBC using the TCN1/4 or TCN4/4 Tiger processor with 512K FLASH and 128/512K RAM. It has 50 I/O lines, 2 RS232/485 ports, SPI, RTC, LCD, 4 ADC, 4 (opt.) DAC, and DataFLASH memory expansion. Various Xilinx FPGAs can add 3x 32bit quad shaft encoder, X10 or counter/timer functions. See www site for data. Isolation for PC boards in cars These two mounting methods were devised to protect PC boards from vibration when installed in the engine compartment of a car. They could also be used in other applications where vibration is a problem. Method 1 involves rigidly mount­ing the PC board inside a diecast box and then mounting the box itself to provide vibration isolation. As shown, small grommets are installed in suitably sized holes in the sides of the box. The box is then secured to angle mounting brackets using M4 screws, washers and nylock nuts. Method 2 involves mounting the diecast case onto the chas­sis of the car and then mounting the PC board as shown, using M3 screws, grommets, hollow spacers and nylock nuts. In this case, the grommets are fitted into suitably sized holes in the PC board itself. Once the nuts are tightened, the PC board should be able to move slightly, relative to the box. The BASIC, Tiny and Economy Tigers are sold in Australia by JED, with W98/NT software and local single board systems. $330 PC-PROM Programmer This programmer plugs into a PC printer port and reads, writes and edits any 28 or 32-pin PROM. Comes with plug-pack, cable and software. Also available is a multi-PROM UV eraser with timer, and a 32/32 PLCC converter. If there is not enough space on the board to fit the grom­mets, then Method 1 is the way to do it. David Boyes, Gordon, ACT. ($35) JED Microprocessors Pty Ltd 173 Boronia Rd, Boronia, Victoria, 3155 Ph. 03 9762 3588, Fax 03 9762 5499 www.jedmicro.com.au April 2002  47 This handy bench power supply has no expensive meters and offers six fixed dualpolarity supply voltages: ±3V, ±5V, ±6V, ±9V, ±12V and ±15V DC. And for added flexibility, you can use any of the first three outputs and any of the second three at the same time. By JIM ROWE F ULLY VARIABLE DC bench supplies with voltage and current meters are great for checking circuits that operate from odd-ball voltages. They’re also essential for checking the voltage range over which a circuit operates correctly. However, for a lot of work, they can represent overkill. Some of the bells and whistles on a typical supply can even be a drawback, when you’re simply trying out an idea 48  Silicon Chip for a cir­cuit that must work from a bog-standard supply rail. For example, on many low-cost bench supplies, the meters are either too small or too inaccurate to allow you to properly check that the output is set within tolerance. So you generally have to reach for your DMM and check the voltages anyway, before even connecting the supply to your circuit. There can also be a problem when it comes to trying out a circuit that needs multiple supply rails. Most bench supplies have two outputs at most and even these are generally balanced – ie, the positive and negative outputs closely track each other. That’s great when you do want balanced supply rails but not so useful if you want say +12V and -5V. In that case, you generally need a second supply altogether. In fact, if you need three rails – say +5V, -5V and +12V – there’s usually no option but to use a second supply. And if you need a fourth rail, you might well have to use either a third supply or at the very least, two different balanced twin sup­plies. All of which demonstrates the truth of that old saying in electronics: “you can never have too many power supplies!” Multiple fixed outputs For a lot of day-to-day bench work, what would be really handy is a small www.siliconchip.com.au supply with four outputs – especially if these outputs could be easily switch­ ed to select commonly used fixed voltages. Such a supply wouldn’t need any voltmeters, because of the fixed outputs, and for a lot of work it wouldn’t need current metering either. And none of the outputs would need to have a high current/power rating, since most bench work now involves very low power circuitry. This line of thinking culminated in the compact, low-cost four-in-one bench supply described in the January 1998 issue of “Electronics Australia”. It was a very handy little supply and quite popular too but it did turn out to have a few shortcomings. For example, it had a choice of only four output voltages: ±5V and ±12V. Obviously, there are situations where other voltages are required. The other “shortcoming” was that it was not suitable for beginners, because of the transformer and mains wiring inside the case. The idea behind this new design has been to come up with a supply that’s not only more flexible than the 1998 version but easier and safer to build as well. It still offers only four output voltages at once (two bipolar pairs) but these can now each be switched between three pairs of voltages. You can have either ±3V, ±5V or ±6V from one set of outputs and either ±9V, ±12V or ±15V from the other set. Despite this extra flexibility it’s even easier to build than before, because all of the internal wiring is on two PC boards which connect directly together. There’s really no off-board wiring at all. There are no safety worries for beginners either, because the supply gets all its power at very low voltage from an exter­nal 9V/1A AC plugpack. The highest voltages anywhere inside the case are only 9VAC and 27V DC. Like the earlier design though, it won’t deliver really high currents. You can draw up to about 750mA at ±3V, 550mA at ±5V, 450mA at ±6V, 600mA at ±9V, 500mA at ±12V and 350mA at ±15V. This is for each output used singly of course but the figures don’t “droop” too rapidly when multiple outputs are in use – the main limitation is the regulation of the AC plugpack. Fig.1 shows the performance details in graphical form (see also the accompanying specifications panel). www.siliconchip.com.au Fig.1: this graph shows the output current capabilities (blue) for the various fixed voltage outputs. The ripple performance is also plotted (green). As you can see, it still has enough “grunt” for most exper­imental bench work. So although it deliberately lacks a lot of the traditional bells and whistles, it’s still a surprisingly practical unit. The outputs are overload and short-circuit protected and the output terminals are spaced on standard 19mm centres to allow the use of dual banana plugs if desired. The circuit Refer now to Fig.2 for the circuit details. It may seem a bit daunting at first glance but it’s really very straight­ for­ward. First, there are four simple rectifier and filter circuits producing raw DC rails from the 9V AC delivered from the plug­pack. Each rectifier then drives an adjustable 3-terminal regula­ tor with a switch to select one of three regulated output voltag­es. It’s mainly the plugpack which sets the unit’s total power rating of around 9W (9V x 1A). The two low-voltage rectifiers are standard half-wave cir­ c uits, each based on a single 1N5404 power diode (D1 & D2) feed­ing a pair of 2200µF filter capacitors. These rectifiers produce about ±13V of unregulated DC under no-load conditions, drooping down to SPECIFICATIONS Outputs: 2 x dual-polarity pairs (VA & VB) plus two common terminals. Output Voltages: 3 x dual polarity low-voltage outputs (VA); 3 x dual-polarity high-voltage outputs (VB), as follows: (1) Low-voltage switch (VA): ±3V <at> 750mA; ±5V <at> 550mA; & ±6V <at> 450mA (2) High-voltage switch (VB): ±9V <at> 600mA; ±12V <at> 500mA; & ±15V <at> 350mA Power supply: 9VAC 1A plugpack Overload and power indication: 4 x 3mm LEDs Load switching: independent toggle switches for each output pair April 2002  49 lower voltages as current is drawn. The 1N5404 diodes have a current rating of 3A continuous and 200A peak, so they should be virtually “unbreakable” here. For the higher voltage outputs, Parts List 1 plastic instrument case, 155 x 160 x 64mm, with metal rear panel (2mm thick aluminium) 2 PC boards, code 04104021 (119 x 124mm) and code 04104022 (134 x 48mm) 6 banana jack screw terminals (2 red, 2 black, 2 green) 2 DPDT miniature toggle switches (S1, S2) 2 2-pole, 3-position rotary switches (S3, S4) 1 DC power socket, 2.6mm (PC-mount) 1 9V 1A AC plugpack 23 PC terminal pins, 1mm diameter round type 4 TO-220 insulating kits 4 M3 x 12mm round head machine screws 4 M3 nuts, flat washers and star lockwashers 2 instrument knobs, 19mm dia. Semiconductors 2 LM317T 3-terminal regulators (REG1, REG2) 2 LM337T 3-terminal regulators (REG3, REG4) 6 1N5404 3A power diodes (D1-D6) 8 1N4004 1A power diodes (D7-D14) 2 3mm red LEDs (LEDs 1 & 3) 2 3mm green LEDs (LEDs 2 & 4) Capacitors 6 2200µF 16VW RB electrolytic 4 1000µF 63VW RB electrolytic 4 100µF 25VW RB electrolytic 4 10µF 16VW RB electrolytic Resistors (0.25W, 1%) 1 9.1kΩ 1 680Ω 1 5.6kΩ 2 560Ω 1 4.7kΩ 1 510Ω 1 3.6kΩ 1 470Ω 3 3.3kΩ 1 430Ω 1 2.4kΩ 1 330Ω 1 2.2kΩ 2 270Ω 2 1.5kΩ 2 240Ω 1 1.2kΩ 1 180Ω 1 1.1kΩ 2 120Ω 1 750Ω 50  Silicon Chip we use half-wave voltage doubling rectifiers, each with a 2200µF series capacitor, a pair of 1N5404 power diodes (D3 & D4 and D5 & D6) and a pair of 1000µF filter capacitors. These rectifiers produce about ±27V of unregulated DC under no-load conditions, which again droops as current is drawn. By the way, the relatively poor regulation of the half-wave rectifiers doesn’t pose a problem. In fact, it helps keep the power dissipation of the regulators down to an acceptable level, by lowering the voltage across the regulators at higher load currents. The maximum power dissipated by any of the regulators is 3.5W, which is reached by the high-voltage regulators when deliv­ering ±9V at 400-450mA. This is acceptable because the regula­ tors are all mounted on a reasonably good heatsink (the rear panel) and have inbuilt thermal overload protection anyway. If they do get too hot, they automatically shut down for a while to cool off. As shown on Fig.2, the positive 3-terminal regulators are LM317T devices while the negative regulators are LM337Ts. Both of these regulator ICs are capable of handling up to 1.5A of current so, like the rectifier diodes, they’re being used quite conserva­ tively here. The regulator circuits all use virtually the same configu­ ration. This is because the LM317 and LM337 regulators work in the same way, acting to maintain a fixed voltage across the resistor connected between their “output” and “adjust’ terminals (240Ω for the positive regulators and 120Ω for the negative regulators). In each case, the regulator keeps the voltage across these resistors fixed at 1.25V. Because virtually all of the current through these resis­tors comes from the output terminal and almost no current flows in or out of the adjust terminal, virtually the same current flows in any resistance we connect between the adjust terminal and ground. So we are able to set the actual output voltage of the regulator by adjusting this lower resistance value, to set up a “bootstrap” voltage drop that’s equal to the desired output voltage less the 1.25V that’s maintained across the upper resis­tor. For example, in the low-voltage positive regulator (REG1), the series 470Ω and 430Ω resistors give a total of 900Ω, which produces +4.75V between the adjust pin and ground. As a result, the regulator’s output is +6.0V (4.75 + 1.25) when these resis­tors are in circuit alone. Similarly, for REG2, the 1.5kΩ and 1.1kΩ resistors alone give an output of +15V, while the 270Ω and 180Ω resistors in the REG3 circuit give an output of -6V, and so on. To set the two lower output voltages for each regulator, we simply switch in additional shunt resistors across these lower resistors, to reduce their value and hence the voltage drop. For example, in the REG1 circuit, we switch in a 3.3kΩ resistor to lower the regulator’s output voltage to +5V, or the parallel 2.2kΩ and 680Ω resistors to bring it down to +3V. Exact­ly the same arrangement is used for the other three regulators. Note that the two low-voltage regulator outputs (REG1 & REG3) are set using switches S3a & S3b, while the high-voltage regulator outputs (REG2 & REG4) are set using S4a & S4b – ie, each pair of outputs is tied together. As a result, S3 and S4 are respectively marked “VA SELECT” and “VB SELECT” on the front panel, to ensure easy operation. In addition, load switches S1a & S1b allow you to switch the two low voltage outputs together, while S2a & S2b perform the same role for the two high-voltage outputs. These switches are miniature toggle types and are positioned quite close to each other on the front panel. So with a little dexterity, it’s quite easy to switch all four outputs on or off within a few millisec­onds of each other. As shown in Fig.2, each regulator has a 100µF filter capacitor across its output and a 10µF capacitor from its adjust pin to ground to provide additional filtering. There are also reverse-biased diodes connected between each regulator’s output and input (D7, D9, D11 & D13) and between the output and adjust terminals (D8, D10, D12 & D14). Fig.2 (facing page): the circuit uses four simple rectifier and filter circuits to produce raw DC rails from the 9V AC delivered from the plug­pack. Each rectifier then drives an adjustable 3-terminal regula­tor to derive the fixed output voltages. www.siliconchip.com.au www.siliconchip.com.au April 2002  51 status indicator, based on LEDs 1-4 and their series resistors. This means that should one of the regulators begin to shut down in response to an overload, that output’s LED will become dim – so you’ll at least be warned of an overload situation. That’s the cue to hit the appropriate switch and investigate the cause of the overload! This simple system works quite well in practice, despite its low cost. Construction Fig.3: install the parts on the main PC board as shown in this diagram. Note, however, that REG1-REG4 are not installed directly on the board – instead, you have to install PC stakes at each of their lead positions and the regulators are then later soldered to these stakes (after mounting them on the rear panel). The “upper” diodes are included to protect the regulators against damage if the outputs are accidentally connected to a voltage higher than that across their input filter capacitors. This can happen, for example, if you turn off the power to the supply’s plugpack and then suddenly turn on one of the two load switches, thus connecting its regulator outputs to charged bypass capacitors in an external circuit. The “lower” diodes similarly protect the regulators from damage due to any charge remaining in the 10µF filter capacitors when the AC input power is removed. To save costs and keep the circuitry as simple as possible, there’s no current monitoring or limiting, apart from that pro­vided inside the regulator chips themselves. However, each of the four outputs has a simple LED The complete supply is housed in a standard plastic instru­ ment case measuring 160 x 155 x 65mm. Inside the case, everything is mounted on two compact PC boards which solder together at right angles: a main board which is mounted horizontally in the lower half of the case and a switch/ output terminal board which mounts vertically behind the front panel. The main board is coded 04104021 (119 x 124mm) and carries all the components used in the rectifiers. The four 3-terminal regulators also mount along its rear edge, so they can be bolted to the rear panel which acts as the heatsink (the usual plastic rear panel is replaced by a 2mm-thick aluminium plate). Also on this board are the basic components used in each regulator cir­cuit and the power supply AC input connector (CON1). The vertical PC board is coded 04104022) (134 x 48mm) and supports mainly the front-panel components: ie, voltage selector switches S3 & S4, load switches S1 & S2, the six output terminals and the four indicator LEDs. Also on this board are the LED series resistors and the voltage selection resistors switched into the regulator circuits by S3 & S4. The connections between the two boards are made via 11 PC terminal pins, which solder to circular pads near the bottom of the vertical board Fig.4: this is the parts layout for the vertical PC board. Refer to the text for the details on mounting rotary switches S3 & S4. Eleven PC stakes have to be soldered to the otherwise vacant pads along the bottom of the board. These are installed from the copper side and connect to matching pads on the main PC board (see Fig.5). 52  Silicon Chip www.siliconchip.com.au Here’s what the completed assembly looks like before it’s installed in the case. We sandwiched two 1mm-thick aluminium panels together to make up the rearpanel heatsink but you can use a single 2mm-thick panel. and to rectangular pads along the front edge of the main board. As well as making the connections, these pins also hold the two boards together at 90°. Putting it together Assembling the supply is easy, particularly if you tackle it in the following order. First, inspect both PC boards and make sure they’ve been trimmed to the correct sizes and that there are no solder bridges between tracks. This done, begin the main board assembly (Fig.3) by fitting three PC terminal pins to each regulator position along the rear edge – ie, 12 pins in all. Next, fit the 2.6mm power connector CON1 to the board, followed by the eight wire links. Note that most of the links can be made using bare tinned copper wire (eg, component lead off­ cuts) but the two longest www.siliconchip.com.au links should be made using insulated hookup wire. With the links in place, you can then fit the resistors, 1N4004 diodes and finally the larger 1N5404 power diodes. Make sure the diodes are all fitted with the correct polarity, as shown in the overlay diagram, and be sure to fit the correct diode in each location. Once the diodes are fitted you can fit the electrolytic capacitors, again taking care with their polarity. Your main board should then be complete and you can put it aside while you work on the second board. Begin the assembly of this board (Fig.4) by checking that the holes have been drilled to the correct sizes to accept the larger items, such as the rear of the output terminals and the rotary switch connection lugs. That done, fit all of the resistors, again using the overlay diagram as a guide. The only other items to fit to the board at this stage are the two rotary switches but first you have to trim their control shafts to about 10mm from the threaded mounting ferrule. That done, rotate each switch shaft fully anticlockwise, remove its locking nut and star washer, and move the indexing collar three positions anticlockwise. Finally, replace the star washers and mounting nuts to lock the collars down. Each switch should now operate over three positions (in­stead of six). You might also want to file a “flat” on each switch shaft (if one isn’t already present), to help prevent the knobs from working loose later. The flat should be diametrically opposite the switch locating spigot, when the rotor is in its centre position After the shafts have been trimmed and given flats, both switches can be fitted to the board, with their locating spigots directly above the shafts (see Fig.4). You may need to straighten their lugs a little, to allow them to mate with all of the board holes correctly. April 2002  53 also a good idea to file the holes for the output terminals with “flats” on each side as suggested by the artwork, to prevent them rotating and working loose later. You may also want to provide small “blind” holes above the main mounting holes for switches S3 and S4, to accept the switch locating spigots. Check also that the holes for the 3mm LEDs will in fact accept the LED bodies without too much force. The ideal hole size is where the LED will just fit snugly, without being loose. The adhesive label can now be attached to the front panel and the holes cut out using a sharp utility knife. This done, mount the toggle switches and output terminals. The switches should be fitted with the nuts adjusted so that the switch bodies are reasonably close to the panel, with the threaded ferrules protruding 1.5mm or so beyond the front nuts (this is to facili­ tate board mounting later on). The green terminals are fitted in the two centre “Common” positions, with the black terminals for the negative outputs and the red terminals for the positive outputs. If your toggle switches are fitted with standard “solder lug” terminals instead of PC terminals pins, now is the time to fit short lengths (say 20mm) of tinned copper wire to the Fig.5: this cross-section diagram shows how the 3-terminal regulators are attached to the rear panel (using TO-220 insulating kits) and their leads bent so that they can be soldered to the matching PC stakes on the PC board. The diagram also shows how the two PC boards are connected together. That done, solder all the lugs to the board’s copper pads, with the switch body in contact with the front of the board. The next step is to fit the four LEDs in their correct positions, as shown in Fig.4. Just tack-solder one lead of each LED at this stage and DON’T cut any of their leads short – they’re just being positioned for final mounting later. Take care to ensure that the LEDs are correctly oriented – the anode lead is the longer of the two (see Fig.2). Before you can proceed any further with this board, you have to prepare the front panel (that’s because they combine to form an integrated assembly). So the next step is to drill and/or ream the holes in the front panel, using a copy of the artwork as a template. It’s Table 1: Resistor Colour Codes  No.   1   1   1   1   3   1   1   2   1   1   1   1   2   1   1   1   1   2   2   1   2 54  Silicon Chip Value 9.1kΩ 5.6kΩ 4.7kΩ 3.6kΩ 3.3kΩ 2.4kΩ 2.2kΩ 1.5kΩ 1.2kΩ 1.1kΩ 750Ω 680Ω 560Ω 510Ω 470Ω 430Ω 330Ω 270Ω 240Ω 180Ω 120Ω 4-Band Code (1%) white brown red brown green blue red brown yellow violet red brown orange blue red brown orange orange red brown red yellow red brown red red red brown brown green red brown brown red red brown brown brown red brown violet green brown brown blue grey brown brown green blue brown brown green brown brown brown yellow violet brown brown yellow orange brown brown orange orange brown brown red violet brown brown red yellow brown brown brown grey brown brown brown red brown brown 5-Band Code (1%) white brown black brown brown green blue black brown brown yellow violet black brown brown orange blue black brown brown orange orange black brown brown red yellow black brown brown red red black brown brown brown green black brown brown brown red black brown brown brown brown black brown brown violet green black black brown blue grey black black brown green blue black black brown green brown black black brown yellow violet black black brown yellow orange black black brown orange orange black black brown red violet black black brown red yellow black black brown brown grey black black brown brown red black black brown www.siliconchip.com.au This close-up view of the rear panel shows how the four 3-terminal regulators are mounted. Note that the regulators must all be electrically isolated from the rear panel using TO-220 insulating kits (see Fig.5). They are connected into circuit by soldering their leads to matching PC stakes on the main PC board. top four lugs of each, pointing directly backwards along the lug axis but with a small loop around the side of each lug before solder­ing – to make sure it can’t drop off when you later solder it to the PC board pad. You should now be ready to mate the front panel and the vertical PC board together. This involves pushing the rotary switch shafts and their threaded ferrules through the front panel holes (you have to remove the locking nuts first) and at the same time pushing the rear spigots of the output terminals and the leads on the rear of the toggle switches through the corresponding holes in the board. It’s a bit fiddly but not too difficult if you take it carefully. Once the two are mated together, you may need to adjust the positions of the mounting nuts and washers for the toggle switch­es so that the switch positions fore-and-aft will allow both panel and board to be truly parallel to each other, with a space of very close to 16.5mm between them everywhere. Tighten the toggle switch nuts at this point, followed by the rotary switch nuts – but carefully, so you don’t strip the plastic threads or slip and scratch the front panel. www.siliconchip.com.au You should now be able to solder the ends of the output terminal spigots to their large pads on the PC board. The toggle switch leads can then also be soldered to their respective pads. That done, you can untack each LED from its initial posi­tion and carefully push it forward until its body fits snugly in the corresponding front panel hole. Its leads can then be sol­dered properly to the board pads and any excess finally trimmed off. The next step in preparing this board/panel assembly is to lay it face down on the bench and fit the 11 PC terminal pins which will connect it to the main board. These are all fitted from the copper side, so their main length protrudes backwards from the board. Solder each one carefully to its pad. The two boards can now be mated The rear panel is pretty uninspiring – just the four screws that secure the regulators plus a hole for the power socket. April 2002  55 Fig.6: these full-size artworks can be used a templates for drilling the front and rear panels. Note that the holes for the for the banana jack terminals have straight sides, so profile these carefully. together, by soldering these same 11 terminal pins to the rectangular pads along the front of the horizontal board. This is best done with the main board upside down (ie, copper side up) and with the other board/panel assembly also upside down but held at right angles using a small strip of 18 x 32mm wood or similar as a guide. It’s a good idea to just tack solder the pins at each end first and then make sure everything is aligned properly in terms of both the 90° angle and the side-to-side positioning. Once all is well, you can then solder all the pins to their pads to complete the assembly. At this point, you can fit the control knobs to the rotary switch shafts, ready to adjust the output voltages. The module is now essentially finished (apart from the regulators which are fitted during the final assembly) and 56  Silicon Chip can be put aside while you prepare the rear panel. Rear panel work In order to provide reasonable heatsinking for the four regulators, the rear panel should ideally be made from 2mm-thick aluminium sheet. I didn’t have this available so I used two 1mmthick pieces in “parallel”. There are only five holes to drill/ ream in the rear panel – 4 x 3mm-diameter holes for the regulator mounting screws and 1 x 8mm-diameter hole to clear the power input socket. Their posi­tions are shown in Fig.6, so there shouldn’t be any problems with them. Just make sure you don’t leave any burrs around the 3mm holes in particular. A countersink bit or a large drill bit can be used to remove any metal swarf and make the edges smooth. With the rear panel drilled, the next step is to crank the three leads of each regulator IC forward, so that they end up immediately behind the terminal pins on the rear of the main PC board after final assembly. This is done by gripping each regulator’s leads with a pair of needlenose pliers about 4mm from the body (just after the leads narrow) and then bending all three upwards at 45°. The pliers are then used to grip them a further 5mm along, after which they are bent back down again by 45° (see Fig.5). The four regulators can now be fitted to the rear panel but first make sure that all the mounting holes are smooth and free of metal swarf. Fig.5 shows the mounting details. Note that each regulator must be electrically isolated from the rear panel using insulating bushes and mica washers. Smear all mating surfaces with silicone grease www.siliconchip.com.au 04104021 C 2002 04104022 C 2002 Fig.7: these are the full-size etching patterns for the two PC boards. Check your etched boards carefully for any defects before installing the parts. before bolting the regulators down. Alternatively, you can use silicone-impregnated thermal washers instead of the mica washers, in which case you don’t need the thermal grease. Make sure that you mount each regulator in the correct location – the two LM317Ts mount on the lefthand side of Fig.3, while the LM337Ts are on the right-hand side. When you have fitted them all, it’s a good idea to check with a DMM or ohmmeter to ensure that there’s no connection between any of the regulator leads and the panel. If you do find a short between any of the leads and the rear panel, remove the regulator and locate the source of the problem before refitting it. Final assembly The next step is to fit the board and front panel module into the lower half of the case. You do that by sliding the ends of the front panel carefully down into the front case slot. This should allow the main board to sit flat on the www.siliconchip.com.au case support spigots, with the mounting holes located over the centre hole in each spigot. If the alignment isn’t quite right, you may need to remove the board assembly again so that you can enlarge one or two of the board holes in the required direction. That done, refit the board assembly and install four 6mm x M3 self-tappers to hold it in position. The rear panel (and its 3-terminal regulators) can now be installed in the rear case slot. This should position each set of cranked regulator leads behind their corresponding PC terminal pins (in fact, they should be just touching). Check that all the leads are correctly aligned before soldering them to their respective PC pins. Checkout time If you’ve followed these instructions carefully, your supply should work correctly as soon as you plug the lead from the 9V AC plugpack into CON1. Each of the two pairs of LEDs should glow as soon as you switch on each pair of supply outputs using the two toggle switches. You can then check each of the output voltage pairs using your DMM. Check that you get the correct readings for each position of the two rotary switches – all voltages should be within about ±1% of their nominal values, under no load conditions. About the only possibilities for error are fitting the electrolytic capacitors or diodes incorrectly to the main PC board; mounting the regulators in the wrong positions on the rear panel; mixing up some of the resistors on the vertical PC board, or fitting one or more of the LEDs the wrong way around. So if your supply doesn’t work properly, check these possibilities first after quickly switching off. And that’s it – you’ve just finished making yourself a very handy little four-in-one bench supply. All that should remain is fitting the top of the SC case and putting it to use! April 2002  57 COMPUTER TIPS Compiled by Peter Smith More FAQs On The MP3 Jukebox The MP3 Jukebox player featured in the September & October 2001 issues continues to be a popular project and hun­dreds have been built. Since we published the FAQs in this pro­ject in the January 2002 issue, more questions have arisen. Here are the answers to some of them. Using A Bigger LCD Q Great project. The MP3 player is just what I have been looking for since I set up my dedicated MP-3 machine about 10 months ago. I have been using an LCD driver I down­ loaded from the net, which is working well, but having a full keyboard around has been a nuisance. So the remote control will be well received around the family! What I would like to know is can the software be easily adapted for a 4-line by 20-column display? I have considered having a go myself but my programming experience is limited to VBA (Excel) and I have no experience with microcontrollers so why not ask the experts! Rob Walls, via email. The IR Remote software could be modified without too much trouble to work with a 20x4 display. All fields of the ID3v1 tag are read and stored and available for use by the LCD output routines. You will need a copy of VB6 Pro (or know someone that does) in order to modify/ A Download Failed On Remote Interface Q I just recently constructed an MP Remote Interface kit which I purchased from Altronics. When the hardware was complet­ed, I went to your website to download all the appropriate soft­ ware (IRRLCD.ZIP) + (IRR10.EXE). After the download, I went to the Hyperterminal as instructed and attempted to download the new file IRREE.EEP. The file was sent to the Interface and a second or so later, a message “Download failed!” appeared on the LCD panel. Can you help? I tried to download the software again with no results and tried using other clone PCs. Apart from that, I noticed that the remote control couldn’t control many functions; IRR10.EXE Won’t Minimise Q I know you don’t offer support on the software at your site but just a quick question you might be able to help me with: the MP3 jukebox kit software IRR10.exe doesn’t seem to minimise once initialised. It says READY, READY then just stays on the desktop without minimising to system tray. I can’t see the system tray icon at all. I’ve tried reinstalling it three times. I’m 58  Silicon Chip using a freshly installed Windows Milllenium computer. Any help would be appreciated. Clinton C, via email. IR Remote won’t minimise to the system tray if any kind of problem occurs during initialisation. You’ll need to scroll up in the list of messages in the little status window in order to determine where the problem lies. A re­compile the code, though. As mentioned in the January 2002 edition (page 21), you can download the source code from the SILICON CHIP website. The microcontroller code would also be quite easy to modify for the larger display size but you will need to know your way around the Atmel AVR chips. Sorry, but we can’t give you actual exam­ples of how to do this right here – we would have to spend quite a bit of time making the changes and testing them and as you can imagine, we’re hard at work on projects for upcoming issues! eg, forward track or shut-down but I believe that this was a result of the download failure. Kwan Lee, via email. It’s unclear from your message why you have tried to reprogram the microcontroller’s EEPROM. As detailed in the article, this step is only required if you wish to change a number of default start-up parameters (which are documented in IRREE.ASM). In order to modify these parame­ ters, you will need at least a basic familiarity with the inter­ nal workings of the Atmel 90S series microcontrollers. The microcontroller you received with your kit should already have both the program (FLASH) and data (EEPROM) memory pre-programmed. This means that you do not have to reprogram it unless you wish to make changes as indicated above. Assuming that you really do want to reprogram the EEPROM, then the first step is to make sure that everything is working correctly before making any changes. The “Download failed” problem you A www.siliconchip.com.au Q Problems With Winamp I recently purchased the MP3 JukeBox kit from Altronics, as detailed in your September and October 2001 issues. I put the kit together and got everything working. Then I downloaded the plugin for Winamp and was less then impressed. I think a more elaborate plugin is needed or an alternative one. Although it seems to work, what is needed is support for a large playlist to just run normally with the remote control support. None of this metalist nonsense. The Plugin works fine but the thing that ruins it is its inability to play random. I tried several play­list files of varying sizes. Also I tried a metalist following strictly the instructions given but instead of detailing the whole playlist in the Winamp playlist window I notice it only displays the current song being played. This also makes this song play over and over again, unless I press next song on my remote control. I have the exact universal remote control detailed in the instructions (AIFA AV8E). I am really anxious to resolve my Winamp plugin describe below could be caused by a number of factors. First, verify that the port set­tings in Hyperterminal are correct (see the September 2001 issue, page 31) and that characters you type in appear correctly on the LCD as detailed in the article. Next, when attempting to download the EEPROM file, make sure to select “Send Text File” (not “Send File”) in Hypertermi­nal. If the above doesn’t help, then suspect a problem with hardware handshaking. This could be caused by a wiring error – check that the “READY” signal from the IR Receiver & LCD Module goes to pin 8 of the female D-9 connector. The remote control should be able to control all functions mentioned in the magazine article, assuming you have successfully assigned each function to a key (see October 2001, page 30). The contents of the EEPROM do not affect the operation of the remote control. www.siliconchip.com.au problems and use my jukebox. I originally intended to purchase one device, get it up and running then purchase several more but this great device is being held back by a heavily limited plugin for Winamp. G. Bulloch, via email. Firstly, we should mention that the IRRemote software was not designed as a true Winamp plugin and was not presented as such in the magazine. The intention is to control Winamp without the graphical interface, which is why the playlist does not appear in Winamp’s window. We put a lot of work into the metalist implementation, so we obviously don’t think it is nonsense. As it is, a single playlist supports up to 199 tracks, which in our opinion isn’t too shabby anyway. We’ve had no other reports of the random (shuffle) play function not working. As detailed in the article, when you’ve enabled shuffle play, a small “S” symbol should appear on the LCD. Note that it’s important that you do not also click on the “Shuffle” button in the Winamp window, as this function is de­signed to be controlled by IRRemote. A MP3 power supply Q You have the MP3 Jukebox powered from a 12V rail but you are using only a 5V regulated supply. Is there any obscure reason why I should not run it from the 5V computer supply and leave the 7805 regulator out? I have had a look through the code for the microcontroller. You have done an excellent job. Brian Stephenson, via email. The MP3 player is powered via a regulator instead of the PC’s +5V rail for three reasons. First, it allows those using it in a remote housing to power it from a plugpack. Secondly, it eliminates the problem that can occur with the LCD module’s viewing angle varying as a result of slight variations in power supply voltage. Finally, it allowed us to fit a series polarity protection diode! There’s no reason why you can’t run it without the diode and regulator but leave the filter capacitors in place. A Winamp Playlist Not Displayed Q I’m having trouble with my MP3 Jukebox. I have a Duron 750 with 768MB RAM, 20GB hard disk, running Windows 98 and Winamp 2.75. The problem is that the irremote program loads the play­ list but only loads the first song and not the others. I only have 40 songs in the playlist and the playlist is in the same directory as my MP3. If I add songs after the playlist loads, the title info stays on the display but the song length changes. Can help me with this problem? Warren Anderson, via email. Only one track is ever displayed in Winamp’s playlist – the track currently loaded by IR Remote (and displayed on the LCD). This is as we intended -remember, the Jukebox software was designed to be used without the Windows graphical interface. However, you should be able to move to any track in your playlist using your remote and the instructions detailed in the article. If not, then examine the information displayed in IR Remote’s status window (use the up arrow to scroll back) for possible problems loading/scanning the playlist file. It’s not possible to manually add tracks to Winamp’s list while IR Remote is running. It is also important not to click on the “Shuffle” or “Repeat” buttons in Win­amp, as this will confuse IR Remote. A Possible Atmel Chip Substitution Q I’d like to build the MP3 player which uses an Atmel AT90S2313 chip for my PC. My question is, can I use an AT89*2051** chip instead with a 12MHz crystal? The pinouts are almost identi­cal. Michael Girton, via email. You must use the AT90S23134 (or AT90S2313-10) with a 4MHz crystal as specified. Although it’s not obvious from the pinouts, the AT89 chips are entirely different internally. SC A April 2002  59 Based on an Atmel microcontroller, this incredibly versatile timer is suitable for a wide range of applications. It’s built on a compact PC board and both the trigger input and the output are fully isolated so that you can trigger from and/or switch high voltages. Multi-Mode Timer By FRANK CRIVELLI & PETER CROWCROFT E VERYONE WHO BECOMES in volved with electronics builds a timer at one stage or another. There are thousands of designs using a variety of circuits, some of which have been around for decades. Witness the 555 timer IC, for example. This is one of the longest surviving ICs, being introduced about 30 years ago. In the past, most timers were quite specialised in that they only performed one function – eg, an egg timer, a delayed timer, a timeout timer, a flasher, or a photographic timer, etc. Those days are now well and truly over – microcontroller ICs now allow us to easily design multi-purpose timers that can perform a variety of tasks, all at very low cost. And that’s exactly what you get with this new “Multi-Mode Timer”. It supports no less than seven different timing modes using two ICs and a handful of other parts. The various timing modes and delay ranges are selected using on-board DIP 60  Silicon Chip switches. You simply select the time delay you want and that’s it – no further adjustments are required. An optocoupler is used for the trigger input and this allows for complete electrical isolation between the trigger source and the remainder of the timer circuitry. This is import­ant when high voltages are to be used for triggering the timer. An on-board relay provides electrical isolation of the output as well. Triggering options A number of triggering options are available, ranging from simple manual pushbutton triggering to electrically isolated voltage triggering. We’ll take a closer look at the various triggering options that can be used later in this article. As shown in the photos, all the parts are mounted on a single PC board, so it’s really easy to build. Power supply re­quirements are quite modest and almost any 9-12V DC power source can be used. A 12VDC plugpack supply rated at 300mA will do the job quite nicely. Timer modes OK, let’s take a look at the various timing modes that are available from this circuit. There are currently seven timer modes defined – mode 8 is unused at present. If there’s another timer variation you would like (or even a completely different set of timing modes), then let us know. After all, it’s only a software change! The various modes are as follows: Mode 1 – Instant On, Delayed Off, Level Triggered: a trigger signal operates the relay and starts the timing cycle. The relay then remains on for the selected delay time and then releases. A loss of the trigger signal also immediately ends the timing cycle and turns the relay off. The timer will then be ready for another trigger signal. Mode 2 – Instant On, Delayed Off, Edge Triggered: this is the same as Mode 1 except that loss of the trigger signal does not effect the timing cycle. www.siliconchip.com.au Fig.1: the circuit for the Multi-Mode Timer is based on IC1, an Atmel 89C2051 microcontroller. This is preprogrammed with software to provide all the timing modes, which are set using DIP switch DIP3 (see Table 1). Triggering is via optocoupler OPTO1, while relay RLY1 isolates the timer’s output. However, applying another trigger signal before the end of the timing cycle will restart the timer from zero. The effect is a “re-triggerable” timer. Mode 3 – Delayed On: a trigger signal starts the timing cycle. At the end of the delay time the relay operates and remains on until the trigger signal is removed or the timer is reset. Loss of the trigger signal during the delay time aborts the timing cycle. Mode 4 – Instant On and Hold, Delayed Off: a trigger signal turns on the relay but does not start the timing cycle. The relay then remains on while ever the trigger signal is present. Loss of the trigger signal then starts the timing cycle and the relay turns off at end of delay time. Mode 5 – Toggling: a trigger signal turns on the relay for the selected delay time. The relay then switches off for the same period. This cycle continues until loss of trigger signal or until a reset signal is applied. www.siliconchip.com.au Mode 6 – Instant On, Delayed Off, With Pause: similar to Mode 1, a trigger signal operates the relay and starts the timing cycle. However, loss of trigger signal causes the timing cycle to pause and the relay remains on. Reapplying the trigger signal then restarts the delay time from the point where it was interrupted. At the end of the delay time, the relay turns off. Mode 7 – Delayed On with Pause: a trigger signal starts the timing cycle. At the end of the delay time the relay operates for 2 seconds and the timing cycle starts again. Loss of trigger signal causes the timing cycle to pause. Reapplying the trigger signal restarts the timing cycle from where it was stopped. Reset is the only way to exit this mode. Mode 8 – Not used. Important: note that for each of SPECIFICATIONS Operating Voltage .............................................................. 12VDC (see text) Trigger Voltage .............................................................. 6-81V DC (see text) Trigger Current ........................... 5mA minimum; 80mA maximum (see text) Trigger Pulse Width ...............................................................20ms minimum Relay Contact Rating* ................................................ 10A <at> 240V AC max. Timing Modes 8 .............................................................................. (see text) Timing Ranges .............1-255s, 10-2550s, 1-255 minutes, 10-2550 minutes NB: although the relay contacts are rated at 240VAC, the relay should be limited to switching voltages up to about 40-50V DC or AC. DO NOT use the on-board relay to switch 240VAC (mains) vol­tages (see text). April 2002  61 ages are to be used, you will need to either increase R1 or add an external resistor. The output from the optocoupler is used to trigger the microcontroller, IC1. This works in conjunction with its internal software program and DIP switches DIP1-DIP3 which are connected to ports A & C of IC1. The internal software reads the DIP switch settings and sets the timing mode and duration accordingly. IC1’s output appears at pin11 and drives transistors Q1 and Q2, which in turn operate the relay. So why are two transistors used here instead of just one? It’s all to do with what happens on reset. On reset, the microcontroller’s I/O ports are configured as inputs (via internal hardware) and “float” high. If only one transistor was used, the relay would be activated during reset. Of course, the relay would be released after reset once the on­board software took over but that’s not what we want. By using two transistors, we can use a low output to oper­ate the relay and a high to release it. And that means that the relay doesn’t turn on during reset! Fig.2: install the parts on the PC board in the order listed in the text but don’t install IC1 into its socket until the test procedure has been completed. A small mini-U heatsink is required for REG1. the timer modes, a reset signal will stop the timing cycle immediately and reset the timer, ready for another trigger signal. The timer is reset by connecting the RST input to the GND input -–see Fig.1. Circuit details Refer now to Fig.1 for the complete circuit details. At the heart of the circuit is IC1, an Atmel 89C2051 microcontroller. This is preprogrammed with software to provide all the timing functions. A 12MHz crystal between pins 4 & 5 provides accurate timing and an easily divisible clock source for the internal hardware timers. Crystals are generally accurate to ±100ppm (parts per million) so, in this case, the actual crystal frequency could vary by as much as 1200Hz either side of 12MHz – an error of .01% maximum. Over a period of 42.5 hours (2550 minutes, the maximum delay time this unit can be programmed for), this amounts to a maximum error of just ±15.3s. The trigger signal is applied to the input of OPTO1, a 4N25 optocoupler. As previously mentioned, using an optocoupler allows the trigger signal to be electrically isolated from the timer circuit. This is especially useful if triggering the unit from high voltages. Diode D2 protects the optocoupler’s input from damage due to reverse voltages, while the 1kΩ resistor provides current limiting. Normally, the optocoupler output is high (ie, at 5V) and goes low (to 0V) when triggered. In this case, the load resistor is 10kΩ, which means that we need a current of 0.5mA through it for the output of the optocoupler to go to 0V. From the 4N25’s data sheet, the input current required is 10 times the output current. This means that we need a minimum input current of 5mA to trigger the timer. The voltage across the optocoupler’s internal LED, Vf, is typically 1V and remains fairly constant regardless of input current. Therefore, the minimum input voltage necessary to trig­ger the timer is given by: Vin = (Iin x R1) + Vf = (5mA x 1kΩ) + 1V = 6V If lower trigger voltages are required, then it’s necessary to reduce the value of R1. The maximum optocoupler input current is 80mA, which means that the maximum trigger voltage is (80mA x 1kΩ) + 1V = 81V. Of course you should allow for a safety margin of say 5-10mA. If higher trigger volt- Power supply The timer requires a nominal 12VDC power supply; eg, a plugpack supply or a 12V battery. The incoming voltage is fed to REG1, a 7805 3-terminal regulator, to derive a regulated +5V rail which is then used to power IC1 & IC2. Diode D1 protects against reverse polarity connection of the power supply, while LED1 provides power-on indication. Note, however, that the relay requires a 12V supply and so it is connected directly to the VIN supply input, rather than to the 5V rail (as is transistor Q1). This also minimises any switching noise on the +5V supply rail to IC1 when the relay turns on and off. Diode D3 is there to prevent back Table 1: Resistor Colour Codes  No.   1   1   1   1   2 62  Silicon Chip Value 10kΩ 8.2kΩ 4.7kΩ 2.2kΩ 1kΩ 4-Band Code (5%) brown black orange gold grey red red gold yellow violet red gold red red red gold brown black red gold 5-Band Code (1%) brown black black red brown grey red black brown brown yellow violet black brown brown red red black brown brown brown black black brown brown www.siliconchip.com.au www.nollet.com.au Basic Stamps BS2/BS2E/BS2P Stamps in Class Basic Stamp chipsets Carrier boards Oz made development kits,as used by schools This slightly larger-than-life view shows just how compact this versatile timer really is. A 9-12VDC plugpack supply rated at 300mA can be used to power the unit. EMF from damaging Q2 when the relay releases. Power on reset is provided by R2 and C3 (the 89C2051 micro­controller has an active high reset signal). In addition, tran­sistor Q3 allows the user to use a low-going signal to reset the timer; eg, by connecting the RESET terminal on connector X1 to the GND terminal via a simple pushbutton switch. Putting it together It’s a cinch to put together – all you have to do is solder all the parts to the PC board as shown in Fig.2. Install the resistors and diodes first, then install LED1, transistors Q1-Q3 and the electrolytic capacitors. Make sure that all the polarised parts are oriented correctly and double-check that Q3 is the BC557. Take particular care when installing the SIL resistor pack (RP1). Pin 1 is identified by a dot at one end of its body and this goes towards the adjacent 0.1µF capacitor. The DIP switches and relay RLY1 can go in next, followed by the 3-terminal regulator (REG1). The latter is mounted flat against the PC board together with a small U-shaped heatsink. That means that you have to bend REG1’s leads down at right angles before fitting it to the board. The best way to do that is to loosely attach the regulator to the board using a 3mm machine screw and then grip its three leads with needle-nose pliers. The screw can then be removed, the regulator lifted clear and its leads bent down through 90°. That done, REG1 and its heatsink can be fastened to the www.siliconchip.com.au Parts List 1 PC board, code K141 1 12MHz crystal (X1) 1 12V relay, RWH-SH-112D (RLY1) 2 3-way PC-mount screw terminal blocks (5mm pitch) 2 2-way PC-mount screw terminal blocks (5mm pitch) 1 8-way DIP switch (DIP1) 1 2-way DIP switch (DIP2) 1 3-way DIP switch DIP3) 1 6-pin IC socket 1 20-pin IC socket 1 3mm x 8mm-long machine screw 1 3mm nut Semiconductors 1 4N25 optocoupler (IC1) 1 AT89C2051 programmed Atmel microcontroller (IC2) 3 1N4004 diodes (D1,D2,D3) 2 BC547 NPN transistors (Q1,Q2) 1 BC557 PNP transistor (Q3) 1 7805 3-terminal regulator (REG1) 1 5mm red LED (LED1) Capacitors 1 10µF 63VW PC electrolytic 1 10µF 16VW electrolytic 2 0.1µF MKT 2 22pF ceramic Resistors (0.25W, 5%) 1 10kΩ 1 2.2kΩ 1 8.2kΩ 1 1kΩ 1 4.7kΩ 1 9 x 10kΩ 10-pin SIL resistor network (RP1) and professional engineers Serial lcd's 2*16 and 4*20 Keypad with serial interface 1 Megabit Memory Module Low cost I/O expander chips A/D and eeprom chips Real time clock kits RC servo and stepper chips Custom chips .. Tech-Tools PIC Tools new PIC emulators Eeprom/Ram chip emulators New PIC Quickwriter programmer TiePie "Most" all in one HP2 & Multimeter HS801 Oscilloscope Spectrum analyzer T ransient recorder plus arb function gen in HS801-AWG ron<at>nollet.com.au R.T.Nollet 35 Woolart street Strathmore 3041 ph/fax 03-9338-3306 April 2002  63 Fig.3: using a pushbutton or relay contacts to trigger the timer. PC board using a machine screw and nut and the leads soldered. Make sure that the heatsink is correctly aligned before tightening the screw, so that is doesn’t foul the relay. Now for the two 5-way screw terminal blocks. These are made by fitting together a 2-way block and 3-way block – just slide the raised edge on the side of one block into the matching groove of the other block. Each 5-way block is then installed on the PC board with the wire entry points facing outwards. Don’t install the ICs yet – that step comes later, after some initial tests. Just install their sockets for the time being, making sure that the notched end of each socket is posi­tioned as shown on Fig.2. Testing Fig.4: triggering the timer using the open collec­tor output of an NPN transistor. Apply power to the board – the RED power LED should be come on and the relay should remain off. Now use a multimeter to check the voltage between pins 20 & 10 of IC1’s socket – you should get a reading of 5V. If this checks out, connect a short length of wire between pins 10 & 11. The relay should immediately operate. If all is well, remove power and install the ICs in their sockets. Make sure that both ICs are correctly oriented and that none of their pins are “bent under” as you insert them. Setting the timer mode The timer mode is set using DIP switch DIP3, as shown in Table 1. You will have to carefully read the details for the vari­ous timing modes at the start of this article before making your selection. Note that mode 8 is unused, as mentioned previously. Fig.5: use this circuit for fully-isolated triggering. Note that the trigger source must not connect to the timer’s power supply if you want complete isolation. Setting the delay DIP switches DIP2 & DIP1 together set the time delay. DIP2 set the base WHERE TO BUY A KIT Kits for the “K141 Multi-Mode Timer” are available from Ozitronics (www. ozitronics.com) for $36.85 (incl. postage & GST). Phone (03) 9434 3806. You can email the authors at peter<at>kitsrus.com if you have any suggestions. Information on other kits in the range is avail­able from http://kitsrus.com If you have any technical problems or questions, you can contact the kit developer at frank<at>ozitronics.com Note: copyright of the PC board and the source code for the Atmel microcontroller is retained by the author. 64  Silicon Chip TABLE 1: MODE SELECTION Mode DIP3-1 DIP3-2 DIP3-3 1 On Off Off 2 Off On Off 3 On On Off 4 Off Off On 5 On Off On 6 Off On On 7 On On On 8 Off Off Off Table 1: the timing mode required is selected using DIP switch DIP3. Note that mode 8 is not used. timing interval, while DIP1 sets the multiplier (ie, Delay Time = base timing interval x multiplier). Tables 2 & 3 shows the possible settings for these two DIP switches. An example will illustrate how this all works. Let’s say that DIP1-8, DIP1-3 & DIP1-2 are ON and that the rest of DIP1’s switches are off. In this case, the multiplier is 128 + 4 +2 = 134. This means that the Delay time will be 134 x base timing interval. So if the base timing interval is 10 seconds, for example, the Delay Time is 134 x 10 seconds = 1340 seconds, or 22 minutes 20 seconds. If DIP1-7 is also turned ON, then this adds 64 to the delay factor making it 134 + 64, or 198. The maximum delay factor is with all switches ON; ie, 255. Setting all the DIP1 switches to the OFF position is in­valid and the timer will not function. Note that there is some overlap between the timing inter­vals. For example, you can get a 10-minute delay by selecting a 1-minute timing interval and setting the delay factor to 10 or by selecting a 10-minute timing interval and setting the delay factor to 1. In summary, here are the time delays possible: • 1 - 255s in 1s steps; • 10 - 2550 seconds (42min 30sec) in 10s steps; • 1- 255 minutes in 1- minute steps; • 10 - 2550 minutes (42hr 30min) in 10-minute steps. The timing accuracy for all modes is .01%. Triggering the timer As discussed earlier, the input trigger voltage needs to be in the range of www.siliconchip.com.au Table 2 (left): DIP switch DIP2 sets the “base timing interval”. This value is multiplied by the “multiplier” (set by DIP1 – see Table 3) to give the Delay Time for the timer. TABLE 2: BASE TIMING INTERVAL Interval DIP2-1 DIP2-2 1 second On Off 10 seconds Off On 1 minute On On 10 minutes Off Off TABLE 3: INTERVAL MULTIPLIER DIP1 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 Table 3: DIP switch DIP1 sets the interval multiplier. Note that if more than one switch is set to ON, the multiplier values are added together; eg, if DIP1-8, DIP13 & DIP1-2 are ON, the multiplier is 128 + 4 +2 = 134. 6-81V, although this can be varied by changing the value of R1 (see earlier text). Just how the trigger voltage is applied will depend on your application and the trigger source available. Figs.3-5 show the triggering options available. Probably the most common device used for triggering the timer will be a simple “make” contact, either from a pushbutton switch or relay contacts. Fig.3 shows the idea. All you have to do is connect the TRIG+ terminal to the VIN terminal and connect the switch or relay contacts between the TRIG- and GND terminals. When the contact closes, the circuit path is complete and current flows, thus triggering the timer. Fig.4 shows how to trigger the timer using the open collec­tor output of an NPN transistor (this can either be a discrete transistor or incorporated into an IC package). Basically, the transistor takes the place of the switch shown in Fig.4. When the transistor turns on, the TRIG- input is pulled low and the timer triggers, as before. Note that you can connect multiple open collector outputs in parallel, together with a common pull-up resistor; eg, if you want to trigger the timer from more than one source. That way, one or more of the open collector outputs can go low without causing damage to the others. In both the previous two triggering methods, the trigger source ground is connected to the timer ground. This is often referred to as “commoning” and is done to provide a common refer­ ence point between the two circuits. However, this bypasses the electrical isolation on the timer’s input because one side of the optocoupler’s input is now connected to ground. Fig.5 shows the circuit to use if you want complete elec­ trical isolation. Note that, to ensure isolation, the trigger source must drive the input without any connection to the timer’s power supply. Relay outputs The relay’s NO, NC & C (normally open, normally closed & common) contacts are brought out to CON2 and can be used to switch external loads or other relays. In addi­tion, VOUT and GND are provided as convenient connection points for powering external devices. The relay outputs can be used to switch voltages up to about 40-50V. However, don’t try to use the relay outputs to switch 240VAC mains voltages – that would be much too dangerous, especially given the proximity of the ground track to the relay outputs. If you do want to switch mains voltages, you can use the on-board relay to switch an external relay that’s adequately rated for the job. Don’t do this unless you are experienced know exactly what you are doing – mains voltages can be lethal! Troubleshooting Poor soldering (“dry joints”) is the most common reason for the circuit not working. If you strike problems, the first thing to do is to check all sol­ d ered joints carefully under a good light and resolder any that look suspicious. You should also carefully check that the parts are in their correct positions and that all parts are correctly oriented. Check also to ensure that the ICs have been correctly installed and that none of the pins have been bent under their bodies. Finally, check that REG1’s output is at 5V. If there is no voltage at the output of this regulator, check the voltage at its input. If there’s no voltage here, then it’s possible that D1 has been installed the wrong way around – either that or you’ve inadvertently reversed the SC supply leads. MINI SUPER DRILL KIT IN HANDY CARRY CASE. SUPPLIED WITH DRILLBITS AND GRINDING ACCESSORIES $61.60 GST INC. www.siliconchip.com.au April 2002  65 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au/ SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au/ Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 PRICE GUIDE- Subscriptions YOUR DETAILS Your Name________________________________________________________ (PLEASE PRINT) Organisation (if applicable)___________________________________________ Address__________________________________________________________ (all subscription prices INCLUDE P&P and GST on Aust. orders) Please state month to start. 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SUBSCRIBERS QUALIFY FOR 10% DISCOUNT ON ALL SILICON CHIP PRODUCTS AND SERVICES# #except subscriptions/renewals and Internet access Item Price Qty Item Description P&P if extra Total Price Total $A TO PLACE YOUR ORDER Phone (02) 9979 5644 9am-5pm Mon-Fri Please have your credit card details ready OR Fax this form to (02) 9979 6503 with your credit card details 24 hours 7 days a week OR Mail this form, with your cheque/money order, to: Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy, NSW, Australia 2097 * Special offer applies while stocks last. 03-01 Just about any IR remote control that’s capable of outputting Philips codes can be used. This is the Select 1 from Jaycar. Last month, we gave the circuit details for our new 6-Channel Remote Volume Control and showed you how to build the PC board assemblies. This month, we complete the construction and give the test and setup details By JOHN CLARKE N OW THAT ALL THE PC boards have been built, it’s time to prepare the metalwork. Hopefully, this unit will be made available as a complete kit, in which case the metalwork will be supplied predrilled. Alternatively, if you’re buying the bits separately, you will have to drill the case yourself. As supplied, the case comes in pieces and it’s a good idea to drill the front and rear panels before putting it together. The front and rear panel artworks (Fig.12) and the main wiring 70  Silicon Chip diagram (Fig.10) show the positions of these holes. Starting with the front panel, you have to drill holes for mains switch S1, the 20-LED display, the three pushbutton switch­ es, the acknowledge LED and the infrared receiver. The rectangular cutouts for the mains switch and LED bargraph can be made by first drilling a series of small holes around the inside perimet­ er of the cutout, then knocking out the centre piece and filing to the correct shape. Don’t make cutout for the mains switch too big – it must be a tight fit so that it is properly secured by its retaining tabs. The pushbutton switch holes should be about 9mm to allow clearance for the 7.5mm diameter switch caps. The rear panel requires holes for the RCA sockets, the safety fuseholder, the mains lead cordgrip grommet and the earth terminal adjacent to the RCA sockets. Take care with the hole for the cordgrip grommet. This hole is not round – instead, it must be carefully profiled to match the shape of the grommet, so that the grommet can not later be pulled out when the mains cord is fitted. The holes for the RCA sockets must be large enough to prev­ent the RCA plugs from making contact with the metal chassis when they are connected. Once these holes have been drilled, assemble the case with­out the lid, using the machine screws supplied. The next bit is important: be sure to scrape away the paint at the countersunk screw points, so that each section of the case makes good metal-to-metal contact. This ensures that each section www.siliconchip.com.au This close-up view shows the mounting details for the Control & Display board. It mounts at the front of the chassis on four tapped 12mm spacers and is secured using eight M3 x 6mm screws. is properly earthed to mains earth (important for safety reasons) and also prevents hum problems. Next, mark out the mounting holes for the three PC boards on the baseplate and drill these holes to 3mm. You will also have to drill mounting holes for the earth lug, the mains terminal block screws and the transformer bolt (see Fig.10). Deburr all holes using an oversize drill. Next, scrape away the paint or anodising from the area around the two earth lug mounting holes. This is necessary to ensure that the earth lugs make good contact with the bare metal of the case and is also an important safety measure in the case of the mains earth lug. For the same reason, scrape away the paint or anodising from the bottom outside of the chassis around the mounting holes for the mains terminal block. This will ensure that the mounting screws are properly earthed. Installing the hardware The various hardware items – including the power transform­er, switch S1, the fuseholder, the mains terminal block, the earth lugs and the PC boards – can now be installed in the case. The boards are installed as follows: (1) Signal board: this mounts on two 6mm-long untapped spacers at the front and is secured using two M3 x 12mm screws and two M3 nuts and star washers. The RCA sockets are www.siliconchip.com.au The Signal Board is secured by attaching it to two 6mm-long untapped spacers along the front edge and by fastening the RCA socket assemblies to the rear panel using 6g self-tapping screws into the plastic mouldings. then secured to the rear panel using 6g self-tapping screws into the plastic mouldings. (2) Display board: this mounts on four tapped 12mm spacers and is secured using eight M3 x 6mm screws; (3) Power supply board: this mounts on four 10mm M3 tapped spacers and is secured using eight M3 x 6mm screws. The toroidal transformer is secured using the supplied bolt, rubber washers, metal mounting plate and nut. The rubber washers are placed between the transformer and chassis and bet­ween the transformer and the metal mounting plate. The assembly is then secured using the mounting bolt. Do the bolt up firmly but don’t overtighten it – you’ll distort the chassis if you do. The mains terminal block is secured to the chassis using two 12mm x M3 screws and nuts. Note that a piece of Elephantide insulation material measuring 35mm x 35mm is mounted under April 2002  71 This view shows how the completed modules are installed in a 1U rack chassis and interconnected using two 8-way cables fitted with pin headers. the terminal block as an additional safety measure. Make sure that the mains earth lug is properly secured – it must be attached using an M3 x 10mm-long screw, nut and two star washers as shown in Fig.11. A second lock nut is fitted to this assembly, so that it cannot possibly come loose later on. Now use your multimeter to confirm that there is zero ohms resistance between the earth lug and all the panels of the case. You should also get zero ohms resistance between the earth lug and the two mains terminal block mounting screws. Before installing the mains wiring, it’s necessary to check that the power switch is the right way up. To do this, switch it to the ON position and use a multimeter to check that the resistance between the two contacts is 0Ω. If the rocker needs to be in the OFF (up) position to get a 0Ω reading, the switch will have to be inverted. Mains wiring Fig.10 shows the mains wiring details. Exercise extreme cau­tion when installing this wiring and be sure to The Power Supply board mounts on four 10mm M3 tapped spacers and is secured using eight M3 x 6mm screws. 72  Silicon Chip follow Fig.10 exactly – your safety depends on it. First, strip back about 350mm from the outer sheath of the mains cord, so that the Active (brown) lead has sufficient length to reach both the fuseholder and the power switch (S1). This done, clamp the mains cord into position using the cordgrip grommet. Check that the grommet properly clamps the cord to the chassis; you must NOT be able to pull the cord back out. Next, trim the Active (brown) lead so that it is about 70mm long. The Active lead then goes to the centre terminal of the fuseholder, while the leftover brown lead is run between the outside terminal and the mains terminal block. Slip a 40mm length of 10mm-diameter heatshrink tubing over the two leads before soldering them to the fuseholder. Once the connections have been made, push the tubing over the body of the fuseholder (so that the terminals are covered) and shrink it down using a hot-air gun. The Neutral (blue) lead from the mains cord goes directly to the mains terminal block, while the Earth (green/ yellow) lead is connected directly to the main earth lug. The Earth lead should be left long enough so that it will be the last connection to break if the mains cord is “reefed” out. Now set your multimeter to low ohms range and check the resistance www.siliconchip.com.au www.siliconchip.com.au April 2002  73 Fig.10: here’s how to install the modules in the chassis and complete the wiring. Take great care with the mains wiring and be sure to insulate the exposed terminals on the fuseholder with heatshrink tubing as described in the text. The mains wiring should also be secured using cable ties as shown, so that the leads cannot possibly come adrift. Another view inside the completed unit. Use cable ties to secure the mains wiring, so that the leads cannot possibly come adrift (see also Fig.10). between the earth pin on the mains plug and the vari­ous chassis panels. In each case, you should get a reading of close to zero ohms. Next, the .001µF capacitor can be installed and the trans­ former and mains switch wiring completed at the terminal block. In each case, make sure that the wire insulation goes into the mouth of the terminal block and is pushed all the way up to the brass Fig.11: this diagram shows the mounting details for the two earth lugs. The second nut locks the first nut, so that there is no possibility of the earth lug later working its way loose. Don’t forget to scrape away the paint or anodising from the area around the two earth lug mounting holes, to ensure proper contact with the chassis. 74  Silicon Chip connector before doing up the screw. Leads that share a common connection should be twisted together and lightly tinned with solder before inserting them into the terminal block. Don’t use a terminal block that’s too small to accept the insulation from two leads – you must be able to push the insulation of both leads fully into the terminal block and all the way up to the brass connector. The connections to the mains switch are made using fully-insulated female spade terminals. Make sure that the spade termi­nals are securely crimped to their leads before fitting them to the switch – a ratchet-driven crimping tool should be used for this job. Finally, connect the transformer secondary leads to the Power Supply PC board as shown in Fig.10. Use cable ties to lace the mains wiring to­ gether. In particular, you should install one tie close to the mains switch, another close to the fuseholder and several more close to the mains terminal block. This will prevent the leads from coming adrift and if one does come loose, it will be held in place so that the exposed end cannot move and make contact with the case. Any remaining cable ties can be used to secure the transformer’s secondary leads. Completing the wiring You now need to make up two 8-way leads with pin header sockets at each end to interconnect the three PC boards. Begin by cutting a 110mm length of 8-way rainbow cable from the 270mm length supplied. That done, strip the wire ends, crimp them into the header pins and insert the pins into the header sockets (note: the header sockets must be oriented as shown in Fig.10). Now repeat this procedure for the remaining 160mm length of 8-way cable. Connect the finished cables to the Signal and Display Boards but leave the Power Supply Board disconnected at this stage. You have to make sure that the supply board is delivering the correct voltages before making this connection. Switching on Before switching on, check the mains wiring carefully to make sure there are no mistakes. Check also that the wiring to the power supply board is correct. Once you’re sure that everything is correct, install a 0.5A fuse in the fusewww.siliconchip.com.au Remote control Assuming everything checks out so far, you can now test the unit with the IR remote control. First, you have to set the remote control so that it trans­mits codes that are suitable for Philips devices. Initially, it is best to set the IR remote to the TV1 code, since this is the default setting for the 6-Channel Remote Volume Control. If you are using the Big Shot 3 IR remote from Jaycar or the Altronics AV8E (Cat. A1007), for example, you need to set it to code 191. This is done by pressing the SET and TV buttons together and then releasing them. The transmit LED will light and you then enter the number 191 using the number buttons. Another suitable IR remote control is the Select 1 from Jaycar. This has to be set to code 11414. To do this, you first press both the CODE and Operate (red) buttons for two seconds and then release them. You then enter the numbers 11414. Note that the Select 1 remote control will only operate the 6-Channel www.siliconchip.com.au Remote Volume Control when it is set for the TV1 code. The Dick Smith Cat. G-1223 remote control works in similar fashion. Having set the transmit code, check that it can operate the 6-Channel Remote Volume Control using the Volume Up/Down, Mute and Channel Up/Down buttons. If you have a different type of remote control, start by selecting a programming number that’s for Philips TV sets. It’s then simply a matter of trying each number in turn until you find one that works. Now test the remote control on your TV set. If it oper­ates the TV set, then you will need to use another code. The choices are SAT1 and SAT2 but note that these options are avail­able only on the multi-function remote controls such as the Altronics AV8E and the Jaycar Big Shot3 (not on the Select 1 or DSE Cat. G-1223). The SAT1 code is 424, while the SAT2 code is 425. The se­lected code (424 or 425) is entered into the IR remote control after first pressing the SET and SAT switches. The 6-Channel Remote Volume Control also needs to be changed to accept the new SAT1 or SAT2 code. The SAT1 address is selected by pressing the Up pushbutton on the 6-Channel Remote Volume Control at power up. Similarly, SAT2 is selected by press­ing the Down pushbutton at power up, while TV1 can be re-selected by pressing Mute at power up. The selection is stored in memory and will not alter unless one of the switches is again pressed during power up. Check that the 6-Channel Remote Volume Control can now be operated using the new code. If you have a different remote control unit to those mentioned above, select a code that oper­ ates a Philips satellite receiver and test it. If it doesn’t work, try other satellite codes until you find one that does. Finally, you can test the 6-Channel Remote Volume Control by hooking it up to the outputs of your DVD player and to your audio amplifiers. Check that the volume changes smoothly for all channels and that the sound is distortion-free and clear of any noise or hum. Hum problems? In most cases, you shouldn’t encounter any problems with hum and Fig.12: these two artworks for the front and rear panels are reproduced here 60% of actual size and may be enlarged to full-size for use as drilling templates on a photocopier (1.67x). If you buy a kit, then the front & rear panels will be supplied pre-punched and with screened lettering. holder, then apply power and check the output voltages from the Power Supply Board. All voltage checks should be made with respect to the 0V (GND) terminal. Check that the ±12V, ±6V and +17V (nominal) rails are all present. If these are all correct, switch off and wait for about one minute to ensure that all rails have dropped to 0V. Now plug the header into the Power Supply Board, switch on and check that one of the display LEDs is lit. You should be able to move the LEDs that are lit up and down the bargraph using the Up and Down buttons. Pressing the Mute switch should immediately cause the LED (or LEDs) to flash. Pressing Mute again (or the Up button) should stop the flashing. It’s now a good idea to check the supply rails to each IC just to make sure everything is OK. To do this, connect your multime­ter’s common lead to the metal tab of REG1 and check that the following voltages are present: +5V on pin 14 of IC1; +11V on pin 8 of IC2, IC3, IC5 & IC6; -11V on pin 4 of IC2, IC3, IC5 & IC6; +6V on pins 13, 14 & 15 of IC4 & IC7; and -6V on pins 7 & 19 of IC4 & IC7. The voltages should all be within about 0.5V of the above values. April 2002  75 Fig.13: here are the full-size etching pattern for the three PC boards. Check your boards carefully before installing any of the parts. noise but if you do, here’s a few troubleshooting tips. First, many power amplifiers don’t have the signal earth connected back to mains earth and this can make the audio signal susceptible to mains switching noise (eg, as appliances are switched on and off). Earthing the signal at one point should reduce this effect and you can do that by connecting the earth track on the Signal Board to the signal earth terminal adjacent to the RCA connectors (see Fig.10). Alternatively, if two or more of your amplifiers connect the signal earth to mains earth, you may get what’s called a “hum loop”. This will cause an audible (and annoying) hum in the audio signal. There are several ways to get round this. First, try con­necting all stereo amplifiers, the DVD player and the 6-Channel Remote Volume Control to the same power point via a multi-way power board. If that doesn’t help, try disconnecting the signal earth (NOT the mains earth) from chassis in each amplifier and then use the optional signal earth connection in the 6-Channel Remote Volume Control unit as the single earthing point. Note: for safety reasons, you must NOT disconnect the mains earth connection (if it exists) inside an amplifier chassis (or any other chassis). As a last resort, the earth tracks on the Signal Board can be broken. This involves cutting the tracks at the 76  Silicon Chip thinned sec­tions labelled “Earth Loop Break” and will separate the earthing into three sections. Use channels 1 & 2 for the first stereo amplifier, channels 3 & 4 for the second stereo amplifier, and channels 5 & 6 for the third stereo amplifier. In addition, the earth connections in the leads from the DVD player to the RCA inputs of the 6-Channel Remote Volume Control will have to be disconnected. You can do that by cutting away the outside earth lugs on the RCA plugs at one end of each lead, where they connect to the 6-Channel Remote Volume Control. Alternatively, the leads can be rewired to new RCA plugs at one end, leaving the earth braid of the cable disconnected. SC www.siliconchip.com.au COMPUTER GAMING SUPER SPECIALS (LIMITED STOCK) ALL BRAND NEW IN ORIGINAL PACKAGING All come with full instructions & EIDOS demo CD and can be played across a network. EIDOS FORMULA 1 Formula 1 racing game, Rated "G" Comes with full instructions and disk: $18 EIDOS DAIKATANA Shoot em up adventure game, Rated "MATURE" Comes with full instructions and disk: $18 EIDOS DEATHTRAP Shoot em up adventure game, Rated "MATURE" Comes with full instructions and disk: $18 THRUSTMASTER STEERING WHEEL AND PEDAL SET IBM games port compatible. 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The plugpack has a different connector and will require changing (correct plug not supplied). ULTRA-VIOLET LEDS!!! MORE NEW STOCK 395nM UV LED's... 200mCD $4.70 Blue LED's 3.5CD $3.50 White LED's 10CD $4 15CD $6 650nM LASER MODULES 3mW $18 6mW $36 10mW $90 25mW $200 C CAMERAS B: MINI HIGH QUALITY LOW LIGHT CMOS PINHOLE CAMERA... 20 X 25 X 19mm. $98 E: MINI HIGH QUALITY LOW LIGHT CMOS BUTTON HOLE CAMERA WITH AUDIO 30 X 30 X 30mm. :$82 MINI HIGH QUALITY LOW LIGHT CMOS F: BUTTON HOLE CAMERA WITH AUDIO and HOUSED IN A SECURITY DOME Dia. 86mm X 60mm. $92 We are selling these modems for a small amount of their retail price: (ZB0302) $22 each (limited quantity) LEDS AND LASERS B We have more used test equipment coming all the time and we need to clear stock to make way for the next lot. The only way to make sure you don’t miss out is to subscribe to our bargain corner & receive advanced notice by E-Mail Just send us a blank E-Mail to.... bargaincorner-subscribe <at>oatleyelectronics.com CK O ST !!! W W NE N NO I G NEW!!!! TRIPLE ELEMENT CERAMIC HEATER ASSEMBLY: As used in small household style heaters, around 2kW total at 240V but not linear, the resistance of each element is around 600ohms when cold, could be used at lower voltages for incubators or dummy loads etc. etc, 240V/120mm fan, plus a triple mains rated switch will be supplied with each unit, the whole assembly for less than the price of the fan!: $15 5 1 $ (NEW) SOUND BLASTER LIVE! 5.1 SE AND BOSTON ACOUSTICS DIGITAL ENTERTAINMENT This special edition is supplied with the PCI card, Software on CD and leads to connect the card to a CD-ROM. Visit the creative website for further information. These are brand new in their retail packaging. A manual is not supplied but can be downloaded The card has a digital output suitable for driving the Boston Acoustics sound system: (SBDE51) $100 These cards can only be purchased with a Boston Acoustics sound system. Previous purchasers of the Boston Acoustics sound system may also Purchase these cards. 9 6 1 $ LIMITED STOCK www.oatleyelectronics.com Orders: Ph ( 02 ) 9584 3563, Fax (02) 9584 3561, sales<at>oatleyelectronics.com, PO Box 89 Oatley NSW 2223 major cards with ph. & fax orders, Post & Pack typically $7 Prices subject to change without notice ACN 068 740 081 ABN18068 740 081 SC_APR_02 VINTAGE RADIO By RODNEY CHAMPNESS, VK3UG The AWA 719C Console; Pt.2 Last month, we took a look at the impressive AWA 719C console radio and described a typical restoration. In Pt.2 this month, we detail the alignment of this complex receiver. All the normal restoration jobs had been completed on this particular set. I’d cleaned the chassis, replaced suspect paper capacitors, tested various other components, replaced perished wiring and had the cabinet restored to its former glory. There was really only one major job left to do – the alignment of the RF, aerial, oscillator and IF circuits. Now as anyone who has ever attempted to align one of these sets knows, it isn’t a 10-minute job as it is for most superhet broadcast receivers. The average superhet set has four IF adjust­ments and four adjustments for the aerial and oscillator cir­cuits, so the job is straightforward. By contrast, the AWA “7-banders” have four IF transformer adjustments plus 19 other adjustments (and some of these are compromises) for the front end of the set. What’s more, some of these adjustments have to be repeated as they tend to interact with each other. In addition, a stable RF signal generator that is well calibrated and capable of operation up to at least 23MHz is required. Apart from the alignment taking more time, there are a few rather nasty problems that crop up during the procedure. First, the dial isn’t attached to the chassis, so how do you align the front end without a dial-scale? If you have the correct alignment data for the particular model set, it is relatively easy to do. The dial drum has a semi-circular scale around one side and there is a pointer that is alongside the scale, as can be seen in one of the photos. It’s then a matter of looking up the “alignment table”. For example, in one of the alignment tables, the listing for 600kHz is 19° on the drum, while for 1500kHz it is 168°. However, as I found out, models that are claimed to be the same electrically, such as the 617T that I have and the 719C that I have been restoring, may not be identical. My set tunes from 540-1500kHz on the BC (broadcast) band, while the 719C tunes from 540-1600kHz. This means that the alignment data for my set and the 719C will be different even though the published data says they are electrically identical! Why won’t it track? This photograph shows the two brackets (coloured with a black felt-tipped pen) that were made to hold the dial in place during alignment. 78  Silicon Chip Normally, you would expect to tune the oscillator slug at the low frequency end of each band and the trimmer at the high frequency end of each band. However, while the alignment freq­ uen­cies are known, the angular position of the dial drum that corre­sponds to the alignment frequencies is often unknown. Initially, I went ahead and used the AWA listings but found that the coil cores and trimmers on the 719C receiver had to be altered considerably to get the set operating as per the align­ment table. This seemed a bit strange, so I held the dial mechan­ism in approximately its correct position and attached the point­er to the dial cord. The alignment points were nowhere near where they should have been. It was then that I realised that the www.siliconchip.com.au 719C covers from 540-1600kHz instead of 540-1500kHz as for my 617T, as noted above. And that explained why I couldn’t get it to track correctly. The 719C I was restoring is obviously a later set due to the extended broadcast band calibrations, therefore the degree settings would be different on the dial drum. But what settings should I use? This was getting messy. A tuning aid So how I could align this set without the relevant set of alignment instructions? After some thinking, I came up with the idea of mounting the dial scale onto the receiver chassis by some means. I had some scrap 24-gauge galvanised flashing (plumbers or hardware stores often have it available) and decided that I could make some simple brackets for the job. It really is a pity the chassis design wasn’t similar to the 805G and other radiogram models, where the dial scale was firmly attached to the chassis assembly – alignment would have been so much easier. The brackets that I made can be clearly seen in one of the photos (they’ve been coloured black using a felt-tipped pen). At the lefthand end, one bracket is attached (using a nut and bolt) to a vertical piece of metal that supports a dial scale pulley. The other end of this bracket then goes to an existing bracket at the bottom of the dial-scale. At the other end, the second homemade bracket goes between another existing dial-scale bracket and a plate which carries the dial-drive mechanism. It was necessary to drill a small hole near the front bottom of this plate to accept a nut and bolt to secure the second bracket in place. Provided you get the brackets right, the dial drive will work quite well. Remember however, that this is a rather flimsy ar­rangement, so take care to ensure that no stress is applied to the assembly. It should be perfectly adequate while the alignment procedure is carried out, however. Tuning the IF stage With the gang closed, the pointer is attached so that it is just below 540kHz (Kc/s) on the dial. This done, the IF trans­formers are tackled first. With the set turned off, attach a digital multimeter (DMM) (set to the 20V DC www.siliconchip.com.au The dial drum has a semi-circular scale (marked in degrees) around one side and this is used in conjunction with the “alignment table” (see Table 1) when making alignment adjustments. The holes adjacent to the two arrows at bottom, left of the chassis allow access to the 9MHz aerial and RF trimmers. range) between the AGC/AVC line and chassis using clip leads. An ideal spot is across C37, with the negative lead going to the unearthed side of the capacitor. With the set turned on, the DMM should read about -3V, which is the standing bias on the front-end valves. Next, attach the signal generator to the aerial terminal of the receiver, set it to 455kHz with (tone) modulation and in­crease the power until the tone is heard from the speaker. You may have to tune around 455kHz on the signal generator to get a response, although I usually find that most sets are close enough to 455kHz in their alignment to make this step unnecessary. Now increase the output on 455kHz (if you can hear it on that frequency) until the DMM shows an increased reading. (It is possible to “walk” the IF frequency up or down to 455kHz if it is way off frequency; eg, if there is a problem with the IF stage due to someone’s fiddling or if there is a fault). That done, adjust the tuning slugs (using a small plastic screwdriver) in the top and bottom of each IF transformer for April 2002  79 9MHz (20) 17.8MHz (11) 9MHz (19) 17.8MHz (10) 11.8MHz (16) 1450kHz (8) 11.8MHz (15) 1450kHz (7) 17.8MHz (9) 600kHz (5) 15.2MHz (13) 11.8MHz 9.5MHz (14) (17) 1.5MHz (6) 4MHz (21) 1.6MHz (22) 3.7MHz (23) 9MHz (18) 21.0MHz (12) This under-chassis view shows the locations of the aerial and RF coil trimmers (white & light green type respectively), the oscillator cores (yellow type) and the trimmers (red type). The numbers in the brackets refer to the corresponding adjustment number in the alignment table. a maximum reading on the meter. All being well with the IF transformers, a peak will be found within a turn or two either side of the initial settings. The screws can then be locked in position with a dab of plastic cement or nail polish. RF, aerial & oscillator circuits Now we come to the “fun” part – the alignment of the front-end of the set. Table 1 (at the end of this article) is an extract from a set of alignment 80  Silicon Chip instructions for the 611-T and a few other sets. This table can be used to tune the RF, aerial and oscilla­tor sections of the set. However, although I used this information to tune my 617-T, some of the component numbers for the 611-T are different. The procedure is as follows. Using the 611-T alignment table, switch the set to the broadcast band and turn the dial drum until 19° appears under the small pointer. This is the 600kHz mark and the dial pointer should also be aligned to the 600kHz mark on the dial scale. Note that I have used “kHz” and “MHz” abbreviations in this article, whereas the dial and tuning instructions show “Kc/s” and “Mc/s”. It is now possible to either use the alignment table or do it directly from the dial-scale that has been temporarily at­tached to the chassis via the brackets described earlier. There is no problem in aligning the set using the bracket method. However, if you use the alignment table and the calibration table for the 611-T, it may be correct for the model that you are aligning, or it may not be – as was the case with the 719C. The alignment table is used for each band but the dial calibrations and not the degree settings must be used to align the circuits correctly. I feel much more confident this way. The location of each of the adjustments is not shown on any literature that I’ve been able to access, so diagrams 2 and 3 have been drawn to show where each of the 19 adjustments are located. This has made it much easier for me to do this job and should help you too. Note that the oscillator adjustments are all made from above the chassis, while the RF and aerial trimmers are under the chassis, as can be seen in the photograph at left. Note also that the 9MHz aerial and RF trim­ mers are accessed through the end of the chassis, as shown by the arrows in the photograph of the dial scale. The broadcast band is aligned as per steps 5, 6, 7 & 8 of the alignment table. I connect the receiver to a “typical” anten­ na, then clamp the output lead from the signal generator over the insulation on the antenna lead. That way, the generator has little effect on the tuning of the aerial coils, although the generator does have to be wound up further to get a reasonable level into the receiver to actuate the AGC. In practice, the generator is set to each of the frequen­cies shown in the alignment data in turn. Note that it’s neces­sary to repeat the adjustments again for maximum reading on the DMM. In fact, you may need to repeat the procedure several times before you are happy that there is no interaction between the individual adjustments. After the broadcast band been completed, the 17.7-22.3MHz band can be www.siliconchip.com.au aligned. This involves setting the dial to 17.8MHz (or 18°) and doing adjustments 9, 10 & 11. You then set the dial to 21MHz and do adjustment 12. On the 15.0-19.0MHz band there is only one adjustment and that is the oscillator at 15.2MHz (adjustment 13). On the 11.7-15.0MHz band, all the circuits are adjusted at 11.8MHz. The adjustment numbers are 14, 15 & 16. Moving now to the 9.4-12.0MHz band, again there is only one adjustment and that is the oscillator on 9.5MHz (adjustment 17). On the 3.6-9.7MHz band, the dial is set to 9MHz and you do the adjustments 18, 19 & 20. The dial is then set to 4MHz for adjustment 21. Personally, I would do 21 first (which is conven­tional wisdom), then 18 and then go between these two until I was satisfied that the oscillator was tracking correctly before doing adjustments 19 and 20. We are now nearly at the end of the alignment procedure. On the 1.5-4MHz band there are two adjustments, both involving the oscillator. Adjust the oscillator core at 1.6 MHz (adjustment 22) and then the trimmer (adjustment 23) at 3.7MHz. Re-check Photo Gallery after adjusting both that the first one is still correct and if not, readjust it. The other adjustment will quite likely be out again but not as much as before. Going between the two adjustments will quite quickly get the oscillator circuit tracking fairly accurately across the band. This technique applies to any of the bands where the oscillator is adjusted at both the low and high ends of the band. Finally, recheck the broadcast band alignment if the 21MHz oscillator trimmer has had to be altered. Note that the informa­tion on the 611-T indicates that the trimmer is C9 but in the 617T and 719C it is C12. The compromises AIRZONE MODEL 300: manufactur­ed by Airzone (Sydney) in 1934, the Model 300 features a classic wooden “Cathedral” style cabinet. The circuit is a 4-valve superhet with the following valve types: 57 autodyne mixer, 58 IF amplifier, 59 anode bend detector/ audio output and an 80 rectifier. Normally, the front end of a set with seven bands and an RF stage will have six adjustments per band, making a total of 42 adjustments. However, there are only 19 adjustments in these particular sets. There are several reasons for this. First, there are no aerial or RF stage adjustments at the low-frequency end of each band. This means that if the coils are not exactly matched, the performance at the low-frequency WHEN QUALITY COUNTS. . . . valve equipment manufacturers and repairers choose only the best... SVETLANA GOLDEN DRAGON EI ELITE GOLD Transformers -- HAMMOND CLASSIC Valves -- 6L6GC, 12AX7, 300B, 6550, EL34, EL509, KT88 KT66, 4-300BM, 300BM 6CG7, 12AX7, EL84, -- gold pins Single-ended 25 watts Push/pull / Ultra-linear 10 to 120 watts Power -- universal primary, secondary to 250mA Filter chokes -- to 300mA HAMMOND MANUFACTURING Stockists -- NSW Victoria New Zealand MEGtronics -- 02 9831 6454 Electronic Valve & Tube Company -- 03 5257 2297 Resurrection Radio -- 03 9510 4486 Logic Research Electronics -- 07 849 5293 E lectronics Distributed by www.siliconchip.com.au 76 Bluff Road St Leonards VIC 3223 PO Box 487 Drysdale VIC 3222 AUSTRALIA Tel +61 3 5257 2297 Fax: +61 3 5257 1773 April 2002  81 Photo Gallery TABLE 1: ALIGNMENT TABLE Test Ins. Alignment Connect To Frequency Order Setting Recei ver Band Setting Cal ibration Scale Setting Circui t To Adjust Adjustment Symbol Adjust To Obtain 1 6J8G Cap* 455kHz Broadcast 0 2nd IF Trans. Core L36 Max. Peak 2 6J8G Cap* 455kHz Broadcast 0 2nd IF Trans. Core L35 Max. Peak 3 6J8G Cap* 455kHz Broadcast 0 1st IF Trans. Core L34 Max. Peak 4 6J8G Cap* 455kHz Broadcast 0 1st IF Trans. Core L33 Max. Peak 5 Aerial 600kHz Broadcast 19 Oscill ator** Core L31 Cal ibration 6 Aerial 1500kHz Broadcast 16 8 Oscill ator C 11 Cal ibration 7 Aerial 1450kHz Broadcast 15 8 Radio Freq. C27 Max. Peak 8 Aerial 1450kHz Broadcast 15 8 Aerial C7 Max. Peak 9 Aerial 17.8MHz 22.3-17.7MHz 18 Oscill ator Core L19 Cal ibration 10 Aerial 17.8MHz 22.3-17.7MHz 18 Radio Freq.** C24 Max. Peak 11 Aeri al 17.8MHz 22.3-17.7MHz 18 Aeri al C4 Max. Peak 12 Aerial 21.0MHz 22.3-17.7MHz 149 Oscill ator C9 Cal ibration 13 Aerial 15.2MHz 19.0-15.0MHz 27 Oscill ator Core L21 Cal ibration 14 Aerial 11.8MHz 15.0-11.7MHz 25 Oscill ator Core L23 Cal ibration 15 Aerial 11.8MHz 15.0-11.7MHz 25 Radio Freq.** C25 Max. Peak 16 Aerial 11.8MHz 15.0-11.7MHz 25 Aerial C5 Max. Peak Recheck 1, 2, 3 & 4 Recheck 5, 6, 7 & 8 17 Aerial 9.5MHz 12.0-9.4MHz 24 Oscill ator Core L25 Cal ibration 18 Aerial 9.0MHz 9.7-3.6MHz 15 6 Oscill ator C13 Cal ibration 19 Aerial 9.0MHz 9.7-3.6MHz 15 6 Radio Freq.** C26 Max. Peak 20 Aerial 9.0MHz 9.7-3.6MHz 15 6 Aerial C6 Max. Peak 21 Aerial 4.0MHz 9.7-3.6MHz 19 Oscill ator Core L27 Cal ibration Recheck 18, 19, 20 & 21 22 Aerial 1.6MHz 4.0-1.5MHz 15 Oscill ator Core L29 Cal ibration 23 Aerial 3.7MHz 4.0-1.5MHz 15 3 Oscill ator C14 Cal ibration Recheck 22 & 23 Finall y, recheck broadcast band. This is necessary onl y wthe setting of C9 has been al tered. * Rock the tuning control back and forth through the signal. ** Wi th grid clip connected. A .001uF capacitor should be connected in seri es wi th the "high" si de of the test instrument. The column headed "Calibration Scale Setting" refers to the 180 degree scale on the ganged tuning capacitor dri ve drum. In taking readings on this scale, read from the right-hand edge of the pointer; ie, the edge nearest the rear of the chassis. Check the setting of the drum before taking readings. The zero mark should be opposi te the pointer wi th the tuning capaci tor ful ly closed. end of the band can be inferior to that obtained at the high-frequency end. Second, on some bands, there are only adjustments for the oscillator at both ends of the band; eg, the 1.54.0MHz band which has no RF or aerial coil adjustments at all. This can be quite a compromise if the coils aren’t accurately matched. In fact, I found that if I wanted good performance at the high end of the band in the 719C, I had to compromise with the oscillator frequency. For this 82  Silicon Chip particular receiver, I found that in order to get good RF sensitivity, I had to adjust the oscilla­tor so that the receiver was actually on 3.65MHz when the dial said it was 3.7MHz. Third, on the 9.4-12.0MHz and 15.0-19.0MHz bands, there is only one adjustment and that is for the oscillator at the low-frequency end. Hopefully the set will track correctly across each of these bands but that’s really a faint hope I’m afraid. The value of C15 is quite critical and by altering GENERAL ELECTRIC MODEL 110: this receiver was made by AWA (Sydney) in 1932 and has the distinction of being the first to be housed in an Australian-made Bakelite cabinet. The same chassis was also marketed under the AWA brand as the Model C87. The circuit is a 4-valve TRF with the following valves: 35 RF amplifier, 24 detector, 47 output and an 80 rectifier. it, it is possible to correct the tracking to some degree. C1 and C22 could also be played with to improve the track­ing of the RF and aerial circuits on shortwave as well. However, it is not an easy task and unless you are a bit of a masochist, it is left well alone. Summary These sets overcome the deficiencies in their tuned cir­cuits by sheer brute force but are not as sensitive as some sets. In addition, the tuning mechanism is free-running and tuning shortwave stations is a dream compared to the “hair’s-breadth” tuning on a conventional dual-wave set. And although the tuning accuracy isn’t as good as it should be, it is better than on most receivers. Most listeners rarely knew the frequencies of the shortwave stations they wanted to listen to anyway. Finally, they are an impressive receiver to look at and well worth a place in your vintage radio collection. If you’ve always wanted to align your AWA 7-bander, this article should be SC all the incentive you need. www.siliconchip.com.au SILICON CHIP WebLINK How many times have you wanted to access a company’s website but cannot remember their site name? Here's an exciting new concept from SILICON CHIP: you can access any of these organisations instantly by going to the SILICON CHIP website (www.siliconchip.com.au), clicking on WebLINK and then on the website graphic of the company you’re looking for. It’s that simple. No longer do you have to wade through search engines or look through pages of indexes – just point’n’click and the site you want will open! Your company or business can be a part of SILICON CHIP’s WebLINK. For one low rate you receive a printed entry each month on the SILICON CHIP WebLINK page with your home page graphic, company name, phone, fax and site details plus up to 50 words of description– and this is repeated on the WebLINK page on the SILICON CHIP website with the link of your choice active. Get those extra hits on your site from the right people in the electronics industry – t he people who make decisions to buy your products. Call David Polkinghorne today on (02) 9979 5644 VGS2 Graphics Splitter NEW! 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Jed Microprocessors Pty Ltd Tel: (03) 9762 3588 Fax: (03) 9762 5499 WebLINK: www.jedmicro.com.au Looking for GENUINE Stamp products from Parallax . . . or Scott Edwards Electronics, microEngineering Labs & others? Easy to learn, easy to use, sophisticated CPU based controllers & peripherals. See our website for new range of ATOM products! MicroZed Computers Tel: (02) 6772 2777 Fax: (02) 6772 8987 WebLINK: www.microzed.com.au When it comes to purchasing quality products over the Web, you can count on the Wiltronics team to provide you with the best value for money. For over 25 years, Wiltronics has supplied the needs of the Electronics Industry, and look forward to continuing this service. Wiltronics Pty Ltd For everything in radio control for aircraft, model boats and planes, etc. We also carry an extensive range of model flight control modules including GPS, altitude and speed, interfaces, autopilot and groundstation controllers. More info on our website! Silvertone Electronics Tel: (03) 9762 3588 Fax: (03) 9762 5499 Tel:(07) 4639 1100 WebLINK: www.wiltronics.com.au WebLINK: www.silvertone.com.au International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. SPECIALISTS in AUDIO, VIDEO, CD, DATA Media and Multimedia manufacturing & wholesale. We also specialise in DVD Prod-uction & editing. We can produce Short Run or Bulk CD Audio, CD Rom & DVD projects. Distributor of Emtec (by Basf) TDK, HHB and Quantegy Professional Products. Av-COMM Pty Ltd Tel:(02) 9939 4377 Fax: (02) 9939 4376 WebLINK: www.avcomm.com.au Fax: (07)4639 1275 PRO-COPY Tel: (08) 9375 3902 Fax: (08) 9375 3903 WebLINK: www.procopy.com.au April 2002  83 April 2002  83 PRODUCT SHOWCASE ezySTAMP BASIC Stamp Kits Auckland-based eSource, a Parallax distributor, has released another incarnation of the popular BASIC Stamp1, the ezyStamp. Building on feedback from teachers and industrial customers who were asking for a new solution to their demanding needs, eSource has redesigned the BASIC Stamp to offer previously unheard of functionality, convenience and robustness. The company is now offering this as a retail package to resellers in Australia and New Zealand. A programming cable is also available. There is also an ezyStamp beginners kit which includes the ezySTAMP plus an experimenter’s breadboard with connecting wires, various components, a 9V battery and a floppy disk with sample software. It suits students aged 12 years and up and anyone wanting to start with the basics of programming. Recommended retail price (not including GST) of the ezyStamp is $AU75, while the programming cable should sell for $AU15. The ezyStamp Beginners kit has a rrp of $AU115. Contact: eSource Ltd PO Box 14 077 Panmure, Auckland NZ Phone 64 0800 376 8723 Fax    649 521 3832 Website: www.esource.co.nz Kycon’s VESA & PS/2 Combo If you’ve ever needed a single keyboard, mouse and monitor connector, this new one from Kycon could be the answer! It has two PS/2 mini-DINs and a 15-pin VESA (D) socket moulded onto the one assembly. Kycon are based in San Jose, California, and can be contacted via their website (www.kycon.com) or phone 0011 1 408 494 0330; fax 0011 1 408 494 0325. Long-range Uniden cordless phone from DSE The new Uniden DS825 longrange cordless phone is the first digital that has additional handset capability. These can also double as “walkie talkies” when out of range of the base station, so can be used, say, on a camping trip. Like the cordless phone itself, they offer a range of up to one kilometre. Up to six additional handsets can be used and there is a keypad on each handset plus one on the base station (with speaker-phone). The phone uses 900MHz spread spectrum technology, which is claimed to give superior voice clarity along with digital security. The handsets feature caller ID, 60-number memory dialling, a back- lit keypad and adjustable earpiece volume. The rechargeable battery has a talk time of up to 4.5 hours and can be left off the base station charger for up to 10 days. Retail price of the phone (with one handset), is $298.00. It is available from all DSE stores, Power-House stores or via DSE Direct Link mail order. 84  Silicon Chip Hart calibrators now from Fluke Australia Following Fluke Australia’s acquisition of Hart Scientific, Fluke is now the Australian and New Zealand source of Hart Scientific Dry-well and Hart Scientific IR Calibrators. Dry-well calibrators are ideal for use at industrial sites, calibrating temperature devices such as thermocouples and RTDs. Hart’s HT9100S is one of the smallest dry-wells on the market. At less than 1kg and a temperature range of 35 to 375°C it is highly portable. The next model up is the HT9102S, which offers two wells; one for a reference thermometer to increase the accuracy. Again the unit is very light (1.8kg) and very easy to operate. The Portable Infrared (IR) Calib-rators (HT9132 and HT9135) provide a stable large (57mm) blackbody target for calibrating non-contact IR thermometers up to 500°C. With an emmissivity of 0.95, the isothermal target can be controlled in set-point increments of 0.1° from 50-500°C. For even higher precision, a contact calibration well is located directly behind the blackbody surface. Using an optional digital RTD thermometer such as the Hart HT1521 and a calibrated secondary probe, accuracies of ± 0.1°C can be achieved. Contact: Fluke Australia Ph: (02) 8850 3333 Fax: (02) 8850 3300 Website: www.fluke.com Contact: Dick Smith Electronics Ph: (02) 9642 9100 Fax: (02) 9642 9153 Website: www.dse.com.au www.siliconchip.com.au Jaycar’s new 2002 catalog Packaged with this issue of SILICON CHIP (or mailed separately to subscribers) is (or was!) the new 2002 Jaycar Electronics Engineering Catalog. At 356 pages, it is the largest and most comprehensive yet produced by the company and is crammed with over 5,000 products and hundreds of new, interesting & innovative items. All product ranges has been expanded and improved, from individual components to kits, projects and fully functional items including test equipment, alarm systems, car sound, home audio, surveillance equipment and much more. Of particular interest are the Cold Cathode Fluorescent tubes which are available in a range of colours. If your copy of the catalog has already been purloined, or you want another copy, it is available from any Jaycar store or via their website for $2.95. A $2.50 CD-ROM version with be available in May. It is fully searchable and features an easy-to-use browser style interface and ‘online’ pricing updates. For more information, contact your nearest Jaycar store or visit their web-site at www.jaycar.com.au TOROIDAL POWER TRANSFORMERS Manufactured in Australia Comprehensive data available Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 9476-5854 Fx (02) 9476-3231 New micro concept Clamp-On Power Meter aids in Energy Conservation The CW120 series of low-cost clamp-on power meters from Yokogawa have been designed as simple tools capable of measuring power values and instantaneous values. With support for a variety of connection types – 2-wire to 3-phase/3-wire or 2-wire to 3-phase 4- wire, up to 495V per phase – plus a comprehensive range of current clamps from 50A FS to 3000A FS, the CW120 can be used for many energy monitoring and logging applications. The CW120 works with very small electric energy values; users can easily change the decimal point position and display units – Wh, kWh, MWh, GWh – on its large backlit LCD. Data can be saved at 1-second inter- Tandy’s Microscope Set vals. This allows the CW120 to respond quickly to load fluctuations and measure transient responses in equipment. Having support for large capacity flash ATA memory cards, measurements can be taken by the CW120 for extended time periods. The CW120 also comes with a Windows-based software package, known as Toolbox. Contact: Yokogawa Australia Pty Ltd Centrecourt, D1&D2, 25-27 Paul St, North Ryde NSW 2113 Ph: (02) 9805 0699 Fax: (02) 9888 1844 Web: www.yokogawa.com.au In these days of all-electronic kits and toys it’s nice to see someone come up with a product to challenge the mind which is not microprocessor-controlled! This 9.5-inch diecase microscope from Tandy has a 10x, 30x & 60x objective lens and 67 items to get you started, including slicers, blank slides, dissecting needles, filters, prepared slides and much more. It’s available from all Tandy Electronics stores throughout Australia for only $64.95 and comes in a hard plastic carry case to store the microscope and all the goodies. www.siliconchip.com.au The NetServe 300 is ideally suited for firewalls, gateways, IP servers or thin clients. Inside an anodised aluminium enclosure is a powerful but low-power single-board-computer based on a Geode GX1 300MHz CPU. Interface connectors are mounted on the rear of the enclosure giving the front a clean and neat appearance. Among the interfaces are: a CRT interface supporting non-interlaced CRTs up to 1024 x 768 resolution and an audio interface compliant with AC97.2 consisting of Mic In, Line In and Line Out. Dual Intel 10/100Base Ethernet interfaces and SSD interface supporting Type I/II Compact Flash are also included. 2 x USB, 2 x serial and 1 x LPT ports are also supplied. The NetServe 300 requires only a single +5V, and a stand-alone power supply is included in the price. The whole unit measures just 178 (W) x 65(H) x 106 (D) and weighs 400g. Contact: Amtex Electronics Phone: (02) 9809 5022 Fax (02) 9809 5077 Website: www.amtex.com.au April 2002  85 REFERENCE GREAT BOOKS FOR ALL PRICES INCLUDE GST AND ARE AUDIO POWER AMP DESIGN HANDBOOK PIC Your Personal Introductory Course From one of the world’s most respected audio authorities. The new 2nd edition is even more comprehensive, includes sections on load-invariant power amps, distortion residuals and diagnosis of amplifier problems. 368 pages in paperback. Concise and practical guide to getting up and running with the PIC Microcontroller. Assumes no prior knowledge of microcontrollers, introduces the PIC’s capabilities through simple projects. Ideal introduction for students, teachers, technicians and electronics enthusiasts – perfect for use in schools and colleges. 270 pages in soft cover. By Douglas Self. 2nd Edition Published 2000 by John Morton – 2nd edition 2001 89 $ $ VIDEO SCRAMBLING AND DESCRAMBLING FOR SATELLITE AND CABLE TV by Graf & Sheets 2nd Edition 1998 If you've ever wondered how they scramble video on cable and satellite TV, this book tells you! Encoding/decoding systems (analog and digital systems), encryption, even schematics and details of several encoder and decoder circuits for experimentation. Intended for both the hobbyist and the professional. 290 pages in paperback. $ AUDIO ELECTRONICS By John Linsley Hood. First published 1995. Second edition 1999. 79 $ UNDERSTANDING TELEPHONE ELECTRONICS By Stephen J. Bigelow. Fourth edition published 2001 4th EDITION Based mainly on the American telephone system, this book covers conventional telephone fundamentals, including analog and digital communication techniques. Provides basic information on the functions of each telephone component, how dial tones are generated and how digital transmission techniques work. 402 pages, soft cover. 65 GUIDE TO TV & VIDEO TECHNOLOGY 3rd EDITION By Eugene Trundle. 3rd Edition 2001 Eugene Trundle has written for many years in Television magazine and his latest book is right up to date on TV and video technology. The book includes both theory and practical servicing information and is ideal for both students and technicians. 382 pages, in paperback. This book is for anyone involved in designing, adapting and using analog and digital audio equipment. It covers tape recording, tuners and radio receivers, preamplifiers, voltage amplifiers, audio power amplifiers, compact disc technology and digital audio, test and measurement, loudspeaker crossover systems, power supplies and noise reduction systems. 375 pages in soft cover. 3rd EDITION $ By Tim Williams. First pub­­lished 1992. 3rd edition 2001. By Ian Hickman. 2nd edition1999. 63 $ Based mainly on British practice and first published in 1997, this book has much that is relevant to Australian systems as a guide to home and small business installations. A practical guide to installation of telephone wiring, ranging from single extension sockets to PABX, with the necessary tools, test equipment and materials needed by installers... 178 pages in soft cover. 86  Silicon Chip EMC FOR PRODUCT DESIGNERS ANALOG ELECTRONICS Essential reading for electronics designers and students alike. It will answer nagging questions about core analog theory and design principles as well as offering practical design ideas. With concise design implementations, with many of the circuits taken from Ian Hickman’s magazine articles. 294 pages in soft cover. VIDEO & CAMCORDER SERVICING AND TECHNOLOGY by Steve Roberts. 2nd edition 2001. 67 85 $ Widely regarded as the standard text on EMC, provides all the key information needed to meet the requirements of the EMC Directive. Most importantly, it shows how to incorporate EMC principles into the product design process, avoiding cost and performance penalties, meeting the needs of specific standards and resulting in a better overall product. 360 pages in paperback. 99 TELEPHONE INSTALLATION HANDBOOK $ 43 85 $ by Steve Beeching (Published 2001) Provides fully up-to-date coverage of the whole range of current home video equipment, analog and digital. Information for repair and troubleshooting, with explanations of the technology of video equipment. 318 pages in soft cover. 67 $$ www.siliconchip.com.au BOOKSHOP WANT TO SAVE 10%? 10% OFF! SILICON CHIP SUBSCRIBERS AUTOMATICALLY QUALIFY FOR A 10% DISCOUNT ON ALL BOOK PURCHASES! ENQUIRING MINDS! LOWER THAN RECOMMENDED RETAIL PRICE Power Supply Cookbook Analog Circuit Techniques With Digital Interfacing by Marty Brown. 2nd edition 2001. An easy-to-follow, step-by-step design framework for a wide variety of power supplies. Anyone with a basic knowledge of electronics can create a very complicated power supply design . Magnetics, feedback loop, EMI/RFI control and compensation design are all described in simple language. 265 pages in paperback. by T H Wilmshurst. Published 2001. 93 $ Microcontroller Projects in C for the 8051 by Dogan Ibrahim. Published 2000. 69 $$ Through graded projects the author introduces the fundamentals of microelectronics, the 8051 family, programming in C and the use of a C compiler. The AT89C2051 is an economical chip with re-writable memory. Provides an interesting, enjoyable and easily mastered alternative to more theoretical textbooks. 178 pages in paperback. 69 $ Antenna Toolkit by Joe Carr. 2nd edition 2001. Together with the CD software included with this book, the reader will have a complete solution for constructing or using an antenna - bar the actual hardware. The software is based on the author’s own Antler program, which provides a simple Windowsbased aid to carrying out the design calculations at the heart of successful antenna design. Free software CD included. 253 pages in paperback. Electric Motors And Drives O R D E R H E R E ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ by Howard Hutchings. Revised by Mike James. 2nd edition 2001. 59 $ ANALOG ELECTRONICS..................................................$85.00 AUDIO POWER AMPLIFIER DESIGN...............................$89.00 AUDIO ELECTRONICS.....................................................$85.00 EMC FOR PRODUCT DESIGNERS...................................$99.00 GUIDE TO TV & VIDEO TECHNOLOGY............................$63.00 PIC - YOUR PERSONAL INTRODUCTORY COURSE........$43.00 TELEPHONE INSTALLATION HANDBOOK.......................$67.00 UNDERSTANDING TELEPHONE ELECTRONICS.................$65.00 VIDEO & CAMCORDER SERVICING/TECHNOLOGY........$67.00 VIDEO SCRAMBLING/DESCRAMBLING..........................$79.00 POWER SUPPLY COOKBOOK..........................................$93.00 M'CONTROLLER PROJECTS IN C FOR 8051..................$69.00 ANALOG CIRCUIT TECHNIQUES WITH DIGITAL INT......$69.00 ANTENNA TOOLKIT.........................................................$83.00 INTERFACING WITH C.....................................................$63.00 ELECTRIC MOTORS AND DRIVES..................................$59.00               ORDER TOTAL: $...................... P&P Orders over $100 P&P free in Australia. AUST: Add $A5.50 per book NZ: Add $A10 per book, $A15 elsewhere 83 $ Interfacing With C by Austin Hughes. 2nd edition 1993. Reprinted 2001. VERY POPULAR BOOK NOW BACK IN STOCK WITH A NEW LOWER PRICE! For non-specialist users – explores most of the widely-used modern types of motor and drive, including conventional and brushless DC, induction, stepping, synchronous and reluctance motors. 339 pages, in paperback. Covers all the analog electronics needed in a wide range of higher education programs: first degrees in electronic engineering, experimental science course, MSc electronics and electronics units for HNDs. Text is supported by numerous worked examples and experimental exercises. 312 pages in paperback. $ 63 Anyone interested in ports, transducer interfacing, analog to digital conversion, convolution, filters or digital/analog conversion will benefit from reading this book. The principals precede the applications to provide genuine understanding and encourage further development. 302 pages in paperback. TAX INVOICE Your Name_________________________________________________ PLEASE PRINT Address ___________________________________________________ ___________________________________ Postcode_______________ Daytime Phone No. (______) __________________________________ STD Email___________________<at>_________________________________ ❏ Cheque/Money Order enclosed OR ❏ Charge my credit card – ❏ Bankcard ❏ Visa Card ❏ MasterCard No: Signature______________________Card expiry date PLUS P&P (if applic): $........................... TOTAL$ AU.............................. POST TO: SILICON CHIP Publications, PO Box 139, Collaroy NSW, Australia 2097. OR CALL (02) 9979 5644 & quote your credit card details; or FAX TO (02) 9979 6503 ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST Silicon Chip Back Issues 200W Inverter; 0.5W Audio Amplifier; 3A 40V Adjustable Power Supply; Engine Management, Pt.5; Airbags In Cars – How They Work. March 1994: Intelligent IR Remote Controller; 50W (LM3876) Audio Amplifier Module; Level Crossing Detector For Model Railways; Voice Activated Switch For FM Microphones; Engine Management, Pt.6. April 1989: Auxiliary Brake Light Flasher; What You Need to Know About Capacitors; 32-Band Graphic Equaliser, Pt.2. Ultrasonic Switch For Mains Appliances; The Basics Of A/D & D/A Conversion; Plotting The Course Of Thunderstorms. April 1994: Sound & Lights For Model Railway Level Crossings; Discrete Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. May 1989: Build A Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference. October 1991: Build A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator For Model Railways Mk.II; Magnetic Field Strength Meter; Digital Altimeter For Gliders, Pt.2; Military Applications Of R/C Aircraft. May 1994: Fast Charger For Nicad Batteries; Induction Balance Metal Locator; Multi-Channel Infrared Remote Control; Dual Electronic Dice; Simple Servo Driver Circuits; Engine Management, Pt.8. July 1989: Exhaust Gas Monitor; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; The NSW 86 Class Electrics. November 1991: Colour TV Pattern Generator, Pt.1; A Junkbox 2-Valve Receiver; Flashing Alarm Light For Cars; Digital Altimeter For Gliders, Pt.3; Build A Talking Voltmeter For Your PC, Pt.2. June 1994: 200W/350W Mosfet Amplifier Module; A Coolant Level Alarm For Your Car; 80-Metre AM/CW Transmitter For Amateurs; Converting Phono Inputs To Line Inputs; PC-Based Nicad Battery Monitor; Engine Management, Pt.9. October 1989: FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 2-Chip Portable AM Stereo Radio, Pt.2. December 1991: TV Transmitter For VCRs With UHF Modulators; Infrared Light Beam Relay; Colour TV Pattern Generator, Pt.2; Index To Volume 4. July 1994: Build A 4-Bay Bow-Tie UHF TV Antenna; PreChamp 2-Transistor Preamplifier; Steam Train Whistle & Diesel Horn Simulator; 6V SLA Battery Charger; Electronic Engine Management, Pt.10. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disk Drive Formats & Options. March 1992: TV Transmitter For VHF VCRs; Thermostatic Switch For Car Radiator Fans; Coping With Damaged Computer Directories; Valve Substitution In Vintage Radios. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Phone Patch For Radio Amateurs; Active Antenna Kit; Designing UHF Transmitter Stages. April 1992: IR Remote Control For Model Railroads; Differential Input Buffer For CROs; Understanding Computer Memory; Aligning Vintage Radio Receivers, Pt.1. August 1994: High-Power Dimmer For Incandescent Lights; Microprocessor-Controlled Morse Keyer; Dual Diversity Tuner For FM Microphones, Pt.1; Nicad Zapper (For Resurrecting Nicad Batteries); Electronic Engine Management, Pt.11. February 1990: A 16-Channel Mixing Desk; Build A High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; IR Remote Control For Model Railroads, Pt.3; 15-Watt 12-240V Inverter; A Look At Hard Disk Drives. March 1990: Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16-Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. October 1992: 2kW 24VDC - 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm, Pt.2; Mini Amplifier For Personal Stereos; A Regulated Lead-Acid Battery Charger. April 1990: Dual Tracking ±50V Power Supply; Voice-Operated Switch With Delayed Audio; 16-Channel Mixing Desk, Pt.3; Active CW Filter. February 1993: Three Projects For Model Railroads; Low Fuel Indicator For Cars; Audio Level/VU Meter (LED Readout); An Electronic Cockroach; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5. June 1990: Multi-Sector Home Burglar Alarm; Build A Low-Noise Universal Stereo Preamplifier; Load Protector For Power Supplies. March 1993: Solar Charger For 12V Batteries; Alarm-Triggered Security Camera; Reaction Trainer; Audio Mixer for Camcorders; A 24-Hour Sidereal Clock For Astronomers. September 1989: 2-Chip Portable AM Stereo Radio Pt.1; High Or Low Fluid Level Detector; Studio Series 20-Band Stereo Equaliser, Pt.2. July 1990: Digital Sine/Square Generator, Pt.1 (covers 0-500kHz); Burglar Alarm Keypad & Combination Lock; Build A Simple Electronic Die; A Low-Cost Dual Power Supply. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Generator, Pt.2. September 1990: A Low-Cost 3-Digit Counter Module; Build A Simple Shortwave Converter For The 2-Metre Band; The Care & Feeding Of Nicad Battery Packs (Getting The Most From Nicad Batteries). October 1990: The Dangers of PCBs; Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; NE602 Converter Circuits. April 1993: Solar-Powered Electric Fence; Audio Power Meter; Three-Function Home Weather Station; 12VDC To 70VDC Converter; Digital Clock With Battery Back-Up. June 1993: AM Radio Trainer, Pt.1; Remote Control For The Woofer Stopper; Digital Voltmeter For Cars; Windows-Based Logic Analyser. July 1993: Single Chip Message Recorder; Light Beam Relay Extender; AM Radio Trainer, Pt.2; Quiz Game Adjudicator; Windows-Based Logic Analyser, Pt.2; Antenna Tuners – Why They Are Useful. August 1993: Low-Cost Colour Video Fader; 60-LED Brake Light Array; Microprocessor-Based Sidereal Clock; Satellites & Their Orbits. November 1990: Connecting Two TV Sets To One VCR; Build An Egg Timer; Low-Cost Model Train Controller; 1.5V To 9V DC Converter; Introduction To Digital Electronics; A 6-Metre Amateur Transmitter. September 1993: Automatic Nicad Battery Charger/Discharger; Stereo Preamplifier With IR Remote Control, Pt.1; In-Circuit Transistor Tester; +5V to ±15V DC Converter; Remote-Controlled Cockroach. January 1991: Fast Charger For Nicad Batteries, Pt.1; Have Fun With The Fruit Machine (Simple Poker Machine); Build A Two-Tone Alarm Module; The Dangers of Servicing Microwave Ovens. October 1993: Courtesy Light Switch-Off Timer For Cars; Wireless Microphone For Musicians; Stereo Preamplifier With IR Remote Control, Pt.2; Electronic Engine Management, Pt.1. March 1991: Transistor Beta Tester Mk.2; A Synthesised AM Stereo Tuner, Pt.2; Multi-Purpose I/O Board For PC-Compatibles; Universal Wideband RF Preamplifier For Amateur Radio & TV. November 1993: High Efficiency Inverter For Fluorescent Tubes; Stereo Preamplifier With IR Remote Control, Pt.3; Siren Sound Generator; Engine Management, Pt.2; Experiments For Games Cards. May 1991: 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1. December 1993: Remote Controller For Garage Doors; Build A LED Stroboscope; Build A 25W Audio Amplifier Module; A 1-Chip Melody Generator; Engine Management, Pt.3; Index To Volume 6. July 1991: 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. January 1994: 3A 40V Variable Power Supply; Solar Panel Switching Regulator; Printer Status Indicator; Mini Drill Speed Controller; Stepper Motor Controller; Active Filter Design; Engine Management, Pt.4. September 1991: Digital Altimeter For Gliders & Ultralights; February 1994: Build A 90-Second Message Recorder; 12-240VAC September 1994: Automatic Discharger For Nicad Battery Packs; MiniVox Voice Operated Relay; Image Intensified Night Viewer; AM Radio For Weather Beacons; Dual Diversity Tuner For FM Microphones, Pt.2; Electronic Engine Management, Pt.12. October 1994: How Dolby Surround Sound Works; Dual Rail Variable Power Supply; Build A Talking Headlight Reminder; Electronic Ballast For Fluorescent Lights; Electronic Engine Management, Pt.13. November 1994: Dry Cell Battery Rejuvenator; Novel Alphanumeric Clock; 80-Metre DSB Amateur Transmitter; Twin-Cell Nicad Discharger (See May 1993); How To Plot Patterns Direct to PC Boards. December 1994: Easy-To-Build Car Burglar Alarm; Three-Spot Low Distortion Sinewave Oscillator; Clifford – A Pesky Electronic Cricket; Remote Control System for Models, Pt.1; Index to Vol.7. January 1995: Sun Tracker For Solar Panels; Battery Saver For Torches; Dolby Pro-Logic Surround Sound Decoder, Pt.2; Dual Channel UHF Remote Control; Stereo Microphone Pre­amp­lifier. February 1995: 2 x 50W Stereo Amplifier Module; Digital Effects Unit For Musicians; 6-Channel Thermometer With LCD Readout; Wide Range Electrostatic Loudspeakers, Pt.1; Oil Change Timer For Cars; Remote Control System For Models, Pt.2. March 1995: 2 x 50W Stereo Amplifier, Pt.1; Subcarrier Decoder For FM Receivers; Wide Range Electrostatic Loudspeakers, Pt.2; IR Illuminator For CCD Cameras; Remote Control System For Models, Pt.3. April 1995: FM Radio Trainer, Pt.1; Photographic Timer For Dark­ rooms; Balanced Microphone Preamp. & Line Filter; 50W/Channel Stereo Amplifier, Pt.2; Wide Range Electrostatic Loudspeakers, Pt.3; 8-Channel Decoder For Radio Remote Control. May 1995: Build A Guitar Headphone Amplifier; FM Radio Trainer, Pt.2; Transistor/Mosfet Tester For DMMs; A 16-Channel Decoder For Radio Remote Control; Introduction to Satellite TV. June 1995: Build A Satellite TV Receiver; Train Detector For Model Railways; 1W Audio Amplifier Trainer; Low-Cost Video Security System; Multi-Channel Radio Control Transmitter For Models, Pt.1. July 1995: Electric Fence Controller; How To Run Two Trains On A Single Track (Incl. Lights & Sound); Setting Up A Satellite TV Ground Station; Build A Reliable Door Minder. August 1995: Fuel Injector Monitor For Cars; Gain Controlled Microphone Preamp; Audio Lab PC-Controlled Test Instrument, Pt.1; How To Identify IDE Hard Disk Drive Parameters. September 1995: Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.1; Keypad Combination Lock; The Vader Voice; Jacob’s 10% OF F SUBSCR TO IBERS O Please send the following back issues:      ____________________________________________________________ R IF YOU BUY 10 OR M Please send the following back issues: ORE ORDER FORM Enclosed is my cheque/money order for $­______or please debit my: ❏ Bankcard ❏ Visa Card ❏ Master Card Card No. Signature ___________________________ Card expiry date_____ /______ Name ______________________________ Phone No (___) ____________ PLEASE PRINT Street ______________________________________________________ Suburb/town _______________________________ Postcode ___________ 88  Silicon Chip Note: prices include postage & packing Australia ....................... $A7.70 (incl. GST) Overseas (airmail) ............................ $A10 Detach and mail to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Or call (02) 9979 5644 & quote your credit card details or fax the details to (02) 9979 6503. Email: silchip<at>siliconchip.com.au www.siliconchip.com.au Ladder Display; Audio Lab PC-Controlled Test Instrument, Pt.2. October 1995: 3-Way Loudspeaker System; Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.2; Build A Fast Charger For Nicad Batteries. February 1998: Multi-Purpose Fast Battery Charger, Pt.1; Telephone Exchange Simulator For Testing; Command Control System For Model Railways, Pt.2; Build Your Own 4-Channel Lightshow, Pt.2. November 1995: Mixture Display For Fuel Injected Cars; CB Trans­ verter For The 80M Amateur Band, Pt.1; PIR Movement Detector. April 1998: Automatic Garage Door Opener, Pt.1; 40V 8A Adjustable Power Supply, Pt.1; PC-Controlled 0-30kHz Sinewave Generator; Build A Laser Light Show; Understanding Electric Lighting; Pt.6. December 1995: Engine Immobiliser; 5-Band Equaliser; CB Transverter For The 80M Amateur Band, Pt.2; Subwoofer Controller; Knock Sensing In Cars; Index To Volume 8. May 1998: Troubleshooting Your PC, Pt.1; Build A 3-LED Logic Probe; Automatic Garage Door Opener, Pt.2; Command Control For Model Railways, Pt.4; 40V 8A Adjustable Power Supply, Pt.2. January 1996: Surround Sound Mixer & Decoder, Pt.1; Magnetic Card Reader; Build An Automatic Sprinkler Controller; IR Remote Control For The Railpower Mk.2; Recharging Nicad Batteries For Long Life. June 1998: Troubleshooting Your PC, Pt.2; Universal High Energy Ignition System; The Roadies’ Friend Cable Tester; Universal Stepper Motor Controller; Command Control For Model Railways, Pt.5. April 1996: Cheap Battery Refills For Mobile Phones; 125W Audio Amplifier Module; Knock Indicator For Leaded Petrol Engines; Multi-Channel Radio Control Transmitter; Pt.3. July 1998: Troubleshooting Your PC, Pt.3; 15-W/Ch Class-A Audio Amplifier, Pt.1; Simple Charger For 6V & 12V SLA Batteries; Auto­matic Semiconductor Analyser; Understanding Electric Lighting, Pt.8. May 1996: Upgrading The CPU In Your PC; High Voltage Insulation Tester; Knightrider Bi-Directional LED Chaser; Simple Duplex Intercom Using Fibre Optic Cable; Cathode Ray Oscilloscopes, Pt.3. August 1998: Troubleshooting Your PC, Pt.4 (Adding Extra Memory); Simple I/O Card With Automatic Data Logging; Build A Beat Triggered Strobe; 15-W/Ch Class-A Stereo Amplifier, Pt.2. June 1996: BassBox CAD Loudspeaker Software Reviewed; Stereo Simulator (uses delay chip); Rope Light Chaser; Low Ohms Tester For Your DMM; Automatic 10A Battery Charger. September 1998: Troubleshooting Your PC, Pt.5; A Blocked Air-Filter Alarm; Waa-Waa Pedal For Guitars; Jacob’s Ladder; Gear Change Indicator For Cars; Capacity Indicator For Rechargeable Batteries. July 1996: Build A VGA Digital Oscilloscope, Pt.1; Remote Control Extender For VCRs; 2A SLA Battery Charger; 3-Band Parametric Equaliser; Single Channel 8-Bit Data Logger. October 1998: Lab Quality AC Millivoltmeter, Pt.1; PC-Controlled Stress-O-Meter; Versatile Electronic Guitar Limiter; 12V Trickle Charger For Float Conditions; Adding An External Battery Pack To Your Flashgun. August 1996: Introduction to IGBTs; Electronic Starter For Fluores­ cent Lamps; VGA Oscilloscope, Pt.2; 350W Amplifier Module; Masthead Amplifier For TV & FM; Cathode Ray Oscilloscopes, Pt.4. September 1996: VGA Oscilloscope, Pt.3; IR Stereo Headphone Link, Pt.1; High Quality PA Loudspeaker; 3-Band HF Amateur Radio Receiver; Cathode Ray Oscilloscopes, Pt.5. October 1996: Send Video Signals Over Twisted Pair Cable; Power Control With A Light Dimmer; 600W DC-DC Converter For Car Hifi Systems, Pt.1; IR Stereo Headphone Link, Pt.2; Build A Multi-Media Sound System, Pt.1; Multi-Channel Radio Control Transmitter, Pt.8. November 1996: 8-Channel Stereo Mixer, Pt.1; Low-Cost Fluorescent Light Inverter; Repairing Domestic Light Dimmers; Multi-Media Sound System, Pt.2; 600W DC-DC Converter For Car Hifi Systems, Pt.2. December 1996: Active Filter Cleans Up Your CW Reception; A Fast Clock For Railway Modellers; Laser Pistol & Electronic Target; Build A Sound Level Meter; 8-Channel Stereo Mixer, Pt.2; Index To Vol.9. January 1997: How To Network Your PC; Control Panel For Multiple Smoke Alarms, Pt.1; Build A Pink Noise Source; Computer Controlled Dual Power Supply, Pt.1; Digi-Temp Monitors Eight Temperatures. February 1997: PC-Con­trolled Moving Message Display; Computer Controlled Dual Power Supply, Pt.2; Alert-A-Phone Loud Sounding Telephone Alarm; Control Panel For Multiple Smoke Alarms, Pt.2. November 1998: The Christmas Star; A Turbo Timer For Cars; Build A Poker Machine, Pt.1; FM Transmitter For Musicians; Lab Quality AC Millivoltmeter, Pt.2; Improving AM Radio Reception, Pt.1. December 1998: Engine Immobiliser Mk.2; Thermocouple Adaptor For DMMs; Regulated 12V DC Plugpack; Build A Poker Machine, Pt.2; Improving AM Radio Reception, Pt.2; Mixer Module For F3B Gliders. January 1999: High-Voltage Megohm Tester; Getting Started With BASIC Stamp; LED Bargraph Ammeter For Cars; Keypad Engine Immobiliser; Improving AM Radio Reception, Pt.3. March 1999: Getting Started With Linux; Pt.1; Build A Digital Anemometer; Simple DIY PIC Programmer; Easy-To-Build Audio Compressor; Low Distortion Audio Signal Generator, Pt.2. September 1997: Multi-Spark Capacitor Discharge Ignition; 500W Audio Power Amplifier, Pt.2; A Video Security System For Your Home; PC Card For Controlling Two Stepper Motors; HiFi On A Budget. October 1997: Build A 5-Digit Tachometer; Add Central Locking To Your Car; PC-Controlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3; Customising The Windows 95 Start Menu. November 1997: Heavy Duty 10A 240VAC Motor Speed Controller; Easy-To-Use Cable & Wiring Tester; Build A Musical Doorbell; Replacing Foam Speaker Surrounds; Understanding Electric Lighting Pt.1. December 1997: Speed Alarm For Cars; 2-Axis Robot With Gripper; Stepper Motor Driver With Onboard Buffer; Power Supply For Stepper Motor Cards; Understanding Electric Lighting Pt.2; Index To Vol.10. January 1998: Build Your Own 4-Channel Lightshow, Pt.1 (runs off 12VDC or 12VAC); Command Control System For Model Railways, Pt.1; Pan Controller For CCD Cameras. www.siliconchip.com.au October 2000: Guitar Jammer For Practice & Jam Sessions; Booze Buster Breath Tester; A Wand-Mounted Inspection Camera; Installing A Free-Air Subwoofer In Your Car; Fuel Mixture Display For Cars, Pt.2. November 2000: Santa & Rudolf Chrissie Display; 2-Channel Guitar Preamplifier, Pt.1; Message Bank & Missed Call Alert; Electronic Thermostat; Protoboards – The Easy Way Into Electronics, Pt.3. December 2000: Home Networking For Shared Internet Access; Build A Bright-White LED Torch; 2-Channel Guitar Preamplifier, Pt.2 (Digital Reverb); Driving An LCD From The Parallel Port; Build A Morse Clock; Protoboards – The Easy Way Into Electronics, Pt.4; Index To Vol.13. January 2001: How To Transfer LPs & Tapes To CD; The LP Doctor – Clean Up Clicks & Pops, Pt.1; Arbitrary Waveform Generator; 2-Channel Guitar Preamplifier, Pt.3; PIC Programmer & TestBed. February 2001: How To Observe Meteors Using Junked Gear; An Easy Way To Make PC Boards; L’il Pulser Train Controller; Midi-Mate – A MIDI Interface For PCs; Build The Bass Blazer; 2-Metre Elevated Groundplane Antenna; The LP Doctor – Clean Up Clicks & Pops, Pt.2. March 2001: Making Photo Resist PC Boards; Big-Digit 12/24 Hour Clock; Parallel Port PIC Programmer & Checkerboard; Protoboards – The Easy Way Into Electronics, Pt.5; A Simple MIDI Expansion Box. April 2001: A GPS Module For Your PC; Dr Video – An Easy-To-Build Video Stabiliser; Tremolo Unit For Musicians; Minimitter FM Stereo Transmitter; Intelligent Nicad Battery Charger. May 2001: Powerful 12V Mini Stereo Amplifier; Two White-LED Torches To Build; PowerPak – A Multi-Voltage Power Supply; Using Linux To Share An Internet Connection, Pt.1; Tweaking Windows With TweakUI. July 2001: The HeartMate Heart Rate Monitor; Do Not Disturb Tele­phone Timer; Pic-Toc – A Simple Alarm Clock; Fast Universal Battery Charger, Pt.2; A PC To Die For, Pt.2; Backing Up Your Email. June 1999: FM Radio Tuner Card For PCs; X-Y Table With Stepper Motor Control, Pt.2; Programmable Ignition Timing Module For Cars, Pt.1; Hard Disk Drive Upgrades Without Reinstalling Software? August 2001: Direct Injection Box For Musicians; Build A 200W Mosfet Amplifier Module; Headlight Reminder For Cars; 40MHz 6-Digit Frequency Counter Module; A PC To Die For, Pt.3; Using Linux To Share An Internet Connection, Pt.3. August 1999: Remote Modem Controller; Daytime Running Lights For Cars; Build A PC Monitor Checker; Switching Temperature Controller; XYZ Table With Stepper Motor Control, Pt.4; Electric Lighting, Pt.14. August 1997: The Bass Barrel Subwoofer; 500 Watt Audio Power Amplifier Module; A TENs Unit For Pain Relief; Addressable PC Card For Stepper Motor Control; Remote Controlled Gates For Your Home. September 2000: Build A Swimming Pool Alarm; An 8-Channel PC Relay Board; Fuel Mixture Display For Cars, Pt.1; Protoboards – The Easy Way Into Electronics, Pt.1; Cybug The Solar Fly. May 1999: The Line Dancer Robot; An X-Y Table With Stepper Motor Control, Pt.1; Three Electric Fence Testers; Heart Of LEDs; Build A Carbon Monoxide Alarm; Getting Started With Linux; Pt.3. April 1997: Simple Timer With No ICs; Digital Voltmeter For Cars; Loudspeaker Protector For Stereo Amplifiers; Model Train Controller; A Look At Signal Tracing; Pt.1; Cathode Ray Oscilloscopes, Pt.8. July 1997: Infrared Remote Volume Control; A Flexible Interface Card For PCs; Points Controller For Model Railways; Colour TV Pattern Generator, Pt.2; An In-Line Mixer For Radio Control Receivers. August 2000: Build A Theremin For Really Eeerie Sounds; Come In Spinner (writes messages in “thin-air”); Proximity Switch For 240VAC Lamps; Structured Cabling For Computer Networks. June 2001: Fast Universal Battery Charger, Pt.1; Phonome – Call, Listen In & Switch Devices On & Off; L’il Snooper – A Low-Cost Automatic Camera Switcher; Using Linux To Share An Internet Connection, Pt.2; A PC To Die For, Pt.1 (Building Your Own PC). July 1999: Build A Dog Silencer; 10µH to 19.99mH Inductance Meter; Build An Audio-Video Transmitter; Programmable Ignition Timing Module For Cars, Pt.2; XYZ Table With Stepper Motor Control, Pt.3. June 1997: PC-Controlled Thermometer/Thermostat; TV Pattern Generator, Pt.1; Audio/RF Signal Tracer; High-Current Speed Controller For 12V/24V Motors; Manual Control Circuit For Stepper Motors. July 2000: A Moving Message Display; Compact Fluorescent Lamp Driver; El-Cheapo Musicians’ Lead Tester; Li’l Powerhouse Switchmode Power Supply (1.23V to 40V) Pt.2. April 1999: Getting Started With Linux; Pt.2; High-Power Electric Fence Controller; Bass Cube Subwoofer; Programmable Thermostat/ Thermometer; Build An Infrared Sentry; Rev Limiter For Cars. March 1997: Driving A Computer By Remote Control; Plastic Power PA Amplifier (175W); Signalling & Lighting For Model Railways; Build A Jumbo LED Clock; Cathode Ray Oscilloscopes, Pt.7. May 1997: Neon Tube Modulator For Light Systems; Traffic Lights For A Model Intersection; The Spacewriter – It Writes Messages In Thin Air; A Look At Signal Tracing; Pt.2; Cathode Ray Oscilloscopes, Pt.9. (1.23V to 40V) Pt.1; CD Compressor For Cars Or The Home. September 1999: Autonomouse The Robot, Pt.1; Voice Direct Speech Recognition Module; Digital Electrolytic Capacitance Meter; XYZ Table With Stepper Motor Control, Pt.5; Peltier-Powered Can Cooler. September 2001: Making MP3s – Rippers & Encoders; Build Your Own MP3 Jukebox, Pt.1; PC-Controlled Mains Switch; Personal Noise Source For Tinnitus Sufferers; The Sooper Snooper Directional Microphone; Using Linux To Share An Internet Connection, Pt.4. October 2001: A Video Microscope From Scrounged Parts; Build Your Own MP3 Jukebox, Pt.2; Super-Sensitive Body Detector; An Automotive Thermometer; Programming Adapter For Atmel Microcomputers. November 2001: Ultra-LD 100W RMS/Channel Stereo Amplifier, Pt.1; Neon Tube Modulator For Cars; Low-Cost Audio/Video Distribution Amplifier; Short Message Recorder Player; Computer Tips. October 1999: Build The Railpower Model Train Controller, Pt.1; Semiconductor Curve Tracer; Autonomouse The Robot, Pt.2; XYZ Table With Stepper Motor Control, Pt.6; Introducing Home Theatre. December 2001: A Look At Windows XP; Build A PC Infrared Transceiver; Ultra-LD 100W RMS/Ch Stereo Amplifier, Pt.2; Pardy Lights – An Intriguing Colour Display; PIC Fun – Learning About Micros. November 1999: Setting Up An Email Server; Speed Alarm For Cars, Pt.1; LED Christmas Tree; Intercom Station Expander; Foldback Loudspeaker System; Railpower Model Train Controller, Pt.2. January 2002: Touch And/Or Remote-Controlled Light Dimmer, Pt.1; A Cheap ’n’Easy Motorbike Alarm; 100W RMS/Channel Stereo Amplifier, Pt.3; Build A Raucous Alarm; Tracking Down Computer Software Problems; Electric Power Steering; FAQs On The MP3 Jukebox. December 1999: Solar Panel Regulator; PC Powerhouse (gives +12V, +9V, +6V & +5V rails); Fortune Finder Metal Locator; Speed Alarm For Cars, Pt.2; Railpower Model Train Controller, Pt.3; Index To Vol.12. January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Build The Picman Programmable Robot; A Parallel Port Interface Card; Off-Hook Indicator For Telephone Lines. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; An Ultrasonic Parking Radar; Build A Safety Switch Checker; Build A Sine/Square Wave Oscillator. March 2000: Resurrecting An Old Computer; Low Distortion 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Glowplug Driver For Powered Models; The OzTrip Car Computer, Pt.1. May 2000: Ultra-LD Stereo Amplifier, Pt.2; Build A LED Dice (With PIC Microcontroller); Low-Cost AT Keyboard Translator (Converts IBM Scan-Codes To ASCII); 50A Motor Speed Controller For Models. June 2000: Automatic Rain Gauge With Digital Readout; Parallel Port VHF FM Receiver; Li’l Powerhouse Switchmode Power Supply February 2002: 10-Channel IR Remote Control Receiver; 2.4GHz High-Power Audio-Video Link; Assemble Your Own 2-Way Tower Speakers; Touch And/Or Remote-Controlled Light Dimmer, Pt.2; Booting A PC Without A Keyboard; 4-Way Event Timer. March 2002: Mighty Midget Audio Amplifier Module; The Itsy-Bitsy USB Lamp; 6-Channel IR Remote Volume Control, Pt.1; RIAA Prea­ mplifier For Magnetic Cartridges; 12/24V Intelligent Solar Power Battery Charger; Generate Audio Tones Using Your PC’s Soundcard. PLEASE NOTE: November 1987 to March 1989, June 1989, August 1989, December 1989, May 1990, December 1990, February 1991, April 1991, June 1991, August 1991, January 1992, February 1992, July 1992, August 1992, September 1992, November 1992, December 1992, January 1993, May 1993, February 1996, March 1998 and February 1999 are now sold out. All other issues are presently in stock. We can supply photostat copies (or tear sheets) from sold-out issues for $7.70 per article (includes p&p). When supplying photostat articles or back copies, we automatically supply any relevant notes & errata at no extra charge. A complete index to all articles published to date can be downloaded free from our web site: www.siliconchip.com.au April 2002  89 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; or send an email to silchip<at>siliconchip.com.au Playing 78s with the LP Doctor I have built the LP Doctor described in the January 2001 issue and may I say that your efforts on this project have been tremendous. I present nostalgic music by playing 78 RPM record­ings which are broadcast to air on our community radio station. I still have a problem getting rid of surface noise on 78s. The LP Doctor does a great job on clicks and pops but as you suggest in your article on the subject, it does little on surface noise. I have done a bit of playing around with a filter published in ETI of September 1980. I managed to achieve fairly reasonable results by using the filter set to 5kHz and incorporating the LPD for dealing with the clicks and pops. I feed the turntable audio into the LPD and I feed the filter by paralleling the LPD’s output (ie, by bringing the L + R positives together and so the commons together). One assumes by doing that this I have created a reasonably effective common mode rejection filter. It does make a difference in regard to the 78s’ surface noise. On a related subject, I have constructed several RIAA phono preamps (from the April 1994 issue) and they Video mixer circuit wanted I would like a circuit that would allow the mixing of two separate video signals into one (a video fader in the same manner as the familiar audio fader). I realise there is a problem with the synchronising of the signals and there would in all probabil­ity be a varying black horizontal and/or vertical bar as a result if the same circuitry as for audio were used. Could this be overcome with some sort of auto delay on one of the signals? Please put on your thinking caps and provide me, and many 90  Silicon Chip are terrific, the low noise factor in particular. My problem is that though they work splendidly playing vinyls, they don’t like the audio from 78s. I assume that the 78s cause the cartridge to produce a higher voltage than vinyl records. This tends to create clipping/ distortion especially on the highs of a 78 recording (eg, a tenor hitting a high note). At first I thought I had a faulty cartridge but not so. I have tried several magnetic cartridges including high quality Stanton and Shure types, which produced little difference. I was once told by an old broadcast engineer that the equalisation required for 78s is different to that required for LPs/vinyls. I managed to solve the problem by installing a pad on the tagstrip under the turntable unit. (K. J., Epping, Vic). • It is true that 78 RPM records will generate higher signal outputs from the cartridge and therefore there will be more likelihood of overload in the preamplifier. The solution to this is to reduce the gain of the preamplifier by increasing the value of the feedback resistor (R4) from 390Ω to 1kΩ or more. Do not reduce the output of the cartridge as you have because this will degrade the overall performance. The equalisation was different for others interested, I’m sure, with a practical answer. (J. S., Woodville West, SA). • As you are aware, the two video signals must be locked together. In practice, the only way of doing this is to feed one of the video signals into a frame store so that it can be fed out in sync with the second video signal. Frame stores are a feature of the “picture-in-picture” chipsets used in upmarket TV sets. Howev­ er, while a PIP chipset could form the heart of a practical video mixer, we have not produced such a design and the chipsets are not readily available. 78s; in fact there were quite a number of different equalisation curves in use before LPs came onto the scene and the RIAA curve became the standard. Each recording company had its own recording characteristic and there­fore the required equalisation could be quite different from the RIAA curve. You can find more info on the this subject in the esteemed “Radiotron Designers Handbook” but the more you look into it, the more it becomes a can of worms. To minimise surface noise from a stereo cartridge when playing 78s, the cartridge left and right channels should be paralleled and then fed to a single channel of the preamplifier. Paralleling the outputs of the LP Doctor is not recommended. You can increase the treble filtering from the LP Doctor by changing 150pF capacitor associated with IC5b & IC7b to 330pF and the 560pF to .0012µF. This is a simpler and more effective ap­proach than using the ETI filter. Immobilising a V6 Commodore My nephew has purchased an engine immobiliser & keypad kit to be fitted to his 1994 VR Commodore 1994. At present, we are unsure what wire is the output from the coil to connect to the immobiliser. He has purchased a manual however it only shows the active from the ignition switch. Have you fitted (or had fitted) a unit to a similar car? Could you please inform us what to do. (G. R., via email). • As described in our feature article on the Commodore in the December 1988 issue, the Commodore V6 uses three double-ended ignition coils. Hence an immobiliser either has to kill all three coils or kill the signal from the Hall Effect pickup on the harmonic balancer. We think the safest (and most expensive ap­proach) would be to use three high-voltage high-current diodes to kill the three coils with the one high voltage transistor in the immobiliser circuit. www.siliconchip.com.au Peak hold for tachometer I would like to know whether a peak hold function could be added to the tachometer circuit featured in the April 2000 issue. I would like to use the unit in a Formula 500 Speedway car which is powered by a single-cylinder 2-stroke engine. Different tracks require different gearing and this feature would be ideal for checking for peak RPM – it becomes very difficult to keep an eye on the tacho when peak revs come at the end of the straight, right when you’re sliding into corners and trying to avoid cars in front of you, while getting mud thrown at your visor. (J. H., Perth, WA). With this approach, the anode of each diode would connect to the switched side of each coil. The cathodes would be connect­ ed together and connected to the collector of the immobiliser transistor. Suggested diode type would be a BYT12P-1000 rated at 12A and 1000V and fast recovery in a TO-220 package. The diodes are available from Farnell, Cat no. 437-700 for $5.10 each plus GST and delivery. Phone 1300 361 005. Light dimmer for halogen lamps I wish to construct the remote controlled version of the lamp dimmer featured in the January and February 2002 of SILICON CHIP. However, I need to make some modifications to the set up for it to work in my particular application. Firstly, I am con­trolling two 12V halogen lamps fed via two transformers fed from a standard domestic dimmer control. Can I simply replace the dimmer control with the remote controlled dimmer? Secondly, I need to mount the infrared sensor off the board some 20 to 30mm away.Will this work satisfactorily? Also would I still need to be shield the infrared sensor and fit the 0.1µF capacitor between the sensor case and the PC board? (T. B., Buderim, Qld). • The dimmer has not been designed www.siliconchip.com.au • Unfortunately, the entire mem­ ory capacity of the microcontroller used in the tacho­meter circuit has been used to provide all the features. Without extensive rewriting of the code, there is simply no space to include a peak hold feature. The accuracy of the peak hold would also be in doubt since many race engines simply change RPM too quickly for a reliable measurement, particularly over the 0.6 second update time for your single cylinder 2-stroke engine. One suggestion would be to set the bargraph to operate over a narrow range of RPM so that peak RPM can be seen as one of the lit LEDs. This will provide a guide as to RPM reached, within the limits set for the bargraph. for use with 12V Halogen lamps. To operate successfully it needs a “snubber” network connected across the Triac so that it will turn off properly with the inductive load presented by the step-down transformers. A suitable snubber network would be a 22Ω 1W resistor connected in series with a 0.1µF 250VAC (class X2) capacitor. This network would be connected between the A1 and A2 terminals of the Triac. Unfortunately, there is no space for these components on the existing PC board. The IR sensor must not be placed away from the dimmer PC board since it is connected to the 240VAC mains and is therefore live (ie, at 240VAC). Capacitance meter switch confusion In the September 1999 issue, an electrolytic capacitance meter was featured which I am currently building in my spare time. I have almost finished and am ready to put it into its case along with all the switches and the rotary dial. My question is this: in the parts list, a 2-pole 6-position rotary switch is required as a range selector. However, in the range selector in the front display only four positions are used. Is this a typo error, actually requiring a 4-position switch? (A. A., via email). • The parts list is correct – you set the stop on the switch to set it to four positions. To do this, undo the mounting ELAN Audio The Leading Australian Manufacturer of Professional Broadcast Audio Equipment Featured Product of the Month PC-BAL PCI Format Balancing Board Interface PC Sound Cards to Professional Systems Not only do we make the best range of Specialised Broadcast "On-Air" Mixers in Australia. . . We also make a range of General Audio Products for use by Radio Broadcasters, Recording Studios, Institutions etc. And we sell AKG and Denon Professional Audio Products For Technical Details and Professional Pricing Contact Elan Audio 2 Steel Crt South Guildford WA 6055 Phone 08 9277 3500 08 9478 2266 Fax email sales<at>elan.com.au WWW elan.com.au nut and remove the stop washer and then place it back on to the correct position to provide four positions. Fuel mixture display sensor wanted I’ve built the Fuel Mixture Display kit (September & Octob­er 2000) which I brought from Dick Smith Electronics in New Zealand. The kit is going to be used on my hotrod. However, I’m having problems locating the Bosch EGO probe you listed in the kit as being matched to the unit. The local Bosch agent said the part number is incorrect (LSM11 , 0258104002). Is the number correct or was there a mistake? Even if you can tell me what type of car the above probe is from it would be helpful. (J. B., Stratford, NZ). • The Bosch type number is correct. It is a sensor generally used for sensing exhaust smoke stacks, not necessarily in the automotive industry. The sensor can be purchased from Farnell (NZ 649 357 0646) but it is cheaper to get an EGO sensor from a wreckers such as used in Ford and April 2002  91 Single phase & 3-phase – what do they mean? Could please explain single and 3-phase? I have been in­formed during my search that 3-phase is only a name used by industry to obtain dollar energy discounts; at home, it is less costly to run an electric stove from a power point than its designated circuit attachments; and you use less power with an arc welder if you use high amp settings! Clearly, these claims are ridiculous and I found it hard to keep a straight face. Give me something nice and techni­cal to really make me think. (R. L., Cool­bellup, WA). • Many books have been written on this subject and you should find a few in your local library. In brief, all power stations around the world generate electricity from alternators which produce 3-phase power. The power comes out of the alternator in three lines (conductors), each of which is a sinewave at 50Hz or 60Hz. The difference between successive phases is 120°; three phases make up 360°. Holden 6-cylinder cars. The Fuel Mixture Display operates successfully with most automotive sensors. How to bridge a stereo amplifier I recently bought a 185W/channel kit stereo amplifier from Jaycar Electronics and I am wondering whether it is bridgeable? If so, how is it connected to the speakers and input and what is the output? (J. S., via email). • You need an op amp adaptor circuit to bridge the two power amplifiers. We published a suitable circuit, although with no PC board, in the February 1988 issue. We can supply a photostat copy of the article for $7.70 including postage. Ceiling fans run too fast Many of the houses I have lived/ live in have the toilet ceiling fan connected to the toilet light. The wiring to the switch is often inaccessible so alterations are difficult. In the ceiling, the fan plugs into a socket which is wired to the ceil­ing light. 92  Silicon Chip Electricity is distributed all over the country as high-voltage 3-phase. That is why all high voltage towers always have three power lines. The same system is used in your street and typically each house is connected between one of the phases (ie, 240VAC) and neutral. Only when a house has a heavy power ap­pliance such as an instantaneous water heater or pool heater is it normal for three phases to be connected. In those cases, you will find that the house has four power lines; ie, three phase lines (each at 240V) and neutral. Many people (including electricians) are confused about 3-phase electricity and cannot understand how there can be 415VAC between each phase line but only 240V between each phase and neutral. The only way to understand the topic is to delve into the textbooks. If sufficient other readers are interested, we may do a short series of articles on the subject. There are several problems with this arrangement. The fan is not always required for a toilet visit. When the fan is re­ quired, it should continue running for a delay time after the visit. Most ceiling fans run too fast/noisy for the toilet and require some form of speed control. This is what I propose: the original switch still controls the fan/light circuit but is left on if the fan is required. The light turns on/off immediately with the switch. If the light is turned on, there is a delay of about two minutes before the fan operates (this allows a short toilet visit with no fan). If the switch is turned off, both the light and fan turn off. If the switch is left on, both the light and fan stay on for a delay of about 15 minutes (the fan/light will run for a period after the visit). If the fan/light have cut out after the time delay, the circuit is reset by turning the switch off then on. The fan has preset speed control. The components would be mounted in a box in the ceiling. (A. D., Erskine, WA). • Unfortunately, your fan control concept involves control of both the light and fan, as well as speed control for the fan. While it is certainly feasible as an electronic circuit, the simplest approach would be to add in a fan switch (ie, separate circuit to the fan) with inbuilt time delay and add a resistor or capacitor in series with the fan to reduce its speed. In this way, you could turn on the fan when required and its noise would be reduced anyway because of the reduction in speed. LEDs flashing on mixture meter I have constructed the Fuel Mixture Display kit described in the “EFI Tech Special” The kit is not functioning how it should with lights buzzing left and right on idle at normal temperature. The red light stays on all the time. If I adjust the trimpot, the yellow light shows. What could be the fault in this situation? (E. B., via email). • There isn’t too much that can go wrong with this kit. It seems that the IC is driving the LEDs from one extreme to the other as the yellow (rich) and red (lean) ones light with varia­tion of VR1. Check that there are no shorts between tracks on the PC board, by scraping between tracks with a sharp knife. Also check that there are no solder bridges between pins on IC1 by comparing the published pattern with the underside of your board. It is possible that the input at pin 5 has been damaged. It can be protected by connecting a .01µF capacitor between pins 5 & 4 and using a 100kΩ resistor in series with the input from the oxygen sensor. Simple train controller wanted I was wondering whether you knew of a circuit that would work as a speed controller on my train motor. The motor is from one of those old electric walk-behind lawn mowers with a roller to drive it and tubular blades. I have the train running from the smallest car battery you can get and that runs it for about 50 to 60 minutes before it starts to go flat. (J. P., via email). • Have a look at the Li’l Pulser train control in the February 2001 issue. Depending on how much current you need to supply, you may have to use a bigger FET, bigger relay and a bigger heatsink. www.siliconchip.com.au Speed Alarm won’t limit car speed Could the PIC-based Speed Alarm described in the November & December 1999 issues be used to limit a car’s speed in a similar way to the PIC Tachometer described in April 2000, which limits the revs via an immobiliser? I guess my question really is “Can the Speed Alarm be interfaced with the immobiliser circuit with only software revi­sion?” Your help would be appreciated. (S. A., via email). • The Speed Alarm is not suitable to actually control the speed of the car. For this you need a cruise control as it re­quires a means to manipulate the air flow to the engine via the carburettor or throttle body in a fuel injected car. Enhanced plugpack power supply I remember a very useful circuit that I’m sure I saw in SILICON CHIP magazine but I’ve looked all though the circuit list­ings and can’t find it. It was a simple circuit to reduce mains hum when you’re using a “plugpack” power supply with any sort of audio device. I thought it was in the “Circuit Notebook” section. (M. C., Eight Mile Plains, Qld). • The article was in the December 1998 issue, entitled: “A Regulated 12V DC plugpack”. Universal battery charger differences I am trying to find out what the differences are between the original and Mk.2 versions of the Universal Battery Charger. Can you help? (C. S., via email). • The main differences are that the Mk.2 version has facility to charge Notes & Errata PC-Controlled Mains Switch, September 2001: to avoid the possibility of electric shock from contact with the power plug’s pins when it is disconnected, a 100kΩ 0.5W resistor should be connected across the Varistor. This will discharge the 0.1µF 250VAC capacitor. Also, to improve the voltage isolation of the PC tracks around the optocoupler, it is recommended that neutral cure silicone caulking compound be applied to pins 4-6 of OPTO1 and the nearby component pads. Pardy Lites, December 2001: the resistor following D1 should be 820Ω instead of 4.7kΩ. Both the circuit on page 68 and the PC board on page 69 have this error. Audio/Video Distribution Amplifier, November 2001: there is an error in the underside copper pattern for the PC board which causes both audio outputs from the fourth socket pair from the right-hand end (looking from the rear) to deliver the R channel output signal. The problem can be fixed fairly Lithium-Ion batteries and there are more voltage ranges available for charging Nicad and NiMH batteries. Also the tenden­cy for the Mk.1 charger to prematurely terminate charging for older batteries has been corrected. You can upgrade the Mk.1 version to the Mk.2 version by transferring the components from the old board to the new PC board. This PC board is coded 14302982 and is available from RCS Radio Pty Ltd. Phone (02) 9738 0330. Hardware items such as the case, easily. First, remove the PC board assembly from the case and turn it upside down with the output connectors on the top. Then locate the fourth audio output pair from the left and verify that the pads at the lower ends of the two output series resistors (originally 47kΩ, now 1kΩ) both have tracks connecting them to the upper ‘R’ signal line track – unlike all the other output pairs. Cut the track on the right and, using a short length of tinned copper wire, connect the resis­tor pad to the lower ‘L’ signal line track instead. Solar Power Battery Charger, March 2002: the MJE2955 labelling for Q2 and Q3 on the overlay diagram on page 85 is incorrect. They should be labelled MTP2955. (Note that an MTP2955 is a P-channel Mosfet while a MJE2955 is a bipolar power transistor). The circuit and parts list are correct. In addition, the parts list incorrectly specifies a 4011 for IC1; it should in fact be a 4093 quad Schmitt trigger, as shown on the parts overlay diagram. the transformer, mains and battery connection wiring, heatsink and rectifier are unchanged. The front panel is changed slightly to accommodate the extra battery type and ranges. Of course, it is not necessary to in­clude all the extra voltage ranges provided by the Mk.2 version or include the Li-Ion selection. Main parts changes are the addition of a 2-pole 4-position rotary switch in place of the DPDT toggle switch used for S3 and some resistor changes. SC WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. 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. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. www.siliconchip.com.au April 2002  93 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $20.00 (incl. GST) for up to 20 words plus 66 cents for each additional word. Display ads: $33.00 (incl. GST) 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, fill out the form & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy, NSW 2097. Or fax the details to (02) 9979 6503. Taxation Invoice ABN 49 003 205 490 _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $­__________ or please debit my ❏ Bankcard   ❏ Visa Card   ❏ Master Card Card No. Signature­­­­­­­­­­­­__________________________ Card expiry date______/______ Name ______________________________________________________ Street ______________________________________________________ Suburb/town ___________________________ Postcode______________ 94  Silicon Chip FOR SALE TELEPHONE EXCHANGE SIMULATOR: test equipment without the cost of telephone lines. Melb 9806 0110. http://www.alphalink.com.au/~zenere KITS KITS AND MORE KITS! Check ‘em out at www.ozitronics.com AMAZING NEW Super Microphone point and listen in 500m away $95. Spy bug 1.2km range $49. Wireless Spy Camera transmits clear picture to TV within 200m $179. Tracking device $89. Professional Bug Detector $269. Camera with VCR, automatic recording, 20m cable, P/S and sensor ready to plug and use only $480. GCS Electronics (02) 4227 9933 gcses<at>aol.com www.gcselectronics.com UNIVERSAL DEVICE PROGRAMMER: Low cost, high performance, 48-pin, works in DOS or Windows inc NT/2000. $1320. Universal EPROM programmer $429. Also adaptors, (E) EPROM, PIC, 8051 programmers, EPROM simulator and eraser. Dunfield C Compilers: Everything you need to develop C and ASM software for 68HC08, 6809, 68HC11, 68HC12, 68HC16, 8051/52, 8080/85, 8086, 8096 or AVR: $198 each. Demo disk available. ImageCraft C Compilers: 32-bit Windows IDE and compiler. For AVR, 68HC11, 68HC12. $396. Atmel Flash CPU Programmer: Handles the 89Cx051, 89C5x, 89Sxx in both DIP and PLCC44 and some AVR’s, most 8-pin EEPROMS. Includes socket for serial ISP cable. $220, $11 p&p. SOIC adaptors: 20 pin $99, 14 pin $93.50, 8 pin $88. Full details on web site. Credit cards accepted. GRANTRONICS PTY LTD, PO Box 275, Wentworthville 2145. (02) 9896 7150 or http://www.grantronics.com.au A NEW RANGE of European kits made by SMART KIT now available in Australia at www.q-mex.com.au www.siliconchip.com.au WEATHER STATIONS: Windspeed & direction, inside temperature, outside temperature & windchill. Records highs & lows with time and date as they occur. Optional rainfall and PC interface. Used by Government Departments, farmers, pilots, and weather enthusiasts. Other models with barometric pressure, humidity, dew point, solar radiation, UV, leaf wetness, etc. Just phone, fax or write for our FREE catalogue and price list. Solar Flair/Ecowatch phone: (03) 5968 4863; fax: (03) 5968 5810, PO Box 18, Emerald, Vic., 3782. ACN 006 399 480. Audio, Video, S-Video and VGA cables distribution amps, switchers, adaptors, price lists at: www.questronix.com.au CCTV EQUIPMENT: Best prices best-tange Cameras from $34. Digital PC Video Recording Dial In/Out Software & much more. www.allthings.com.au CONTROL ANYTHING BY REMOTE CONTROL. We supply a 14 button remote control unit and a decoder IC for all 14 buttons. You use these active low outputs in your own project. Kit 92 at www.ozitronics.com Contact Frank Crivelli at (03) 9434 3806. $22.00 plus postage and GST. RCS HAS MOVED to 41 Arlewis St, Chester Hill 2162 and is now open, with full production. Tel (02) 9738 0330; Fax 9738 0334. rcsradio<at>cia.com.au; www.cia.com.au/rcsradio PCBs MADE, ONE OR MANY. Low prices, hobbyists welcome. Sesame Elec­tronics (02) 9586 4771. sesame<at>internetezy.com.au; http:// members.tripod.com/~sesame_elec MOTORBIKE ALARM KITS $49.50 + $5.00 P&H. Includes programmed microprocessor, quality sensor, PCB, heatshrink, miscellaneous and tilt switch. Details at: www.users.tpg.com. au/micwen USB KITS: DDS-HF Generator, 4-channel Voltmeter, I/O Relay Card. Also SILICON CHIP www.siliconchip.com.au Subscribe and get a free book* *Offer applies to Aust. only Buy a 12-month subscription to SILICON CHIP and we’ll give you “Electronics Testbench” or “Computer Omnibus” for free. Or you can choose the SILICON CHIP Data Wallchart. www.siliconchip.com.au Satellite TV Reception International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. AV-COMM P/L, 24/9 Powells Rd, Brookvale, NSW 2100. Tel: 02 9939 4377 or 9939 4378. Fax: 9939 4376; www.avcomm.com.au Need prototype PC boards? We have the solutions – we print electronics! Four-day turnaround, less if urgent; Artwork from your own positive or file; Through hole plating; Prompt postal service; 29 years technical experience; Inexpensive; Superb quality. Printed Electronics, 12A Aristoc Rd, Glen Waverley, Vic 3150. Phone: (03) 9545 3722; Fax: (03) 9545 3561 Call Mike Lynch and check us out! We are the best for low cost, small runs. Positions At Jaycar We are often looking for enthusiastic staff for positions in our retail stores and head office at Silverwater in Sydney. A genuine interest in electronics is a necessity. Phone 02 9741 8555 for current vacancies. New New New Mark22-SM Slimline Mini FM R/C Receiver • • • • • 6 Channels 10kHz frequency separation Size: 55 x 23 x 20mm Weight: 25gm Modular Construction Price: $A129.50 with crystal Electronics PO Box 580, Riverwood, NSW 2210. Ph/Fax (02) 9533 3517 email: youngbob<at>silvertone.com.au Website: www.silvertone.com.au Digital Oscilloscope and Temperature Loggers. www.ar.com.au/~softmark KIT ASSEMBLY NEVILLE WALKER KIT ASSEMBLY & REPAIR: • Australia wide service • Small production runs • Specialist “one-off” applications Phone Neville Walker (07) 3857 2752 Email: flashdog<at>optusnet.com.au WANTED HELP! Somewhere in Australia must be the other half of my National FRR-59A receiver. I am looking for the front-end section. Will ship from anywhere in Oz. Melb. (03) 9824 8988 (AH) or morriso<at>vifp.monash.edu.au WANTED: EARLY HIFIs, amplifiers, Speakers, Turntables, Valves, Books; Quad, Leak, Pye, Lowther, Ortofon, SME, Western Electric, Altec, Marantz, McIntosh, Good­m ans, Wharfe­d ale, Tannoy; radio and wireless. Collector/ Hobbyist will pay cash. (07) 5449 1601. johnmurt<at>highprofile.com.au April 2002  95 Silicon Chip Binders Keep your copies safe, secure and always available with SILICON CHIP binders: they’re cheap insurance!  Heavy board covers with 2-tone green vinyl covering Advertising Index AC Eletronics...............................81 REAL VALUE AT Alltac International.......................83 PLUS P &P Allthings Sales & Services...........95 $12.95 Altronics................................. 66-68 Av-Comm Pty Ltd.........................95  Each binder holds up to 14 issues so that you can include catalogs Dick Smith Electronics........... 20-23  SILICON CHIP logo printed in gold-coloured lettering on spine & cover Elan Audio....................................91 Price: $12.95 (includes GST) plus $5.50 p&p each (available Aust. only). Price includes GST. Harbuch Electronics.....................85 eLabtronics..................................85 Grantronics..................................94 Hy-Q International........................83 Order by phoning (02) 9979 5644 & quoting your credit card number; or fax the details to (02) 9979 6503; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. Instant PCBs................................95 Jaycar .......................................IFC JED Microprocessors..............47,83 Microgram Computers...................3 MicroZed Computers...................83 Subscribe & Get this FREE!* Oatley Electronics........................77 Ozitronics.....................................95 Printed Electronics...................... 95 Polykom................................ 4-6,11 *Australia only. Offer valid only while stocks last. Quest Electronics.........................83 THAT’S RIGHT – buy a 1- or 2-year subscription to SILICON CHIP magazine and we’ll mail you a free copy of “Computer Omnibus”. RCS Radio...................................95 RF Probes....................................83 RTN..............................................63 Subscribe now by using the handy order form in this issue or call (02) 9979 5644, 8.30-5.30 Mon-Fri with your credit card details. Silicon Chip Binders.....................96 Silicon Chip Bookshop........... 86-87 SC Computer Omnibus................96 NOW AVAILABLE FROM SILICON CHIP SC EFI Tech Special................OBC SC Electronics Testbench..........IBC Silicon Chip Subscriptions...........24 www.siliconchip.com.au Silicon Chip Order Form..............69 Project Reprints Limited Back Issues Limited One-Shots Silvertone Electronics..................95 If you’re looking for a project from ELECTRONICS AUSTRALIA, you’ll find it at SILICON CHIP! We can now offer reprints of all projects which have appeared in Electronics Australia, EAT, Electronics Today, ETI or Radio, TV & Hobbies. First search the EA website indexes for the project you want and then call, fax or email us with the details and your credit card details. Reprint cost is $8.80 per article (ie, 2-part projects cost $17.60). SILICON CHIP subscribers receive a 10% discount. We also have limited numbers of EA back issues and special publications. Call for details! Wiltronics.................17,33,43,65,83 _________________________________ visit www.siliconchip.com.au or www.electronicsaustralia.com.au 96  Silicon Chip Solar Flair/Ecowatch....................95 VAF Research.........................13,83 PC Boards Printed circuit boards for SILICON CHIP projects are made by: RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. www.siliconchip.com.au www.siliconchip.com.au April 2002  97