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Bonus 180-page Jaycar Catalog*~~EJ· $3.95 MARCH 1993 NZ $5.50 ~s\L SERVICING - VINTAGE RADIO - COMPUTERS - AMATEUR RADIO - PROJECTS TO BUILD ◄ SOLAR CHARGER FOR 12V BATTERIES LOW-COST AUDIO MIXER FOR CAMCORDERS ALARM-TRIGGERED SECURITY CAMERA T •· FLUKE PHILIPS ,~ r i Fluke and Philips handheld tools ,. so advanced they're simple to use A host of user-friendly features Many special features make the Fluke OM Ms and Philips ScopeMeter \ more convenient and easier to use. The display screens are easy to read. Touch Hold(!) on the Fluke 70 and 80 series freezes the display on, stable readings - so you can use f both hands to take a measurement. The Fluke 10 series features a time 'saving v chek'". a Fluke innovation . •• t. impressive range of measurement capabilities for the 'price. All series teature auto and manual ranging. In short, these user-friendly tools make taking measurements a great deal easier tor the on site technician. The Philips 90 Series ScopeMeter The Fluk Multimeter Series How pwch meter can you get into a multimeter? The Fluke series ot versatile multimeters blend state-of-the-art .,__: /,J ~,,.,..-...,: .· ·r."'~- ,; -~~ 2:~: "'_ _.... THE UN-BREAKTHROUGH ~-THAT WILL HAVE YOU SMILING FROM VOLTS TO OHMS J Fluke and Philips present the StopeMeter. Plus a ·-..i.JP,'1.911 .~ange of Digital Multimeters I l)ES\GNED··~ illl USER SAFITT IN MltfD. . . ·mary consideration t user safety ,s a pn A safe investment Fluke and meone whO owns a ·t As so Th ,\\ tell you tnat even , - Philips ~eter. II ey er\oad it or hOOk it up , you acc1denta Yov d n it \ ou can depen o . f ~ wrong, Y d Philips meters of, er · Fluke an . excellent overload protection. .nc\ude further safety featur~sf\a1mmab\e · ks non-in . recessed input 1acd , with shrouded cases, test \ea s ds ·~ onnectors and Mge~ guar_, . . "' t k ~ ·~· ✓ .r• ~ .¥; ' HOW TO BEAT · THE HIGH COST OF CHEAP METERS ., Ooops! . A tool isn't very useful if it won't .w1t~stand the hazards of everyday use. h y putting them through some of i t e .toughest simulated acc idents imaginable, Fluke and Ph·1· 1 1ps meters . are as tough as they are affordable Tough enough to work where~er you work, they offer a long battery l1'e "· . And to make sure your modest vestment in a meter i·s ll d FI we procte ' uke and Philips build th o last : inside and out • with rugg:J1 otect1ve casings and , sign. error-proof The result? A wide eh . f • tOugh h ·g.1i 01ce o ; , performance diagnostic too 1s ,or the •. tnc,an on the go . .. ,;; - For further information please contact your local Philips Test & Measurement Organisation: NSW (02) 888 8222 VIC (03) 881 3666 WA (09) 277 4822 QLD (07) 240 3700 SA (08) 384 2888 NZ (09) 849 4160 You'll measure better performance le PHILIPS 7 1 /4-) ;-w_, 1~/2' /21Ii j ! -...11111 · 1 [ " 1I/7 /;/I -.J I a / /I a.. I I 1" I 1 I I 1 / ..A. -~ / I A Vo/.6, No.3; March 1993. KEEP THAT 12V battery topped up with this solar cell charger & matching voltage regulator. It's ideal for use on camping trips & in boats, tractors & electric fences. Details page 20. FEATURES 4 Sanyo's Big Screen Video Projector by Leo Simpson Combine it with surround sound for true home theatre 16 Sony's New VGP-G700 Colour Video Printer by Leo Simpson Prints colour snapshots from videotapes & off-air signals PROJECTS TO BUILD 20 Build A Solar Charger For 12V Batteries by Branco Justic Ideal for boats, tractors & electric fences 32 An Alarm-Triggered Security Camera by Tony Nixon It captures the thief on film using a low-cost camera 50 Low-Cost Audio Mixer For Camcorders by Darren Yates HIT BACK AT THIEVES with this alarm triggered security camera. It automatically captures a thief on film using a low-cost motordrive camera. See page 32. Lets you add background music to your home videos 57 Test Yourself On The Reaction Trainer by John Clarke Use it for fun & to improve eye-to-hand coordination 74 A 24-Hour Sidereal Clock For Astronomers by Bob Flynn Chose between two versions - one digital, the other analog SPECIAL COLUMNS 42 Serviceman's Log by the TV Serviceman The search for the missing link 81 Amateur Radio by Garry Cratt THIS 2-CHANNEL audio mixer uses one common IC & can be built in a couple of hours. Use it to jazz up your home videos by mixing in some background music. Turn to page 50. A general-coverage shortwave receiver from England 84 Vintage Radio by John Hill Paper capacitors cause lots of trouble DEPARTMENTS 2 11 24 66 88 Publisher's Letter Mailbag Circuit Notebook Product Showcase Back Issues 90 Ask Silicon Chip 92 Notes & Errata 93 Order Form 94 Market Centre 96 Advertising Index THIS SIDEREAL CLOCK has a 4-digit liquid crystal display & can be run from batteries or mains power. Alternatively, you can build the analog version. See page 74. MARCH 1993 1 Publisher & Editor-in-Chief Leo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) PUBLISHER'S LETTER Technical Staff John Clarke, B.E.(Elec.) Robert Flynn Darren Yates, B.Sc. Reader Services Ann Jenkinson Sharon Macdonald Sales & Marketing Mgr. Sharon Lightner Phone (02) 979 5644 Mobile phone (018) 28 5532 Regular Contributors Brendan Akhurst Garry Cratt, VK2YBX Marque Crozman, VK2:ZLZ John Hill Jim Lawler, MTETIA Bryan Maher, M.E., B.Sc. Jim Yalden, VK2YGY Bob Young Photography Stuart Bryce Editorial Advisory Panel Philip Watson, MIREE, VK2ZPW Norman Marks Steve Payor, B.Sc., B.E. SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. A.C.N. 003 205 490. All material copyright©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Magazine Printers Pty Ltd, Alexandria, NSW; Macquarie Print, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $42 per year in Australia. For overseas rates, see the subscription page in this issue. Liability: Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. Editorial & advertising offices: Unit 1a/77-79 Bassett Street, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 979 5644. Fax (02) 979 6503. ISSN 1030-2662 2 SILICON CHIP Computer monitor reliability leaves a lot to he desired Over the last 20 years or so, the reliability of consumer electronics appliances has become almost legendary. As a result, many TV servicemen have either retired or gone out of business. But there is one area where the overall reliability leaves a great deal to be desired and this is in regard to video monitors for personal computers. While you would think that the enormous complexity of the new motherboards or hard disc drives would make them suspect, it is the computer monitor which, more often than not, is the first item to fail. This is despite the fact that computer monitors are much simpler than the average colour TV set and the · deflection circuitry is probably not working as hard. Yet computer monitors fail often, usually in the power supply or deflection circuitry- actually there is not much else to fail. This is not a new phenomenon by any means and in the days when monochrome monitors were standard, it was usually cheaper and much more convenient to buy a new monitor than to repair a failed unit. These days though, VGA and large screen monitors cannot be simply discarded when they fail;. they must be repaired. When that time arrives, be prepared for a large bill. Many authorised service centres only do board exchange and the cost can range from a few hundred dollars to six hundred or more. Even though the fault may be relatively simple to fix, the companies concerned often have a deliberate policy of doing board-level repairs only and the consumer really does pay through the nose. In one very well-known brand, a resistor in the starting circuit of a monitor's switchmode power supply regularly fails. The obvious and easy cure is to replace that resistor with one of a higher rating and yet the company concerned has never made any move to change it. In effect, you pay over $200 for a burnt out five-cent resistor. The situation is made even more difficult because computer monitors are not supplied with a circuit diagram and they always use Japanese or Asian parts which are often difficult to_obtain. Nor will most importers even deign to sell a service manual or circuit diagram. And if the company concerned goes out of business you are really on your own. It would be easy to conclude that there is a certain amount of unfair trading going on in this field. That means that consumers should try to at least obtain a circuit and preferably a service manual when they purchase their monitor. I say that, knowing just how difficult it is in practice. It also leaves the way open for importers to establish a more enlightened policy on this often unhappy aspect of computing - their customers will love them for it. Leo Simpson SODIUM VAPOUR LAMPS <at>s EL-CHEA PO LASER l9n Brand new 140W low pressure sodium vapour low pressu re lamps. Overall ler,ghl 520 mm, 65mm diam. , G.E.C. type SO1/1-1. We supply data for a very simHar lamp (135W). LIMITED QUANTITY. PULSE COUNT PASSIVE INFRARED MOVEMENT DETECTOR $25 Ea. (Ref: XXFEB93103) SOLAR LIGHTNING BARGAIN (E.A. NOV. 92) This kit has three separate sectio ns that are contained on one PCB , but can be separated: (1) A crystal locked ultrasonic movement detector, (2) A fluorescent tube inverter (4·20W) with logic circuitry, (3) A solar battery charging regulator, and an incalescent lamp switcher - pulser, which employs a mosfet switch , as a package special we are offering the complete kit for the three sections plus six 6V/1 W so lar panels for a total Probably the cheapest visible red Helium Neon laser and power supply every offered. ANYWHERE' The kit includes a PCB , transformer, and all the components needed to make a 12V operated laser power supply. The PCB -and all t he onboard assembly is the same as the one used in our EHT GENERATOR (11 also now comes with a PCB) , but a f(IN extra necessary components and corresponding instructions are providedwlth the kit. INCREDIBLE VALUE AT: $50 For the 12V inverter kit and a visible red Laser Tube . cost at: ONLY $99! (REF: XXFEB93104) SOLAR PANEL GIVEAWAY Brand new 6 volt 1 watt amorphous solar panels . Two of these in se ries make a great 12V battery maintainer/ charger. Incredible pricing. $10ea for 10 for $85. Item No. 0130 IR FILTER LARGE LENSES ~ This high quality Australian made PIR FEATURE S TRUE PULSE COUNT CIRCUITRY: Digital circuitry that actually counts the number of pulses, not just an R-C time constant. The pulse co unt is even registered by a separate green LED, and the number of pulses desired is se1 by a DIP swnch: 1·6 pulses. Both the green LED (PULSE), and the red LED (DETECT) can be switched off after testing: Switched by the dip switch. 12M range with the standard 90 deg. wide angle lens supplied, or 20M range with an optional narrow angle corridor lens. SPECIAL INTROOUCTORY PRICE : $46 ACTIVE AND PASSIVE NIGHT VISION Two pairs of these new lenses were originally used to make .up one large lens, for use in IBM equipment. Made in Japan by TOMINON. Both lenses are precision ground, have an anti reflective coating, and are not frequency se lective. The larger of the two lenses has a diameter of 80mm and weighs 0.5kg. Experimenters delight at only :. A high quality military grade deep infra red (IR) filter. Used to filter the IA spectrum from medium and high power incandescent spotlights and flood lights. It's glass base makes it capable of withstanding high temperatures. Approx. 130m · diameter and 6mm thick. Can be used in conjunction infra red night viewers and IR responsive CCD cameras: Many colour video cameras and most monochrome video cameras have good IR response: Check by viewing the LED's in an TV or VCR infra red remote control. Excellent tor night surveillance equipment! At a FRACTION OF THEIR REAL PRICE. ON SPECIAL AT ONLY: $45 MYSTERY LASER Includes 1 12VMK3 universal power supply kit, plus a used laser tube with a power rating in the 1-3mW range. A laser tube and a power supply for a little more than the price of the inverter only: $89 (Item No. 0110 ) VU METERS Twin (STEREO) VU meters. calibrated from -20 to +3 dB's, and also have a 0-100% modulation scale. The meter movements are very easy to remove for rescallng . overall lace dimensions 81 x 41, 26mmdeep. $3 Ea. or four fo r $1 O ELECTRIC FENCE KIT Coming soon is our easy to construct electric fence kit. It features very low power consumption, a so lar charging/regulating and indicating circuit, and it can be easily solar powered . The PCB (Screened and solder masked) and all components kit will cost under $50 We have available a limited number of complete electronic assemblies that we re originally used in 300Watt and 600Watt UPS's: Some of these may be faulty! Acircuit and any necessary modification instructions will be provided with each unit. consist of a PCB that contains all the necessary transformers and eledronic circuitry, which is screwed to a heat sink to make one complete module which is easy to separate and service. The compact size is made possible by the use modern techniques in the inverter section: A high lrequency inverter that uses a compact high power ferrite core transformer, which is followed by a switching sine wave coriverte r and a lo w pass fi lter. The assembly contains a battery charging circuit tor a 24 V bariery (Uses a small mains transformer), mains failure detection, and a 24V DC to 240V AC (S0HZ) sine wave inverter circuitry. The original UPS's used two 12V 6 .. SAHr batteries conneded in series'. Inexpensive and common locally available devices are used throughout: LM324's , 400106's, TL494, 7815, LM317, etc. The power switching devices used in the inverter, and the sine wave converter are MOSFETS (T0220 package): IRF540 and IRF830 respectively . The giveaway price for the complete module? $30 We also have available some complete but possibly faulty UPS's that use these modules . $60 Ea. or $100 with both the batteries fitted. $15 for the pair. Alternatively the complete lens assembly that contains two pairs of these lenses (F:4.S·focal length 230mm) in an aluminium frame, can be purchased for $30: DWficult to pull apart! Total weight 1.7kg, 93mm diameter by 106mm · long. UNINTERRUPTIBLE POWER SUPPLY (UPS) We have previousty sold out at these hard to obtain components, but at the time of publication we should have available a good supply of some matching Infra Red night vision components: Lens, image converter tune, eyepiece and a power supply. These components are suitable tor constructing complete Infra Red night viewer, and the price of the sets will start from under $200. We should also have available some fibre optically coupled, second generation image intensifier tubes , with built in power supplies: Operate of a 3V battery. To make a complete scope which will respond in as little as starlight illumination, all that Is needed Is a 3V battery , a switch a low light lens, and an eyepiece. The tubes are used (Ex-milnary) , and may have some minor blemishes . but all produce full gain. Priced at a small fraction of the real value at: PASSIVE NIGHT VIEWER NEW 12 CHANNEL UHF REMOTE CONTROL $89 (Item No. 011 t) We can also supp ly a sim ila r kit which inc lud es a laser diode, unmounted lens, and a driver kit. $200 $45 MONOCULAR VIEWER (Item No. 0111X) Note that a suitable receiver for use in perimeter protection is the one published in E.A. April 81 . . al ":. ... •· :;,,,,•..~0.-;.. A very small but complete IR tele- sco pe which only needs an EHT power supply. which is provided in kit form. MARINE SEARCHLIGHTS $279 Item No. 012 1A Includes a "Free" 75mm IR lilter. VULTURE CAR ALARM E.A. Nov 89. Best value car alarm kit!! Fully adjustable voltage drop and vib.ration sensor on board , instant and delay inputs, flashing light output. alarm me mory, battery back up provision. provision for U. H.F. remote control, etc. INCREDIBLE VALUE at PRICE OF ONLY: $29.90 $299 4 This precision co llimator assembly was removed from working lase r printers and II is suppli ed with an extra brand new laser diode to suit. A produces a well collimated laser beam at 780nM/SmW. Barely visible. We also supply a PCB and components kit plus instructions, for a suitable digital driver circuit that can be used to complete the laser transmitter. Suitable for communications. data llnKs, perimeter protection. barcode reading, medical use, etc . Co ming soon is ou r new 12 channel UHF remote control c hann el that is easily expar,dable to 16 channels. The syste m features a SAW reso nator locked transmitter, preatigned and assembled receiver "front end" which solders onto the main receiver PCB, and a very compact 2 channel relay driver PCB which can be used in multiples: Up to eight units. As a price indicator, we will be offe ring a package deal consisting of 2 transmitter kits, plus one rece iver kit, plus th r~e re lay driver kits, for a total cost of a CLEARANCE The firs! generation (XX1080) passive IR night viev,ier tube features excellent gain, and when used with a very low tight objective tens, it can produce useful images under almost as little as submoon!ight illumination. Cal also be IA assisted. We will supply a XX1080 lube, plu s a sui table Lens , plus a kit of pans for an EHT power supply (PCB and components only) lor a total price of IR LASERS For the complete P .C.B. and components kit: Whilst stocks last. ..(Cat No. GKt 24 ) LASER POINT~R > High quality pen sizea SmW laser diode pointer for teachers, doctors, etc. On Special $199 Item No. 0101 These new 0.5 metre diameter military grade search lights were made by LUCAS in the U.K. Th ey are pa inted grey and are almost totally made of brass, except for a few stain less steel screws and nuts, a mirrored glass parabolic reflector. and a glass cover plate, They have a detachable mounting pillar which brings the total height of the searchlight and the stand to approximately 2 meters. Fully adjustable positioning and focussing. Supplied with a 1000W/240V quartz halogen lamp (T1 1): 23,000 lumens. A very impressive uniqu e, product with many appl ications . Approximate weight of pillar and Spotlight is 60KG. $1100 (Ref:XXFEB931 0t) The $6 P+P charge doesn't apply to this one II "'Ring"' OATLEY ELECTRONICS $500-$700 PO Box 89 , Oatley NSW 2223 VISIBLE LASER DIODE KIT Telephone : (02) 579 4985 Fax : (02 ) 570 79 10 Brand new 5mW-670nM lase r diode, plus a collimating lens, plus driver kit, plus, hardware, plus instructions. MELBOURNE AG ENT : TRU SCOTTS (031 723 3860 MAJOR CAR DS ACC EPTED WITH PHONE · FAX ORDERS . P+P $89 FOR MOST MIXED ORDERS : AUSTRALIA $6 . N.Z (Ai r Mall ): $ 10 Item No. 0164 Sanyo's big screen video projector + Yamaha's surround sound system= 4 S ILICON CHI P This photo shows the dramatic sweep of the picture available from the Sanyo liquid crystal video projector. For best results, the room should be completely darkened. Would you like to bring the large screen & big sound of a cinema into your home? Now you can, as we found when we reviewed the combination of Sanyo's PLC-200PP liquid crystal video projector and Yamaha's RX-V1050 stereo receiver with Dolby Pro-Logic surround sound. By LEO SIMPSON No matter how much you may enjoy movies and documentaries on your TV set at home, their impact is but a pale shadow of what you see when you visit your local cinema. Big screen and big sound is what you get at the cinema and these are sadly lacking when you watch the same programs at home. Even if you have one of the later model TV sets with screen sizes up to 80cm diagonal, they are still small relative to what you see in a cinema. And while you may have quite a respectable sound system, it is out of place with a small screen. The only remedy has been to obtain a video projection system but these have been large, unwieldy and expensive. Up until about 12 months ago, video projectors have all been based on three high power CRTs which produce separate red, blue and green beams which must be carefully converged and focused onto a fixed screen. Now there is a new type of video projector with 'just a single lens system. It is simple to set up, takes only a moment to focus and can be zoomed up or down to give the picture size you want. Th ere are no bulky CRTs (cathode ray tubes). How do you produce a full colour video picture if you do not employ one or three CRTs? The answer is to use a completely new technology based on liquid crystal panels. But these panels are far removed from the everyday liquid crystal displays used in watches, digital M A RCH 1993 5 This photo of the projector shows the flip-up lid which conceals the controls, although all functions can also be accessed by the remote control. The real magic is in the liquid crystal panels concealed inside the chassis. multimeters and a host of consumer appliances. Most LCDs are reflective but some are backlit so that they can be seen at night. The liquid crystal devices used in the Sanyo video projector are transmissive which means that they work in a similar way to a backlit LCD but that is where the -comparison ends. The diagram of Fig. l shows the general principle used. Inside the projector is a 160 watt metal halide discharge lamp which is the sole light source for the projector. It is fitted with a dichroic reflector and its light output is directed through filters which remove ultraviolet and infrared (heat). The focused beam then passes through a dichroic mirror (DMl) which splits off (reflects) the red light while allowing green and blue light to pass through. The green and blue light is then split in another dichroic mirror (DMZ) so that now we have three separate beams. Each of the three beams is passed through a liquid crystal panel which has 110,450 pixels (picture elements) and these individual picture elements modulate the beam to make up the picture. The modulated red, green and blue beams are then combined into a single beam by two further dichroic mirrors (DM3 and DM4) and then passed through the 67mm zoom lens system to project onto the screen. The above description is highly sim6 SILICON CHIP plified and encompasses new technology which is breathtaking in its scope. Just think of it: hundreds of thousands of liquid crystal picture elem ents being turned on and off with refresh rates of 25 or 30Hz. Moreover, the pixels are being constantly modulated so that they can provide a contrast range of 100:1. In essence, it is a completely new technology for projecting a moving colour image onto a screen and it has arrived at this advanced stage of development with almost no fanfare at all. Projector features Sanyo's PLC-200PP can be used in virtually any room and can produce a picture which ranges from 63cm diagonal to 7.6 metres diagonal. The smallest projection distance it will allow is 2.3 metres from the lens to the screen and since the zoom range is 2:1 the picture size can range from 63q:n to 114cm diagonal. !Ii a larger room, where the projection distance might be say, 6 metres, the maximum · picture size would be 3.4 metres diagonal. That might not seem all that big until you realise that the picture would be about 2. 7 m etres wide and 2 metres high. That's about as big as would be practical in most homes, given the standard ceiling height of 2.4 metres. If you want a larger image, you will need a much larger room and then you tend to run out of brightness. Even with smaller pictures, the most impact is obtained with the room in complete darkness - the same as in a cinema. Setting the unit up is dead simple and you don't even need a screen - a blank wall is ideal and it doesn't even have to be white; a pastel colour will do. You can use any PAL, SECAM or NTSC video source and that includes TV tuners, camcorders, VCRs and laser disc players. All you do is set the projector up on a table or bench square to the wall and turn it on. The lamp takes 30 seconds to come up to full brilliance and during this time it projects a blue image with the message "A MOMENT/UN MOMENTO" together with a countdown in seconds to zero. After that, the video signal can be seen on screen. The projector has adjustable feet at the front and a click-out foot at the back so that it can be set up to project down or up by 5°. With any normal projector, whether film or video, this leads to an image which is trapezoidal rather than rectangular. However, the Sanyo projector has electronic "keystone" correction so that the image can be "squared up " simply by pushing a recessed button on the remote control. By the way, pushing any button on the remote control or the equivalent button on the projector brings up a message on the screen. For example, pushing one of the Focus buttons on the remote control brings up "FOCUS" on the screen and you can then precisely focus on that text. Similarly, pushing one of the Zoom buttons brings up "ZOOM" on the screen and you can then adjust the picture to size as required. Each onscreen message disappears after eight seconds. Remote control features While all of the features of the projector can be operated by buttons which are-underneath a flip-up cover on the machine, it is far more convenient to use the remote control. This can be used as a conventional infrared remote control or as a wired remote with a cable. While the wired remote is tethered to the machine, you don't have to worry about aiming it in the general direction of the unit. Since the Sanyo video projector performs best in completely darkened Sanyo's top of the range VHR-290 hifi stereo video recorder is an ideal program source for the video projector. It is a very fast machine which means that you don't spend any time waiting for it to put the picture on the screen. rooms, it follows that a normal remote control is pretty useless because you can't see the buttons. Sanyo has recognised this by providing a remote where all the buttons light up. Just press the "Light Up" bar on the remote and all the buttons light up for a period of five seconds. Also on the remote control are buttons to turn the projector on and off, select the video source, select the video standard (auto, PAL, SECAM, NTSC, adjust the sound level, mute the sound, picture adjust (contrast, sharpness, brightness, tint and colour saturation), normalisation (restores picture and sound to standard settings) and expand. This last button allows the central portion of the image to be blown up to twice size which may be useful in some circumstances. All your settings are stored in memory, so there is no need to go through the set-up procedure each time you turn on the projector unless, of course, you have moved it to a different position. There is also an S-video socket and a 21-pin SCART socket. The projector has an internal speaker and 3 watt amplifier (mono sound) and the remote control can be used to adjust the sound, as noted above. Interestingly, the remote control has no effect on the sound level if an external amplifier and loudspeakers are used. Styling of the unit is definitely low key. While it is robustly built inside, as it needs to be to maintain all those mirrors and liquid crystal panels in alignment, its outer plastic case is Picture reversal One feature which is not available on the remote control but accessible on the projector itself is picture reversal. This allows the machine to be used in a rear projection set up. On the rear of the projector are a number of sockets for video and audio connections. There are three RCA sockets for video plus audio left and right inputs and a further two RCA sockets for audio left and right connections to an external amplifier. The rear of the video projector has sockets for audio & video connections, including S-video. The unit also has an internal loudspeaker but using external amplifiers & speakers gives a much better result. very subdued, finished in matt grey. In fact, it looks a lot smaller than its overall dimensions suggest. It measures 572mm from the lens cap to the rear, 268mm wide and 253mm high. It is also fairly heavy at 13kg but it is quite comfortable to carry. Lamp life Metal halide lamps do not last as long as CRTs but they are much longer lived than conventional slide or movie projector lamps. Sanyo recommends lamp replacement at 2000 hours and there is a LED which comes on when this time has been reached. Picture quality Ah, now this is where we come to the nub of the matter. In the past, it has been accepted, by most people who bothered to think about the subject, that for optimum picture presentation, you should sit far away enough from your TV set so that the line structure is not readily apparent. Clearly, a lot of people don't bother with this and sit quite close to their TV sets. With the very large picture presented by the Sanyo projector, the line structure is clearly apparent. And depending on how close you are to the screen and how keen your sight is, the individual pixels of the image can also be seen. Nor.is the picture quality really anything to write home about, if you are judging it on a purely objective basis. As you can imagine, if you blow up a standard PAL picture by many times, the limited video bandwidth is readily apparent in the relatively soft focus. It is certainly not high definition TV and it is a long way short of the best 35mm film images. On the other MARCH 1993 7 Sanyo's flicker free video - how it works There are many aspects of Sanyo's PLC-200PP video projector which beggar the imagination. For example, most people who have any knowledge of liquid crystal displays know that are they digital in nature, either fully on or fully off. But Sanyo's 110,450 pixel liquid crystal panels produce the full range of colours expected from a standard colour TV set and with a contrast range (bright to dark) of 100:1. Just how does Sanyo manage that? And the projector copes with any standard video source whether it is PAL, NTSC or SECAM (or S-video). The normal method of doing a full video standards conversion would be to incorporate a "frame store". This would also enable the field rate to be doubled (to 10OHz) and thus avoid flicker which is otherwise very troublesome on large screen sets. But the Sanyo projector does not have a field store for standards conversion and nor does it double the vertical scan rate . And yet, that large and dramatic screen is completely free of flicker, in spite of being scanned at the normal 50Hz rate for PAL sources. Let's consider how the liquid crystal panels are driven first. Each of the pixels is controlled by its own thin film transistor (TFT) which is on the pixel itself (ie, the light passes through it. Each TFT is essentially a Mosfet which naturally has a fairly substantial gate capacitance and this provides a sample-and-hold facility. The gate of each TFT is supplied with a sample of the video signal and this signal is analog which means that the transistor does not have to be either on or off, it can also be anywhere in between and hence the "twisted nematic" fluid of the pixel can be anywhere between fully transmissive and opaque. hand, in view of the poorly fo cused images you see in man y cinemas, th e Sanyo projector stands up pretty well by comparison. So on a purely objective assessment, concerned with line and pixel structure and video bandwid th, the picture quality is pretty ordinary. However, that is not the end of the matter by a long shot. The strong point of the Sanyo video projector is that it produces such a large and bright picture and furth ermore, it is completely fli cker-free. The simple fac t is that, after watching that dramatically' large picture for a few minutes, line and pixel structure becomes unimportant. You become so engrossed in the program that you just don 't notice the line structure. 8 SILICO N CHJ P Sample & hold But why doesn't the picture flicker? The answer is because of that "sample and hold" facility on the gate of each TFT. In a normal television picture tube, the image is created line by line, with the electron beam scanning rapidly over the picture tube. In the 625-line PAL system, the image is scanned at 50Hz, alternating between odd and even lines which build up a complete frame in 1125th of a second. After the electron beam has passed over a particular spot on the tube, the phosphors will continue to emit light for a brief period of time but the system also depends on persistence of vision so that we see a constant image on the screen. However, while the screen may be Sound quality Sound quality is a most important factor. While the Sanyo projector does have an inbuilt speaker, its mono output quality is no more than could be expected and it also has to compete with the noise of the internal cooling fans. To do justice to the system , you need good quality stereo sound at the very least. That means that any video source you are using shoul d provide stereo sound. For the purpose of our review, we used a Sanyo VHR 290 video recorder with hifi stereo sound. This VCR is the flagship of Sanyo's range and has scanned at 50Hz (the field rate), the complete image is updated at 25Hz and this leads to residual flicker which can be very noticeable on bright parts , of the screen. In the Sanyo projector, the pixels are split between odd and even lines and they build up the picture in the same way as in a cathode ray tube. The difference is that whereas the image from a picture tube depends on phosphor spots which are excited very briefly every 1125th of a second, each pixel TFT is fed a sample of video signal every 1125th of a second and its stays turned on to that value until it receives the next video sample. Thus, most of the pixels of the screen stay on all the time, constantly transmitting light at whatever the required value is and only changing if the signal changes. This means that there is no apparent flicker in the picture at all. Standards conversion So how does Sanyo manage video standards conversion without resorting to a frame store? In essence, the projector is designed to the American NTSC standard as far as line scan rate is concerned. This means that the picture is essentially 525 lines with a field rate of 60Hz for just about every feature you could want. If you want a first class video signal with stereo sound, whether "off air" via its inbuilt tuner or from tape, it is the ideal source to team with the Sanyo PLC-200PP video projector. With the program source catered for, we still had the problem of the amplifier and loudspeaker system. To do the Sanyo projector full justice, you really should settle for nothing less than a system which can produce full surround sound. To obtain that from pre-recorded video tapes , that means you need an amplifier system which has Dolby's Pro-Logic decoder. Anything less is just short-changing the system . Sanyo do not have a surround sound Red panel Projection lens Dichroic reflector LCD panel Condenser lens Fig.1: the Sanyo projector uses four dichroic mirrors to first split the light beam from the metal halide lamp & then to recombine the red,• green & blue beams after they have been modulated by the liquid crystal panels. Ultraviolet filter NTSC program material and 50Hz for PAL material. To convert 625-line PAL pictures to 525 lines, the projector could do it by simply omitting one line in every six but this wou ld lead to jagged diagonal lines on the screen . Instead, the conversion is done by means of a "line store" (much simpler than a frame store) and a complex averaging scheme is used. For example, the first PAL line becomes the first NTSC line. The second NTSC line is a combination of 4/5ths of the 2nd PAL line and 115th of the 3rd PAL line. The third NTSC line becomes 3/5ths of the 3rd PAL line and 2/5ths of the 4th PAL line. The 4th PAL line becomes 2/5ths of the 4th PAL line and 3/5ths of the 5th PAL line. Finally, the 5th NTSC line becomes 115th of the 5th PAL and 4/5ths of the 6th PAL line. The process then repeats. Get the picture? When you thin k about it, while the Sanyo projector does not use a frame store to do the standards conversion , the LCD panels themselves are effectively a frame store. After all , they hold the video signal constant between each update, which happens every 1125th of a second. amplifier so we turned tOYamaha and arranged for the loan of their RXV1050 AM/FM stereo A/V receiver. If ever a product was made to complement the Sanyo projector, this Yamaha stereo receiver is it. It not only incorporates Dolby Pro-Logic decoding but also has has digital sound fi eld processing, as pion eered in the Yamaha DSP-1 a few years ago. With five amplifie r ch annels to drive front , rear and middle speakers, the DSP system can imitate the reverberation times of large and small concert halls. Not only that but the RXV1050 is also designed to switch video program sources so that it can handle video and audio signals from three sources; it even has S-video inputs. This makes it ideal as the program selector for the Sanyo projector. We set u p the San yo projector and Yam aha surround sound amplifi er combination with Dynaudio Image 4s as the main lou dspeakers (to be reviewed in a future issue), together with Yamaha NS-A102s as the rear speakers an d a Yamaha NS-Cl 10 as the centre effect speaker. Also hooked into the system was a Yamaha CD player. All of this equipment was set up in the reviewer's home, in a room measuring about 4.8 x 3.6 metres. This room is normally used as a music listening room and so is ideal fo r a "h ome cinema" . Th e final essential ingredients were a number of video Dichroic mirrors As Fig .1 shows, the Sanyo projector uses four dichroic mirrors to first split the light beam from the metal halide lamp and then to recombine the red, green and blue beams after they have been modulated by the liquid crystal panels. However, some readers may wonder why the lamp reflector is also labelled as being dichroic. How and why should a simple lamp reflector be dichroic? Should it not reflect all light equally well? The answer is that a dichroic mirror reflects some light and passes through the remainder. In the case of the lamp reflector, it reflects all light up into the ultraviolet range but most of the infrared (ie, heat) passes through it. This needs to be the case because the liquid crystal panels cannot stand very much heat. That is why there are also UV and infrared filters in front of the lamp. In fact , the liquid crystal panels can only withstand a maximum temperature of 80°C. Contrast that with the bulb temperature of the metal halide lamp which normally runs at 1000°C. No wander the projector has two fans to keep the interior cool. tapes of current action movies with lots of special effects and featuring Dolby Surround Sound. Audio/video integration With all of these factors brought together, the system really comes to life and is capable of providing an entertainment experience every bit as dram atic as that experienced in any picture theatre. The large screen is good, for all the reasons we have listed above, but it really needs a full range surround sound system for maximum impact. Once you sat down in the darkened room and pressed the play button on the VCR remote control to start the program you were then immersed in a MARCH 1993 9 Yamaha's RX-V1050 stereo receiver offers full Dolby Pro-Logic decoding & DSP to give a variety of surround sound environments. It has five amplifiers with a total power output of 390 watts into 8 ohms. It also has 40 preset AM/ FM stations & a comprehensive remote control with "learning" facilities. complete cinema experience. The larger than life-size images combined with spectacular surround sound make it all happen. Switching on the lights at the end of the program is just like emerging from a theatre and coming back to everyday reality - it's that good. In fact, with this combination of the Sanyo video projector and the YamahaRX-V1050 stereo receiver, we finally have achieved the "audio/ video integration" that the Japanese manufacturers have been talking about for years. Sound simulation Yamaha's RX-V1050 could be the subject of a complete review just by itself as it has so many features. With Dolby Surround Sound, the dialogue comes from the front speakers (in stereo) while music and sound effects come from the front, rear and centre channels to give dramatic reinforcement to the visual happenings. Yamaha has also added Enhanced Dolby mode which, as the name suggests, beefs up the sound effects. As well, there is Concert Video, Mono Movie, Rock Concert and Concert Hall effects. Concert Video is intended for movie soundtracks with stereo but without Dolby. Mono Movie is good for ordinary VCR tapes with mono sound - it gives a good simulated stereo spread. Rock Concert and Concert Hall are, as the names suggest, mainly intended for listening to music rather than as accompaniment to video but there is 10 SILICON CHIP no reason why they could not be used to provide the sound field for music videos, both rock and classical. And if you want to dispense with any enhancement, you can always listen to your music in unadorned stereo. be written the programmed functions. Naturally, it could be used to control both the Sanyo projector and VCR. Now if we had remote controlled room lighting as well, we would have total bliss! Juggling the remotes Closing thoughts And now to a few practicalities. Ever had the feeling that your remote controls were conspiring against you? They have the habit of hiding underneath the couch, underneath papers on the coffee table or even sliding behind cushions so that you go through enormous frustration when you suddenly need them. Well, home theatre is like that only worse. Each piece of equipment used in the above setup has its own remote control and only the one for the Sanyo projector has buttons which light up. In a darkened room, you then have the added complication of not being able to see which buttons to press, as well as the problem of finding the right remote control in the first place. The remote control for the Yamaha stereo receiver is a partial solution. As well as controlling its own extensive range of features, it can be used to control a Yamaha CD player and cassette deck so that meant I was not forced to use the remote control for my CD player. Still, you can't see the buttons in the dark. Furthermore, the Yamaha receiver's remote control has learning functions so that it can also be programmed to control other appliances. It comes with paper templates on which can So what is the overall picture? In our opinion, the Sanyo video projector will find a ready market both in teaching and training institutions, as well as in the home. In teaching applications, the internal speaker in the projector is adequate although a modest stereo setup with speakers either side of the screen is a big improvement. In the home, you really need to go for the full Sanyo and Yamaha combination. Going for one without the other would be a waste of money and even then, it is a choice which will only be available to the well-off. The recommended retail price of the Sanyo PLC200PP is $7499 while the RRP of the Sanyo-290R hifi stereo VCR is $899.00. The Yamaha RX-V1050 stereo receiver is $1399. To those figures must be added the cost of main and surround sound loudspeakers. For further information on the Sanyo video projector and hifi stereo VCR, contact Sanyo Australia Pty Ltd, PO Box 401 , Homebush, NSW 2140. Phone (02) 763 3822. For further information on the range of Yamaha surround sound equipment, contact Yamaha Music Australia Pty Ltd, 1733 Market Street, South Melbourne Vic 3205. Phone (03) 699 2388. SC MAILBAG More wanted on appliance servicing Many thanks to J. E. of Blackburn (SILICON CHIP, November 1992) for the article "Dirty Heads On Beta VCR" in the Ask Silicon Chip column. I came across a similar problem some weeks ago on an AWA VCR. This machine was plagued with constant flickering picture problems. When I think back, had I spent more time cleaning around the video heads gap area, it may have helped solve the problem quicker. My reason for writing is to encourage more readers to write in with similar questions about faults in radios, TVs, videos and other appliances. This in turn will spark a response from readers who know how to fix the various problems or who can advise on the best approach to tackling the problems. The Serviceman column is excellent and contains lots of good information on servicing. However, that column can only cover cases which come across his and his colleagues' workbenches. My proposal is for contributions from readers and their various mixed bag of electronics problems. R. Pankiv, Sheffield, Tasmania. Howl suppression in PA systems This letter is in answer to the letter from W. P. of Werris Creek, NSW about howl suppression in PA systems. The howl suppression concept does work. I have used one in a PA system and find that the gain of the amplifier can be increased a further 3db. And even with vocals, the pitch shift is not noticeable. So with eagerness I tackled the SILICON CHIP circuit in the June 1991 issue but unfortunately, I could not get it to work. I spent weeks breadboarding the circuit and eventually made a PC board but to no avail. A device that electronically changes the pitch of an audio signal by an unnoticeable 5Hz could be used in megaphones to stop that annoying squealing and to allow an increase in gain. It could also be used in PA systems or with individual microphones to stop feedback. A stereo version could also be used to stop the acoustical feedback with record players when the vibrations are transmitted through the floor to the stylus. Perhaps SILICON CHIP may care to have another go at this very useful concept. S. Pickford, Attdale, WA. Comment: the circuit published in June 1991 does work but is difficult to adjust. That's the reason we didn't publish a PC board for this project. If other readers are interested in this subject, we'll see what we can do. Drawing symbols don't comply with Australian Standards I see that the logic symbols used for circuits in your magazine ·do not comply with current Australian Standards. The relevant Standards were published in 1986 (publication s AS1102.9 , AS1103.8 and SAA HB8) and comply with international standards, ratified by the International Electrotechnical Commission (IEC). They are in use in digital data books from a number of manufacturers, such as Philips (Signetics) and Texas Instruments, and will become more common. The "new" rectangular symbols are generally easier to read and draw, both manually and via CAD, and use a rational approach to symbol construction and notation. For simple devices (eg, AND and OR gates), the symbols are self-explanatory and would have been seen before by most readers. Even relatively complex devices can be interpreted after a little thought and circuit study. I suggest that you publish a series of educational articles to introduce and explain the basic concepts of AS1102.9 symbols and dependency notation to your readers, with the aim of adopting this Australian Standard in your magazine. P. Lonick, Beckenham, WA. SILICON CHIP, PO Box 139, Collaroy Beach 2097. Criticism of PC board tracks Thank you for producing SILICON CHIP. One comment I would like to make is about PC boards. My criticism is demonstrated by the board for the Number Cruncher on page 48 of the December 1992 issue. Here is a fun project but look at the board layout. We have up to five tracks located inside DIL ICs. Being a hobbyist who enjoys making his own PC boards, I cannot handle more than two tracks inside DIL ICs and definitely not tracks between pins. Some of the parallel tracks are also very close. This Number Cruncher looks like fun but I will either have to buy the PC board or redraw it. G. Donaldson, Bonney Hills, NSW Comment: because this project uses a Jot of !Cs and little else, we had no alternative but to run many of the tracks close together to keep the board to a reasonable size. The only other approach would have been to make the board double-sided but that would have greatly increased the cost. Tyre valves recycled as rubber feet I have a useful hint to readers who build a lot of electronic projects and who, like myself, are always looking for rubber feet. Whilst getting some new tyres on my car the other day, I noticed on the surrounding cement floor thousands of items that looked like rubber feet. Closer examination showed them to be valve stern ends, which are snapped off when the valve is to be replaced in the rim on tubeless tyres. These rubber feet are for free. Just get down to a local tyre dealer that does•volume sales in tyres and valves and the feet are there by the thousands. I can guess that I am not going to be popular with suppliers who sell the real thing. But I like to recycle useful throw-away items and the back end of a valve stern is especially useful to project buffs. R. Barham, Cairns, Qld. MARCH 1993 11 lt\-ONE A-ONE A-ONE A-ONE A-ONE ~ A-ONE 1ST BIRTHDAY 0 PDP~~otM~~RSARV S~kr§.RcH ~ ~ r--r.., ~o ~ r7' 20% OFF ALL (UNTIL STOCK SOLD OUT) Cat. # S0207 Cat. Cat. Cat Cat: # S0208 # S0209 # s0210 # S0006 Cat.# S0007 I Cat. # S0008 Cat. # S0009 Cat.# S0311 Cat. # S0312 ~ Cat. #S0314 Cat. # S0315 Cat. # S0316 I < r--r.., ~ ~ 0 Cat. # S0317 Cat.# S0318 Cat. # S0319 ~ ~ Cat. # S0320 Cat. # S0321 Cat. # S0322 ~ Cat. # S0323 ~ Cat.# S0324 ~ Cat. # S0325 ~ ~ •93 o N, v Cat.# S0326 Cat.# S0332 Cat.#S0401 Compact e!ectronic digital switch Mini Timing Switch Mini Electronic Organ FM Wireless Transmitter 0-30V 20A Regulated PSU with ful l protection +/- 9.730v 2.5A Dual Regulated PStJ 0-30V 1OA Regulated PSU 0-50V 6A Regulated PSU with full protection Stereo Tone Control Amplifier Complete Stereo Speaker Protector 125Wx2(320W BTL) MOSFET Amplifier 40Wx2 Low Voltage Amplifier 60Wx2 (200W BT L) Super LOW T IM Amp 120W MOSFET Mono Power Amplifier Stereo All FET Pre-Amp with 5 band SEA EQ 80Wx2 All FET Stereo Main Amplifier 50W Class A Mono Power Amplifer Stereo 10 Band SEA Graphic EQ 2W Stereo Class A Pre-Amplifier 160W Stereo, Class A Complete Amplifier Mixer with Surround Mixing System Stereo 4ch Mixer with 3 band SEA EQ KARAOKE Mixer Pre-Amplifier 50Wx2 (1 50W BTL) Power Amplifier Dual LCD Digital Panel Meter was was was was $15 $15 $1 2 $11 .50 now now now now was $149 now $12.00 $12.00 $9.60 $9.20 $119.20 was $48 was $84 now$38.40 now$67.20 was $89 was $15 now $71.20 now$12.00 was $ 19 now was $199 was $33 SALE $100 BOTH FOR ONLY $358 $15.20 now $159.20 now $26.40 was $87 now $69.60 was $69 now $55.20 was $94 now $75.20 was $124 now $99.50 was $69 now $55.20 was $84 .50 now $67.60 was $54.50 now $43.60 was $119.50 now $95.60 was $64.95 now $51.90 was $64 .95 was $79.50 now now $51.90 $63.60 was $48.50 was $94.50 now now $38.80 $75.60 10% OFF ALL TYPES OF TRANSFORMER IN STOCK • Teroidal Power Transformers • Step Down 240V-110V Isolation Transformers • Adjustable Voltage Variable Transformers • Isolation Variable Transformers • And all of General Purpose Transformers SPECIAL! Computer Grade Lug Mounting Capacitor (made in USA) suitable for Hi-Fi Amplifier to give Best Quality Sound output Cat.# E0007 16,000 uF 50VDC (2" W x 4 1/8" H) only $34.95 Cat. # E0008 18,000 uF 50VDC (2" W x 3 3/8" H) only $29.95 SM-302 120W STEREO POWER AMPLIFIER A0001 $219 SM-333 surround soun d processor employs the most updated int egrated circu its as its heart . It is also equipped w it h a (DNA) Dynamic Noise Reductor systems IC made by " National Semicond uctor" to particularl y filter out the annoying noise t hat is commo nly found on tapes or CD disks; t herefore (DNA) system is suitable for and has outstand in g performance on d ifferent video types, CD , LD, or Dolby Surround encod ing d isks and tapes, etc. The internal noise reduced to its m inim um level, to produce ultimate live performance effect. SPECIFICATIONS & ELECTRICAL CHARACTERISTICS: FREQU ENCY RESPONSE T.H.D . (Front channel) T.H.D. (Rear channel) Input signal voltage Front channel output voltage Input impedance Surround sound output Voltage Del ay time Power Dimensions : 20 Hz-20KHz+/-5dB : 0.05 % 20Hz-20KHz : < 0.25% : 0.1V-3.5V(MAX) : 0.1V-3.5V(MAX) : 47Kohms :6.6V(MAX) : 5ms-50ms : AC240Vat 50Hz : Wide 360mm,(14 .2in .) Depth 122mm ,(4 .82in.) Height 53mm ,(2.10in.) SM-333 VIDEO/AUDIO SURROUND $239 SOUND PROCESSOR A0002 In order to match w it h the SURROUND SOUND PROCESSOR , our co mpany has spec ially designed a 120W Stereo Power Amp. This amp lifier not on ly acts as a perfect partner of Surround Sound Processor b ut also many other audio sources. The special design of all components are soldered on one P.C. Board . SPECIFICATIONS & ELECTRICAL CHARACTERISTICS: FREQUENCYRESPONSE : 20Hz-20KHz TOTAL HARMONIC : LESS THAN 0.1% DISTORTION : 60W/4 ohms, 33W/8 ohms per channel POWER OUTPUT INPUTSENSITIVITY :10mV MIG :380mV LO :640mV HI : BETTERTHAN 70d8 S/N RATIO LOADIMPEDANCE : 40HM-80HM POWERCONSUMPTION : 130VA : 360mm(W)x75mm(H)x220mm(D) DIM ENSIONS 14" X 3" X 8-5/8" ~ONE A-ONE A~ONE A-ONE A-ONE HIGH QUALITY DIGITAL PANEL METERS 41/2 DIGIT HI-PRECISION DPM S0406 $79.50 This precision digital meter is a standalone voltmeter - ammeter or can interface with a computer! 4½ digit 0.55" LED display. Temperature compensated to 100 PPM!°C. Operating temperature range is 0°C to +70°C. Outputs include BCD data, Busy and strobe. Panel reading can be latched on hold . SPECIFICATIONS Range: DC vo ltage: DC current: Stability: Power requirements: Dimensions: 31/2 MULTIFUNCTIONAL LCD DPM (WITH HOLD FUNCTION) S0408 $59.50 S0408 Digital Panel Meter which employs high quality AID converter IC as a main device. The IC drives the 3½ digit of LCD digital display directly. By connecting one or two resistors to produce al l range of vo ltmeter, ohmmeter and currentmeter. Besides, this unit has detail circuit diagram on temperature meter. Frequency meter.. .etc for reference . Being of high impedance due to FET input , and low bias current, the digital panel meter SM series is furnished with the automatic zero adjustment circu it and automatic polarity transfer, with 100 PPM/°C temperature compensated voltage reference, high reliable within 0°- 50°C. Input sensitivity of S0408 Digital Panel Meter is DC± 199.9mV for fu ll scale display. Input impedance: 100M ohm. Working voltage of S0408 is DC 9V, 1.8mA. In order to upset the meter's stability and accuracy, a 100ppm/°C temperature Compensated Voltage Reference Diode is employed, to make this meter work, in the best way within 0-50°C. SPECIFICATIONS DC Voltage Range: AC Voltage Range: Thermometer Range: DC Current Range: Capac itance Range: Frequency Counter: Display: 1mVto 1000V 1mVto 1000V 0°C to 100°c 1 microamp to 2 amps 1 pf to 2 microfarads 10 Hz to 20 KHz 3½ digit 15mm high LCD Maximum Indication: -1999 or +1999 Power Supply: DC9V±5% Po wer Consumption: 16mW Outline Dimensions: 3¾" (W) x F/s" (H) x 4-1/16" (D). DIN standard This Case meets West German DIN standard. 3'½ MULTIFUNCTIONAL LED DIGITAL PANEL METER S0405 $64.50 This is a high quality device with excellent 1mVto 2000V 1 microamp to 20 amps ±0.025%±2 digits 5 to 6 volts DC at 200 ma 4-5/16" (W), 3¼ (D), 1¾"(H). specifications. Instruct ions are included to use th is instrument as a vo ltmeter, ammeter, temperatu re meter, frequency meter and capacitance meter. The accuracy of this meter is ± 0.1 % , ± 1 digit. Input impedance is 100 megohms. It has high vibration res istance and so can be used in a mobile or portable environment. Resets to zero automatically. The meter is temperature compensated so that is can be used from O to + 150 degrees fahrenheit. SPECIFICATIONS DC Voltage Range: AC Voltage Range: Thermometer Range: DC Current Range: Capacitance Range: Frequency Counter: Display: Maximum Indication : Power Supply: Dimensions: 1mVto 1000V 1mVto 1000V 0°c to 100°c 1 microamp to 2 amps 1 pf to 2 microfarads 10 Hz to 20 KHz 3½ digit 0.5" high LED -1999 or +1999 5 to 6 VDC, 200 ma 3¾" (W) x F /s" (H) x 4-1 /6" (D). Th is Case meets Germany DIN standard. 41/2 DIGIT HI-PRECISION DPM WITH DIN CASE S0407 $89.50 This is essentially our very popular S0406 digital panel meter but in a standard DIN case. Like the S0406, it has a large 0.55" LED readout. It is also temperature compensated to 100 PPMl°C . Operating temperature range is 0° to +70°C. A MEMORY SYSTEM can HOLD the input reading for comparison and monitor. This is a sensitive unit. An input of 1.9999 volts results in full scale display. The unit operates on 5 VDC at 200ma. SPECIFICATIONS Rear outputs: Range: DC vo ltage: DC current: Accuracy: Power requirements: BCD data, Busy, Strobe 1mVto 2000V 1 microamp to 20 amps ±0.025%±2 digits 5 to 6 volts DC at 200 ma 3¾"(W) x 17/s"(H) Dimensions: 4-1/16" (D). This Case meets Germany DIN standard. 31/2 DIGITAL PANEL METER S0402 $49.50 S0404 $59.50 These meters use a Teledyne AID converter integrated circuit. The display is a 0.6" LED for high visibility. These kits are easy to assemble and the instructions provide information on how to use the meter as a voltmeter, ammeter, ohmmeter, thermometer, frequency counter or capacitance meter. A red plastic face is provided to enhance viewing contrast. The S0404 has a HOLD FUNCTION, so the last readout can be held! SPECIFICATIONS DC Voltage Range: AC Voltage Rang e: Thermometer Range: DC Current Range: Capacitance Range: Frequency Counter: Display: Maximum Indication: Power Supply: Dimensions: 1mVto 100V 1mVto 1000V 0°c to 100°c 1 microamp to 2 amps 1 pf to 2 microfarads 10 Hz to 20 KHz 3½ digit 0.5" high LED -1999 or +1999 5 to 6 VDC, 200 ma 4.75" (W) x 1.75" (H) x 1.56" (D). >. ~ ~ INO-V :tINO-V :tlNO-V :tINO-V :tINO-V A-ONE A-ONE A-ONE A-ONE A-ONE ~ ~ ~ ~ +I• 0-50V 6A REGULATED PSU r....-, Output voltage: .. Z 0 < S0010 $159.95 +- 0-S0V DC (+- 0-35V SA RMS Regulated) ·Current: 2A, +2A=4A, +2+2=6A Overload Indicator: Current Limit Sharp cut out Output reset turn the selector to current limit point. I/P Transformer: +/·0·35V 2.5A DUAK REGULATED PSU S0007.$48:tl0'" + 0-35V/0-70V $38.40 Output voltage: OA HEAVY-DUTY REGULATED PSU SOOO&J,149:0IJ' $119.20 Output voltage: 0-32V Current: Overload Indicator: Protection method: I/P Transformer: Recommended: Current: 20AMAX Overload Protection Ranges: CUSC Overload Induced Sharp Cutting Method (SC). Overload Induced Current Limiting Method (CL). Limiting Range: (Basic) 5A+5A+5A+5A Total 20A 18V-24Vx2/30A 24+24V/800VA 2.5A LED Current Limited 18-24Vx2/6-8A 22+22V/225VA R~ommeadod, · ~ ~ < ~ ~ 0·20V 20A REGULATED PSU S0005 $134.00 6.5V TO 18V DC REGULATED PSU S0011 $149.00 Output voltage: 0-20V Current: 20AMax Overload Protection Ranges: (CUSC) (Basic) 5A+5A+5A+5A Total 20A Switch Setting. I/P Transformer: 12V-18Vx2/30A Recommended: 18+ 18V/S00VA Output voltage: 6.5V to 18V DC (25V Max) Fully adjustable Output Current: 20A Max Current limit control:4 Steps (5A,10A,15A,20A) Ripple and noise: 15 mV Line Regulation: 0.08% + 20mV Load Regulation: 0.08% + 20mV Input Power: 18 to 20V AC 50-60HZ, 20-30A Recommended 18+18/S00VA Transformer: (T0238-Parallel Secondary) 100W CLASS 'A' MAIN AMPLIFIER (MONO) S0313 $79.00 120W MOSFET PGWER AMP (MONOI S0329 $195.00 100W DYNAMIC CLASS 'A' MAIN POWER AMP (MONO) S0310 $89.00 Power Output: Frequency Response: Input. Impedance: Input Sensitivity: Supply Voltage: Current: Power Bandwidth: THD 1KHz 1W: Transformer: Recommended Transformer: Power Output: Frequency Response: Power Output: < 0-50V 3A PRECISION PSU SD001 $49.00 Output voltage: Current: Overload Indicator: Protection method: I/P Transformer: Recommended: 0-S0V 0.5 to 3A LED Auto shut on overload and short circuit 22V-36Vx2/3A 50Vx2/3A for High O/P 36+36V/160VA 45+45V/160VA High O/P ~ ~ I < . Z 0 < I Recomm ended Transformer: 100W8 OHM 0-100KHz 22K. 0.8V DC+/-30 -42V(MAX) SA 5-S0KHz 0.001 % 28Vx2/5A 30+30V/ 160VA. (T0209) MONO 30+30V/300VA. (T0217) STEREO 120W RMS into 8 OHMS 8Hz to 20KHz, +0 to 0.4db Input Sensitivity: 1V RMS for 120W Output Power Requirement:+/- 45 to 55 VDC at 3AMono 40Vx2/3A/160VA for MONO 40Vx2/6A/300VA for STERO Recommended Transformer: 40+40V/160VA. (T0212) MONO 40+40V/300VA. (T0219) STEREO Frequency Response: T.H .D.: TIO: Input Sensitivity: S/N Ratio: Power Supply: Power Consumption: Recommended Transformer: Recommended Transformer: 100W RMS into 8 OHM .150W RMS into 4 OHM 10Hz to 20KHz Less than 0,008% Less than 0.008% 0.75V-1V Better than 80db +/-35VTO +/-45V DC 3.5A per channel. 30+30V/160VA (T0209) Mono 30+30V/300VA (T0217) STEREO ~NO-V ~NO-V ~NO-V ~NO-V ~NO-V -ONE A-ONE A-ONEA-ONE A-ONE DC FET SUPER CLASS 'A' PRE-AMP S0330 $145.00 FULL COMPLIMENTERY SYMMETRY FET STEREO PRE-AMP S0308 $159.00 300W HI-FI POWER AMP(MONO) S0331 $175.00 Frequency Response: Frequency Response: Power Output: T.H.D.: Input Sensitivity & Impedance: Phono: Output Level: Pre-AMP Output: Recording Output: Input Power: Recommended Transformer: ~ Overall (AUX to pre output) (at rated ouput) 10 to 100,000HZ +0.5-1 db Overall (From AUX) Less than 0.01 % (1,000HZ for rated output) 47K OHMS.2mV Rated Output (0.01% THD) 1.3V (20V MAX. 0.1% THD) 130mV 36+36V/0.2A 30+30V/15VA. (T0231) 10 to 100KHz +0.5db -1db T.H.D. (From AUX): 0.005% at/below rated O/P Channel Separation (at rated O/P 1 KHz) Better than 70db. Phono: HUM & Noise (IHF) Better than 70db. Phono: Better than 90db. AUX: Input Sensitivity & IMP. (1 KHz for rated Phono 47K OHM,2mV output): Rated O/P(0.01 % THD). Output Level: Pre-AMP output 1.5V Max Output: (0.1% THD) Pre-AMP output 15V. AC 30V x 2 400mA Input Power Vol: Power Consumption: 12W Recommended 30+30V/15VA (T0231) Transformer: Frequency Response: T.H .D.: I.M. Distortion: Input Sensitivity: Power Requirement: Recommended Transformer: 300W RMS into 8OHMS 500W Music Power into 8OHMS 10Hz to 20KHz Less than 0.05% Less than 0.05% 1V RMS at 47K +/- 60 to 75 VDC at BA Mono 48-53x2/6-8AMP AC >. ~ tfj >. ~ tfj >. ~ ~ 50+50V/500VA. (T0225) MONO --------A-ONE NF-CR BI-FET PREAMP/3-WAY TONE CONTROL S0307 $72.00 Frequency Response: T.H.D.: 1.M. Distortion: Power Requirements: Input Sensitivity: -DC to 100KHz +- 0.5d8 0.005% at/below rated 0/P 0.005% at/below rated O/P +-15 VDC, 0.2A MAX Phono-2.5mV. Tuner, AUX and Tape-100mV Input Impedance: Phono-47 K. Tuner, AUX and Tape-100K Output Voltage: 1V Tone Control Range: BASS,+-10 db at 50Hz MID, +-5db at 1Hz TREBLE, +-10db at 15KHz RIAA Equalization: +-0.2db from 20J:::!z to 20KHz Phono,75db. Tuner, AUX SIN Ratio: and Tape, 90db. ELECTRONICS PTY LTD 432-434 Kent Street, Sydney NSW 2000. Phone: (02) 267 4819. Fax: (02) 267 4821. A.C .N. 003 88 2 S13. MAIL ORDERS WELCOME: CHEQUE, MONEY ORDER, AMERICAN EXPRESS, BANKCARD,MASTERCARD AND VISA. POSTAL CHARGE $5-25 .......... $4.50 $26-$50 ...... $5.50 $51-$100 ........ $7.00 Over $100 ...... $10.00 Phone or write to us for a copy of your price list. Shop hours Mon-Fri 9-6. Sat 9-4. All prices include sales tax. >. ~ tfj 3 O-V 3 NO-V 3NO-V 3NO-V 3NO-V . Sony's new VGP-G700 colour video printer How would you like to print colour snapshots from your favourite videotapes or from off-air signals. Now you can you can do it and quite cheaply too, with this brilliant new printer from Sony. By LEO SIMPSON M ANY HOUSEHOLDS have camcorders and they are used a lot for recording family events, holidays and so on. But the trouble with video tapes is that you have to turn on your VCR and TV every tim~ you want to look at them. This is why people still need conventional cameras to take family snaps. But what if you were 16 SILICON CHIP able to easily produce colour prints from any picture displayed on the screen? Well, now you can. The process for making colour prints is simple. You need the Sony CVP-G700 colour video printer hooked up to your VCR or camcorder. You also need a video monitor which can accept a video signal from the CVPG700 colour printer. With the gear all set to go, you press playback on the VCR and watch the monitor until the image you want is on the screen. You then push the CAPTURE button on the printer. Theimage will then freeze and a number of menu options will be displayed on the screen, superimposed over the captured image. You can either respond to the menu options, or just press the PRINT button. Less than 70 seconds later, the printer will feed out a beautiful colour print. It's that simple. Print quality The colour prints are 140.5mm wide and 101mm high and the picture area is 101.5mm wide and 76mm high; ie, the prints are a little smaller than the colour prints you would normally obtain from your local photo processing outlet. But provided the original video images are good, the colour prints are every bit as good if not better than can be obtained from a photo processor and their quality is r.onsistently high. As you might expect with today's feature laden equipment, the CGPG700 has a lot of other options which allow you to do more than just print out simple colour pictures. For example, you can have the date printed out on each picture and you can also have a caption which you load in before you press the PRINT button. You can also store and print more than one image on each colour print. For example, you could have four images on one print, 16 images on one print or picture-in-picture. The last option gives you the choice of having a 1/4 or 1/16-size insert in the corner of the main image. To use the Sony CVP-G700, you need a source of video images which can be a VCR, camcorder or laserdisc player. You will also need a video monitor which can accept a composite video signal. That's the basic setup. Sony's new colour video printer, the CVP-G700, allows the user to create a photographic print from a video recording in just 67 seconds. The prints are of surprisingly good quality & compare favourably with those from your local rapid photo processing store. For our evaluation of the CVP-G700, we did not have a video monitor but we did have a standard PAL TV set. Hence, we used the Sony CCD-TR805E video camcorder (reviewed last month) together with a standard PAL VCR. We coupled the video signal from the camcorder direct into the · CVP-G700 and connected the colour printer's video output to the VCR's video input. By using the VCR in the AUX mode and connecting its modulated RF output to the TV set, we were able to view the captured images. So if you have a VCR, a TV set and a camcorder, you already have all the gear needed to work with the Sony colour printer. Remote or not remote As with most VCRs and other video equipment, the Sony colour printer comes with its own infrared remote control which provides access to all the menu functions. As a bonus, it will also control most current Sony VCRs and camcorders which means that you don't have to shuffle between printer and VCR remotes when going through the process of selecting images to print. The printer remote control, or Remote Commander, as Sony calls it, also allows quicker selection of the printer options than if you use the front panel controls. For example, when you capture an image for printing, there is a question asking you how many prints you want (ie, "QTY") and the answer can be anywhere from 1-30. If you are using the front panel buttons, you must push the MENU button and then select the quantity by pressing the <> buttons. The same menu screen lets you set the date and select Title, Print mode (ie, normal, 4way split, 16-way split, etc) and Picture Adjust. On the other hand, if you use· the Remote Commander, you can select the number of prints directly, without having to go through the menu. Similarly, the Remote Commander lets you go direct to the Picture Adjust menu. The Remote Commander also lets you turn the data screen on and off. This allows a captured image to be displayed without the various print messages. Massaging the picture The Picture Adjust menu is a very useful option. Say you have a picture of yourself or a loved one (or both) and it is too red. You can reduce the red content and thus make the picture more acceptable. Or perhaps your picture looks too pale in which case you can increase the red. You also can adjust the .green and blue levels, picture brightness and sharpness. And if you've altered the image beyond recognition and wish to start again, you can always use the STANDARD option to recall the original picture. Selecting a title to go with your prints is a matter of going to the TITLE page and then picking one letter at a time by moving the cursor around the screen menu. The maximum number MARCH 1993 17 Video Titler !XV- T33F. etc.! I Pr.oto VCR Video 1 - - - - - - - ; - Camera TV Equipped with · VCR/Monitor Outputs Fig.1: Sony's video printer can be hooked up to a camcorder, a standard VCR or a TV set with video outputs. You can even print pictures from off-air signals. A monitor needs to be connected to the video printer in order to select the image to be printed. of characters is 40 and they can be virtually any of the characters on a typewriter, including upper and lower case. Print method While Sony's new colour printer looks no more imposing and only a little larger than the average VCR, the technology inside it is very impressive. Not only does it have all the digital circuitry and processing to provide what is effectively a frame grabber, it also has the bells and whistles to provide date, title and the other menu functions. On top of that, the CVP-G700 is a colour sublimation heat transfer printer and until now, such printers would set you back by tens of thousands of dollars. Interestingly, the CVP-G700 can be regarded as a considerably refined version of the old tried and faithful thermal printer. The essential difference is that whereas in the old ther- mal printers the image was burnt into the paper by the thermal print head, in the colour sublimation printer, the heated print head causes the coloured inks on the ribbon to be transferred to the surface of the paper (hence the term "colour sublimation"). By way of explanation, the term "sublimation" refers to the process which causes a solid to go directly to the vapour phase and then back again. Thus, the print head causes the solid ink on the ribbon to sublimate whereupon it is deposited on the paper surface as a solid. The hotter the print head, the darker becomes the image. The ribbon cartridge is essentially a 90mm wide plastic strip with four colours, cyan (blue), yellow, magenta (red) and black running across it in strips (ie, it is a conventional CYMK printing process). The print head must print each of these colours separately to build up the complete image and this explains the fairly long print time The CVP-G700 lets you store & print more than one image on each colour print, or you can print a 1/4 or 1/16-size insert with the selected image. In this case, there are four pictures on the print (eg, for family photos or insurance). 18 SILICON CHIP of 67 seconds for each print. The ribbon cartridge lasts for just 30 prints and then must be replaced. The special paper for the printer is loaded into a small cassette, just as in a photocopier or laser printer, and this is pushed into a compartment behind a door in the centre of the front panel. The paper compartment door also carries pushbuttons for selecting the print options. During printing, an array of LEDs shows the progress so that even though nothing appears to be happening apart from various clicks and the sound of paper moving through the unit, you are reassured that it is doing the job. The dot structure of the prints is only barely discernible, even under a magnifying glass. The number of picture elements is 700 (horizontal) by 540 (vertical) which is equivalent to about 175 dots per inch. Total gradation is 256 levels (8 bits) each for yellow, magenta and cyan. For comparison, the colour printing in this magazine is 120 dots per inch. Conclusions Our overall impressions of the Sony CVP-G700 colour video printer were very favourable. The unit is simple to use and gives excellent results. And considering the advanced technology it uses , its price is very reasonable. Recommended retail price for the CVP-G700 is $2699.00. For further information, contact Sony Australia Pty Ltd, 33-39 Talavera Rd, North Ryde, 2113. Phone (02) 878 9712. SC A 16-image print is convenient for portraits of team members or for 16-image strobe shots. An image can be used more than once or you can have 16 copies of the same image. DAVID REID ELECTRONICS 127 York Street, Sydney 2000 Ph: (02) 267 1385 Fax: (02) 261 8905 Mailorders to: P.O. Box Q103, Sydney N.S.W. 2000 Cheque, Moneyorder, Bankcard, Visa, Mastercard, Amex, Diners accepted Postal Charges: $5 - $25 .. $4; $26 - $50 .. $6; $51 - $100 .. $7; $101 - $499 .. $9; $500+ .. FREE; [F□ ~[E~LJ DIGITAL MULTIMETRS FINEST 185 * Auto Power Off. * Splash/Dust Proof Case. * Max/Min/ Av. Recording. * Freq., Cap., Temp. * Relative & % Modes. * 3.75 Digit Display. * 4000 count. * Bargraph Display. * Plus more ! * 12 months warranty $195.00 FINEST 187 * Auto Power Off. * Max/Min/ Av. Rec ording. * Freq., Temp. * Relative & % Modes. * 3.75 Digit Display. * 4000 count. * Splash/Dust Proof Case. * Bargraph Display. * Auto Ranging . * 12 months warranty $238.00 FINEST 285 * True RMS . * Auto Power Off. * Splash/Dust Proof Case. * Max/Min/ Av. ~ecording. * Freq., Cap., Temp. * Relative & % Modes. * 4.25 Digit Display. * 4000 count. * Bargraph Display. * Plus more! * 12 months warranty $298.00 Dial Cord Com1n1tor Hack-u1> 10 meter reel only$1.00 Record Cleaning Brush only$1.00 Hattorios Batteries dead? Yes ? We have a good selection to choose from. 3/v 60R 3.6V NiCad 3.6v Lithium TL-5242/w $13.95 $37.95 Courier Sydney Metro .. $8 Wolfenstein 3 - I> Multifunction Tester Two weeks ago, you were flying for the allied air force. Now, you 're a prisoner held by enemy intelligence in a castle from which nobody's es caped - ever! In a break that only comes once in a lifetime, you've overpowered the guard and taken his gun! Now, can you make ii out alive! $9.95 Suitable for -testing continuity, detecting the presence of 240V AC, or even low voltage DC. This tool can virtually replace a multimeter in many instances. Built-in Audible & Visual Indication ! $17.95 3.5· or 5_25• format (IBM) Protection ! for your P.C., Office Equipment, etc. Protect your expensive equipment against voltage spike's, surges, RF noise, etc. Many unexplained errors, program corruption and general inconvenience are eliminated by a Squeeky Clean Mains Filter. All Squeeky Clean filters are approved by the Energy Authori ty and are guaranteed for 12 months. We have four models available, to suit your requirements. All filters are rated at ten (10) amps. LF-1 LF-2 LF-4 LF-8 Single filter, Single outlet. Single filter, Dual outlet. Four outlets, each individually filtered. Eight outlets, Dual filter in two banks. Filter A (four outlets), Filter B (four outlets). $99.00 $119.00 $269.00 1 game/9 levels SPIRAL WRAP Ideal for keeping wiring looms neat. Available in two siz:es. 6mm min. I.D. 13mm min. I.D. Colour: Black $1.95/ mtr. $239.00 AC/DC Cooling Fans PLCC Extrac~tor 25 x 25 x 10mm 12V DC 40 x 40 x 10mm 12V DC 40 x 40 x 20mm 12V DC 60 x 60 x 25mm 12V DC 80 x 80 x 25mm 12V DC 120 x 120 x 38mm 12V DC 120 x 120 x 25mm 24V DC 80 x 80 x 38mm 115V AC 80 x 80 x 38mm 240V AC 92 x 92 x 25mm 240V AC 120 x 120 x 38mm 115V AC 120 x 120 x 38mm 240V AC 80mm Metal Fan Grill 120mm Metal Fan Grill 1.3CFM 5.3CFM 6.9CFM 21.5CFM 35CFM 109CFM 80CFM 30CFM 30CFM 36CFM 115CFM 115CFM $19.95 $14.95 $14.95 $14.95 $14.95 $22.95 $23.90 $23.95 $22.95 $28.50 $24.95 $24.95 $2.4 5 $2.45 only $14.95 ~psaksr Cabls 12•• Woofsr fGWF/2) MESSAGE STOPPER 100 W4ffG RHG This inexpensive device, w hich connects direct to your answeri ng machine will automatically disconnect your answering machine whenever ANY PHONE is answered. If your answering machine answers your call before you do, simply pick up any phone; your answering machine will immediately disconnect and you can speak without interference. * 93 dB * 100W RMS * 23 Hz - 4.2kHz * 30 oz Mag. * 8 ohms Build this SOLAR CHARGER FOR 12V BATTERIES Keep that 12V battery topped up with this solar cell charger & matching voltage regulator. It's ideal for use on camping trips & in boats, tractors & electric fence installations. By BRANCO JUSTIC Do you have a 12V battery that's seldom used and often goes flat due to self-discharge? Or how about a battery that's used continuously but which should be trickle charged to keep it operating correctly (eg, in an electric fence or on camping trips)? If you answered "yes" to either of these questions, this project will solve 20 SILICON CHIP your problems. It uses a low-cost amorphous solar-cell array to provide a charging current for the battery, plus a simple voltage regulator to ensure that the battery cannot be overcharged. The solar cells specified in the parts list are 150 x 150mm units rated at 6V 1W. Depending on the application, they can be made up into either 2-cell or 4-cell panels. The 2-cell version has an open circuit output voltage (Voc) of about 20V and a short circuit current (Isc) of about 160mA in bright sunlight. By contrast, the larger 4-cell panel has an Isc of about 32DmA (Voc = Z0V). Note, however, that the actual power. that a panel can deliver to a load is just under 2/3(Voc x Isc) (not simply Voc x Isc). In practice, this means that a 2-cell panel can deliver just over 120mA of load current at 15V in bright sunlight, while a 4-cell panel can deliver around 240mA. The voltage regulator contains all the circuitry necessary to interface the solar panel to the battery. Its main features include an indicator LED to indicate that the solar panel is working, a shunt regulator circuit to prevent the battery from overcharging, a Z-LED charging current indicator, and an isolating diode to ensure that the battery cannot discharge back into the panel when there is no sunlight. The regulator circuit is suitable for use with solar panels rated from 0.5W to 10W. However, if a solar panel with an output above about 3W is used, a bigger heatsink than the one originally specified should be fitted to the shunt regulator transistor (Ql). D1 1N4004 D2 1N4004 VR1 1000 02 BC558 C FROM SOLAR PANEL TO BATTERY K LED2 R8 4-?k LED3 R7 1k How it works Fig.1 shows the circuit details. LED 1 functions as a voltage indicator and is connected in series with its current limiting resistor directly across the output of the solar panel. When LED 1 lights, the solar panel is delivering at least ZV. Darlington power transistor Ql serves as the shunt regulator. This transistor remains off when .the output from the solar panel is less than about 15.3Vand so the battery charges via diodes Dl & DZ (provided the battery voltage is 1.ZV less than the panel voltage). However, if the output from the solar panel exceeds the voltage across ZDl, ZDZ and Ql's base-emitter junction (about 15.3V), Ql begins to turn on. Ql thus loads the solar panel by shunting part of the charging current to ground and this prevents the panel's output from rising above 15.3V. Because Ql 's collector is isolated from the battery by diodes Dl & DZ, this corresponds to a battery charging voltage of about 13.8V. Essentially, the shunt regulator stage prevents the battery from being overcharged by high output voltages from the solar panel during bright sunlight conditions. Current indicator QZ, LED Z and LED 3 serve as a charging current indicator. LED Z comes on when the charging current reaches about Z0% of maximum, while LED 3 comes on when it reaches 80%. Essentially, the charging current indicator monitors the voltage across Dl. This voltage varies from approximately 0.5V at a few milliamperes to about 1V at 1A (ie, the greater the current, the greater the voltage across Dl). A voltage proportional to this PLASTIC SIDE A ITT B EQc VIEWED FROM BELOW ECB SOLAR PANEL VOLTAGE REGULATOR Fig.1: the circuit uses shunt regulator transistor Ql to limit the voltage from the solar panel to about 15.3V. It does this by shunting part of the charging current to ground when the voltage rises above this level so that the battery is not overcharged. Q2, LED 2 & LED 3 provide charge current indication. , < :' • '' -.. ' I; • • :· ·-· -~ -t ~ f > (:~ { %. : (.. / i'"·~ · '""~';-:µ :'.;; ) / ~ . 0 0 . 0 .~ \~010 $1 ~ - - SOLAR PANEL LED1 voui-" teDr tED~ Fig.2: install the parts on the PC board exactly as shown in this diagram. Note that Ql is installed with its metal face towards ZD1 & ZD2. current appears at the wiper of VR1 and is applied via a 22Q resistor to the base of QZ. QZ serves as a current amplifier. When its collector current reaches 0.5mA, LED Z begins to light. If the charging current now increases, QZ's collector current also increases and the brightness of the LED increases accordingly. This continues until QZ's collector current reaches about ZmA, at which point LED 3 also begins to light. Both LEDs then further increase their brightness as the collector current increases beyond ZmA. When VR1 is properly adjusted, the maximum current through QZ is about 5mA. Although this is negligible for the solar panels specified, it may be a problem if very small panels are substituted. This "waste" current can be eliminated by connecting a normally closed switch across Dl to hold QZ off. The charging current could then be checked by pressing the switch. Alternatively, a link could be substituted for D1 and QZ and its associated parts left off the board. Construction Fig.Z shows the parts layout on the PC board (code OESOLARSC). Install the parts as shown, taking care to ensure that all polarised parts are correctly oriented. These include the diodes, zener diodes, transistors and LEDs. It's easy to identify the LED terminals, as the anode lead is always the longer of the two. Transistor Ql is installed with its metal face towards the two adjacent zener diodes. A small finned heatsink is then bolted to the transistor to provide cooling. The regulator board can now be placed to one side while the solar panel is constructed. Warning: do not try to test the regulator by connecting it directly to a variable power supply. The current output capability of the MARCH 1993 21 SOLAR CELL + SOLAR CELL +-----~- + SOLAR CELL + SOLAR CELL + Fig.3: this diagram shows the wiring details for a 4-cell solar panel. If you only want a 2-cell panel, just leave off the bottom two cells. supply will be sufficient to blow the shunt transistor (Ql) if you do. The way around this is to connect a 22Q 5W resistor is series with one of the supply leads. This will limit the output current and protect the regulator transistor and the supply as well. To test the regulator, wind the supply up to about 20V and check the voltage output from the regulator atDZ 's cathode. You should get a reading of about 13.8V. 350 x 350 x 3mm ALUMINIUM PANEL MOUNT SOLAR CELLS ON MATCHSTICKS AND SEAL EDGES WITH NEUTRAL CURE SILICONE SEALANT This 4-cell array was made by mounting the cells on a 3mm-thick aluminium panel. The cells are mounted on matchsticks so that they don't short on the panel & the edges sealed using neutral-cure silicon sealant. Building the solar panel If you are buying the bare solar cells, they will have to be wired together, attached to a panel and waterproofed at the rear (note: the panels specified in the parts list come with a glass cover at the front). Fig.3 shows the wiring details for a for a 4-way panel. If you only want a 2-cell panel, just leave off the bottom two cells. Note that the cells in a 2way panel are simply wired in series, whereas those in a 4-way panel are wired in series-parallel combination. Before wiring the cells, you first have to identify their positive and negative terminals using a multimeter (this is best done in bright light). Mark the cell terminals with a felt pen as they are identified, then fit the spring clips supplied to the terminals. A small strip of copper foil goes under each clip on the back of the cell. The cells can then be interconnected by soldering leads to the copper strips. Don't try to solder the leads directly to the solar panels, as the solder won't "take" to the aluminium backing. The best way to mount the cells is to attach them to a sheet of 3mm-thick aluminium. A 4-cell panel will require a sheet of aluminium measuring 350 x 350mm. Eight matchsticks can be used under each cell (two at each corner) to space it off the aluminium sheet to prevent shorts. The procedure is to first mark out RESISTOR COLOUR CODE 0 0 0 0 0 0 22 No. Value 4-Band Code (1%) 5-Band Code (1%) 2 1 2 4.7kQ 1.5kQ 1kQ 100Q 22Q yellow violet red brown brown green red brown brown black red brown brown black brown brown red red black brown yellow violet black brown brown brown green black brown brown brown black black brown brown brown black black black brown red red black gold brown 2 SILICON CHIP A small finned heatsink is fitted to the BD679 shunt regulator transistor (Qt) to provide cooling. Trimpot VR1 , to the right of Qt, is adjusted so that both LEDs shine brightly when the solar panel is in full sunlight & the battery is connected. the positions of the solar cells on the panel - they can be carefull y aligned on the pan el using several 20mm spacers between them to achieve even spacings . This done, the panels can PARTS LIST 1 PC board, code OESOLARSC, 70 x 35mm 1 small heatsink 2 2-way PC-mount screw terminal blocks . 1 1oon horizontal trimpot Semiconductors 1 B0679 NPN transistor (01) 1 BC558 PNP transistor (02) 1 6.8V 400mW zener diode (ZD1) 1 7.5V 400mW zener diode (ZD2) 2 1N4001 silicon diodes (01 ,02) 3 red LEDs (LED1 -LED3) be lifted up and the matchsticks attached to the panel at the cell corner positions using neutral-cure silicone sealant. The cells can then be dropped into position and secured by running a fillet of n eutral-cure silicon e sealant right around their outside edges. Make sure that th e edges of the cells are all properly sealed. The edges of the terminating clips sh ould also be sealed but try not to get too much sealant on the front surface of the cells. Any excess sealant that you do get around the edges can later be rubbed off when the sealant dries. Alternatively, the cells can be held together by fitting them into plastic edging strips an d then edge-sealing them front an d back with silicone sealant as before. The aluminium backing of each cell must then be waterproofed by spraying it will a clear hard-setting lacquer. This technique was used for the 2cell array pictured with this article, although mounting the cells on an alu min ium panel is the method we recommend. Once the panel has been completed, place it in direct sunlight and check th at its open-circuit output voltage is about Z0V. After that, it's simply a matter of installing the panel in a convenient location and connecting it to the battery via the shunt regulator circuit. Adjust VRl so that LEDs 2 & 3 shin e brightly when the solar panel is in full sunlight & the battery is connected. Performance The full voltage and current capabilities of a solar panel can only be checked in direct sunlight in the middle of the day, during the summer months. The output from the panel will be reduced under any other conditions. Obviously, weather factors play an important role in determining the output from any solar panel installation. If we assume that the amount of full sunlight averages about five hours per day, it follows that the 2-cell panel can provide about 0.6Ah/day while the 4-cell panel can provide about l .2Ah/day. In practical terms, this means that the battery can be continuously discharged at 24mA if a 2-cell panel is used, or at 48mA if a 4-cell panel is used. SC Resistors (0.25W, 5%) 2 4.7kn 1 1oon 11.5kQ 2 22Q 21 kQ Where to buy the parts A kit of parts for this project is available from Oatley Electronics, PO Box 89, Oatley, NSW 2223, Australia. Phone (02) 579 4985. This kit includes four solar cells plus all the parts for the regulator & is priced at ·$42 plus $4 for packing & postage (aluminium sheet metal, silicone sealant & hookup wire not included). Note: copyright © of the PC board is retained by Oatley Electronics. The solar cells are wired by soldering connecting leads to small pieces of copper foil which are held in place by spring clips. Use your multimeter to identify the positive & negative terminals before installing the wiring. Note that the 2-cell array is shown here; the 4-cell array is wired as shown in Fig.3. MARCH 1993 23 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. 10011 ANTENNA +5V + .0047+ + .001 + + 220i 100+ 1+ 7 RF GAIN II VC1 II 10.60pF II L1 VR1 5k 7 220k 7 + +9V IC1 NE602 T 81 I 9V I ...I.. 7 +ft7 "I "~ .001 +9V -- 33011 T~~l,~G VR2 5-150pF r::~FII p - - - - --- -- I 1 ~~: 10-S0pF - L - SHIELD A 20-metre direct conversion receiver The circuit of this direct conversion receiver can be broken into five blocks: an RF filter, mixer, VFO , AF filter and audio amplifier. The RF input filter is designed to resonate at 14.05MHz and uses a tapped capacitor network to match · the 50Q antenna impedance to the 1.5kQ input impedance of ICl, an NE602 double balanced mixer. ICl mixes the incoming RF signal with a signal from the VFO (Ql, etc). The difference in these two signals is then fed to the audio filter and then to the amplifier. A Hartley oscillator based on FET Ql is used for the VFO (variable frequency oscillator), tuning from 14.000MHz to 14.117MHz. Inductor L2 consists of 15 turns of 0. 5mm wire SILICO N CHIP _J -: 10k 24 7 -: - I 3311 I - - - - -1----- --- -- --- ~J on a 7mm outside diameter Bakelite former, tapped four turns from the end. The former was glued to the PC board and the whole inductor coated in Q-Dope to prevent changes in frequency due to knocks or vibrations. A 2-transistor buffer follows the oscillator to prevent loading effects altering the frequency. The buffer provides approximately 2.5V peak-peak but this is too much for the NE602, so a voltage divider couples the oscillator signal to pin 6. The entire VFO sub-assembly was built into a box made from doublesided PC board material to provide good shielding. The output of the NE602 is fed to a 741 op amp connected as a differential amplifier/bandpass filter. The 0. lµF capacitors control the lower cutoffpoint, while the .00lµF capaci- -: tars limit the high frequency response. The measured gain at 800Hz was +33dB , with the -3dB points at 420Hz and 1.8kHz. IC3 functions as the audio amplifier and drives an 8Q loudspeaker. Inductor L1 was wound using 20 turns of 0.8mm enamelled wire on a T-50-2 powdered iron core. The trimmer capacitor is used to adjust the midband gain to a maximum. S. Merrifield, Heidelberg, Vic. ($40) Blown fuse indicator This circuit is a worthwhile addition to any equipment which blows a fuse or trips a circuit breaker as a normal part of its operation; eg, mains transient protectors, motor overload +5V _ _ _ _ _....,__....,__ _ _ _ _ __,.._ _....,__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __,.._ ____, 0.1! 10k 33011 16 14 LE~1 -6 EXOR 27k IC1 555 QO 13 ~ 1 t , a - - - - ~ ~ CLK1 3 C QO .,::8;...._--r::~ ir:3 ° 1 --- A IC4 10 74LS138Y41-11---sf-Nt-+---◄ 0.1! Simple 2-input logic gate identifier This circuit can be used to identify TTL and CMOS 2-input gates. It uses LEDs to indicate the type of gate under test; ie, AND, NAND, OR, NOR, XOR and XNOR. The circuit works as follows: the 555 timer (ICl) is used in an astable mode to produce the required clock signals for the circuit. These signals clock a 74LS93 counter (IC2) which counts through the binary cut-outs, etc. It is a little more complicated than the usual neon and 220kQ resistor across the fuse but it has some unique advantages. Firstly, it offers three-state indication, as follows: (1). Steady glow power available; (2). Off - power off; (3). Flashing - fuse blown. Secondly, no load is required for correct indication. In fact, no power is fed through to the load side of the circuit when the fuse is blown or removed. When the fuse is open, Cl is charged via a 4. 7MQ resistor and Dl. . When the voltage across Cl reaches about 80V, the neon ionises and the capacitor discharges through the neon via DZ and the lkQ resistor, giving a brief flash of light. Towards the end of the flash, the voltage and current become too low to sustain the ionisation and the neon turns off. Cl then charges again and so the cycle repeats, with the flash rate largely determined by Cl and the 4. 7MQ resistor. The lkQ resistor is necessary if Cl 5 6 8 sequence 00,01 ,10,11; ie, through all the possible input combinations for the 2-input gate. The output of the device under test (DUT) is then fed to shift register IC3 (74LS95). When the entire input sequence has been applied to the device under test, the shift register will contain the signature for that particular gate. This signature is then decoded by IC4 (74LS138) to identify the unknown device. The 74LS138 decoder must only be enabled when the whole truth 01 1N4007 03 1N4007 02 1N4007 TO 240VAC LOAD 1M C1 0.22 N is greater than 0. lµF, to protect the neon against excessive discharge currents. You can tell if you are pushing the neon too hard, as the orange colour of a "glow" discharge changes to the blue-white of an "arc" discharge. When the fuse is intact, the 470kQ resistor and D3 feed regular 50Hz voltage pulses through to the neon, causing it to appear continuously lit. In table has been entered into the shift register, hence the need for NAND gates IC5a and IC5b. Proper operation of the shift register is assured by inverting the clock signal using IC5c. To use the identifier, simply connect the inputs of the unknown gate to pins 8 & 9 of IC2 and its output to pin 1 of IC3 . The appropriate LED will then light to show the type of the gate. D. Klimovski & A. Cricenti, East Coburg, Vic. ($35) this case, Cl doesn't get time to charge fully and the flashing is effectively inhibited. The 1MQ resistor across DZ prevents any stray capacitively coupled voltages from prematurely triggering the neon in the same way. The voltage across Cl will never exceed lO0V in normal operation, so you could make do with an ordinary "greencap" here. However, be careful if you are breadboarding this circuit and the neon bulb becomes disconnected, as the capacitor may charge to 400V. You have been warned! Finally, a word about safety. If you must breadboard circuits like this, use a pair of small step-down transformers back-to-back to obtain a doubly isolated, current-limited 240V AC supply. The common 2155 type transformers work well. The output voltage is still potentially lethal, however, so never attempt to alter the circuit with the power on. Steve Payor, Kogarah Bay, NSW. ($30) MARCH 1993 25 UL'.' r , rcroo, 11c c DOD IP\IJ!,10 Cl CC TQOh,JJCS AOD IAYIN<1 !=J EC TRONIC S RO.l1!RVING ELECTRONICS An alarm-triggered security c3lllera Have you been through the trauma of having your house burgled? This device will capture the thief's action on film using a low-cost motor-drive camera. By TONY NIXON There have been numerous designs for burglar alarms presented over the years but never one to record a thief in action. It's a simple security camera system that's designed to photograph a thief in action. It's similar in concept to the security cameras used in many banks and building societies, 32 SILICON CHIP except that this unit takes photographic stills. Imagine a family that has just returned home from an outing only to find that someone had robbed them of their valuables. After the initial shock they check the alarm and, yes, it had gone off only to be ignored by neigh- hours as a false alarm. Obviously, the burglar had quickly taken all he could and fled the scene with no-one the wiser. A subsequent call to the local police station reveals that they know of a burglar operating in the vicinity but they don't know who the person is. "We'll get the offender sooner or later but we don't have any clues at the moment", is the reply. So the family sits down, feeling somewhat helpless by it all. Hang on a minute - the camera! A quick scurry to its hiding place reveals that , yes, it has taken a few shots . Within a few hours, the film has been processed and there 's the ◄ Left: the author, caught in the act of "nicking" his own VCR. Provided it's properly set up, the hidden security camera should be able to provide positive identification of a thief should the need ever arise. burglar in all his glory, lifting up the video player. From that point on, it should be relatively easy for the police to identify the burglar and put an end to his activities. The point is that if it can work for the banks, it can also work at home. The project described here can accomplish this at a fraction of the cost of commercial units. It uses a passive infrared (PIR) sensor, a low-cost motor-drive camera, and a small electric motor and gearbox. It's easy to build ·using "off-the-shelf" components and the mechanical work is quite straightforward. The installation is also straightforward and the unit can be used on its own or integrated with an existing burglar alarm system. In the latter case, the unit is armed only when the main burglar alarm has been triggered and ceases to- operate when the alarm has timed out. In addition, you can either switch the unit to take a single photograph each time it senses movement or to take a complete sequence of photographs at preset intervals (AUTO mode). How it works The circuit may appear complicated at first glance but can be broken down into .sections. Fig.1 shows the circuit details. When power is first applied to the circuit, presettable up/down counter ICl (4029) is reset by a high pulse from Cl. This high is inverted by IC3f, the output of which then resets the latch formed by IC2a & IC2b. It also resets 556 timer circuits IC4a & IC4b. At the same time, pin 13 of IC2d is pulled low via D11, which means that pin 11 of IC2d is high. When ICl resets, its internal counter is preloaded with a value that corresponds to the logic states on its J1-J4 JAM inputs, as set by switches SW1-SW4. This sets the number of "shots" that can be taken by the cir- The Alarm Security Camera is connected to the main alarm system & is armed only when the alarm is triggered. The camera is then activated when a passive infrared sensor detects movement. Alternatively, the unit can be used by itself & armed using a hidden switch near the front door. cuit. Since the maximum possible · count is 15, a 12-shot film should be used and the film counter set to 12. This film count can be changed at any time by altering the switches and then momentarily operating reset switch SW5. If switches SW1-SW4 are all left open, then the maximum film count will be set. SWl sets the most significant bit (MSB). As long as this count is not zero, the circuit is enabled. Arming options The circuit is armed when pin 9 of IC3d is pulled low via optocoupler IC5. This optocoupler is in turn controlled by a relay in the central alarm system. Normally, the "Y" terminal is connected to ground in the central alarm system and the "X" terminal switched to +12V by the external relay when the alarm triggers. This then turns on the transistor inside the optocoupler to arm the camera circuit. In this way, no photos can be taken during exit and or entry periods, or if the alarm times out. Alternatively, if the alarm relay switches to ground, the "X" terminal should be connected to the +12V supply rail in the alarm and the "Y" terminal connected to the relay contacts. When movement is detected, the PIR sensor's normally open (SNO) contacts close and IC3e's pin 10 output switches high. R14 and C4 prevent any glitches from false triggering the circuit. The resulting low from IC3a is then inverted by IC3b and turns on Ql and relay RL1 for the same duration as the relay in the PIR sensor. RLl thus operates as a slave relay for the sensor and its contacts can be used to trigger the main alarm panel. This means that the P IR sensor can function as an alarm sensor in addition to its role as a trigger for the security camera. When the alarm triggers, pin 9 of IC3d is pulled low and R7 pulls pin 13 of IC2d high. If SW7 is open, no further action takes place. If, on the other hand, SW7 (ACTIVATE) is closed, the high from IC3b pulls pin 12 of IC2d high via D3. IC2d's output thus switches low and the resulting MARCH 1993 33 ;:; ; ~ + ;; r ~.. "' I• ,. > !; ; . 1;-1•· + ~ . .,- <0- c~ c( a: w c~ ~; 0~ ... m a~~ ~g ~., WW ; w !!! > :E < (.) >r- cc ~ :::> (.) w w en < .... ==~ :E ... ,-.u, a: 0 < c( ...J c( I• I• ~ g;g a.; + I• :I 0 0 <O~ -o a::;! ... <O ~~ _o a::,! ... 0---,•· ::, 0 "'~ ~"' I· + ~ tjt,-1•· .,->., 0~ "'., a:..; I• >< ► ~ ~ ., !a? I• -"' o .,; <O~ cc:;! ...w"' "' "'~ a: Wu, ~ I&~ !! ., ., "' o"! ...... 0 ~ -·. t ~ ~-H•· I• .... !a? C .;i --~ I· ... ~ ~ :; + "'~ >:;! ...._o ~ ~ •- I-;--!•· I """ 0"' a:O \!! I-;--!•· I ::;- + a::;! ~ "' ~ •· ; ~ "' ~ "'o ~•- "':;! - o ~ "' ~•· "':;! ~ "' 34 SILICON CHIP ;!: H •· oo ......., I· !,?V> <O o- ii:,. >- I-;--!•· +..,,._ I 0 .. Fig.1 (left): the circuit is armed when pin 9 of IC3d is pulled low via optocoupler IC5. When the IR sensor detects movement, pin 11 of IC2d switches low & resets monostables IC4a & IC4b via C2 & D2. IC4a sets the delay between consecutive photos, while IC4b generates the starting pulse for the motor. negative-going pulse from C2 sets the latch formed by ICZa & ICZb. This switches pin 3 of IC2a high and lights LED 2 to indicate that the unit has triggered. In addition, the negative-going pulse from CZ triggers monostables IC4a & IC4b. These two monostables are part of a 556 dual timer IC and work in the same way as the morefamiliar 555 timer IC. When triggered, their outputs at pins 5 and 9 switch high. IC4a sets the delay between con secutive photographs. When its output switches high, C7 charges via Rl 7 and, after a short delay, pulls IC3c's input (pin 5) high also. The resulting low output from IC3c then pulls pin 13 ofIC2d low, thus forcing its output high for the duration of IC4a's delay. Any further sensor pulses are now ignored until this delay is over. The high from IC4a also clocks !Cl to reduce the film count by one. When this count reaches zero, pin 7 (carry out) of !Cl goes low and pulls pin 13 of IC2d low via Dl to disable the circuit. This also extinguishes LED 1 to indicate that the film has run out and to indicate that no further photos can be taken until the circuit is reset. IC4b is also wired as a monostable but has a much shorter delay than IC4a. Its function is to start the motor via D9, R18 and Q2 . Once the motor is running, it closes microswitch S9 via a motor-driven cam. This ensures that the motor completes one full revolution only, so that only one photograph is take!]. each time the system is triggered. When the motor has completed one revelution, the microswitch opens again and the motor stops. IC4a now times out and its output at pin 5 switches low again and reenables IC2d via IC3c and D7. Any further input pulses from the sensor will now retrigger the circuit, provided ICl 's counter is not at zero. Thus, each time the IR sensor detects +12V 0 - - - 1 - - . . - - - 1 + 01 ov~ · 100 + 25VW+ GND t------•8V 10 + .,. 16VW+ Fig.2(a}: this circuit can be used to generate an +8V supply rail for the camera circuit if this rail is not already present in your central alarm system. r----------------•12V t12V FROM PLUG-PACK ~ + BATTERY T BACK-UP I 12V 1.2AH .l_ l IGO Fig.2(b): use this circuit to generate the required +12V & +8V supply rails if the security camera is to be used independently of an alarm system. movement, the camera takes another photo. VRl sets the delay for IC4a and thus sets the delay between photographs. The maxi_m um setting is about 60 seconds. VRZ controls the length of the motor start pulse from IC4b. Auto function Switch SW8 controls the AUTO function. If SW8 is closed, a high logic level will remain on pin 12 of IC2d after the first photograph has been taken. Thus, as soon as IC4a times out, pin 13 of ICZd will go high again and retrigger IC4a & IC4b to take a second photograph. This sequence will continue until the counter reaches zero. As a result, the camera will take a complete sequence of photos, the interval between each photo depending on the setting of VRl. Cut wire sensor Pin 9 of IC2c is normally held low by a link which connects the CUT terminal to ground at the sensor. If the sensor wires are cut to try to defeat the system, pin 9 of IC2c is pulled high by R16 and its pin 10 output switches low. This in turn pulls pin 11 ofIC3e low via DlO and thus turns Ql on to trigger the alarm. The camera circuit now goes into AUTO mode and takes a sequence of photos until the film counter (ICl) reaches zero. SW6 functions as the TEST switch. When this switch is closed, it pulls pin 9 of IC3d low and this enables the camera circuit so that its various functions can be tested independently of the central alarm system. If, at any time, the photographic option is not required, it can be disabled by opening SW7. The alarm system will still trigger via the slave relay (RL1) however, either due to the sensor detecting movement or the wires being cut. Note that if the alarm times out, then the camera circuit will be disabled even if there is still film available. Power supply Power for the circuit is derived from +12V and +8V rails in the main alarm system. Fig.Z(a) shows how a suit.able +8V rail may be derived using a 3terminal regulator if this rail is not already present. Fig.Z(b) shows a suitable power supply for the circuit if it is to be used without an alarm system. The motor is operated by a separate 3V battery which connects via switching transistor QZ. This method was used because the start-up current of the motor is quite high and this may cause difficulties with some alarm PARTS LIST 1 PC board, code 03103931, 140 X 85 1 PC board, code 03103932, 105 X 57 1 motor drive camera (eg, Hanimex 35HL) 1 plastic jiffy box, 196 x 113 x 60mm 1 self-adhesive front-panel label, 186 X 100 1 motor-gearbox kit (Jaycar· Cat. YG-2712) 1 8-way SPST OIL switch (SW1SW8) 1 microswitch (S9) · 1 12V SPOT relay 8 2-way PC-mount screw terminal blocks 1 2 x AA square battery holder 1 1MQ trimpot (VR1) 1 100kQ trim pot (VR2) 1 75mm length of aluminium angle (25 x 25 x 3mm) 1 piece of aluminium sheet, 30 x 87 x 1mm 6 plastic cable ties 1 passive infrared sensor Semiconductors 1 4029 presettable up/down counter (IC1) 1 4011 quad NANO gate (IC2) 1 74C14 hex Schmitt trigger (IC3) 1 556 dual timer (IC4) 1 4N25 optocoupler (IC5) 1 BC548 NPN transistor (01) 1 BO649 Darlington transistor (02) 10 1N914 silicon diodes (01-03, 05-011) 1 1N4002 silicon diode (04) 2 5mm green LEDs (LED1, LED3) 1 5mm red LED (LED2) Capacitors 1 100µF 25VW PC electrolytic 1 47µF 25V PC electrolytic 1 22µF 25V PC electrolytic 2 2.2µF 16VW PC electrolytic 1 1µF 16V PC electrolytic 3 0. fµF metallised polyester 2 .01µF metallised polyester Resistors (0.25W, 5%) 14100kn· 210kQ 1 3.3kQ 31.5kQ MARCH 1993 35 Fig.3: here are the wiring details for the two PC boards & the passive infrared sensor (PIR). Take care with the orientation of the ICs when installing them on the main board & note that Q2 is installed with its metal face towards the relay (RL1). SWl-8 is the DIL switch & its settings are shown in the table below. PASSIVE INFRARED SENSOR - +12V NC COM NO 1 n1=1 GND +12V CUT SNO TO MAIN PCB DIL SWITCH SETTINGS Switch Function systems, particularly those with "power fail" detection. These batteries should last a couple of years and can also be used to power the camera. Finally, the circuit should not affect the operation of the back-up battery in the main alarm system since its standby current is only about 25mA. This rises to about 80mA when the relay and LEDs are on. Assembly Most of the parts are mounted on a main PC board coded 03103931. A second PC board (coded 03103932) provides interfacing for the motor and microswitch (S9). Fig.3 shows the wiring details. Comments SWl Film Set Open for logic 1 (MSB) SW2 Film Set Open for logic 1 SW3 Film Set Open for logic 1 SW4 Film set SW5 Reset Normally open. Resets film counter. SW6 Test Normally open. Close for testing. SW7 Activate Norma lly closed. Open to disable circuit. swa Auto Close for full sequence of shots at first triggering . Begin construction of the main board by installing the wire links, then install the resistors diodes, transistors, capacitors and ICs. IC sockets were used on the prototype but these can be considered optional. Be sure to install Q2 as shown, with its metal tab towards the centre of the board. Once these parts are in, the larger components can be installed on the board. These include the relay, the miniature DIL switch (SW1-SW8) and the two PC-mounting insulated screw terminal blocks. Fig.4 shows the dimensions of the mechanical parts. After the parts have been made, remove any burrs on them and make sure that the plunger fits Open for logic 1 (LSB) easily into its support bracket. The mechanism is designed around a motor-gearbox kit from Jaycar Electronics and a Hanimex 35HL motordrive camera. The motor sells for around $20.00 and the camera for about $50.00. All of the parts, apart from the main PC board, fit into a large plastic case as shown in the photos. The three aluminium brackets and the gearbox mounting holes can be used as templates for drilling mounting holes. You will also have to drill a large hole in the case directly in front of the camera lens. .The 0. lµF capacitor can now be soldered directly to the motor terminals, along with two flying leads which can later be connected to the interface board. This done, the brackets and motor-gearbox assembly can RESISTOR COLOUR CODES D D D D D 36 Value 4-Band Code (1%) 5-Band Code (1%) 2 100kQ 10kQ 1 3 3.3k0 1.5k0 brown black yellow brown brown black orange brown orange orange red brown brown green red brown brown black black orange brown brown black black red brown orange orange black brown brown brown green black brown brown No . 14 SILICON CHIP 14 I 12.5 ... "' ~ ~r'I. FRONT FRONT "' N '-IJ' -- I A PLAN PLAN A 15 PLUNGER MATERIAL: 25 x 25 x 3 ANGLE ALUMINIUM 25 PLUNGER SUPPORT BRACKET MATERIAL: 25 x 25 x 3 ANGLE ALUMINIUM SHAFT SUPPORT BRACKET MATERIAL: 25 x 25 x 3 ANGLE ALUMINIUM I I I I I I~ 10 zl ~I o, C> N HOLES: A • 3mm DIA B • 3mm DIA, CSK ... C> 1::: I I I I ~ z ffi• ml 20 - ~"' 50 I I I ~ I 20 f.-JL.-~ I 90 CAMERA HOLDING BRACKET MATERIAL: 1.6 ALUMINIUM ti: .. J-:=::::::::-:::::---i-•1--~ 1. . . . 1• • •1 .. 1. .. :I DIMENSIONS IN MILLIMETRES DRIVE SHAFT Fig.4: this diagram shows the dimensions of the three metal brackets, the plunger & the motor drive shaft. These parts may have to be varied to suit different cameras. be secured inside the case using machine screws and nuts. Note that the two mounting screws for the plunger bracket will have to be countersunk to clear the plunger. The dimensions shown for the motor drive shaft are for the Hanimex 35HL camera. If a different camera is used, then this distance may need to be altered. The microswitch is attached to the motor board using two screws and its normally closed contacts (ie, the two outer contacts) wired to the terminal block. If necessary, the microswitch can be adjusted by filing a slot in the PC board at the top mounting position. The motor board can now be slid partly into the case using the second set of guides and the leads from the motor connected. This done, the board can be pushed right down into the case so that the microswitch arm sits between the switch body and the motor shaft (see photo) . Don't install the wiring between the motor board and the main board at this stage - that step comes later. Testing To test the motor and plunger assembly, go to the interface board and MARCH 1993 37 The PC board was mounted on the back of the case but there's no reason why it cannot be housed in the case used for the alarm system if there's sufficient room. The IR sensor can also be mounted separately from the camera. temporarily connect the "+8V" terminal to the "M" terminal and connect the "H" terminal to the "GND" terminal. This done, connect the batteries. If the microswitch contacts are closed when the battery is connected, the motor will operate until the contacts open again (ie, when the motor shaft presses the actuating arm down). When the motor stops, momentarily short the "GND" terminal to the "M" terminal and check that the motor starts again and completes one revolution. If the motor continues to operate, adjust the position of the microswitch so that the motor stops when the actuating arm is pushed down by the motor shaft. At this point, the shutter plunger should be in its normally up position. When everything is working OK, remove the batteries °from their holder. The motor board can now be connected to the main board so that the entire assembly can be tested (do not connect the infrared sensor or install the camera at this stage). VR1 and VRZ should initially' be set to mid- The large cutout in the motor interface board is used to provide clearance for the motor. Don't forget to solder a 0.1µF capacitor directly across the motor terminals. 38 SILICON CHIP position and a jumper wire temporarily connected between the CUT terminal (middle of the board) and the GND terminal (top of the board). The "X" and "Y" terminals should be left disconnected and all of the switches should be left open except for SW6 (TEST) which should be closed. When the switches have been correctly set, reconnect the batteries and apply power to the main board. LED 1 and LED 2 should immediately light to indicate that the power is on and that film is available. Check that the slave relay operates if the SNO terminal is momentarily shorted to ground. The main board can now be tested for correct operation by closing SW7 (ACTIVATE) and momentarily shorting SNO to ground again. If all is correct, the slave relay will operate as before, LED 2 will light to indicate that the circuit has triggered, and the motor will start and complete one revolution. If the motor now keeps going or if it just starts and then quickly stops , adjust VRZ until it operates correctly. When the adjustments are correct and the motor stops turning, no further action should take place until IC4a times out, even if SNO is shorted to ground again. After IC4a times out, the sequence can be repeated. Now check that LED 2 goes out if the RESET switch (SW5) is closed. If it does, open SW5 again, close the AUTO switch (SW8) and momentarily short SNO to ground again. The motor should now start and stop as before and LED 2 should come on again. As soon as IC4a's delay ex- This close-up view of the motor-gearbox assembly shows how the motor shaft normally holds the microswitch arm depressed to keep its normally closed (NC) contacts open. OFFER- CRAZY BATTERY The first generation (XX 1080) passive IA night viewer lube features excellent gain. and when used with a ve ry low light objective lens, it can · produce useful images under almost as little as submoonlight illumination. Cal also be IR assisted. We will supply a XX1080 tube, plus a suitable Lens . plus a kit of parts for an EHT power supply (PC B and components only) for a total price of $299 Used air cooled ARGON laser heads, that produce a BLUE bea m ! Power output is in the 30-1 00mW range. Lim ited stock, at a fraction of thei r $600-800 ... real value: For the Argon head only. We also provide a circuit for a simple power supply . Item No. 0109 MARINE SEARCHLIGHTS two months ~ This prec1s1on collimator assemb ly wa s removed from working laser printers aod it is su pplied with an extra brand new laser diode to suit A produce s a well collimated lase r beam at 780n M/5mW . Barely visible . We also supp ly a PCB and components kit p lus instructions. for a suitable digital driver c1rcu1t that can be used to complete the laser transmitter . Suitable for commun ications , data ti11ks . perimeter protection . barcode reading. medical use . etc. $89 (Item No. 0 111 ) W e can also supply a sim ilar kit wh ich inclu des a laser diode, unmounted lens. and a driver kit. $45 (Item No. 0 111 X) Note that a suitable receiver for use in perimeter protection is the one published in E.A April 8 1. r· , ·- These new 0.5 metre diameter military grade search lights were made by LUCAS in the U.K. Th~y are painted grey and are almost totally made of brass , except for a few stainless steel screws and nuts, a mirrored glass parabo lic reflector, and a glass cover plate, T hey have a detachable mounting pillar which brings the total height of 1he searchlight and the stand to approximately 2 meters. Fully adjustabl e positioning and focussing . Supplied with a 1000W/240V quartz ha logen lam p (T11) : 23 ,000 lumens. A very impressive unique, product with many applications. Approximate weight of pillar and Spotlight is 60KG. $1100 (Rei :XXFEB93101) The $6 P+P charge doesn't apply to th is one!! "Ring " DI VER GING LEN S INDUCTIVE PROXIMITY SWITCHES ~l l'l" ,....____ $5.00 ea. LASER GUN SIGHT· . $23 Item No. 0161 NATIONAL SEM ICONDUCTOR seven segment . Common cat hode . 12 digit, multiplexed, LED display with 12 decimal points. Overall size is 60 x 18mm and a pinout diagram is provided . ONLY $2.50 ea.or 5 for $ 10. 12V OPERATED LASER BARGAIN $28 ~ . ·---~~~ A 5mW gunsight at an unbeatable price . $279 Item No. 0108 Includes one "Free" rifle or pistol mount. X .. ,-- - -- - = \1,)\~~\t;,';.\;· VISIBLE LASER DIODE KIT Brand new 5mW-670nM lase r diode , plu s a collimating lens, plus drive r kit, plus. hardware, plus instructions. $89 Item No. 0164 $38 ea. (Ref.XXFEB93101 ) Furthermore . here is the CRAZY OFFER. Buy three of these batteries at the above price . and we will deliver them to any ma il addresses in Austra lia at no additiona l costs! 1 YES $11 4 TOTAL COST, TO HAVE TH REE OF THESE B A TTE RfES DELIVERED TO YOUR DOOR !! We also have avai lable a su itable overn ight charger for these batteries (500m A) .. .$25ea . No additional delivery cha rge applies if the c harger/s is/are bought.with the above three battery oiler. These are new 16 character by 2 line alphanumeric LCD display modu les, with surface mount control ci rcuitry mounted on the rear of the display. Requ ire a few milliamperes at SV to operate, information included: Based on a brand new . very compact modern EHT llyback transformer which includes an EHT diode rectifie r. We supply the transformer, a very simple circuit, and the components to suit . All you need to make a very simple EHT, DC or pulsed AC supply. Powered from 12V DC supply. G reat for EHT experiments , EHT testing, pla sma displays, etc . Total price for the transformer and the components is ONLY ; , These industrial qua lity detectors wil l detect ferrous and non-ferrou s metals at close pro ximity . Some are DC powered (10-30V0, some are AC powered (Mains) . and all w ill switch loads directly. All have a three wi re for co nnect· ing in to ci rcuitry: Two fo r th e supply, and one for switc hing the load. LIMITED QUANTITIES at a small fraction of their real price : PRICE? EHT GENERATOR KIT 'I LED DISPLAYS A high quality laser beam diverging (bea m ex pander) glass lens. mounted on an aluminium plate. with mounting screws provided Dimensions : 25 x 25 x 6mm Use it to expand the laser beam tor Holography. Special Effects. or one of the two lenses requ ired to fine focus a laser beam . for Surveying and Bar Code Reading. . $79 (Item No. 0166) Note that an LSI surtace mount controller IC for this display is available. This IC has a built in ch aracte r set generator and many other features . It is compatible with 8080 and 6800 MPU's. The IC is available elsewhere for about $35 , and we will supply more information upon request . IR LASERS SPECIAL Brand new large 640 x 200 dot matrix LCD displays , made by EPSON - SEIKO, screen size is 120 x 265m m , has built in drivers. Four bit TTL intertace , a total of 14 connections are requ ired for signal and powe r (+5V, - 12V). Capable of displaying characters , graphs, patterns etc. 28 pages of information included. ON SPECIAL Jar Brand new industria l grad e PANASON IC 12V/6.5AH sea led gel batteries at a reduced price . Yes 6.5 AMP ERE HOURS! Use them in lighting , alarm s. commu nications. laser power suppli es. so lar systems etc . Dimensions: 100 x 94 x 65mm. Weight o f one battery is 2.2KG! The SPECIAL --- ~"<':"'"#'·:: •"' "" ;'_L_, r,..,· "°J""'•j,;·i ~-~,~---~ ~-. _) ~~ - , 1wo used 3mW Siemens HeNe visible red laser tubes, and one of our efficient 12V universal laser supply kits. $109 Item No. 00105X $18 5 $80 ea. or for (Ite m No. 0131) MASTHEAD AMPLIFIER KIT Based on an IC with 20dB of gai~. a bandwidth of 2Ghz and a noise figu re of 2,Bdb this amplifier kit out performs many other IC's , and is a fraction of their cost. The complete kit of parts for the masthead amplifier PCB and components, and the power and signal combiner PCB and components, is priced at an incredible : $18 Fore more info rmation see a novel, extremely popular, and an ·effective active antenna design which employs this amplifier: MIRACLE T V ANT ENNA - E.A. May·-1992. TUNING FORK in -- SIX DIFFERENT MOTORS FOR A TOTAL COST OF $30. ULTRASONIC BURGLAR ALARM KIT ···• • ·. ·· . '! , ' ' ., . . . Each one of these ide ntical PCB filter assemblies contains six three terminal tuning fork l ifters (IN•GNDOUT), at different frequencies in the audio range: 1.8·3 .1 Khz. These high quamy dual fork filters have very narrow bandwtdths , and could be use d as the basis of a selective call system , high stability osci llators etc. $20a pair, Sma ll PCB Assembly based on a ULN22321C. This device has a bu ilt in light detector , fil ters, timer, narrow angle lens, and eve n a siren driver circuit that can drive an external speaker. Will detect humans crossing a narrow corridor at distances up to 3 metres. Much higher range s are possible if the detector is illum inated by a remote visible or IA light source . Can be used at very low light levels . and even in total darkness. W ith IR LED . Full information provided . The IC only . is \-.\.irth $16! OUR PRICE FOR THE AS~~BLYIS : ;Jib EA. OR 5 FOR $25 Item No. 0163 D.C. MOTORS · We have good stocks of 5 different high quality JAPAN ESE DC Motors. These should suit many industrial, hobby, robotics and other applications . Check out the SPECIAL prlces, and com pa re! M1 • 24V, I No load = 50mA · 22 ,000 RP M at 24V, main body 28mm Diam - 40mm long ... $5.50 M4 • 3-15V, I No load, 20 mA at 12V, main body 3 1mm Diam · 22mm long ... $ 3 M5-3-15V, I No load • 60mA · 5700 RPM at 12V, main body 28mm Diam • 40mm long ... $2.50 M9-12V, I No load= 0.52A · 15,800 RPM at 12V, ma in body 36mm Diam • 67mm long ... $8.50 M 14 • Made for slot cars. 48V, I No load = 0.84A at 6V, at max efficiency 1,,. 5.7A. 7500 RPM, main body 30mm Diam - 57mm long ... $9.50 Further to the above special prices, during Feb.-March we are offering an introductory package w hich includes O NE O F EACH O F TH E ABOV E MOTORS, and one of the STEPPER MOTORS advertised elsewhere in this ad . (Item No. 0 140) . PROJECTION LENS .a See S.C. May 88 for this high quality crystal locked ultraso nic design. Ca n be used as a detector or a self standing alarm , has provision for bonnet/boot protection and flashing light and back up battery . Easily combined with ou r U.H. F. Remote Control. CL EARANC E PRICED AT ONLY: $29.90 (Cat. No. GK125) For the P.C. B. and all parts, except the screw term in als. A pair of ultrasonic transducers is included!! DON'T MISS OUTI ELECTRONIC KEY KIT =·- ~ Main body has a diameter of 117mm and is 107mm long. The whole assembly can be easily unscrewed to obta in three very large lenses : two plastic and one glass. The basis of the cheapest large magnifier or projection sy$1em? Experimenters delight at ON LY$28 - "~'~.,.~.~~ strikers for entering buildings, car alarms , central locking , the most secure key ever (See E.A. July 92): ON $49.90 SPECIAL<at> For two keys, and one decoder kit. Cat. No. GK138 . !afl~f~!~!s~~~•cs I/ f:-Telephone : (02) 579 4985 Fax : (02) 570 791 0 1..i • MELBOURNE AGENT TRUSCOTT S (03 ) 723 3860 ..... MAJOR CARDS ACC EPT ED WITH PHONE ,. . FAX ORDERS . P+P . ~:~.''!'· . . • i,,.,,£,Q.R MOST MI XED ORDERS : AU STRALIA : $6. N .Z . !Air Mail) : $ 10 :-c. • ,-.·~ Each time the motor starts, the motor drive shaft operates the plunger, the camera shutter trips & the camera automatically "winds on" to the .next frame. The motor drive shaft also releases the microswitch arm to ensure that_the motor completes one full revolution. pires, this cycle should repeat automatically and continue to do so until the film counter reaches zero. At this point, LED 1 (FILM) should extinguish and the motor should stop permanently. If all is well so far, reset the system again (by closing and opening SW5), open SW8, and remove the link fitted between the CUT terminal and GND (this simulates the sensor wire being cut). The slave relay should now come on and stay on, while the motor should operate repeatedly until the film counter reaches zero. Finally, the camera can be installed in the case and tested for correct operation. There should be a small clearance between the bottom of the plunger and the camera button, otherwise the button may not fully release. If this happens, the film will not automatically wind on. Note that the base of the camera may need a bit of packing under it to wedge it into the correct position. 40 SILICON CHIP Don't forget to open SW6 (TEST) when the above test procedure has been completed. . ALARM REL~Y CONTACTS +t2V 1 IC5 4N25 ALARM SYSTEM Installation On the prototype, the main board was mounted on standoffs on the outside of the lid and secured using screws and nuts. Alterna-· tively, it could be mounted in a separate case or, if there is sufficient room, inside the case used for the central alarm system. Obviously, the camera must be installed in a location so that it doesn't stand out. Some houses are fitted with removable vents in the walls near the roof. This makes an ideal spot in which to hide the camera, although you will need to cut a neat hole in the vent X .....,_-------0-----, y DV R20 3.3k (a) X +t2V IC5 t 4N25 ALARM SYSTEM Y R20 3.3k ALARM RELAY CONTACTS DV (b) Fig.5: the alarm s_e curity camera is armed using a relay in the main alarm system. Connect the X & Y inputs as shown in (a) if this relay switches to +12V & connect them as shown in (b) ifit switches to OV. so that the camera lens can "see" the room. Another approach would be to fit the unit into a strong steel box and use "Bandit" glass over the lens opening. This could then be mounted up high in a garage or workshop. When the camera unit is in position, the various connections can be run to the central alarm system. These include the power supply connections, the "X" and "Y" terminal connections, and the (optional) slave relay contact connections. Fig.5(a) shows how to wire the "X" and "Y" terminals if the external alarm relay switches to +12V, while Fig.5(b) shows how to wire the terminals if the external relay switches to ground (GND). The infrared sensor can either be mounted on the camera box or installed separately. It should be wired to the main board as shown in Fig.3. Satellite siren Because the camera generates some noise while it is operating, a small piezo siren should be mounted inside the room. This siren should be wired to sound at the same time as the main alarm siren and will mask any sounds from the camera. As a bonus, it will also annoy the intruder with its piercing sound and hopefully encourage him to leave quickly. · The flash on the camera should be turned off to ensure good battery life. This means that the system as described will only work satisfactorily during daylight hours or if the lights are on. It cannot produce useful results if the room is in darkness. Note that, for normal operation, switch SW7 (ACTIVATE) -is closed while switch SW6 (TEST) is left open. SW8 should be closed for AUTO operation, while switches SW1-SW4 should initially be set to suit the number of shots on the film. For 12 shots, leave SW1 and SW2 open and close SW3 and SW4 (leave all switches open for a maximum count of 15). Switch SW5 (RESET) is normally left open. It should be closed and then opened again when· the camera is set up to reset the film counter. After that, it is only used to reset the film counter if it counts down to zero. If the unit is to be used on its own, . connect it to the power supply shown in Fig.Z(b). The unit can then be armed or disarmed by connecting the Y terminal to GND and using a hidden SC03103932 Fig.6: here are the full-size etching patterns for the two PC boards. switch to connect the X terminal to the +12V rail. This switch will have to be located somewhere near the front door, so that you don't trigger the unit while you are leaving the house. One last point: it's worth keeping any security system like this a secret. Word does get around. SC MARCH 1993 41 SERVICEMAN'S LOG The search for the missing link I hardly need emphasise that the service game is mostly about diagnosis. Once a fault has been diagnosed, the repair is usually routine. But finding the fault is the real job & this one took months to find & seconds to fix. The set concerned was a Samsung 34cm colour TV set, model CB 349Z. The "Z" suffix indicates a remote control version, while an "F" suffix indicates a standard version. Both use the P50F chassis. The owner uses this set in two locations: at his Sydney home and at a holiday cottage down the coast. As a result, the set has been programmed for city VHF channels 2, 7, 9 & 10, SBS UHF channel 28, and south-coast UHF channels 30, 33, 42, 45 & 48. But that is more or less by the way, except that the large number of channels emphasised the fault's nuisance value. The fault itself was a tendency to spontaneously change channels. In greater detail, it didn't simply jump from one channel to another; it would go into a search mode which took it Our loss is your gain Fracarro's ESVU2. The really low loss VHF/ UHF mixer with areasonable price tag. Peter C. Lacey Services Pty. Ltd. P.O. Box 678 (74Fulton Rd.) Mount Eliza 3930 Tel:03 787 2077 Fax:(03) 787 3460 ACN006893438 42 SILICON CHIP right through the 10 channels, then· repeat this procedure, before finally going into standby mode. Turning the set off and on again would usually cure the fault temporarily and it might then work normally for a few hours, several days, or even weeks. And, as I established later, it didn't seem to matter whether the set was hot or cold. Nor was there any other pattern to the fault. In short, it was completely unpredictable. Search function The search function just described is a quite legitimate feature in this set. Basically, it is a self-seeking, automatic tuning function, its primary purpose being to facilitate the initial setting up of the channels. There are two sets of UP/DOWN buttons in the system: the search buttons and the channel selection buttons. It is important to clearly differentiate between the two. The setting up procedure is initiated by activating one of the two search buttons (UP or DOWN). This causes the set to search until it receives a signal of adequate strength to lock onto, while very weak signals are ignored. In the unlikely event that no signals are detected, the system will search right through both the VHF and UHF bands, then go back to the beginning, repeat the search, and go into standby mode. In practice, of course, it would normally lock onto a signal somewhere in either the VHF or UHF band. When it does, it stores this channel in memory, waits for the button to be pressed again, then continues the search, stores the next channel it locks onto, and so on. When all the available channels have been stored, they may be selected in two ways: (1) sequentially by using the UP or DOWN channel select buttons on the front of the set; or (2) directly by pressing the appropriate channel number on the remote control unit. And how doEls the system know when it has found a channel? The relevant part of the circuit is shown here, including the PWB-CONTROL board and a section of the PWB REMOCON (remote control) board. Most of the work is performed by RIC01 (M50431), the main IC in this section. Pin 12 of this IC is fed with sync pulses and these provide the locking command. So inuch for the general background. When the customer described the fault, I immediately took the precaution of warning him that, since it was capable ofrurining OK for weeks at a time, it could well take me many weeks to find the cause. Fortunately, he had anticipated this and added that he had another set which would serve in the meantime. And just as well as it turned out. RR65 • RC11 ', UND : 1 SY '' -l RR36 1W,24»< RC06 1 t60V 1, '' ' '' RR40 I., 11< RR4 I 4. ?K sov,1,.. RR4 RR37 10K ~ K5C815-Y ROOS l-: 25C1815-\ RC09 2K RQ04 K~C81S·Y 2SC1815-Y RC01 Tip, 334 I0334 f tOOV I • -: IOOV RC08 22 130CH I R014 ROO? UPC574J JN4148 IBfil2l I START l 1:, _ _ _ " ROIS €e ~;;~,22 RC12 30 RR63 10K C !1i 0 ' a, ' ,... 82 I Reos• 103.SOV ~ RR67 30K RR33 30K RR32 I0K RR34 10K RR35 30K Fig.1: the relevant circuit section of the Samsung CB 349Z TV receiver. The microprocessor controller (RIC01) is on the PWB-REMOCON board & locks onto sync signals on its pin 12 input. The PWB-CONTROL board is to the left of this board and carries the display unit and most, but not all, of the control buttons. The fault was hidden under other components. Knowing how the system sensed the presence of a signal, my first step was to check pin 12 ofRlCOl for sync pulses. Because of the intermittent nature of the fault, all I could do was switch the set on and wait for the fault to appear. It took its time but, after a couple of days, it eventually showed up. I checked pin 12 with the CRO but there were the sync pulses, exactly as before. So that ruled out that theory. I wasn't quite sure where to look next , so I decided to see whether Samsung's service department had any ideas. After all, there is not much point in spending many hours trying to track down a fault when someone else has already been there and the · details are on record for the asking. So I rang Samsung outlined the symptoms, and asked whether anyone else had encountered the problem. The technician had not heard of any such fault but immediately made his own diagnosis. "Oh yes, the problem is the microp'rocessor chip, RICOl. Replace that and it should solve your problem". Frankly, I was highly sceptical of this suggestion. It had all the earmarks of a snap diagnosis, based on the obvious, but without too much thought about the fine details of the symptoms. On the other hand, the set was still under warranty, and if they were prepared to cover the cost of supplying and fitting a new IC -with 42 pins - who was I to quibble? So a new IC was ordered and duly fitted. And that solved the problem, or so it appeared. The set ran for over three weeks and never missed a beat so, when the customer called one day to check my progress, I suggested that he take it away. After all, it might just as well be tested in his lounge room as on my workbench. But I warned him that, in spite of Samsung's suggestion, and my bench testing, I was still not convinced. If it failed, he was to bring it back immediately. Several more weeks went by with no word from the owner and I was beginning to think that Samsung had been right after all. The next thing I knew, the set was back on the shop co·unter. "It went real beaut until yesterday. Then it was up to it's old tricks; really bad". Control board So we were back to square one. Well, almost; at least I could now rule out the IC. In the meantime, I had noted one more aspect of the fault; it always searched up, never down. On this basis there seemed to be only one line of investigation left: the control board (PWB-CONTROL) and, in particular, the channel UP and search UP pushbuttons. If one of these somehow jammed on, either mechanically or electrically, it could create this effect. The' PWB-CONTROL board measures about 200 x 600mm and sits at the front of the set beneath the picture tube. It is offset to the right, with the speaker in the remaining lefthand space. As well as the pushbutton controls just mentioned, it also carries the volume, contrast, colour, fine tuning and on/off controls, plus the remote control receiver and the channel number display. MARCH 1993 43 Fortunately, this board is fairly easy to get at by slipping the main chassis out and undoing several screws. The main chassis can then be replaced, giving a working set with the control board accessible behind the cabinet. So, with everything set up like this, I waited for the fault to re-appear. The set then ran for weeks without any sign of trouble but eventually it did misbehave. When it did, I tried twisting and bending the control board and this provided the first confirmation that the fault really was on this board. I could more or less create or cure the fault in this way. But I say "more or less" because I could not establish any exact pattern that would affect the set's behaviour. On some occasions, the fault seemed to be at one end of the board, while at other times it seemed to be at the other end. And sometimes twisting was the most effective, while at other times bending seemed to work. Whatever it was, I just couldn't pin it down. But with the board clearly established as the culprit, a replacement board seemed the logical answer. The only problem with this was that, when I called in on Samsung, there were no boards in stock. Instead, they were "on back order, delivery date indefinite". How often have I heard that phrase! At this point, I had two choices: either wait, for who knows how long, for a new board or fix the old board myself. If it was to be the latter, then I needed help more than ever. I tackled 44 SILICON CHIP the service department again, determined to check out everyone if necessary in order to get a clue. Fortunately, the first bloke I buttonholed was quite helpful. He listened carefully and didn't make any snap diagnosis. On the contrary, I could tell by the expression on his face that the wheels were turning. Yes, he had heard of such a fault. Well, that was the good news. The bad news was that it was so long ago and had reached him by such a devious path, that he couldn't recall much in the way of detail. In fact, he couldn't recall anything initially but, after much brain racking, he came up with one thought. It concerned the wire links on the PWB-CONTROL board and, in particular, the possibility of two of them touching. And that was all the help he could offer. I thanked him and went on my way. At least it was something but, on the other hand, it didn't seem to make TETIA TV TIP Hitachi VT-640E VCR Symptom: Machine does not want to accept cassette. If the cassette is pressed into the cassette carrier and held there for several seconds, the machine will accept it briefly then immediately eject it. A repeat performance may finally persuade the machine to accept the tape. Cure: Replace the tape end sensors in the cassette housing . Faulty sensors give the control microprocessor the wrong information and makes it think a cassette is already installed. A clue is that the machine can be put into play mode without a cassette in place. TETIA TV Tip is supplied by the Tasmanian branch of the Electronic Technician's Institute ofAustralia. Contact Jim Lawler, 16 Adina St, Geilston Bay 7015. much sense. There are several links on this board but I couldn't imagine how any of them could touch. This was confirmed when I checked the actual board - there was no way any of the links could touch each other, or anything else for that matter. Yet, for all his vagueness, the technician had been adamant that the fault involved the links. Display unit More or less in desperation, I went back to my twisting and bending routine. The set's behaviour was much as before except that I gained the im, pression that the area around the channel number display unit (top left of Fig.1) was marginally more sensitive. This didn't make sense. The display should have no electrical connection whatever with the control functions. Nevertheless, I had to be sure. The display unit is a dual-inline, 18-pin package, fed independently from the PWB-REMOCON board via plug/socket CNR03. This all seemed perfectly straightforward until I took a closer look at the copper side of the board around the display unit. It was easy enough to account for the copper tracks running to the display unit but there were other tracks as well, with several connections coming through from the component side that obviously did not belong to the display. Well, there was clearly no alternative; the ·display unit had to come out. It wasn't all that difficult and when I finally pulled it away, the cause of all the bother was plain to see. Hidden under the display unit were four extra w,ire links. And two of them had been bent so that, at best, they were only a gnat's eyebrow apart and, at worst, were actually touching. In this situation, almost any variable (temperature, vibration or attitude) can change the status of these links, which is a flash way of describing an intermittent. The irony was that having found the fault, it took less than 10 seconds with a screwdriver blade to cure it. But that's the way it goes; finding the fault is the real job. What caused it? But how did the faulty condition come about in the first place? It seems unlikely that the links were bent in that formation when they were fitted, so what happened? From what I could work out, it would appear that the links were sitting too high on the board when they were initially fitted, either because they had not been pushed down far enough or because they were bowed slightly upwards. Either way, they would be pushed sideways when the display module was fitted. It wouldn't have mattered if they had both moved in the same direction, but Murphy saw to it that they moved in opposite directions towards each other. And he also took care to see that they did not touch each other while the set was tested; that had to wait until it was in the field. Well, that's enough from my bench for the month. Let's now take a hop, step and a jump across Bass Straight, for a story from our colleague J. L. in Tasmania. The fishnet VCR This story comes from a colleague who lives and works in the country, 100km from the city. It concerns a Teac video cassette recorder, model MV307, with a very obscure problem. The customer complained that watching a video recording or the ABC on VHF channel 2 was like looking at the program through a nylon fish net. The commercial VHF station and SBS on UHF showed no signs of the trouble. In fact, the "fish net" turned out to be shimmering white lines that flickered across the screen in a diagonal pattern. They were never still and moved at a constant speed. In all other respects, the picture was normal and was quite watchable if one could only ignore the white lines. The customer put up with the lines while watching video recordings but took to feeding the TV receiver directly from the antenna, bypassing the video recorder, to watch channel 2. But this introduced another problem. They were in a remote area and he had come to rely on the extra gain provided by the video recorder's frontend amplifier. Without that gain, the picture from channel 2 was not so good and so he eventually decided that the recorder just had to be fixed. My colleague soon found that the fault was a fundamental one. It not only appeared on the off-air TV program and pre-recorded video tape signal, but could also be recorded onto -WHA1'"'S MORE: 11"" WAS STlt-1IHe: SAME. ~'HEAVY 'RA\N .. .,. tape and replayed on any other machine! This particular fault was not an easy one to diagnose. At first glance, it looked as though it could be a power supply problem since similar problems in TV sets had been traced to this source. However, the nature of this problem - though not the extentcould be changed by altering the tuning of channel 2 on the recorder. This suggested a possible fault in tuner. Since my friend did not have a service manual for this model, he contacted a colleague who does have a manual and asked if he would care to take over the repair. This serviceman works in the city but, after the most exhaustive testing, he could find absolutely nothing wrong with the machine. It tuned and recorded channel 2 perfectly. He did reset the tuner AGC in case of problems there but otherwise he could do nothing to help. And so my friend took the machine home and tried it again. The fault was still present, which suggested that it was related in some way to the weaker signal at his location. For a time, he thought that the trouble might be due to interference from noisy power supply lines. However, the trouble was identical at both the customer's home and at my colleague's workshop. What's more, it was still the same after heavy rain. MARCH 1993 45 '1k«,, 1:J~ ,l!:euu;e ,li:eteaae li : i:11::~:1,t:m:1:mi::i i :i l :il i:l :¼JE;l:1: 1;1:1 :1 :11il il i ffl.il !l i! : 1:1: ~11:1;:: : :i :il i ~ ll::~:m:1:1:1:!l il il i: : 1: 1 11 1:1:l:imil il l!;.1:~::i ~ ZI - I ~ OFFERING i-"'""'"!'_ 11 _ _ _i EXTRA SIZES a MORE ACCESSORIES LOWER PRICES 11 NATURAL or BLACK ANODISED FRAMES II FOREST GREY or BLACK TEXTURE COVER FINISHES READER INFO NO. 6 THE UNIQUE ZIP-RACK DESIGN SIMPLE,FAST & EFFECTIVE THATS ZIP-RACK Twelve lengths of ZIP-RACK hollow section aluminium extrusion are interconnected using black ABS plastic corner connectors. This requires only a rubber mallet or similar tool. The assembly is self aligning and can be further strengthened by 'pop' riviting the overlapping flanges at each corner. TYPE 46 RACK DATA: RACK WIDTH 540mm. RACK DEPTH 460mm. 1U (RACK UNIT) =44.45mm OR 1 3/4". FOR EQUIPMENT/PANEL CAPACITY DEDUCT 90mm FROM TOTAL RACK HEIGHT ZIP-RACK FRAME sro'.DEN[IliAPK lll 1) :; ~si~j 268 357 490 F04 F06 F09 II C12 C15 C18 624 757 890 C24 C30 C40 1157 1424 1868 6/01BK 6/02 6/03 6/03BK 6/04 6/04BK CT2 CT3 CT4 ZIP-RACK is made by "The ZIP-RACK Company" Factory 2, 7 Michellan Court, Bayswater Victoria 3153. Australia. Under licence to AUTOTRON AUSTRALIA P/L. The ZIP-RACK Designers Beware of illegitimate copies without the ZIP-RACK name. For product sales, wholesale pricing & product literature Phone: {03) 729 7255 or Fax: {03) 729 6017 SERVICEMAN'S LOG - CTD So the idea of mains-borne interference had to be discarded. In any case, the interference pattern was nothing like that normally caused by faulty mains insulators and hardware. Next up, he phoned Teac in Sydney and asked their technical department if they had any answers to the problem. He wasn't particularly pleased when their only suggestion was that he should check the antenna. I suppose that might be a typical first response to a question posed by an uninformed owner but it's hardly likely to impress an experienced serviceman. Anyway, the conversation continued for a time and eventually all concerned came to the conclusion that the trouble must be in the tuner. So a new tuner was duly delivered and fitted but to no avail. The problem continued. Another call to Teac produced the suggestion that perhaps it was a power supply problem. Nobody could offer a convincing explanation as to what was happening but an offer by Teac to investigate the supply was too good to miss. My colleague removed the supply from the chassis and packed it off to Sydney. But again it was all to no avail because Teac could find no fault of any kind. After this, the machine sat on the bench for several weeks. In the meantime, the owners had borrowed another machine. This machine worked perfectly at their location and finally scotched any suggestion of local interference being the cause of the trouble. After that, each time he came to town, my colleague would ask some of our mutual friends if they had ever seen the trouble. He had a recording of the effect which he would play to anyone who showed the slightest interest in the problem. It almost reached the point where he took on the nickname of "Fishnet". But nobody had ever seen or even heard of the problem. · And so time passed and the machine sat gathering dust, until one day my colleague was called to another job which really did involve mains-borne interference. In this case, the owner had obtained a copy of the Department of Communications booklet on TV reception problems. He was into self-help and only called on my friend when he reached the stage of needing professional help. It was while browsing through the DOC booklet that my friend came across an idea that he felt might be worth trying on the Teac recorder. This suggestion involved winding a TV receiver power cord around a ferrite rod to minimise mains-borne interference into and out of the set. Back at his workshop, he lost no time in salvaging an antenna rod from an old portable radio. It was about 13mm in diameter and 100mm long. He wound the power lead onto the rod, fitting as many turns as possible. At switch on, he was amazed·to see that all traces of the fishnet interference had disappeared. The picture on all channels was as clean as one could ever wish. Just to make sure, he began to remove turns from the rod. The first three of four turns made no difference but then a faint trace of the fishnet pattern became visible. And, as he removed further turns, the pattern became stronger and stronger, until it had returned in all its annoying glory. He repeated the experiment at the owner's home and found that it worked just as well there. So the machine was eventually set up with a dozen or so turns of its power lead wound around a ferrite rod, tucked into the back of the video cabinet. We have had long and detailed discussions on the problem and the most likely answer is that it is a power supply fault. Radiation from the recorder's switchmode supply is one possibility, perhaps caused by the accidental omission of a suppression component during assembly. Ferrite beads are often fitted to the emitter leads of chopper transistors for just such suppression purposes , so this suggestion is not entirely fanciful. The problem is that the fault doesn't exist in strong signal areas. This means that it would never have been detected during factory tests, nor would it have ever been detected if the machine had gone to a city-dwelling owner. At this point my colleague doesn't feel like recalling the machine and working over the power supply. If it ever comes in again, he will look into that possibility but for the time being the makeshift mains filter solves the problem. Footnote And now for a footnote. At a recent meeting of the Tasmanian Division of TETIA, the fishnet problem was raised yet again. Discussion circulated ad nauseum but one member joined in with more than a little interest. It turned out that he had an identical machine with the same problem in another low signal area. Our colleague could not wait to get home to try the ferrite rod exercise. We've not yet heard whether it was succei,sful. So far, on the basis of just one unit, the idea of a factory error appeals strongly. However, it could be a design problem - the Teac MV 307 is a fairly new model, so there may not be too many of them in country areas where weak signals . allow the problem to reveal itself. It will be interesting to hear if the fishnet turns up in other places. SC MARCH 1993 47 12 Double sided copper coated fibreglass PCB. These are offcuts from a PCB various sizes. We have rough ly separated them into 2 different size (large and smal l) and we cannot guarantee that you will receive these actual sizes. SMALL - approx 100 x 300mm Cat. HP-9522 ONLY $1.00 LARGE - approx 200 x 260mm Cat. HP-9524 ONLY $2.00 VOLT FLASHING FLOURESCENT LIGHT FITTING Another surplus stock purchase Limited quantity- grab one while they last. This unit was designed for use as an illuminated flash ing sign, F probab1y for cars. It looks a bit like the signs you see on taxis. It incorporates a 40 watt Li-shaped flourescent tube (supp lied) and it's housed in awhite plastic case size 760 x 305mm with an opaque I1Iusrrateawimourperspex cover ·· white perspex cover. It has a dual timer - one to delay operation between 1 and 4 hours, and the other to control the duration of operation between 1 and 4 hours. There is also a reset switch which halts the flashing, so could be shorted out to stop the flashing totally. Ideal for shop advertising, by using awhieboard marker. you can eas ily change the message, or even in the windows of cars in a car yard. As parts it contains a 40W inverter to run a fluro from 12V, and a dual ti mer board. Made in New Zealand. Flash rate3 sec on 3 sec off. Cat. ST-3050 f· lr - r. A Bargain at $49.95 Have you been through the trauma of having your house burgled? This kit will automatically capture the thiefs action on 35mm film using a passive infra red sensor and almost any motor driven 35mm SLR camera. Imagine you've just returned home to find your house robbed. Yes, the alarm went off, but was ignored by the neighbour as a false alarm. A cal l to the police reveals that they know of a burglar operating in the vicinity but they don't know who it is. "We'll get himsooner or later" is the reply. Wait a minute - the camera! Yes its taken some shots. Within a couple of hours the fi lms processed and there's the burglar 1 TheJaycar kit includes 2 x PCB's, box, panel label and al l specified components. Motor gearbox extra Cat. YG-2712 $21.95. Cat. KC-5130 $49.95 PRO QUALITY INSTRUMENT CASE This box is the largest one in the range of 3. It has been used in countless kits, including test equipment, power supplies etc., etc., etc. Grey colour, with black plastic panels. Size 260(W) x 190(D) x 80(H)mm. Catalogue price is $20.95. We're overstocked. Stock up now at this crazy price. CatHB-5910$12.95 ea SAVE $8 SLASHED -- r---------------------, STETHOSCOPE See Electronics Australia January 1993 Build a 200W rms subwoofer. After the June subwoofer article which featured our 8" subwoofer, EA was beseiged with requests for a higher power unit. They have used our Re/Sponse 12" driver and we have had cabinet kits made to suit. SPEAKER Re/ Sponse 12" driver Cat. CW-2145 $199 CABINET KIT The cabinet is not cheap, but we found that there is an enormous amount of work for the home constructor to line up all the wood, drill and screw. Our cabinet kit is made from 18mm MDF customwood, as recommended in the article. There are 64 holes pre-drilled to fix the 32 x 50mm screws supplied and needed for strong assembly. The baffle has been routed and the T nut sockets are-in place to mount the driver. There is a 50mm round hole to mount the rear terminal which is supplied. The MDF customwood is supplied in a natural state with a view to painting Low-cost audio mixer for camcorders Jazz up your home videos by mixing in some background music from either CD or tape. This simple 2-channel mixer runs off a 9V battery, uses only one common IC & can be built in a couple of hours. By DARREN YATES Although camcorders have made home-movie "blockbusters" easier to make than ever, the soundtrack on most of these recording is usually pretty boring. Most of the time, you find that it's just people talking, while sometimes there is no significant sound there at all. Again the age-old question comes up: "wouldn't it be nice if... ?" This handy 2-channel audio mixer is ideal for adding some "aural interest" to your home videos. It allows you to mix the camera recorded audio with audio from an external source when you copy the camcorder tape to VHS format on the VCR. Generally, the extra audio to be added to the soundtrack will come from a CD player or tape deck, but you can use other audio sources as well. In operation, you simply feed the audio output from the camcorder into one channel and a (mono) signal from the external source into the other. The relative levels of both inputs can then be adjusted using the Channel 1 and Channel 2 level controls, while a Master control sets the overall output level. The maximum output level is about Two of the RCA sockets accept mono input signals from the camcorder & an external music source, while the third provides a mono output for the VCR. The front-panel controls allow the input & output levels to be adjusted. 50 SILICON CHIP 4Vp-p, which is more than ample for any VCR. An on/off switch completes the front-panel line-up, while input/output connections are made via three RCA sockets mounted on one side of the case. The remaining parts are all mounted on a small PC board and this fits neatly inside a small plastic case. These parts are all readily available and, in fact, you may already have most of them sitting in your junkbox. Circuit details Refer now to Fig.1 for the circuit details. As you can see, there's not a lot to it. ICl is a TL064 quad FETinput op amp package. Three of its op amps (ICla, IClb & ICld) are used to mix the audio signals, while the fourth (IClc) is used to provide circuit biasing. At the channel 1 input, the incoming audio signal is AC-coupled via a 2.2µF capacitor to level control VRl. The resulting signal is then fed to pin 3 of ICla via a lkQ stopper resistor to reduce the op amp's sensitivity to RF breakthrough. ICla is configured as a non-inverting amplifier with a gain of 3.2. Its high frequency response is rolled off above 72kHz by the lOOpF feedback capacitor between pins 1 & 2, while the low frequency response is rolled off below 7Hz by the lOkQ resistor and its series 2.2µF capacitor. IClb is used to amplify the channel 2 signal and works in exactly the same fashion as ICla. The outputs from these two op amps (at pins 1 & 7) are then mixed via two lOkQ resistors and applied to pin 12 of ICld via master level control VR3. ICld also functions as a non-inverting amplifier with a gain of 3.2, while VR3 sets the overall signal level at the output. Power supply Power for the circuit is supplied · from a 9V battery, with IClc used to Fig.1: the circuit uses IC1a & IC1b to amplify the input signals which are fed in via VR1 & VR2. The amplified signals are then mixed via 10kQ resistors & applied to op amp IC1d via level control VR3. IC1c is used to derive ±4.5V supply rails from the 9V battery. 10 14 + 100pF ~ · 1&VW ~ 47kI 22k OUTPUT -f 22k 10k 10k 2.2 + 18VW+ 2.2 + 25VW+ POWER S1 ~~-----------~+LSV 100pF 22k J_ ,---....---.... T 9V: ..&.. 10 + 10k 18VW 2.2 + 18VW+ -----------------u-4.SV AUDIO MIXER FOR CAMCORDERS derive ±4.5V supply rails. This op amp acts as a buffer stage, with its inputs and output biased to half the 9V supply from the battery. Its output (pin 8) can sink and source up to 20mA of current and this becomes the circuit ground rail. By using this arrangement, the positive terminal of the battery becomes the +4.5V rail, while its negative terminal becomes the -4.5V rail. All circuit connections to ground are connected to the output of IClc. This configuration is necessary to prevent clipping of the negative-going portions of the audio input signals. The circuit consumes about 4mA, which means that a 9V battery should last for approximately 100 hours. CHANNEL 1 INPUT CHANNEL 2 INPUT OUTPUT ,!' ,,J .t Construction Most of the parts are installed on a small PC board coded 01112921 (103 x 52mm). Fig.2 shows the assembly details. Begin the board assembly by installing the resistors, then fit the capacitors and the IC. Either 5% or 1% resistors can be used here and it's a good idea to check each one using your DMM before mounting it on the board. The resistor colour codes are also shown in the accompanying table to prevent confusion. Most of the capacitors used in this circuit are electrolytic types, so pay special attention to their polarity. Take care also when installing the IC; pin 1 of this device is adjacent to a notch in one end of the plastic body. If you do install the IC the wrong way around, it will self-destruct as soon as power is applied. The board assembly can now be completed by mounting Fig.2: install the wire link under IC1 before installing any of the other parts on the PC board. The wiring to the pots & RCA sockets can be run using rainbow cable. MARCH 1993 51 PARTS LIST 1 PC board, code 01112921, 102 x54mm 1 PC-mount battery holder (to suit 9V battery) 3 RCA panel mount sockets 3 knobs to suit 1 plastic zippy case, 130 x 68 x 41mm 4 rubber feet 1 SPST toggle switch 3 10kn log potentiometers (VR1-VR3) Semiconductors 1 TL064 quad op amp IC Capacitors 4 10µF 16VW electrolytics 5 2.2µF 16VW electrolytics 2 100pF ceramic Resistors (0.25W, 1%) 3 47kQ 5 10kQ 3 22kn 2 1kn Miscellaneous Hookup wire, solder, screws, nuts & washers. The PC board is secured to the bottom of the case using machine screws & nuts, with additional nuts used as spacers. Take care to ensure that the CHANNEL 2 & OUTPUT RCA sockets are spaced far enough apart to clear the battery. o· 0 0 0 0 0 Fig.3: this is the full-size etching pattern for the PC board. Check your board carefully for defects before installing any of the parts. the battery holder. This part is secured to the PC board using three screws and nuts. Don't forget to solder its positive and negative terminals to thei:· respective pads on the board. The PC board can now be used as a template for marking out its mounting holes on the bottom of the case. Drill these holes to 3mm, then fit the adhesive label to the front panel (case lid) and drill holes for the on/off switch and the level controls. In each case, it's best to first drill a 3mm pilot hole and then carefully enlarge the hole using a tapered reamer until the part is an exact fit. The three RCA sockets are mounted along one side of the case. These sockets should be positioned roughly inline with their corresponding front RESISTOR COLOUR CODES 0 0 0 0 0 52 No. Value 4-Band Code (1 %) 5-Band Code (1%) 3 3 5 2 47kQ 22kn 10kQ 1kQ yellow violet orange brown red red orange brown brown black orange brown brown black red brown yellow violet black red brown red red black red brown brown black black red brown brown black black brown brown SILICON CHIP panel controls but make sure that they don't foul the battery when the PC board is later mounted in CAMCORDER ~ position (the battery should fit AUDIO MIXER snugly between two of these sockets). Mount all items of hardware in position when the holes have OFF been drilled. Standard rainbow cable is used for the wiring between the PC board and the front panel conON trols. Complete this wiring as MIN MAX MIN MAX MIN MAX shown in Fig. 2, then fit three short lengths of 2-way rainbow POWER CHANNEL1 CHANNEL2 MASTER cable to the board for the RCA socket wiring (ie, to points 1-6) . This done, the PC board can be Fig.4: this full-size layout can be used as a drilling template for the front panel. secured inside the case using Drill small pilot holes first, then enlarge the holes to size using a tapered reamer. machine screws and nuts, with additional nuts used as spacers. The wiring can now be completed amplifier. This done, connect a 9V put stage (either IC1a or IC1b). by making the connections to the three battery to the circuit and switch on. Similarly, if there's no output, careRCA sockets. Check all wiring care- You can now determine whether or fully check the circuit around IC1d fully when the job is finished to make not the unit is working correctly by and check the supply rails. In particusure that there are no mistakes. varying the three level controls. lar, check the underside of the board If one channel doesn't work, first for missed solder joints and possible Final check-out make sure that an audio signal is be- shorts between the IC pins. To test the unit, feed some audio ing fed in (you can do this be swapThat's it - you can now easily add signals from a couple of sources into ping the two inputs). If there is signal music or voice commentary to your the two inputs and connect the out- coming in, the next step is to check home movies after they have been SC put to an auxiliary input on your stereo the circuitry around the relevant in- recorded. :::flll!I!#- ~ lf!!!!3' QQQ 0 IAN J. TRUSCOTT'S ELECTRONIC WORLD 30 Lacey Street, Croydon, 3136. Phone (03) 723 3344; Fax: (03) 725 9443. Now also at: 200 Smith Street, Collingwood. Phone (03) 419 8208 Mail & Credit Card Orders Welcome We now have a range of 5,6,8,9 & 1O pin Ask about our range of E.A.O. precision push button switches, motor start resistor networks and a comprehensive range of micro's and eproms at ridiculous capacitors and Beckman Industrial prices .. Quote this ad and receive another multimeters. 5% discount. MARCH SPECIAL: 27C020-15 2 meg eprom 150ns.... 6 ea. 27C010-15 1 meg eprom 150ns....... 8. 2. ea. SAB8031 P Romless Micro........ ea. $2. ea. , 62256-LP S-Ram ..................... $9. ea. $2. ea. MAB8049H Romless Micro ....... 41256 D-Rani ..... ........ ... .. ............... BECKMAN DM15XL Multimeter $119 .00ea. 99.00 ea. 6 volt 1 watt Solar Panels 3mw Laser Tube & inverter Infra Red Night Viewing Monocular (kit) • COMPONENT PHONE ORDER HOTLINE (03) 723 3344 I MARCH 1993 53 e .ALTR..C>~IC COMPONENTS ~ J l.,,i, e AUSTRALIA WIDE L.u'\.-J-.n vvv ALTRONICS 24 HOUR EXPRESS DELIVERY 'Our customers are often amazed at the speed and efficiency of our Jetservice Courier delivery. Phone your order Toll Free 008 999 007 and presto we can deliver your order next working day (country areas 24-48 hours later). Our famous 14 day satisfaction money back guarantee protects your hard earned $$$' s should ever a purchase be unsuitable for your needs. I invite you to try Australia's best electronics phone order service soon.' Regards, Jack O'Donnell Playmaster 'Pro Series One' High Power Mosfet Amplifier Kit Fluorescent Light Inverter Kits (EA Dec '89-Jan '90) This d esign has been carefully d eveloped to produce a high definition audio output with reliability, ease of construction and low cost. Kit comes complete with all components, toroidal transformers and case. The diecast front panel doubles as the heatsink. The chassis is supplied in kit form and assembles in minutes. Features: • Individual toroidal transformers for (SC Feb '91) This kit enables you to build a high power DC Video to TV Transmitter Kit inverter suitable for driving fluo- each channe l for low residual hum • Individual power su pply components for each channel • Diecast front panel doubles as the main rescent lights from a 12V source typically a car battery. Ideal for use in camping or boating as fluorescent light offers 2 big advantages over heatsink • Straight forward construction • Mosfet technology for ultra-high performance • normal incandescent lights. Namely more Overload indicator indicates when distortion is above 0.05% • Performance: Power even 360' light spread and low current K5070 $599·00 Studio 200 Stereo Control Unit Kit (SC June-July '88) Housed in slim 1 unit rack case. Inputs include phono, CD, tuner, VCR, two auxiliary and tape loop. Virtually all components mount on PCB's, making assembly and constru ction a breeze. Altronics kit includ es fully professionally punched and printed panels. Features: • Extremely low noise on drain. Two kit versions to choose from - 16W and 20 to 40W. This kit enables you to transmit TV signals from the UHF output of your TV on your VCR to a second TV set in the house, The kit is complete with box and has a range of about 20 metres. Requires 12 Volts DC. (pictured without case-included). K 5860 Normally $74· 95 $35· 95 95 K 6360 20-40W Version $43· 1 - - - - - - - - - - - - 1 Beat Triggered Strobe 4-Digit Capacitance (AEM July '85) Designed •t by Australian Electronics Meter Kl Monthly. Flashes in time K 6350 16W Version phono and line level inputs • Very low harmonic and inter-modulation to your music. Will also work as normal strobe. distortion • Separate headphone amp for clarity and definition • Tone defeat switch • Tone and balance controls with centre Exclusively customised detent K 5015 $229·00 by Altronics into our H 0480 Instrument Case, Ideally Suited to Above K 5070 Amp! 2 Sector Alarm System (EA March-April '89) Features: • Includes 12V 1.2 Amp hour inbuilt sealed lead-acid backup battery • Easy to build as it all assembles on a single PCB • Two sectors - delayed and instant inputs • 2 Way Active Crossover Kit (EA Jan 92) This great new kit enables you to customise your sound system in your car or at home. The c ircuit simply connects between the audio source and the amplifiers. The re are two ou tputs one for bass and another provides signal making construction a breeze and improv- (SC May '90) This attractive 4-digit capacitance meter is designed for the workshop or laboratory. It can measure capacitance from lpF up to 9999µF in seven ranges w ith an · accuracy of better than + / -1 %. An overrange LED flashes w henever the capacitance Designed to rid your nicad batteries of the ca ted to a frequency range (Le. one for bass, fu ll recharge potential. It discharges your nicads correctly to enable a full e tc • Key switch operation • Operates on and - 15V rails. The result is much better virtually any type of sensor • Can be easily customised to accept Digital Keypads (as left sound with less distortion. or in Alarm Accessories Section) 00 K 1910 K 5570 $89• Improve Your Hi-Fi's Sound Qualitt;! DiscoLite Chaser & Colour Organ Kit (SC July-Aug '88) The Discolite flashes party lights on and off in beat with music from your amplifier. Features: • 4 light channels controlled by 4 separate audio channels • Forward reverse and autoreversing chaser patterns • Simultaneous strobe on all four channels • Alternating light patterns • K 5795 Two Tube Option $16.50 General-Purpose 3.5 1 - - - - - - - - - - - - 1 Digit LCD Panel Ni-Cad Battery Meter Kit Discharger Kit (SC Sep '92) memory effect and regain $19·95 recharge. Suits most bat- tery packs. Great for mobile phones, battery drills, toys etc. $24·95 Looking for a general-purpose 3.5 digit panel meter that doesn't cost the earth? This unit has switch- able decimal points and can be built to read either volt- ages to 200V DC and current up to 2 amps. Operates from a 9V DC supply. $34·95 Multi-Station Headset Intercom Kit K 1640 K 2528 This multi-station headset intercom is designed to provide clear communication in high noise environments such as at race tracks and rock concerts. It is designed to operate with a headphone and mic combination. Each headset requires a station module. Stations are simply connected in a daisy- chain fashion. Up to 12 units (stations) can operate from the Music modulation available on chaser strobe and power supply. Fearures low noise circuity and compares equivalents. Mics can be switched on confumously at one alternate patterns • Inbuilt microphone or direct inputs for beat triggering or audio modulation of lights • Sensitivity control • Individually pre-settable sensitivity levels for each channel • Front panel LEDs mimic light display • Altronics Kit pre-punched and silk screened attenuating Aviation Headset. K5so5$159·50 $79· 95 K2524$119· 95 for the upper range. Thus each amp is dedi- passive crossover is required in the speaker one per channel is required. Operates on + K 5790 Strobe Kit value is too large for the range selected. Entry and exit delay • Panic alarm input • Battery backup • Line monitoring • Soft pre-alarm • Lamp tell-tale output • Auxiliary relay for external siren one for midrange and treble). Because no ing stability, safety and overall appearance. Includes silk screened panel. Two tube option available which boosts lighting output. time for hands free operation of all stations. Also includes visual and audio call function. Ideally suited to our C 9055 headset mic and the C 9070 noise K5250 Station Module $74·95 K5255 Power Supply $64·95 PHONE ORDER - FREECALL 008 999 007 AUSTRALIA e ~ e ALTR.C>~IC WIDE J 1.;"' ~ A JJ' 1.;vv COMPONENTS A-B Switch Box D25- Passive Infra-Red Lite Aide Floodlight Universal Swivel 95 D25 Control s 5350 $49· Wacl<l Bracket How often have you thought there could be a prowler outside your door? Install a Lite Aide and (once armed) any "guest" will be floodlit when detected by this highly sensitive Infra-Red Detector wi th D25 female The Light Aide detects a moving person or vehicle by sockets. Allows two printers to be run off one computer and individually selected or comparing the background temperature with a rapid allows one printer to be run off two computchange of temperature across the detection beams. So when Lite Aide detects movement across the coverage area, it will turn on the floodlight(s) ers and individually selected. for 10 seconds to 15 minutes as pre-adjusted. D 1570 Normally $49·95 1--W1-,-y-P_a_y_A_C_o_11_11n_e_r_cz_·a-l-Se_c._11_n_·1:1-y""F-in-,-,A_F_o_rtz-,-,,-,-J:-o_W_ir_e_l:'._0_11r_H_o_11s_e_o_r_O_ffi_·c-e.-Th-is----1 95 This Month Only Fautastic System Installs In An Hour or Two And Uses No Wires Two way print- er-peripheralcomputer switch $39· Universal Testlead Set This great set includes just about everything Costing up to 60% less than inferior imported products. This Australian designed and manufactured bracket has a multitude of uses. Ideal for mounting speakers, strobe lights, security lights, CCfV cameras etc, in fact the uses are as wide as one's • UHF M lCroprOCeSSOr imagination. The unique design allows up to 500 angle variation either vertically or hori- Controlled Wireless Security System H 8012 Black ~;~~\vhite$ 95 39 . per pair Apart from the flawless operation of the system one of you would need. the great features is its application with rented or Supplied with 2 leads leased premises - let's face it, money spent on which are ready to accept a range of screw- installing a wired system in your home or office, factory, etc is irrevocably lost when you move on. With this on fittings. system you simply take it with you. Fully self contained on Screw-on Fittings Complete system includes: a single gang switch Include:• 4 x Croc Clips • 2 x Fork Connectors • 2 x Pin Plugs • 2 x Hand Probes .• 4 x Banana Plugs 1 x Control Panel 1 x Passive Infra Red Detector-Transmitter 1 x Door-Window reed SwitchTransmitter 1 x Hand Held remote Control-Transmitter 1 x Horn Speaker - 10 watt-wired 1 x 240V AC adaptor 1 x l .2Ah Back-up Battery 1 x Set of batteries for all transmitters oo S 5240 Complete System Price Only · plate. Supplied with mow,ting block. 5 settings plus off. Complete ·th · · · tru wi wmng ms c- Attenuator This stereo volume control is rated at 60 watts. $679 $6·45 1-------------...;..---------------------1 tions. All connections are via screw terminals - - - - - - - - - - - Car Alarm Long Distance Pager mounted on the integral PCB. Compatible with virtually all alarm systems on the market, Universal this device simply connects to the output of your alarm. lf Stereo Extension it sounds it automatically transmits a signal to the pocket Remote pager which alerts you that your car is being tampered Ceiling Speaker Kit with. It has a range of over 1 km in ideal conditions . Gives Control extra peace of mind when your away from your car. p 0413 Ideally sults Altronics alarms S 5220 and S 5230. This Universal Remote Control makes all other Features: • Compatible with most alarms • Complete with transmitter and receiver (pocket pager) • Easy to install • 1000 security codes 00 remotes superfluous. Designed to combine all s 5233 $174· infra red remote controls into one handy unit. No more search- High-Tech Remote Car Alarm ing through piles of This amazing model features just about everything you could imagine! Multi-function keyring remote control will arm and disarm alarm (and activate central locking if fitted), chirp the horn, tum on the car headlights, panic and even open the boot (if actuator fitted). remotes. -----------------1 One remote can control two alarms (in two cars). Other features include starter inhibit, valet mode, you can monitor any central locking interface, flashes car indicators when tripped, auto reset, user programmable options plus much more. door in your house. This S 5230 Normally $249· 00 With this simple device two piece alarm consists of a control box and a magnet. The magnet simply onto the door frame while the control box is mounted on the door, s This Month Only m your the system. The performance of these drivers is quite amazing. · Kit Contents: • 2 x Redford C 0626 Drivers • 2 x Redford C 0810 Grilles • 1 x Redford A 2300 60 Watt stereo volume controller • 2 x 20M rolls speaker wire • Mounting $229·95 Satellite Siren Connects easily into most car or house alarm systems. This self contained compact unit delivers a massive 120dB of deafening sound pressure once activated. It connects simply via 3 wires to any alarm system (car or house) that has an output that is normally negative (or low). When the alarm system is activated and the out- that they are opposite when the door is closed Easy to use on/ off switch. Built-in beeping when tripped. Requires S 5315 NORMALLY$ This Month Only omp ete syste home. REDFORD wide range C 0626100mm (4") 15 Watt drivers comprise of the heart of Motorola KSN1151A/1142A put goes positive (or high) the siren will sound. The siren will also operate if the wires to it are cut. Hence it adds extra security to your system $7 if someone tampers with it to disable it. Simply armed and disarmed via inbullt key switch. 5235 Normally $69 95 S Oxygen Free Cable This Month Only $59·95 13.SVlA UPS We have a limited supply of OFC cables in Designed for critical appli- two varieties. Both 2 RCA to 2 RCA with earth leads. cations where it is important P 0446 900mm in length, Normally $1 fr 00 remain operational during mains failure, This Month Only that products this UPS (Uninterruptible Power Supply) will supply 12V at 1.2 Amps via its internal $10 inbuilt sealed lead acid battery even when P 0448 1.8m in length Normally $19 This Month Only $14 50 the mains has failed. Ideal for use with alarm systems etc. 95 M 9090 $69· 6.5" Carbon Fibre Woofer ►·Mid/A A lightweight cone helps to produce a more Dimensions:..... Frequency Response: SPL: ...... . Rated Power Input: $90·00 Fans accurate reproduction of the signal. These drivers also use a kapton voice coil which disappears heat faster than conventional C 6155 speakers. Rated Power .. ..30W RMS Impedance ........ 8 ohm RES Frequency .65Hz Sensitivity ......97dB/W (0.5m) :aJj~o;n:er~:~~r:;=~~~1- C 3034 NORMALLY $82 55 95 This Month Only$59· Fantastic computer type ing of power supplies, ~O;oe1~ov 80mm' $25'° F 1030 240V 120mm' $25·40 F 1040 24V DC 120mm' $23·" F 1050 12V DC 80mm' $17· 50 PHONE ORDER - FREECALL 008 999 007 e A. L TR. C> N"I C COMPONENTS Portable Gas Soldering Iron Kit ~ J l.--i- Audio & Video Head Stereo Headphones Cleaners with Dynamic Mic dynamic mic gas. Includes: • Hot Blower Tip • Hot Knife A 9200 Audio Cassette $3 .95 Sorry - Not A vailable from ALTRONIC Dealers at these Prices! T 2470 N ormally $79· 95 This Month Only $64·95 C 9055 Hole Punch Set $49· Blank Rack Panels Cuts holes in metal up to 1.6mm (16 gauge). Set of Soldering Iron 5 punches • 370' C. • and tapered ciency the earpho nes anda3.5mm plug for the microphon e. Great for hands free dictati';:m, intercom s etc. 95 $12·50 A 9310 VHS Video ital multimeters reamer. must go at these crazy prices. Stock is limit- circuit loading, Punch sizes, 16mm, 18mm, 20mm, 25mm ed with definitely no backorders. at these high accuracy etc. and 30mm. T 2360 NORMALLY crazy prices . $ $97- 00 2 Unit-All w ithout the mis- S8·00 3 Unit-ALL S12·95 69· Assorted Battery Bargain $2 $3 teel construction . 2710 Flat Nose Pliers Centre zero pointer setting allows+ and readings. This meter has the advantage of dig'ie. insignificant 00 chrome plated , long life interchangeable This Month Only H 0422 Nat Alum H o423 Nat Alum tips. Tip life expectancy is many times that 1 - - - - - - - - - -- - ----~-H_04_3_2_G_r_e_ _ _ _ _H_o4_3_3_G_r_e ~----1 of conventional plated tips. Supplied with T 2424 Tip. Energy authority approved. T 7 .95 Be quick for this amazing battery special. All discontinued stock must go. Three types 2420 -- - - - - - - - - - - - - - - 1 available - standard zinc chloCat No. Size & Type Pack Was NOW S 4920 AA Zinc Chloride Pk4 $2.50 $2.00 AAA Zinc Chloride Pk4 $2.50 $2.00 9V Zinc Chlorid e Pk2 Pk2 $2.50 $2.00 AA Mercury Free Pk4 $1.80 $1.50 AAA Mercury Free Pk4 $1.55 $1.40 C Mercury Free Pk2 $1.60 $1.45 D Mercury Free Pk2 $2.10 $1.90 9V Mercu ry Free Pk2 $1.25 $1.15 .00 C Alkaline Pk2 $4.95 $4.50 This Month Only D Alkaline Pk2 $5.95 $5.45 must for all tool boxe ize features s pring retu Electronic FET Multimeter Top quality blank panel clearout. All stock patented heating element • Iron clad, Palm-Grip Series Hand Tools voltage, switch selectable adaptor enables you to run a fantastic array of cigarette lighter socket. Comes complete w ith 2m lead and universal star adaptor to suit most appliances. Output Voltages: 3, 4.5, 6, 7.5, 9, 12V Output Current: 800mA Includes 3.5mm stereo plug for or audio cassette player w ith inferior units. This handy multi- DC operated devices. Simply plugs into the combination. they are gentle on your heads. Why risk damaging your vid eo Tip • Polyfoam Cutter Tip • Burner Tip A US TRALIA WIDE Car Adaptor DC-DC Simply brilliant Mylar stereo headsets and Our exciting range of head cleaners are the best we've seen and more importantly refill lasts up to60 minutes. Uses standard cigarette lighter butane e ~AJ-n l.--vv leading a nd erroneou s readings that DVM's are famous for. Includes AC and DC volts, resistance, AC and DC current (up to 12 amps), testleads etc etc. Q 1050 Normally $99.50 This Month Only $89·00 Switches SPST chassis mount. With built in 240V AC Neon light. S321s,95 ~ea . Super Large Instrument Cases ocks st the shot for wire ter. ation to PCB for yo test project. Enables ea Designed to house amplifiers, inverters, power supplies micro-processor equipment etc. Builtin mounting posts for PCB's, transformers etc. ion) of wire and cables t PCB. 45' type. A vailabl 2 and 3 way configura Ventilated for efficient air-flow cooling. Extra tou gh, Super finish front and rear panels. 3 colours available. Pictured battery for size ions . comparison o_nly . onnection (and disconn 2042 2 Way WAS .60<!, N w w . H 0490 Case $29·95 HEAVY HEAVY SERVICE.All orders of lOkgs or more must travel Express Road~ Please allow 7 days for delivery. $12.00 to !Okgs. $15.00 over l0kgs. INSURANCE.As with virtually every other Australian supplier, we send goods at con$3.50 to 500gms, $5.50 500gms -1 kg, $8 signee's risk. Should you require comprehensive insurance cover against loss or damage lkg-5kg AUSTRALIA WIDE-We process your order the day received and despatch via. please add $1.00 per $100 of order value (minimum charge $1). When p hone ordering please Australia Post. Allow approx 9 days from day you post order to when you receive goods. request "Insurance". OVERNIGIIT JETSERVICE Up to 3kg is $10.00, 3kg to 5kg is $23.00--We try to process TOLL FREE PHONE ORDER-Bankcard, Visa, Mastercard Holders can phone order toll free your order the day received and despatch via. Overnight Jetservice Courier for delivery up to 4pm Eastern Standard Time . Remember with o ur Overnight Jetsezvice we deliver next next day Country areas please allow additional 24-48 hours. day. ALTRONICS RESELLERS Chances are there is an Altronic Reseller right near you--<:heck this list or phone us fo r details of the nearest dealer. Blue Ribbon Dealers are highlighted with a • These d ealers generally carry a comprehensive range of Altronic products and kits or w ill order any required item for you . WA - C OUNTRY BP Electronics e ..... (098) 412681 Micro Electronics .... (098) 412077 BUNBURY Micro Electronics. .. .... (097) 216222 ESPERANCE Esperance Comm................... 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(055) 627 417 ENFIELD Aztronics • .................... .. ..... .(08) 3496340 COUNTRY WHYALLA Eyre Electronics .................... (086) 454764 T A S QLD - CITY HOBART George Harvey e ................. (002) 342233 Delsound PL .......................... (07) 8396155 LAUNCESTON George Harvey e .................. (003) 316533 WEST END B.A.S. Audiotronics.. ...(07) 8447566 NSW _ C ITY 8082777 ~~~y David Hall Elect. e ...(07) A-One Electronics .................. (02) 2674819 GLADSTONE Gladstone Elect. Services ...... (079) 724459 David Reid Elect. e ...............(02) 2671385 . Electronic Enterprises .... (079) 726660 SMITHFIELD Chantronics ....................... .... .(02) 6097218 MAROOCHYDORE Mals Electronics e .. .. ........ (074) 436119 COUNTRY TOWNSVILLE Super Solex e........... .. ..... (077) 724466 COFFS HARBOURCoffs Habour Elect. ................ (066) 525684 S A - C ITY NEWCASTLE Novocastrian Elect.Supplies .(049) 621358 Force Electronics • ................ (08) 2125505 WARNERS BAY Vilec Distributors .......... .........(049) 566792 BRIGHTON Force Electronics e ................ (08) 3770512 M & E Elect. and Comm. .(045) 775935 CHRISTIES BEACH Force Electronics e ................ (08) 3823366 WINDSOR FINDON Force Electronics• ...... (08) 3471188 WOLLONGONG Newtek Electronics e ........... (042) 271620 Vimeom Electronics .............. (042) 284400 HOLDEN HILL Force Electronics e ................ (08) 2617088 LONSDALE Force Electronics e ............... (08) 3260901 WOY WOY Alphatran Electronics .......... (043) 434919 PHONE ORDER - FREECALL 008 999 007 ,;, = ~ :;, -...."-~'ii ~::.m::~"-~~ 0 • 13.79• ' Test yourself on the Reaction Trainer Improve your skill at your favourite sport by practising on this Reaction Trainer. It can be used to improve eye-to-hand response & coordination, or it can be used as a fun toy at parties or at school. By JOHN CLARKE The Reaction Trainer is our version of a device shown recently on the TV show "Beyond 2000". It was touted as one of a number of electronic training aids for testing and improving eyeto-hand response for sportsmen and women. Our version consists of 10 LEDs plus 10 pairs of associated touch plates scattered over a large board, together with a 4-digit counter which indicates time up to 99.99 seconds. Touching the START plates resets the counter and then a LED lights at random. The counter starts counting from the time the LED lights to when the plates associated with that LED are touched. The counter then stops until another LED lights at random. The player continues to respond to illuminated LEDs until the FINISH LED lights and the game is over. Since the LEDs light at random , there is no way of anticipating which LED will come on next and so the game is unpredictable, even for those who have become familiar with it. An extra level of unpredictability has also been added in that the next LED in the sequence does not necessarily illuminate immediately after the previous LED has extinguished. This keeps the player searching for a LED on the board until it lights. Of course, the reaction time counter does not increment until a LED is lit. The score on the counter indicates the total time taken to respond to all the illuminated LEDs. The total number of LEDs to be illuminated is set by MARCH 1993 57 a DIP switch; you can select an 8, 16, 32 or 64 LED sequence. I Circuit details The circuit comprises a 1-in-10 LED driver, a random sequence generator, a test length counter and a reaction time counter - see Fig. i. ICl is a decade counter and 1-of-10 decoder. It is clocked by IC2b, a Schmitt trigger oscillator connected to run at 10kHz. Provided the CE input (pin 13) of ICl is low, it is clocked and each of its 10 outputs goes high for 0. lms every lms. The 10 outputs ofICl drive transistars Ql-QlO via lOkQ base resistors. These transistors in turn drive their respective LEDs (LED 1 - LED 10). However, even though ICl may be counting rapidly and driving the transistor bases, none of the LEDs is allowed to turn on until transistor Ql 1 switches on. This transistor remains off while ICl is counting and turns on only when ICl stops. ICl is stopped at random to make one of the LEDs come on by pulling pin 13 high. This pin is driven by pin 1 of flipflop IC5b. This flipflop also controls Ql 1 so its operation is central to the whole circuit. We will come back to IC5b later. ,, \"w\'\ ~ 0 0 ; H•· ~ a. 0 "' "' ~ ... < 0 I• "' ~ ... < C> "' 0 ~ ... < "'0 "' "' ~ ... < I• .... "' ~ ... I• < ~ ~ ... < Touch plates Each LED has a pair of touch plates associated with it. One touch plate connects to the collector of the driving transistor (Ql-Ql0) while the other touch plate of the pair is commoned with all the other touch plate pairs and connected to the pin 1 input of Schmitt NAND gate IC2c. A 2.2MQ resistor normally holds this input high and so the output at pin 3 is normally low. If you place your fingers across a set of touch plates associated with a lit LED, your (relatively) low skin resistance and the conducting transistor cause pin 1 of IC2c to be pulled I 0 I• .,, "' 0 ~ "' ... < 0 I• "' "' ~ I· < < I• < ... ~ ::: I• ~ Fig.1: the circuit uses 1-of-10 decoder ICl to drive 10 LEDS & 10 touch plates via Qi-QlO. These LEDS come on at random, as controlled by a pseudo random sequence generator based on IC3, IC4a & IC4b. IC7 & IC8 record the elapsed time for a complete game & display this on 7-segment LED readouts. 58 SILI CON CHIP -0~ .., .,., w 0 0 ::!'. ~"' "'°' Q~ a: g"' 0 ....... ~ 0 H•· 0 0 ~ ~ I• i:0 1:,1 co w .... co ::i: :i:, (") s:: > 0.1 7 7 +5V r 5V 8 IC3 4015 7 DA RB 7 6 B 03B 11 8 IC4a 4030 7 15 DB VIEWED FROM BELOW EOc RANDOM PULSE GENERATOR 14 +5V 10 O4A 1 CKB 9 CKA RA 11 TEST LENGTH COUNTER 7 8 5 4 64 10 IC6 3 CK 4040 16 2 32 R 16 2 I GO ~ 11 7 7 ~K 12 3 +5V 01 1N4148 7 +5V 7 1 7 1 IC7 7555 8 .047+ REACTION TRAINER 4 +5V 12 5 6 18 13 CK LE OS R 9 IC8 74C926 7 DISP1 4xHDSP5303 15 17 g f 4 2 •3 d 1 C 16 b a D 11 C 10 B 6 9-12V INPUT 013 BC336 7 3,6 7x68D 02-D5 4x1N4004 B 014 BC338 3,8 5 DP B 015 BC338 +5V 68D DI_SP2 DISP3 7 3,8 ~ f1:-,b 7 7 • 100 5x0.1 16VWi 3,8 d 6 c 4 7 I ' b ·/=I!: I g 10 • DISP4 I OUT ' B 016 BC338 I_I 1=1 ,_,. 1=1 ,_,. ,_,. 9 START +5V +5V RESISTOR COLOUR CODE o No. Value 4-Band Code {1%) 5-Band Code {1%) 0 1 0 1 2.2MO 1MO 150k0 100k0 47k0 210k0 1800 680 red red green brown brown black green brown brown green yellow brown brown black·yellow brown yellow violet orange brown brown black orange brown brown grey brown brown blue grey black brown red red black yellow brown brown black black yellow brown brown green black orange brown brown black black orange brown yellow violet black red brown brown black black red brown brown grey black black brown blue grey black gold brown 0 1 0 2 0 ' 0 0 2 0 8 Below: take care to ensure that the decimal points on the 7-segment LED displays are oriented towards bottom right when installing the displays in their sockets. A small heatsink is sandwiched between the 3-terminal regulator & the PC board for cooling. low. IC2c drives the reset pin of IC5b. Hence, when IC5b 's Q output goes high, it stops IC1 and allows a LED to light. When you touch the appropriate pair of touch plates, IC2c then resets IC5b which allows IC1 to start counting again and so no LEDs are alight. At least, no LEDs are alight until IC5b is toggled and changes state again. IC5b is toggled by flipflop IC5a and the associated "pseudo random sequence generator" which we will now discuss. Random sequence generator The pseudo random sequence generator consists of a clock (IC2a), a shift register (IC3) and two XOR gates (IC4a & IC4b). IC2a is a Schmitt trigger oscillator with its frequency set by trimpot VR1. The oscillator output at pin 10 clocks the two inputs of shift register IC3. IC3 is wired as a single 8-bit shift register by connecting the fourth output (Q4A) of the first stage to the Data input (DB) of the second stage. The Data input of the first stage (DA) connects to the output of XOR gate IC4b. XOR (exclusive OR) gates only have a high output when the two inputs are different. In other words, the output is low when both inputs are high or both inputs are low. It is high otherwise. IC4a acts as an inverter for pin 11 of IC3, so the only XOR gate we are really concerned with is IC4b. This produces a low output to DA (pin 7 of IC3) whenever pin 6 ofIC4b and Q4B (pin 2) ofIC3 are different. The result is a series of low and high outputs at Q4B with a sequence that continually varies between the limits of one high output per eight clock pulses to seven high outputs per eight clock pulses. This is called a "pseudo random sequence". The output of IC3 is fed to IC5a, a D-flipflop which divides the Q4B output by two. Its output at pin 13 is in turn fed to flipflop IC5b which has its 60 SILICON CHIP Fig.2: install the parts on the PC board & complete the external wiring as shown here. Take care to ensure that the correct part is used at each location & don't forget the four wire links that run beneath the 7-segment LED displays. Note particularly that Qt 1 is a BC328, while Qt-QlO are all BC338s. 1 0 2 LE02 LEOS LE04 LEOS LEOS LE07 LEOS LE09 LED10 START TOUCH PLATES 0 - - - - - - - - , ---- SHIELDED CABLE TO TOUCH PLATES 2-10 (DAISY CHAIN CONNECTION) data input (pin 5) tied to the positive supply rail. On the first positive clock input, its Q output at pin 1 goes high and the Q-bar output at pin 2 goes low. As noted previously, the Q output of IC5b connects to the clock enable (CE, pin 13) of ICl and prevents it from clocking when it is high. At the same time, the Q-bar output is low POWER SOCKET and this turns on transistor Ql 1 so that one LED is lit. As soon as IC5b is reset by ICZc, ICl begins to count again and it continues to do so until IC5b is again clocked by MARCH 1993 61 (REG1). The 5V output from the regulator is decoupled with a lO0µF capacitor. Construction This rear panel view shows how the commoned touch plates terminals are daisychained together using shielded cable. The LED anodes are daisychained in similar fashion using hook-up wire & connected back to the PC board . . IC5a. Normally, IC1 has time to run through all its outputs several times before it is stopped again by IC5b. Test length counter IC6 is the test length counter. This counts the number of times the clock enable (CE) pin of IC1 goes low and this controls the number of times a random LED is displayed. The 8, 16, 32 & 64 outputs ofIC6 are selected by DIP switch DIP1. When the selected output goes high, it resets IC5a, thus preventing further clocking of IC5b. At the same time, the high output drives transistor Q12 which drives the FINISH indicator (LED 11). This leaves the circuit with the Q output of IC5b low and Q-bar high. IC1 is thus stopped, transistor Ql 1 is off and no LEDs are lit. This state will remain until IC6 is reset by pressing the START touch plates. These control Schmitt NAND gate IC2d which is connected as an inverter. A 1MQ resistor normally holds the pin 13 input of IC2d high. When the start plates are touched, pin 13 is pulled low and IC2d's output goes high. This resets IC6 and so the selected output goes low to release the reset on IC5a. Diode Dl now holds the reset on IC5b high so that the LEDs are kept off until the START touch plates are released and flipflop IC5b is clocked by IC5a. The reaction time counter consists 62 SILICON CHIP of IC7, IC8 and four 7-segment LED displays. IC7 is a CMOS 555 counter which is set up to produce a 100Hz signal from its pin 3 output, provided the reset input at pin 4 is high. When pin 4 is low, no oscillation occurs. As well as all its other functions, IC5b controls the reset pin of IC7. So when pin 1 of IC5b is high, IC1 will have a LED lit and IC7 will oscillate to clock IC8. IC8 is a 4-digit counter and display driver. The 7-segment LED displays show time in seconds; eg, 23.45 seconds. And guess what! When the game is to be started again, IC8 is reset by IC5b, via diode DL So IC5b is the hub of all the circuit operations. Let's recap on the circuit operation. IC1 is clocked by IC2b but it can't count while its CE pin is high and nor can any LED be displayed until Ql 1 turns on. Both are controlled by IC5b which in turn is clocked by IC5a and the pseudo random sequence generator. This ensures that the LEDs turn on randomly for 8, 16, 32 or 64 times, depending on the setting of switch DIP1. IC7 and IC8 record the duration of the game and everything starts anew when the START touch plates are touched. Power for the circuit is derived from a 9-12V AC or DC plugpack. Its output voltage is rectified by diodes D2-D5, filtered by a lO00µF capacitor and applied to the input of a 5V regulator Most of the circuitry for the Reaction Trainer is mounted on a PC board measuring 143 x 194mm (code 08312921) - see Fig.2. We mounted the PC board and the remaining components on a sheet of white Perspex measuring 670 x 450 x 2.5mm. This Perspex sheet was supported on a timber frame made from 25 x 25mm Ogee moulding. The touch plates were made from self-adhesive aluminium strips (the kind used to make front-panel labels), but you could also use suitable pieces of thin aluminium sheet and affix them using contact adhesive. A cutout was made in the top right-hand corner of the white Perspex sheet to allow the LED displays to be seen and this was fitted with a red Perspex viewing window. Naturally, you can make the game board as large or as small as you wish, depending on the size of the Perspex offcut you can obtain from your local plastics retail outlet. Nor do you have to use Perspex. You could use a sheet of plywood, Laminex or virtually any insulating material. Begin construction by checking the PC board for shorted and open circuit tracks. Shorted tracks can be corrected by scraping between them with a sharp hobby knife, while open circuit tracks can be repaired with a short length a tinned copper wire and solder. Once the PC board pattern has been checked, you can install all the PC stakes and links. Don't forget to install the links that sit under the dis. plays. This done, install the resistors, DIP switch, trimpot VR1, the diodes and ICs, making sure that each is inserted correctly. The capacitors can be installed next. Note that the electrolytic capacitors should be laid flat on the PC board to provide sufficient clearance between them and the Perspex panel. The transistors can then be inserted, noting that Ql 1 is a BC328 while the others are BC338s. The regulator is mounted with its leads bent at rightangles, so that its metal tab can be bolted to the PC board. It should be fitted with a small U-shaped heatsink made from scrap aluminium - see photo. PARTS LIST 1 PC board, code 08312921, 143 x 194mm 1 front-panel label, 178 x 237mm (available from RCS Radio) 1 500mA 9-12V AC or DC . ·plugpack 1 sheet of white Perspex, 670 x · 450 x 2.5mm 1. piece of red transparent Perspex, 207 x 67 x 2.5mm 1 15 x 30 x 1.6mm aluminium panel.for heatsink 1 ~mm screw & nut for heatsink 22solder lugs 10 5mm LED bezels 26 3mm x 10mm screws & nuts 14 countersunk wood screws 4 12mm tapped brass spacers 4·4mm x 6mm screws 1 SPOT toggle switch 1 4-Way DIP switch 1 panel mount DC socket 2 2.5mm screws & nuts to suit socket 1 1.5-metre length of shielded cable 1 1-metre length of 10-way Finally, the displays are mounted on Molex strips to raise them above the PC board. First, cut the Molex strip into 10 5-way lengths, then insert and solder them into the board. This done , snap off the shorting strip on the top of the pins before inserting the displays into the resulting Molex sockets. LED 11 is inserted so that it is at the same height above the PC board as the displays. Initial testing For the initial testing, you will need to temporarily solder each of the LEDs (1-10) to the PC pins at the bottom of the PC board. Set the DIP switch for a sequence of eight and apply power. Check that the digital displays light up. If they do not, switch offimmediately and check that all the parts on the board are correctly located and oriented. If all is well, the display should be counting up and one of the 10 LEDs (LED 1 - LED 10) should be alight. If you now momentarily touch the START PC stakes (A & B) with your fingers, the display should reset to 00.00, after which it should begin rainbow cable 1 700mm length of 0.8mm tinned copper wire 17 PC stakes J 40-way Molex socket strip (for mounting !.,ED displays) 1 1Mn miniature horizontal trimpot (VR1) (01-010, 012-016) 1 BC328 PNP transistor (011) 1 1N914, 1N4148 diode (D1) 4 1N4004 1A rectifier diodes (D2-D5) 4 HDSP5303 common cathode red LED displays 11 5mm red LEDs Semiconductors 1 4017 decade counter & decoder (IC1) 1 4093 quad 2-input Schmitt NANO gate (IC2) 1 4015 dual 4-bit shift register (IC3) 1 4030, 4070 quad 2-input XOR gate (IC4) 1 4013 dual D-flipflop (IC5) 1 4040 binary counter (IC6) 1 ICM7555, LMC555 CMOS timer Capacitors 1 1OOOµF 16VW PC electrolytic 1 1OOµF 16VW PC electrolytic 7 0.1 µF 63VW MKT polyester 1 .047µF 63VW MKT polyester 1 .01 µF 63VW MKT polyester 1 .001 µF 63VW MKT polyester 2 220pF ceramic (IC7) 1 74C926 4-bit counter & display driver (IC8) 1 7805 3-terminal 5V regulator (REG1) 15 BC338 NPN transistors counting again and another LED should light. If you now touch PC stakes C & D, that LED should extinguish, the display should momentarily stop and another (or the same LED) should light up. Trim pot VR1 sets the speed at which the next LED comes on after the previous LED has been extinguished. If this time is too short, the LEDs will appear to come on instantaneously and that removes some of the difficulty from the game. Note that the outputs of IC1 are not in sequence. This was done to simplify the PC board layout. Since we want randomly lit LEDs, the order is not important. You should be able to continue your test until the FINISH LED lights; ie, after eight LEDs have been lit. Note that one or more LEDs may light more than once in a particular sequence. Completing the assembly You are now ready to complete the construction and so we will outline how we put ours together. The first step is to cut out the top right-hand corner of the white Perspex Resistors (0.5W, 1%) 1 2.2MQ 1 47kQ 1 1MQ 1210kQ 1 150kQ 2 180Q 2 100kQ 8 68Q Miscellaneous Contact adhesive, PVA glue, masking tape sheet so that the red transparent piece can be fitted. We assembled the timber frame with PVA glue and affixed the Perspex to it with contact adhesive. Countersunk screws through the Perspex and the frame can be used for added strength and to further support the red Perspex window. You will need to drill holes in the Perspex for the 10 LEDs, the power switch, the input socket, the four mounting pillars for the PC board and the touch plate contact screws. You will also need a cutout to provide access to the DIP switch. The positions for two of the pillars for the PC board, the DIP switch cut-out, the power switch and socket are shown on the front panel label and this can be fitted and used as a drilling template. The top two mounting positions for the PC board are found by placing the board against the Perspex and marking out the locations. When marking out the hole locations for the LEDs, try to position them so that they are randomly placed. Keep in mind that there needs to be sufficient room for two touch plates around each LED and be careful that MARCH 1993 63 ... N N CJ' .... SI C) ~ A ' I0 I you don't encroach on the space needed for the two START touch plates which are mounted below the front panel label. It's best to drill small pilot holes for the LEDs first and then ream them to size so that the LED bezels are a tight fit. It's also necessary to drill each touch plate to accept a machine screw. This is then used to secure a solder lug on the underside of the Perspex to 64 SILICON CHIP terminate the leads from the PC board. The power switch and power socket can now be mounted and the wiring completed as shown in Fig.2. Note that a separate lead is run from the PC board to the cathode (K) of each LED via a touch plate terminal. The LED anodes are commoned and connected to the PC board adjacent to Ql 1. The other touch plate terminals are commoned to the centre conductor of a shielded cable to prevent noise pickup. The START touch plates are connected via a single length of shielded cable. With all the wiring complete, you should test the circuit operation again to ensure that everything is operating correctly. Note that you may need to clean the touch plates periodically with methylated spirits to ensure reliable operation. SC SILICON CHIP AUSTRALIA'S BRIGHTEST ELECTRONICS MAGAZINE ENJOY THE WORLD OF ELECTRONICS & COMPUTERS EACH MONTH * Constructional Projects For The Enthusiast * The Serviceman's Log * Vintage Radio: Technology From The Past * Articles On Computers & Radio Remote Control * New Circuit Ideas & Techniques * Amateur Radio Projects & Features Subscribe today by phoning (02) 979 5644 & quoting your cred.it card number, or fill in the form below & fax it to (02) 979 6503. 0 New subscription - month to start._ _ __ __ _ __ 2 years (24 issues) RATES (please tick one) 1 year (12 issues) Fax or mail coupon to: 0 $A42 0 $A53 0 $A120 Silicon Chip Publications 0 $A84 0 $A105 0 $A240 Australia Australia with binder(s)* Overseas airmail 0 Renewal - Sub. No. _ _ _ __ Freepost 25 PO Box 139 Collaroy Beach 209 7 *1 binder with 1-year subscription; 2 binders with 2-year subscription Your Name - - -- -- - - - -(PLEASE PRINT) Address - - - - -- _ - --- Signature - - -- - - - - - - _ _ _ _ _ _ __ Card No. - _ __ _ .Postcode_ _ _ Card expiry date_ _~/_ __ I I II I I I II I I I II I I I MARCH 1993 65 I PRODUCT SHOWCASE I Digital storage oscilloscopes The 4164 and 4162 from Gould are two new digital storage oscilloscopes which combine high digitising speed with long stores of 50K words per channel. The extended store length means that users can examine fine detail within a stored waveform, while .at the same time being able to look at long-term trends. The long store also means that the instruments are suited for use in a "baby sitting" mode for capturing random or intermittent signals. · The 4164 and 4162 are extensions of the well-established Gould 4060 series of digital storage oscilloscopes and feature 100 megasample/second sampling, 150MHz equivalent realtime bandwidth, 8-bit resolution at all input sensitivities, on-screen cursor based measurement functions , full programmability and internal hardcopy capabilities. The 4164 is a full 4-channel instrument, while on the 4162 two of the channels have been optimised for electronic control signal acquisition. A variety of display modes , including conventional Y/T, X/Y, roll, persisted and interpolated, allow acquisition data to be presented in the most meaningful form to the user. To allow detailed examination of trace data, the 4164 and 4162 incorporate a variable "zoom" facility which provides up to 1000:1 trace Miniature fans for microprocessors Are you concerned at the relatively high temperature of the microprocessor in your PC? Or perhaps a critical component in a power supply or other equipment is running a shade too hot. The remedy is to fit that red-in-theface component with its own personal cooling fan? Don't laugh. These teensy little fans do work and could be just what's needed in a confined space where the draught from a larger fan would not penetrate. The larger of the two fans is 40mm in diameter and produces quite a draught. It runs quietly but is rated at6.9 cfm (cubic feet per minute) at 6000 RPM. The smaller fan is 25mm in diameter and as you might expect, 66 SILICON CHIP produces noticeably less movement of air. It is rated for 1.3 cfm at 10,000RPM. No mounting hardware is available so you will need to contrive your own installation. It should be poss ible to mak e a mounting bracket from a small piece of aluminium. The 40mm fan is priced at $14.95 and the 25mm unit at $19.95 from David Reid Electronics, 127 York St, Sydney NSW 2000. Phone (02) 267 1385. expansion. This displays either the actual acquired data points or in situations where less than 500 points would be displayed, a linear interpolated trace. The user can select a combination of normal and zoomed traces, which allows the fine detail of the magnified trace to be viewed in conjunction with the overview. The new oscilloscopes feature a large (7-inch) display screen with an electronically generated graticule. Hard copy can be produced on an optional internal thermal or 4-colour plotter, and IEEE-488.2 and RS-423 interfaces are provided for interfacing with external HP-GL plotters, computers or controllers. For furth er information contact Elmeasco Instruments Pty Ltd, PO Box 30, Concord, NSW 213 7. Phone (02) 736 2888. Austel approved power supplies Alpha Kilo Services has released two series of power supplies that have been Austel approved. The UP0403A series are 40 watt switching supplies that have triple output voltages ranging from 5V to 24V with overvoltage and short circuit protection. Efficiency is claimed to be a m inimum of 70% and operating temp erature range 1s from zero to 70°C. The USUl00T Series are 100 watt supplies that also have triple outputs ranging from -5V to 24V with overvoltage and short cir- cuit" protection and a VDE level "B" input filter. For further information contact Alpha Kilo Services, PO Box 180, Lane Cove 2066. Phone (02) 428 3122. New ferrite materials with high saturation Siemens Matsushita Components has developed three new ferrite materials which. are mainly intended for use in switched-mode power supplies. The outstanding property of the new N97 ferrite is its low core power loss of 70mW/g under typical operating conditions (lO0kHz, 200mT, 100°c), which is approximately 18% less than comparable materials. N62 ferrite has a high saturation inductance of510mT (at 2kHz, 1200A/ m, 20°C). It gives better DC biasing compared with the previous.material; not until current intensity reaches values 10% higher does a 20% loss of inductance occur. The new material has an initial permeability of 1900 continued on page 72 EHT generator/low cost laser How many different ways can you power a small laser tube? The answer is quite a few and many of these have been explored by Oatley Electronics over the last few years. Now they have excelled themselves by releasing an EHT power supply at a very low price. Based on a TV flyback transformer and high voltage transistor, the supply is powered from 12V and will deliver a peak output of about 1 lkV. The main application being promoted is as a low cost laser power supply but the circuit could have other applications such as high voltage experiments (Jacob's Ladder, etc), replacement parts in TV sets and computer monitors and even for plasma displays such as described in the August and November 1988 issues of SILICON CHIP (copies are still available). The EHT power supply kit includes a small PC board, all the · on-board components, and the circuit and wiring diagrams. It is priced at only $23.00. Also available is a kit which adds a lm W red Helium-Neon laser tube for a total cost of $50. That is cheap. Both kits are available from Oatley Electronics, 5 Lansdowne Parade, Oatley NSW 2223. Phone (02) 579 4985. YOU CAN .NOW AFFORD A SATELLITE TV SYSTEM $ 5 99 For many years you have probably looked at satellite TV systems and thought "one day". You can now purchase ihe following K-band system for only: Here's what you get: • A 1.6 metre prime focus dish antenna, complete with all the mounting hardware. • One super low-noise LNB (1.4dB or better). • One Ku-band feedhorn and a magnetic signal polariser. • 30 metres of low-loss coaxial cable with a single pair control line. • lnfrared remote control pre programmed satellite receiver with selectable IF & audio bandwidth, polarity & digital readout Your receiver is pre-programmed to the popular OPTUS transponders via the internal memory. AV-COMM Pty Ltd, PO Box 225, Balgowlah NSW 2093. Ph: (02) 949 7417. Fax: (02) 949 7095. All items are available separately. Ask about our C-band LNBs, NTSC-to-P~L converters, video time date generators, FM2 &EPAL &Pay TV hardware. r - .- ------------· ~ I YES GARRY, please send me more information on K-band I satellite systems. I Name _ _ _ _ _ _ _ _ _ _ _ __ I Address: _ _ _ _ _ _ _ _ _ _ _ __ : - - - - - - - - ~ P'code: _ _ __ _ _ _ _ __ I Phone: _ _ _ _ _ __ I ACN 001174 478 10/91 If You want something Done LED VU Meter I Yourself NEW! Two-channel Camcorder Mixer One of the things that decides whether a home video movie is a bore Designing your own audio system or just updating older-style equipment that uses an analogue V/U meter? This unit offers the advantages of fast response and peak hold display. Comes with PCB, red , yellow and green LEDs plus all necessary components and hardware. Cat K-5370 or a block-bu ster is the soundtrack . Thi s inexpensive kit makes it easy to give you r videos that Hollywood feel, complete with music and sound-effects I 9V battery-powered, the kit co mes in full-form with PCB, case, front panel label , hardware , battery holder and all components, including IC socket. Q $2495 exclusive ~..,.'If $2 ~ Feb.'93 Low Fuel Indicator $1495 Q CHANNEL I C!W91EL 3 ~[R M<ISTER Low-Cost 1GHz Frequency Counter Just because your budget's tight, you don't have to settle for lower resolution or frequencies I Th is 1GHz counter is an inexepensive variation on the 50MHz counter design published in February '93 Electronics Austra lia. By substituting an uprated display module and adding to the prescaler circuitry, a truly ingenious 1GHz counter can be built -for under $160! The Kit includes case, PCB , all mounting hardware and componentry . $1059 With features usually only found in speaker systems costing thousands of dollars, this crossover improves the performance of your system by overcoming the limitations of passive systems. By preceding the power amplifier, this active crossover kit gives ideal high-impedance loads, less discrepancies in speaker driver efficiency and less resistance between the voice coil and amplifier. Comes as a short-form kit with PCB and all _[i;:--:_ , components. 1~ Cat K-5405 April , <at> IGH, IREQUEHCY COUNTER [1] Diesel Sound Simulator If your model railway looks great, but doesn't sound true-to -l ife, here's _the solution: Our_ Diesel Sound _Simulator Kit is easy to bui ld , fits inside most locomotives (speaker included) and takes its power from the rails. What's more, using some very clever circuitry , the pitch reflects the loco motor's speed - how's that for a realistic simulation! Supplied in Shortform with all components, PCB and mini speaker. $a1K 295 Q t> ,, 92 PLEASE CHECK YOUR NEAREST STORE FOR AVAILABILITY, AS SOME KITS MAY STILL BE IN PRODUCTION. SILICON CHIP nf oo . April '93 QQQ Active Crossover For Two-Way Q Speaker Systems 68 /8) <at> Feb. '93 3495 Q ON ~1;~~~ March '93 "'-....___ _ _ _ _ _ _ _ __,,/ If you 've ever run out of fuel in your car, you 'll see the value of this low-cost kit. It lights a 12V warning lamp when the fuel drops below a pre-determined level. Harder to ignore than your standard gauge, the light could save you a great deal of inconven ience and embar, rassment. Comes with PCB, case, 12V panel mount lamp and all necessary components, including auto connectors for easy installation Cat K-4210 $ i • Battery not included. K-5408 Complete with holster! Cathode Ray Oscilloscope 3.75 Digit (4,000 Count) 6.5MHz - Single Trace A bargain-priced instrument that's great for Multimeter vice , repair and design work. At 6.5MH suits audio work, project builders, classroom applications, etc. Its features include retrace blanking for a clearer display and internal or external sync. Low drift and quick warm-up make it the ideal service tool. A rugged meter that's great for both field and workshop use, it's shock. water and dust resistant. featuring rubber a-ring gaskets on its rotary switch. input jacks and case. Supplied with a thermocouple probe for temperature measurement from -40°C to 260°C, the meter features most standard ranges plus: • • • • C•s;ve$50 ""'E'P.I \ Continuity Diode Test , , ."4'4 • Logic Test Frequency (Auto-ranging) ~:~~',';:\$ 17 Specifications: Vertical bandwidth: DC to 6.5MHz (-3dB) Attenuator: 1/1, 1/10, 1/100 and ground Horizontal sensitivity: 250mV/div or more Timebase: 1OHz to 1OOkHz Sync: External or internal Input Impedance: 1 Meg/35pF 9 With Period Counter! 1 GHz Digital Frequency Meter Searching for a frequency meter that can do it all? .... look no further! Measures from a phenomenal 0.1 Hz to an amazing 1GHz. This meter will measure it all in a fraction of a second with a minimum 5 digit accuracy right across the range ... from subsonic to ultrasonic. Packed with unique features, it has the accuracy and specifications to out perform just about any meter in its class. High resolution and fast response time make it a must for the workshop. 5;;; $100~~:=;;::=~~~--4 • • +oaaaa 8 8 Ptio-~· Channel A: ChannelB 0.1 Hz to 80MHz 50MHz to 1GHz Freq . Range: Sensitivity: Coupling: Max. Input: Input Imped: Accuracy: Trig. Mode: Period Range: Gate Time: The world's in your pocket! Micro Compact 9-Band Receiver 15mV to 50MHz 20mV to 650MHz 25mV to 80MHz 55mV to 1GHz AC/ DC AC only 3VRMS 3VRMS 1Mohm/40pF 50ohms 50PPM 50PPM Auto or manual 1Ons to 1O seconds Variable Irani 60ms to 1Os (or 1 period of input signal, wh ichever is longer.) 5ANC5EAN It covers 7 shortwave bands as well as your local AM/FM bands . Its highly sensitive micro-circuitry allows it to receive international shortwave broadcasters such as: The Voice of America, BBC , Radio Australia and Radio Moscow. What's more, you get one-touch power & AM/FM/SW selectors, power safety lock, FM stereo & SW tuning indicator. It also has easy-to-read dial markings , telescopic antenna, and a DC jack for mains power (with optional adaptor) . Includes earphones for FM stereo and a soft carry case. Requires 2 x AA batteries . Specifications: Frequencies Cat D-2827 FM 87.5-108 MHz MW 530-1605 KHz SW1 (5.90-6.20 MHz) SW2 (7.05-7.40 MHz) SW3 (9.50-9.90 MHz) SW4 SW5 SW6 SW? (11.65-12.05 (13 .55-13 .85 (15.10-15.60 (17.50-17.90 MHz) MHz) MHz) MHz) $9995 MARCH 1993 69 CALLING ALL ENTHUSIASTS DON'T MISS THESE BARGAINS! I QUALITY SCREWDRIVERSBARGAIN-PRICED! Crescent 6 x 40mm Flat stubby screwdriver 3 x 75mm Flat screwdriver with pocket clip 4 x 100mm Flat blade 5 x 100mm Flat blade 6 x 150mm Flat blade 6 x 150mm Insulated flat blade 40mm Phillips stubby #2 75mm Phillips #0 100mm Phillips #1 150mm Phillips #2 Crescent 4-piece screwdriver pack T -6300 T -6302 T -6304 T-6306 T-6308 T-6310 T-6312 T-6314 T-6316 T-6318 T-6130 $5.95 $2.95 $3.95 $4.95 $6.95 $5.95 $7.95 $3.95 $6.95 $8.95 $19.95 SAVE ON BULK CAPACITOR PACKS! ELECTROLYTIC CAPACITOR PACK Save $6 on a pack of 50 mixed quality RB electrolyic capacitors. Cat R-7030 $995 SAVE $6 ON GREENCAP 100V VALUES! ELECTRICIAN' NYLON 12-WAY TERMI STRIP BLOCKS Now available in two sizes/ Pack of 60 mixed value polyester capacitors. Cat R- 7040 $ 95 9 Large Cat P-4850 PACKS OF 50 POLYESTER VALUES! Small Cat P-4855 PCB-MOUNTING TERMINAL BLOCKS 240 Volt, 10 AMP, 3-way, with 10mm pitch leg spacing. Cat P-4834 WAS $3.95 11nw $ IIU 2 95 SINGLE AM RADIO RECEIVER I.C. A 10-transistor tuned radio frequency circuit that provides a complete R.F amplifier, detector and AGC circuit. It requires only six external components to give a high quality A.M tuner. 6520 CatZ- WAS $5.75 NEW LOW PR/Cf $395 ULTRASONIC TRANSDUCERS A quality Japanese matched pair of tranducers with data sheet. Cat L-7054 70 S1uc c5N C111P 0.001 to 0.0022mfd 0.0027 to 0.0056mfd 0.0068 to 0.015mfd 0.018 to 0.039mfd 0.47 to 0.1 mid R-7041 R-7042 R-7043 R-7045 R-7050 $7.95 $7.95 $7.95 $7.95 $6.95 MONOLITHIC MULTILAYER CERAMIC CAPACITORS (50 V) In packs of 50 0.01 mid 0.1mfd R-7060 $11.95 R-7062 $13.95 .25 WATT CARBON FILM RESISTOR PACKS A mix of the 300 most popular values 130 piece pack, values from Oto 8.2 ohms 120 pieces, 1o to 82 oh ms 120 pieces, 100 to 820 ohms 120 pieces, 1k to 8.2k ohms 120 pieces, 10k to 82 ohms 130 pieces, 1m to 10Mohms R-7010 R-7100 R-7104 R-7106 R-7108 R-7110 R-7112 $9.95 $3.95 $3.95 $3.95 $3.95 $3.95 $3.95 GET MORE FROM YOUR PC! The advice you need - from beginners to advanced users. THE IBM PC CONFIGURATION HANDBOOK DUMMIES BOOKS For those who wan t to get into Microsoft DOS and IBM PC's but have been too afraid to ask 1 DOS for Dummies Cat B-6602 PCs for Dummies Cat B-6604 1/, s349s A complete guide to troubleshooting, enhancing. configur ing, reconfiguring and maintaining the PC / XT I AT/386/486-based machines and peripherals. --_.__ Cat 8-6203 -- i...'-'-~ s599s ...,._._.., each WE BSTER's QUICKSTART GUIDES Specially written for beginers, the Visual Quickstart Guides are the fundamental starting level books.They take an easy visual approach to learning, where pictures guide the user through the software.Written by Australian authors, the Quickstart Guides are concise and easy to comprehe nd. Webster's Coreldraw 2.0 Quickstart Guide 8-6392 $24.95 Webster's Coreldraw 3.0 Visual Quickstart Guide 8-3650 $34.95 Webster's Excel for Windows Version 4.0 B-6355 $29.95 Webster's Windows 3.1 Visual Quickstart Guide B-6391 $24.95 Webster's Wordperfect for windows Visual Quickstart Guide 8-6397 $29.95 Webster's Windows 3.1 Visual Quickstart Guide 8-6389 $34.95 (The expanded version for students; wit h more pages than the standard vers io n - includes self-paced exercises in running Windows 3.1 I WEBSTER'S QUICKSTART REFERENCES These are expanded , more advanced versions of the Visual Quickstart Guides. With this reference Guide the user needs only to look up what is required and they're provided with a straightforward explanation. They're easy to follow and excellent va lue! Webster's Works for Windows Quickstart Reference Guide B-6385 $24.95 IBM PC ARCHITECTURE AND ASSEMBLY LANGUAGE Covers nearly everything one needs to know in assembly prog ramming for the IBM PC, including the internal architecture of this most popular computer. Suits students ·and enthusiasts. Cat 8-6099 QUE UPGRADING AND REPAIRING PC's Virtually the ultimate source for personal computer upgrading, maintenance and trouble shooting information with tips and advice on preventative maintenance. Also includes: Solut ions to commo n PC problems and purchasing decisions , ASCII charts and various expe rt recommendations. WE BST ER'S BY EXAMPLE REFERENCE GUIDES 95 Cat B-6195 Similar to the reference guide but includes a basic training disk program designed to start the beginner on a hands-on training program . All vers ion s of the training disk are sim ilar .. in format so the DOS 5.0 USERS GUIDE user doesn't need to re-learn the train ing format in other books and The intermediate user's guide wr itten by an expert in a packages. manner that is easy to follow for users .. 95 B-6386 E9.95 Webster's Works 2 for windows By Example Cat 8-6101 B-6398 9.95 Webster's Word Perfect for Windows By Exam ple 8-6399 9.95 Webster's Microsoft Word 2.0 For Windows, By Example $69 $39 DS XPRESS PHONE & MAILORDER SERVICE Outside Sydney (Free call) 008 22 8610 Sydney And Enquiries -888 2105 FAX: (02) 805 1986 or write to DS XPRESS, PO BOX 321 N/RYDE NSW 2113 All Major Credit Cards Accepted. O/Nite Courier Available. 24 HOUR DESPATCH OF ALL ORDERS N SW • Albury 21 8399 • Bankstown Square 707 4888 • Black town 871 7722 • Brook vale 905 0441 • Bond i 387 1444 • Campbe ll town 27 2199 • Chatswood Chase 4111955 • Ch ullora 642 8922 • Gore Hill 439 5311 • Gos ford 25 0235 • Hornsb y 477 6633 • Hurstville 580 8622 • Kotara 56 2092 • Liverpool 600 9888 • Maitland 33 7866 • Mirand a 525 2722 • Newcastle 611896 • Nort h Ayde 878 3855 • North Sydney (Greenwood Plaza) 964 9467 • Orange 818 400 • Parramatta 689 2188 • Penrith 32 3400 • Rail way Square 211 3777 • Sydney City 267 9111 • Ta mworth 661711 • Woll ongong 28 3800 ACT • Belconnen (06) 253 1785 • Fyshwick 280 4944 VIC• Ballarat 31 5433 • Bendigo 43 0388 • Box Hill 890 0699 • Coburg 383 4455 • Oande no ng 794 9377 • East Brighton 592 2366 • Essendon 379 7444 • Footscray689 2055• Frankston 783 9144 • Gee long 232 711 • Me lbourne City 399 Eliz abeth St 326 8088 & 246 Bourke St 639 0396 • Richmond 428 1614 • Ringwo od 879 5338 • Spr ingvale 547 0522 QLD • Booval 282 6200 • Brisbane City 229 9377 • Buranda 391 6233 • Cairns 311 515 • Capalaba 245 2870 • Chermside 359 6255 • Maroochydore 791 800 • Rockhampton 27 9644 • Southport 32 9033 • Toowoom ba 38 4300 • Townsvi ll e 72 5722 • Underwood 341 0844 • SA• Adelaide City 232 1200 • Beverley 347 1900 • Eli zabeth 255 6099• Enfi eld 260 6088• St. Marys277 8977 WA • Cannington 451 8666 • Fremantle 335 9733 • Perth City 481 3261 • Midland 250 1460 • Northbridge 328 6944 TAS • Hobart 31 0800 • Launcest on 344 555 NT• Darwin 811977 STORES ACROSS AUSTRALIA AND NEW ZEALAND MAR C H 1993 71 Infrared remote control switch This fully assembled infrared remote controlled kit will switch a relay at distances up to 10 metres. The remote control transmitter is housed in a plastic case measuring 140 x 68 x 30mm and is powered by an internal 9V battery (not supplied). The receiver PC measures 110 x 55mm and it can be powered from a 9-12V supply. Current drain at 12V is 35mA on and is suitable for frequencies up to 300kHz. N59 ferrite material has been developed specifically for high frequencies up to 1MHz. Under conditions of 1MHz, 50mT and 1()0°C, it exhibits a core power loss of only 110mW/g. Saturation occurs at 480mT (20°C) and the initial permeability is 900. N59 ferrite is available now, while N62 and N97 are available in sample form only. For further details, contact Malcom Evans, Siemens Ltd, Electronics Components Department, 544 Church St, Richmond 3121. Phone (03) 420 7716. Sanyo large screen television receiver Sanyo's new TEIOO large screen television is an imposing piece of furniture in a glossy camphor wood design, with a 68cm screen. 72 SILICON CHIP standby and 120mA when the relay operates. Supplied with the kit is a 4-page reprint which features the circuits, wiring diagrams and explanatory text. So if you want to get an IR remote control system up and going with the minimum amount of electronics assembly, this is the way to go. The kit is priced at $44 and is available from A-One Electronics Pty Ltd, 432-434 Kent St, Sydney, NSW 2000. Phone (02) 267 4819. This low distortion, flat , square screen has 750 lines horizontal resolution, a wide viewing angle and reduced glare. Fuzzy Logic picture control circuitry continuously monitors the brightness of the room and the viewing distance and adjusts the image brightness to minimise eye strain. This means the set makes its own adjustments to give a high definition picture in a bright room, and a softer picture in a dark room. The Fuzzy Logic circuit also works to reduce picture noise. Picture quality is enhanced by the use of a shadow mask made from Invar, an alloy of steel and nickel to eliminate picture distortion caused by the tube's heat. A PAL/NTSC comb filter eliminates colour and dot interference for improved sharpness and definition. The set has a sub-woofer stereo sound system with Sanyo's Cascade Tuning Port system and speakers with cones made from a polymer and pulp sandwich material. Other features include inputs for S-Video and phono, a camcorder input, mini headphone jack and extension speaker terminals plus Teletext facilities. Sanyo's TEIOO model CPP2940TX has a recommended retail price of $2,999.00 and comes with a matching stand. It is available from selected retailers throughout Australia. Emtek DCT-310 AC/DC clamp meter If you are an electrician, an auto electrician or you need to measure very heavy currents without inserting a meter in series, then this AC/DC clamp meter is for you. As an example of the capabilities of this instrument, say you want to measure the current drawn by your car's starter motor but without having to disconnect any battery leads. With the Emtek DCT-310 you just set it into DC mode on the 400A range, snap the tongs around the positive or negative battery lead and then have someone start the motor. As the reading comes up on the display you can then switch to "Peak Hold" and the reading will be held until you switch it off. Many older clamp meters cannot measure DC current; they have a current transformer based on the laminated core of the tongs but this does not work at DC. This unit can measure direct current because it uses a Hall Effect device instead of a current transformer. Two AC and DC current ranges of 200A and 400A are provided, as well as a temperature range reading from -40°C +750°C using a type K thermocouple which is supplied with the unit. There is also a resistance range reading up to 2kQ and two voltage ranges , 200V AC and DC and 2000V DC or 750V AC. A very good feature of the unit is that it comes with a sturdy carry case which will be invaluable in protecting the meter against the inevitable knocks that it would otherwise get in the average toolbox. All told, the Emtek DCT-310 AC/ DC clamp meter is something of a bargain at the price of $225 plus 20% sales tax. For further information, contact Emona Instruments Pty Ltd, 86 Parramatta Rd, Camperdown, NSW 2050. Phone (02) 519 3933. 300 watt power amplifier This rugged power amplifier has an interesting circuit based on a TL071 op amp and 13 transistors. The op amp essentially provides the differential input stage and the circuit is more or less conventional following that. The four NPN output transistors are arranged in quasi-complementary symmetry, a fairly common approach in high power amplifiers. Two transistors provide overdrive protection although it is not clear from the circuit information whether this is simple drive limiting or foldback protection. Rated power output is 300 watts at .05% harmonic distortion while music power output is quoted at 540 watts. Both of these figures will depend on the voltage output and regu- Low cost answering machine This surprisingly compact answering machine is based on a single microcassette. This holds the answer message which you record and all the messages which are left by callers. As well as normal answering functions, the Hardie AM100 also includes Memo, Call Screening and Remote Access via telephone. Memo is a handy feature whereby you can leave a voice message for your family, to be played back when any other messages are reviewed. Call screening, as the name suggests, allows you to screen a call before personally answering the phone. You just let the machine answer the phone, listen to the caller speak and if you want to take the call, you just press the Stop button. Remote access is another useful feature which allows you to playback any messages over the phone. To do this you must be using a tone dialling phone or a DTMF encoder. The unit comes with a plugpack supply and is Austel approved. It is available for $89 from all Rod Irving Electronics stores. lation of the power supply which will require a rating of about 500 watts if the amplifier is to work at its maximum capability. As is usual with these fully assembled modules from A-One Electronics, the unit appears to be well made and uses readily available components. A-One can also supply suitable Australian made transformers and other power supply components, as well as rack mounting cases. The price of the 300W amplifier module is $175. It is available from AOne Electronics Pty Ltd, 432-434 Kent St, Sydney NSW 2000. Phone (02) 267 4819. SC ANTRIM TOROIDAL TRANSFORMERS • Now made in Australia. • Standard range 15VA to 2kVA. • Large ex-stock quantities available. • Competitive pricing available for OEMs & resellers. • Simply the best transformers all round. HARBUCH ELECTRONICS PTY Lm 90 George Street, Hornsby NSW 2077. Telephone (02) 476 5854. Fax (02) 476 3231. MARCH 1993 73 A 24-hour sidereal clock for astronomers If you are involved with amateur astronomy, you will want to know the sidereal time which is related to the motion of the stars across the sky. This is different from solar time which is related to the motion of the Sun. This sidereal clock has a 4-digit liquid crystal display & can be run from batteries or mains power. DESIGN BY ROBERT FLYNN A mean solar day is the average time between successive transits of the Sun across the meridian and is defined as 2~ hours. By contrast, the mean sidereal day is the average time between successive transits of a star (specifically the first points of Aries) across the meridian and is actually shorter than the mean solar day by about four minutes. The evidence of this fact is that each star rises from the eastern horizon four minutes earlier each night (or day). Hence, if you p lan to observe particular stars or other heavenly bodies during an evening, it is desirable to know the sidereal time. In fact, the mean sidereal day is 235.909 seconds shorter than a mean solar day (ie, just under four minutes shorter). In effect, sidereal time is 1.00273790934 times faster than solar time. Fot a watch or clock intended to run with a 32,768Hz crystal , the input frequenc y would need to be increased to 32,857.716Hz. A standard 32kHz watch crystal cannot be made to run this fast so our The Sidereal Clock is housed in a low-cost plastic case & has a 4-digit liquid crystal display. Because it measures star time rather than solar time, it runs almost four minutes per day faster than a conventional clock. 74 SILICON CHIP circuit uses BCD rate multipliers to increase the frequency to the required figure. However, we are running a little ahead of our story. Features This sjdereal clock is housed in a standard plastic utility case with a 4digit liquid crystal display. On the front panel are three switches for time setting and a red LED to indicate low battery. Two of the switches are selfexplanatory and are labelled "SET HOURS" and "SET MINUTES". The other switch is labelled "CORRECT ±2 MINS". This is used to set the clock to the exact hour provided it is within plus or minus two minutes of the hour. Inside, most of the parts are mounted on-a single PC board which accommodates nine ICs. These comprise five 4527 BCD rate multipliers, one 4069 hex inverter, one 4020 binary divider, one S-8054 voltage detector.and one PCFl 171 4-digit clock. This last IC is a 40-pin surface mount chip which is normally used in car clocks. It drives the 4-digit liquid crystal display but is used in an unorthodox way as part of the method of obtaining sidereal operation. Now let's have a look at the circuit ofFig.1. The core of the circuit is IC8, the PCFl 171 clock chip which is normally run with a 4.19MHz crystal. We did not wish to use this crystal, however, because it is not readily available and it cannot be made to provide sidereal time. Hence, instead of connecting a 4.19MHz crystal across the oscillator pins on the PCFl 171, we are using it in the "test" mode which allows us to run the chip with a much lower clock frequency. In normal use, ICl divides the clock frequency by 222 . Hence, a crystal operating at 4.194304MHz is divided down to lHz. In the test mode, IC8 is made to operate 65.,536 times faster; ie, 16 of its frequency divider_stages +SV 0.1:: 0.1:: 16 14 ..! 2 l15 A B IC2 4527 CP .,. 3 5 CAS CE STR CL PL 12 11 10 113 14 fc 15 16 114 A D 0 1 ~ CA$ 10 STR C ili ce CP 8 9 12 B C IC3 4527 0 CL + 16 14 12 10 fc + +5V - PL 113 14 .,. la D 6 D1 0.1:: 0.1:: A CA$ Ia D 01 ..L...!,g CAS IC4 4527 1 STR ili ce CP IB 12 C 15 8 CL 9 .,. 16 14 10 fc PL 15 A IC5 4527 3 STR ili ce . CP CL 3 12 C 8 0.1:: .,. 16 14 D 0 1 ~ CAS PL 10 fc 15 Ia 2 8 C STR CP 9 ~8 CL 113 .,. D IC6 4527 6 u; ce 9 TB A 01~ PL J4 + IB +SV IC1a 4069 IC1b 5 ...... 6 ~? yv- J. X1 : 330k 32.788kHz 10 + l401is 18 23 6 37 7 34 a3 l10 Is 10 11 29 30 7 34 37 5 6 35 (VDD) TR VDD A1, B1 C1 A2 82 C2 02 .!,____! D2 C2 82 A2 C1 81 G1 E1 D1 A1 E2 E2 01, IC7 13 2 LTD242F-22 E1, F2 ~ F2 4020 Q8 ,-.....- OSC IN G1 1 2 4 . 3 36 32 G2 G2 A 28 25 RESET A.3 A3 PS F/ G /e 27 24 83 83 ~1 13 15 E/ /c P4 C3 C3 12 14 SET MINS D 108 03 03 51 PCF1171 P3, E3 ..!!.........!! E3 ----.,_!! MINS F3 G3 A4 84 C4 04 E4 F4 G4 P4 BP OP1 DP2 OPS F1 SET HAS 26 27 21 20 19 16 17 22 23 28 1 1s 112 116 136 S2 29 F3 30 HAS G3 ±2 MIN CORR 24 S3 A4 17 ......... ■■-.....! CORR 84 16 SET 24 P3, C4 TS VSS CONT HA BP P4 G4 F4 E4 D4 -Hl18p F"" J. 22 ii• O.l! 10VW! o.1I ~ 10M CK VC1 ■ Ii SOpF' I .,. -------- .µ ,-,,=, . . ,-,,=, ,_, 1=1 .........----2 -- 1a9 J 20 9V FROM PLUG-PACK "--+ + 01 1N4002 I':';'\ \;:.,,I 02 IN ( ~ 2.2~ REG1 OUT LP2950 , GNO O.l J. 21 22 5 32 26 25114 11s +5V I IC9 REG1 GNoOouT INOouT IN GND VIEWED FROM BELOW ~ A K SIDEREAL CLOCK Fig.1: the circuit uses rate multipliers IC2-IC6 to multiply the 32.768kHz crystal frequency by 0.50136 to obtain 16.428kHz. This is then divided by 256 in IC7 & then fed to clock chip ICB to give sidereal time. are bypassed. This means that a precise 64Hz signal fed to pin 2 of !Cl would allow it to keep correct time. Our circuit runs the clock at a slightly higher frequency, 64.17522579Hz to be exact, in order for it to operate at sidereal time. This frequency is obtained in the following way. ICla, one inverter of a 4069 hex inverter chip, operates as an oscillator with a 32.768kHz crystal (ie, a standard watch crystal). The output signal from this oscillator is buffered by IClb and then fed to the clock inputs of five 4527 rate multiplier chips. Rate multipliers We have not used these chips in the past so they will probably be unfamiliar to most of our readers. Suffice to MARCH 1993 75 Fig.2: pay careful attention to component orientation during the board assembly, especially when installing the LCD. The three parts marked with an asterisk are installed on the copper side of the PC board. know that BCD rate multipliers are used to produce an output frequency which is a rational fraction of the clock frequency. A 3-decade BCD rate multiplier will produce an output frequency of nnn/ 1000 where nnn is a 3-digit number specified as three BCD characters. Each rate multiplier has its number "n" programmed into it by tying each of four BCD input lines high or low. Our circuit uses a 5-decade rate multiplier to provide a multiplication factor of 0.50136. In fact, if you look closely at the five rate multipliers, IC2 to IC6, you will see that each one is labelled with its multiplication factor; ie, IC2 is programmed with "5" (pins 14 & 2 high), IC3 is programmed with "O" (pins 14, 15, 2 & 3 low), IC4 is programmed with "1" (pin 14 high; pins 15, 2 & 3 low), IC5 is programmed with "3" (pins 14 & 15 high; pins 2 & 3 low) and IC6 is programmed with "6" (pins 15 & 2 high; pins 14 & 3 low). The output of the five rate multipliers acting together is taken from pin 6 of IC6 and is equal to 16.428564k.Hz. Interestingly, this signal is not a regularly spaced pulse waveform but comes in irregular pulse patterns whose average rate is equal to the required frequency. The output signal from pin 6 of IC6 is fed to IC7, a 4020 binary divider. It divides the signal by 256 to obtain the frequency of 64.17 408Hz. This is not the exact frequency we want though. We want 64.17522579Hz which is only a small fraction away. To obtain this exact frequency, we use the trimmer capacitor at pin 3 of IC1a to adjust the crystal frequency to 32,768.585Hz. Now when this is multiplied by 0.50136 in IC2-IC6 and divided by 256 in IC7, the result is exactly 64.17522579Hz. Not a great deal more needs to be said about IC8 and its functions. It contains all the circuitry necessary to drive the 4-digit liquid crystal display and there are no external components apart from the three time setting switches. All the ICs run from a 5V rail provided by an LP2950 (REG1) low dropout regulator and this is fed from an external 9V or 12V DC plugpack via diode D1. An internal 9V alkaline battery is also provided to keep correct time when mains power is not available. It feeds the 5V regulator via diode DZ. Low battery indication is provided by IC9, a Seiko S-8054 voltage detector. This device is connected across the 9V battery and it turns on a LED if the voltage falls below 4. 7V. The inclusion of the low voltage detector is important because when the battery falls to some point below 3.5V, the clock signal fed to pin 2 of IC8 will fail, because one of the preceding chips will stop operating. The problem is that IC8 will still drive the liquid crystal display but without the correct AC backplane signal. If left operating under this condition for long, the display may be damaged or its life shortened. Hence, when the "Low Battery" LED lights, it is time to replace the battery. Construction Below: all external leads except for the power supply connections, are soldered directly to the copper side of the PC board. Note the small wire strap that's used to hold the crystal in place, to prevent its leads from breaking. 76 SILICON CHIP All the circuitry for the Sidereal Clock is mounted on a PC board measuring 97 x 85mm and coded 04103931. The 40-pin surface mount PCF1171 PARTS LIST 1 PC board, code 04103931, 97 x85mm 1 front panel label, 153 x 90mm 1 plastic case , 157 x 95 x 53mm 1 9VDC plugpack 3 momentary contact SPST pushbutton switches 1 9V battery 1 battery clip 1 polarised DC connector 4 3mm untapped spacers 4 3mm x 15mm CSK machine screws 8 3mm nuts The main clock chip (IC8) is a surface mount device & must be carefully soldered directly to the copper side of the PC board. Use a clean fine-tipped iron for this job & tin the tracks first before soldering the pins. Semiconductors 1 4069 hex inverter (IC1) 5 4527 BCD rate multipliers (IC2-IC6) 1 4020 ripple carry binary divider (IC?) 1 PCF1171 clock chip (IC8) 1 LTD242F-22 LCD 1 S-8054HNM low voltage detector (IC9) 2 1N4002 diodes (01 ,02) 1 red LED (LED1) Capacitors 1 22µF 16VW electrolytic 1 2.2µF 16VW electrolytic 8 0.1µF 50VW or 63VW monolithic (multi-layer ceramic) 1 18pF NPO 9eramic 1 50pF trimmer (Altronics Cat.R4011) (VC1) Resistors (0.25W, 1%) 1 10MQ 5% 1 470Q 1 330kQ This close-up view shows how trimmer capacitor VCl is mounted. It is adjusted experimentally until the clock keeps correct sidereal time. clock chip is mounted on the copper side of the board while all the other parts are mounted in the normal way on the component side. We suggest that you mount the surface mount chip first and then all the conventional components. While mounting a surface mount chip with pins spaced at 0.76mm may seem difficult, it can be done without too much trouble. The first step is to make sure that the copper pattern is thoroughly clean of all dirt and oxidation. If the board has been roll soldered and has.a protective coating, so much the better. A bench magnifying lamp will also help a lot. At the very least, you will need bright lighting and a magnifying glass to check your soldering. The second step is to use a very fine tipped soldering iron and tin all the SMD copper tracks and all the leads of the 40-pin device. Use the very minimum of solder on the iron while doing this, as it is very easy to bridge the device pins or the tracks. Having done that, place the SMD chip in its correct position on the board, with the pin 1 end facing IC7, and solder Parts availability The 4527 rate multipliers, PCF1171 clock IC & LTD2424-22 LCD are available from Geoff Wood Electronics, 229 Burns Bay Rd, Lane Cove West, NSW 2066. Phone (02) 428 4111. The Seiko S-8054HNM IC is available from the cash sales counter at VSI Promark Electronics Pty Ltd, 16 Dickson Ave, Artarmon, NSW 2064. Phone (02) 439 8622. tack pins 1, 20, 21 & 40 to their respective tracks. After that, each pin should be soldered by holding it down firmly with a fine tipped jeweller's screwdriver MARCH 1993 77 Analog sidereal clock driver 0.1 16 14 A 16 14 15 8 C IC2 4527 5 CP. +3V 0.1 0.1 16 14 15 8 IC3 4527 0 CAS CE STR CL PL 12 11 10 13 CL PL 15 B C - 7 TC 11 ce 16 14 2 C 12 IC4 4527 1 CAS lO STR A 15 8 IC6 ~527 _6 fc 7 11 2 C 3 56k OUTPUT 16.429kHz TO CLOCK ~ 0 56k 01 6 CE CP CP ~ X1 330k 32.766kHz ANALOG SIDEREAL CLOCK with six CMOS ICs and then the clock signal from the board is connected to one of the now vacant crystal pins in the clock module. The advantage of using this circuit to produce a sidereal clock is that it uses cheap and readily available ICs and can be used with vir- tually any analog crystal clock. The disadvantage is that the resultant 24-hour clock will need a new dial in order to tell the time. However, a new dial can be easily fashioned from a piece of white card and Letraset® rub-on lettering. The whole circuit works from a 3V supply provided by two 1.5V batteries connected in series via a suitable 2-cell battery holder. IC1a, a 4069 inverter runs as a crystal oscillator at 32kHz. This is buffered by IC1b and fed to a five decade rate multiplier consisting of IC2-IC7. These provide a multiplication factor of 0.50136. With the crystal running at 32. 768kHz exactly, the resultant assembly procedure is fairly straightforward. Solder in the wire links, resistors and 0.1µF monolithic capacitors first, then install the diodes and electrolytic capacitors. Note that the ZZµF capacitor and 50pF ceramic trimmer are mounted on the copper side of the board. The 32kHz crystal is soldered into the board and then laid over on its side and secured in place with a wire link over it. This done, solder in all the integrated circuits, the 3-terminal regulator and low voltage detector (IC9). Both the last two devices have T0-92 encapsulation, so they look just like ordinary transistors. This 24-hour sidereal clock driver can be used with virtually any clock which runs from a 1.5V battery & uses a 32kHz crystal. The circuit provides a signal of 16.4kHz instead of 32.768kHz so that the clock hands move at half speed. In other words, the hour hand will make a complete revolution in one sidereal day. This design uses the same rate multiplier principle as used in the digital sidereal clock described in this issue. Essentially, what you have to do is disassemble the clock movement so that you can remove the 32kHz crystal. This is then wired onto the small board along and then applying heat with the soldering iron tip. After all pins have been soldered, check the board under a magnifying glass to see that there are no fine solder bridges between tracks and that all connections are good. After the surface mount device is soldered to the board, the rest of the 78 SILICON CHIP Fig.3: this crystal oscillator & rate multiplier circuit can be used to convert a conventional analog clock to sidereal time. Protect your valuable issues Silicon Chip Binders Fig.4: this board can be used to convert a standard crystal clock to 24-hour sidereal time. Its output connects to the clock board in place of the original crystal. output from pin 6 of IC 7 would be 16.42856.4kHz. The required frequency for 24 hour sidereal time is 16.428858Hz and this can be easily provided by a very slight tweak of the crystal, by adjusting the trimmer. The 16.4kHz signal is taken from a voltage divider between the pin 6 output ofIC6 and the +3V line. The voltage divider gives a signal amplitude of close to 1.5V peak-topeak, thus making it compatible with the 1.5V circuitry of a standard clock. The +3V line from the PC board connects to the +1.5V line of the clock module while the voltage divic:led 16.4kHz signal connects to one of the vacated crystal pins on the clock module board; which one is a matter of trying it to see which one works. These beautifully-made binders will protect your copies of SILICON CHIP. They feature heavy-board covers & are made from a distinctive 2-tone green vinyl. They hold up to 14 issues & will look great on your bookshelf. The clockface was fitted with a new 24-hour dial so that it would display the correct sidereal time. On the rear, the modifications included the additional PC board, plus a 3V battery pack to power this board. There are just two connections between the board & the original clock board. * High quality * Hold up to 14 issues * 80mm internal width * SILICON CHIP logo printed in gold-coloured lettering on spine & cover Price: $A 11.95 plus $3 p&p each (NZ $6 p&p). Send your order to: Silicon Chip Publications PO Box 139 Collaroy Beach 2097 Or fax (02) 979 6503; or ring (02) 979 5644 & quote your credit card number. Use this handy form l -·- '! rn . ,, , \~ ----------Enclosed is my cheque/money order for $_ _ _ or please debit my O Bankcard O Visa O Mastercard Card No: Do not solder in the liquid crystal display until the circuit operation has been checked. How can you do that unless the LCD is in place? Easy, it's just a matter of a few voltage checks. Before you can do that though, you will need to temporarily connect a 9V battery or a 9V plugpack. With power applied, check that +5V appears at pin 14 of the 4069 (IC1) and at pin 16 of the 4527s and 4020 (IC7) . If your multimeter has a good AC frequency response, you can also check for the presence of an AC signal of about 1.5-2V AC at pin 10 of IC7. This effectively checks that the crystal oscillator (IC1) and the rate multipliers (IC2-IC6) are working correctly. Card Expiry Date __!_ _ Signature _ _ _ _ _ _ _ _ __ Name _ __ _ _ _ _ _ __ _ Address_ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ P/code_ __ . _-·- -------- . MARCH 1993 79 0 0 CORRECT LOW ± 2mins. Fig.5: this full size · artwork can be used as a drilling template for the front panel of the Sidereal Clock. BATTERY 0 0 SET SET MINUTES HOURS 0 Sidereal Clock 0 0 0 iO o7 aaa 04103931 Now check that the clock signal (64Hz) is present at pin 13 ofIC7. This should be at about 2. 7V AC. Interestingly, you can also measure the same signals on the DC range; in this case, you should obtain about 2.5V (ie, ½Voo), The final tests are to check for the presence of the backplane signal at pin 5 of IC8 and to check for the presence of an AC signal between the packplane pin and any of the liquid crystal display lines. Note that for this test, not all segment lines will be active and therefore some segment lines will have no voltage on them. The backplane signal is 64Hz and should be about 2. 7V AC or 2.5V DC. When measuring the voltage between the backplane pin and any active segment line, the AC voltage should be close to 5.5V AC. Inserting the LCD Fig.6: the PC artwork for the digital version is coded 04103931 & measures 97 x 85mm. Check your etched board careful~y against this pattern before installing any of the parts, particularly around the surface mount IC. ~ ~ _sc_ ~ o,,l,,,,G °""""° ~-----------E393~ Fig.7: use this PC board to build the analog version of the Sidereal Clock. It is coded 04103932, measures 101 x 35mm & can easily be accommodated on the back of most crystal-controlled clocks. 80 SILICON CHIP If all these checks are positive, you can insert and solder the liquid crystal display into place. Make sure that it is inserted the correct way around. As shown on the component overlay diagram, the lefthand side of the display (looking at the front) has a slight bulge in the edge of the glass. With the LCD soldered in, re-apply power and check that the clock works. If so, the unit can be completed. You will need to drill the holes and make a 70 x 28mm cutout in the lid of the case. The PC board is attached to the lid of the plastic case using four countersunk screws and 6mm spacers. When these screws and spacers are fitted, you will need to make and attach a Dynamark® adhesive label and fit it to the lid. It is then a matter of completing the wiring and the clock is finished. To set and regulate the clock you will need to consult an astronomical almanac and calculate the sidereal time for your longitude. SC AMATEUR RADIO BY GARRY CRATT, VK2YBX A general coverage shortwave receiver from England Ever wanted a first class communications receiver but without all the complexity that seems inevitable with sets from Japan? If so, consider the Lowe Electronics HF-225 general coverage receiver. It is made in Derbyshire, England. With well over one million active amateur operators in such a small country, it is not surprising that most amateur equipment manufactured today originates from Japan. Their huge domestic market represents sufficient commercial incentive for manufacturers to design new models on a regular basis. However, it should not be taken for granted that Japan is the only source of amateur radio equipment. A Brit- ish company, Lowe Electronics, has achieved notable success in recent years with its range of shortwave receivers. Their initial model, the HF125, has now been superseded by the HF-225 and the professional version , the HF-235. The design and development was, according to Lowe, based on straightforward objectives: (1) to obtain sufficient RF performance for the receiver to operate without problems in crowded bands with many strong signals; (2) to combine complete control of a necessarily complex piece of equipment with easy operation for the user; and (3) to achieve these objectives within a reasonable price range. The result is a compact desktop receiver offering multimode coverage from 30kHz to 30MHz, microprocessor controlled PLL tuning, dual conversion, three selectable IF filter bandwidths, a backlit 5-digit liquid crystal display, and an analog signal strength meter. The receiver also has 30 memories for storage of oft-used frequencies, an inbuilt lithium battery for memory backup, and can be operated from a 12V car battery or the supplied AC adaptor. Circuit features The interior of the Lowe HF 225 shortwave receiver is very clean & easy to access. The microprocessor which controls it operates in "static idle" mode for most of the time so that it does not produce any unwanted signals. The, HF-225 is a dual conversion superhet receiver, using up-conversion to a high first intermediate frequency (IF) of 45MHz, and a second IF of 455kHz for the selective filters. This design gives good image rejection at all tuned frequencies in the HF band (any image frequencies will fall outside the coverage of the receiver) and good filter shape factors for the 455kHz IF. MARCH 1993 81 The Lowe HF-225 shortwave receiver covers the range from 30kHz to 30MHz & eschews the complex styling & controls of most Japanese receivers. Despite its straightforward front-panel layout, it features microprocessor controlled PLL tuning & has 30 memories for storage of oft-used frequencies. control which can be set for treble cut or bass cut. Receiver tuning is achieved by varying both the local oscillator and the heterodyne oscillator (used for IF conversion). The local oscillator ranges from .45.030MHz to 74.999MHz in lkHz steps, while fine tuning is provided by the heterodyne oscillator covering 44.544MHz to 44 .545MHz, in 128 steps. The final carrier insertion frequency is determined by the mode selected, so that the appropriate IF passband filter is in the correct position relative to the carrier for sideband reception, either USB or LSB. The local oscillator signal is produced by a PLL synthesiser but all frequencies affecting the on-channel tuning of the receiver are crystal derived to ensure good accuracy and low drift. All switching and tuning functions of the receiver are controlled by a dedicated microprocessor which receives commands from the front panel controls and sends information to the receiver control register and the PLL system on a serial data bus. The single-chip microprocessor is supported by a controller driving the LCD and a frequency mem.ory with battery backup. No spurious signals All these components are mounted away from the main RF PC board on a separate board behind the front panel. The rear panel carries sockets for an external keypad, 12V DC power, record The control system uses the "static out & an external loudspeaker. There's also an FM squelch level control, inputs idle" principle, where there are no for both 50Q & 600Q antennas & a switch to select the antenna type. signals other than a basic clock oscilThe most gain in the receiver oc- lator running until the operator reSignals from the antenna pass curs at 455kHz, where several stages quires a change in the receiver conthrough one of six band-selecting filusing multi-element ceramic filters figuration. The system then reacts to ters before being fed to the first mixer. These filters attenuate strong signals are configured to give bandwidth po- commands from the controls, before that are well removed from the de- sitions of 2.ZkHz, 4kHz, 7kHz and · returning to the "idle" condition. lOkHz. This method of operation virtually sired frequency and help to reduce eliminates spurious signals from the interference from even order control system from being picked up intermodulation products. Particular Signal detection Following the second IF, a full-wave by the receiver. Fig.1 shows a block attention has been paid to separating diagram of the receiver. strong medium-wave signals from the envelope detector serves as a low disThe performance of the receiver is rest of the HF spectrum and to attenu- tortion AM detector and as a source of indeed impressive. At frequencies ating signals above 30MHz which AGC (automatic gain control) voltage. When noise spikes are detected, these above 2MHz, its sensitivity to SSB might be received as IF images. signals was measured at 0.3µV for Surprisingly, there is no RF stage pulses fire a monosfable which mutes l0dB signal to noise ratio, and 0.6µV before the mixer and this, coupled the audio stage for the duration of the pulse. The second IF also feeds a prod- for AM signals modulated to a depth with the use of a high-performance uct detector, used for SSB and CW of 70%. The dynamic range is better transistor mixer, gives high dynamic range and good overload immunity. A reception, when the IF is mixed with than 90dB at 50kHz spacing and the 4-pole 45MHz crystal filter with a a carrier signal. Audio filtering is ob- reciprocal mixing is also better than 15kHz bandwidth limits the signals tained through the use of a high Q 90dB at l0kHz in the SSB mode. All peaked response filter centred around image and spurious responses have fed to the second mixer and removes 800Hz. The receiver also has a tone greater than 80dB rejection. image responses from the second IF. 82 SILICON CHIP Fig.1: this block diagram of the HF-225 receiver shows its complex IF filter set-up. It is a dual conversion superhet receiver, with a first IF of 45MHz & a second IF of 455kHz for the selective filters. OPTJ)NA,L lw"".Slf/ri\ DETECTOR ,r-,f1: '"'" .,.,., VOL TONE EXTLS -q:J NT LS Rfte:IVER COHTROL DISPLAV DRIVER SER l~L 88.888 eus FRfQUEMCY >'EMORV LCD FREQUENC Y DISPLAY Operating the receiver is quite simple. The unit is switched on using the combined ON/OFF-Volume control and displays the last frequency used on the 5-digit display. Two buttons, UP and DOWN, select the required frequency in megahertz and the exact frequency is then tuned using a conventional rotary control. Tuning on SSB and CW is in 8Hz steps. This allows accurate resolution of SSB and ECSS reception in the AM mode. Those unfamiliar with the term ECSS (exalted carrier, selectable sideband) may be interested in the basic principle. The ECSS technique makes use of the fact that with a good selective receiver, capable of resolving SSB, an AM signal can be passed through an SSB filter which is wide enough to allow only one sideband. This filter must attenuate the carrier by a minimum of 20dB for the technique to work with any degree of success. The receiver can be used in the SSB mode, with the incoming carrier tuned to zero beat, and the accompanying sideband treated as a true SSB signal. Either the upper or lower sideband can be selected using either LSB or USB modes, so interfering stations can often be eliminated. This can improve MOO< SWITCH T'UN.,.G intelligibility of the signal dramatically and the ability to select an IF filter having a 2.2kHz bandwidth is a most desirable feature. Mode selection S-l"ETER SHAF'T ENC00£1t OPTIONAL l(EYPAO gation and fading, particularly after dark when the ionosphere reflects most HF signals. The FM detector is designed to decode signals having a bandwidth of 12kHz or less and the receiver has a squelch control which can be turned on manually via a rear panel control, or via the filter select control located on the front panel. Mode selection is achieved by a rotary switch and initial filter selection is automatic and dependent on the mode selected. AM switches in the ?kHz filter, while selecting SSB (USB or LSB) or CW selects the 2.2kHz Conclusion With a recommended retail price of filter. Checking the filter in use is easy; a $1425, the HF-225 may not fit every momentary press of the "Filter Se- · budget but for those shoitwave enlect" button causes the LCD to dis- thusiasts seeking close to the ultimate play the current filter bandwidth. A shortwave receiver, this model is cersubsequent press of the same button tainly worth serious consideration. A causes the next filter to be selected number of accessories for the HF-225 and displayed. After three seconds, are available, including the K-225 exthe display returns to indicate the ternal keypad, B-225 nicad battery receiver operating frequency. pack, W-225 whip antenna and the SThe synchronous AM detector uses 225 external loudspeaker. The unit is a narrow deviation phase locked os- supplied fitted with the D-225 "decillator to replace the incoming AM tector unit" , a PC board containing a carrier. When phase locked, this osnarrow band FM detector and a syncillator has exactly the same frequency chronous AM detector. as the incoming signal but incoming Our sample receiver came from the level changes have no effect on the Australian distributor, Emona Elecdetector, provided that there is some tronics Pty Ltd, 92-94 Wentworth Ave, signal on which to lock. This helps Sydney, NSW 2000. Phone (02) 211 reduce the effect of multipath propa- 0988. SC MARCH 1993 83 VINTAGE RADIO By JOHN HILL Paper capacitors cause lots of trouble Paper capacitors cause lots of problems in old valve radio receivers. Often, the best approach it to simply replace the lot with modern equivalents. A fellow collector came to see me recently, asking if I would repair his late 1940s mantle model Radiola. He had not been collecting old radios for long and did not know how do his own repairs. There was a specific and most unusual request regarding this repair. I .was not to replace any of the capacitors because the owner wanted the set to look completely original both inside and out. Readers who are familiar with Radiolas of that era will know that that's an impossible task. How can one repair a Radiola of that vintage without replacing capacitors? I questioned the owner for a reason. It appeared that the guy he bought the set from had told him that it only needed a valve but the owner didn't know which one should be replaced. We've all heard the old "it only needs a valve" story before, haven't we? Original condition The control knobs and chassismounting bolts were removed and.the chassis slid out of its cabinet. It was then up-ended on the workbench and a quick glance indicated that the set was still in its original condition. However, there were signs of capacitor problems everywhere. As was typical of AWA sets of that era, the capacitors were black moulded types carrying the MSP (Manufacturer's Special Products) brand. Many of them were showing that characteristic bulge near the ends where separation had taken place inside. It is simply amazing that some of these receivers continue to function (not very well, I admit) when almost every paper capacitor has become faulty or ineffective. I took hold of one of the smaller capacitors and broke off one end of it with a "snap". The owner looked stunned and uttered not a word. I then cracked off the other end and gave him the centre section of the capacitor to view more closely, pointing out the dull appearance of the foil where it had been separated from the ends for many years. By the time the owner left, I had permission to replace all the original paper capacitors. Suddenly, originality no longer seemed important and I had won another convert to my way of thinking. New wine, old bottle When discussing this problem with a colleague, he reminded me of a trick which I mentioned in these notes some years ago. Where original appearance is important, the trick is to carefully open the capacitor at one end, saving any wax involved, extract the "in. nards"; and replace them with a modern capacitor of similar value. The end is then sealed with the salvaged wax. Most modern capacitors are signifiIt's impossible to repair a late 1940s 5-valve Radiola like this unit while leaving cantly smaller than their older all of the original paper capacitors intact. Paper capacitors cause a multitude of problems & should all be replaced with modern polyester units. counterparts and this trick works well 84 SILICON CHIP This old paper capacitor behaves more like a lMQ resistor than a capacitor. A receiver full of such defective components has little chance of working efficiently, if at aJI. the set is used , the sooner this happens. Many end up behaving more like resistors than capacitors. That said, one should not be overcritical of paper capacitors. They were originally developed at a time when paper was about the only practical and economical material that could be used in their manufacture. What's more, some of them still work OK despite all the uncomplimentary things I have said about them. Modern high voltage capacitors use a thin film of polyester to separate the layers. These polyester capacitors are · also better sealed and their epoxy coating is completely moisture-proof. If a well-made paper capacitor can last up to 50 years and still work OK, then a polyester capacitor should last a hundred years or longer. I have always been an advocate of the "clean sweep" technique whereby all paper capacitors are replaced with ,;a; The ends of these old MSP moulded capacitors have completely separated. Old paper capacitors can be easily described in one word - trouble! with most cardboard tube type assemblies. But the black moulded MSP types used in AWA sets are not candidates for this trick. This material is ex tremely brittle and is almost imposs_ible to work with. There is little option but to replace these. About the only thing in favour of these black moulded capacitors is that they are well-labelled and their capacitance value is easily identified. Today, some 40-50 years after they were made , they are no longer capable of doing the job and must all be replaced. No doubt, many other brands of paper capacitors are just as bad but, when they are encased in a These black moulded paper capacitors were used in AWA receivers from the mid 1930s to the mid 1950s. They were and still are a common source of trouble and are usually found with their ends either split, bulging or completely separated. Replacement is the only solution. cardboard tube, at least the ends don't drop off. Leakage problems Paper capacitors are aptly named they have a waxed paper dielectric between the foil layers and that's all there is to insulate the two capacitor plates. Age, moisture, and chemical impurities in the paper combine forces and eventually the dielectric breaks down. This situation is further aggravated by the voltage applied to the two plates, which encourages the chemical action. As a result, the capacitor develops an electrical leakage problem. And the higher the voltage and the more This old capacitor has obviously been running much hotter than its maker originally intended. If a leaky capacitor passes enough current, overheating soon becomes a problem. MARCH 1993 '· 85 .~,;,,,.:,-.---~ Successful restorations depend on a clean-sweep approach to the paper capacitor problem. Replacing all of a receiver's paper capacitors will often solve many otherwise difficult to locate faults. A handful of burnt-out resistors. While a resistor can break down under normal working conditions, an overload caused by a faulty capacitor is usually the cause. Replacing the resistor is pointless unless the real culprit (the leaky capacitor) is also replaced. modern counterparts. Readers may think that such a move is not totally necessary and that some of the old originals will still work, but I do like to do things properly. Replacing all the paper capacitors will not only solve a few hard to locate problems but also prevents future problems from occurring. Now I know that I have mentioned these things before. It's a very important aspect of vintage radio repairs and that's why I keep reminding readers of the troubles that old capacitors can create. What I haven't mentioned 86 SILICON CHIP in the past is what specific problems a particular capacitor fault can cause. Let's take a look at some. Coupling capacitor One of the most troublesome paper capacitors in a valve radio is the coupling capacitor between the plate of the driver valve and the control grid of the output valve. This capacitor has a high positive (plate) voltage at one end and a negative (grid bias) voltage at the other end. If it develops a leakage problem, lots of nasty things happen. Leakage in this capacitor will allow the plate voltage to override the negative grid bias and apply a positive bias to the grid. This has two immediate effects: gross distortion of the audio signal and excessive plate current drawn by the output valve. Running a receiver for a long period while in this state will shorten the life of the output valve. But the problems do not end there. If the output valve is drawing excessive current, then the rectifier valve will endeavour to supply it. Accordingly, the rectifier may also be overloaded and its life reduced if the set continues to work under these conditions. And there are other components which can be effected by this one leaky capacitor. The excessive current also flows through the output transformer primary and the loudspeaker field coil, or high tension choke. A hot field coil or choke is a good indication of excess high tension current flow. Field coils and high tension chokes should not run any hotter than moderately warm. No, we haven't finished yet! Any component breakdown that causes excessive high tension current can also overload the power transformer, which may also overheat. Replacing the faulty coupling capacitor with a modern high voltage equivalent will most likely mean that this problem will never happen again for as long as the set is in existence. This is just one reason that I am so enthusiastic about replacing old paper capacitors with superior modern types. Overloaded resistors A leakage problem or an internal short in any high tension capacitor may cause similar overload problems. However, the problem may be more localised, involving simply an overloaded resistor. If a faulty screen bypass capacitor is allowing current to flow from the screen to chassis, then the resistor that feeds the sere.en grid must bear the overload. Often it can't, becomes open circuit, and the receiver stops working. In such a case, it is pointless replacing the burnt-out resistor without also replacing the faulty capacitor that caused the overload in the first place. So, a burnt-out screen resistor is a Paper capacitors come in all shapes and sizes. The larger ones are "block capacitors", a metal cased variety that were used for high tension filtering & cathode bypassing before the advent of electrolytics. tions and may have little or no voltage across them. Even so, these capacitors can still become leaky and cause all sorts of problems. For example, leaky capacitors in the AGC (automatic gain control) line can cause trouble and reduce the effectiveness of the system since they behave like resistors! I remember trying to repair my first dual-wave receiver many years ago. The broadcast band was working reasonably well but the shortwave section was really "short"; in fact, it was so "short" that there was nothing there at all. In desperation, I eventually went to see our village expert on such matters. "Get rid of all those useless old capacitors", was his first comment, "and any resistors in there that have gone high too"! That was the best piece of vintage radio advice I have ever received. After replacing the paper capacitors and two resistors in the frequency converter circuit, the shortwave section sprang into life. Without that timely advice, I would probably still be floundering around in the dark. SC RESURRECTION RADIO One of the most troublesome paper capacitors in old radios is the coupling capacitor between the plate of the driver valve and the control grid of the output valve. This capacitor has a high positive voltage at one end & a negative (bias) voltage at the other. Ifit becomes leaky, lots of nasty things happen. pretty sure sign of a faulty capacitor. A couple ofmilliamps screen current doesn't usually cause a resistor much concern and its failure is reasonable evidence of an overload problem. Of course, there's such a thing as a faulty resistor but there are a lot more faulty capacitors. While on the subject of resistors, I always make a "finger check" to test for overheating. This is done with the receiver switched off after it has been operating for half and hour or so. If there are any hot resistors, it's important to find out why. There are often some that work quite warm but if they run really hot, it's advisable to do some checking. If the current is around normal, there may be a problem with that particular resistor. Often, a few simple checks like this can prevent a future and possibly expensive breakdown. This is most important when doing repairs for others; if a set stops working soon after it has supposedly been fixed , it becomes a reflection on the repairer. The fact that he is expected to guarantee dozens of 50-year old parts to work forever is another matter. Not all of the capacitors in a valve radio work under high voltage condi- Vintage Wireless Specialists Repairs - Restoration - Sales Our skilled technicians offer QUALITY repairs and restoration. We also have a large stock of bakelite and timber radios fully restored and for SALE. Parts are available for the enthusiast, including over 900 valve types, high voltage capacitors, transformers, dial glasses, knobs, grille cloth etc. Circuit diagrams for most Australian makes and models. Send SAE for our catalog. WANTED: Valves, Radios, etc. Purchased for CASH Call in to our showroom at: 51 Chapel Street (PO Box 1116), Windsor, Vic 3181. Phone: (03) 529 5639; Fax (03) 510 4486 MARCH 1993 87 Silicon Chip BACK ISSUES July 1988: Stereo Control Preamplifier, Pt.2; Fitting A Fuel Cut-Off Solenoid To Your Car; Booster For TV & FM Signals; The Discolight Light Show, Pt.1; Tone Burst Source For Amplifier Headroom Testing; What Is Negative Feedback, Pt.3. August 1988: Building A Plasma Display; Universal Power Supply Board; Remote Chime/ Doorbell; High Performance AC Millivoltmeter, Pt.1; Discolight Light Show, Pt.2 ; Getting The Most Out Of Nicad Batteries; Data On Insulated Tab Triacs. September 1988: Hands-Free Speakerphone ; Electronic Fish Bite Detector; High .Performance AC Millivoltmeter, Pt.2; Build The Vader Voice; Motorola MC34018 Speakerphone IC Data; What Is Negative Feedback, Pt.4. October 1988: Stereo FM Transmitter (Uses Rohm BA1404); High Performance FM Antenna; Matchbox Crystal Set; Electronic House Number; Converting A CB Radio To The 28MHz Band; Queensland's Powerful Electric Locomotives. November 1988: 120W PA Amplifier Module (Uses Mosfets); Poor Man's Plasma Display ; Automotive Night Safety Light; Adding A Headset To The Speakerphone; How To Quieten The Fan In Your Computer; Screws & Screwdrivers, What You Need To Know; Diesel Electric Locomotives. December 1988: 120W PA Amplifier (With Bal- anced Inputs), Pt.1; Diesel Sound Generator; Car Antenna/Demister Adaptor; SSB Adaptor For Shortwave Receivers; Why Diesel Electrics Killed Off Steam ; Index to Volume 1. January 1989: Line Filter For Computers; Ultrasonic Proximity Detector For Cars; 120W PA Amplifier (With Balanced Inputs) Pt.1; How To SeNice Car Cassette Players; Massive Diesel Electrics In The USA; Marantz LD50 Loudspeakers. February 1989: Transistor Beta Tester; Minstrel 2-30 Loudspeaker System; LED Flasher For Model Railways; Build A Simple VHF FM Monitor (uses MC3362), Pt.1; Lightning & Electronic Appliances; Using Comparators to Detect & Measure. March 1989: LED Message Board, Pt.1; 32-Band Graphic Equaliser, Pt.1 ; Stereo Compressor For CD Players; Amateur VHF FM Monitor, Pt.2; Signetics NE572 Compandor IC Data; Map reader For Trip Calculations ; Electronics For Everyone Resistors. April 1989: Auxiliary Brake Light Flasher; Electronics For Everyone: What You Need to Know About Capacitors; Telephone Bell Monitor/ Transmitter; 32-Band Graphic Equaliser, Pt.2; LED Message Board, Pt.2. May 1989: Electronic Pools/Lotto Selector; Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference; LED Message Board, Pt.3; Electronics For Everyone - All About Electrolytic Capacitors. June 1989: Touch-Lamp Dimmer (uses Siemens SLB0586); Passive Loop Antenna For AM Radios; Universal Temperature Controller; Understanding CAO Probes; LED Message Board, Pt.3. July 1989: Exhaust Gas Monitor (Uses TGS812 Gas Sensor); Extension For The Touch-Lamp Dimmer; Experimental Mains Hum Sniffers; Compact Ultrason ic Car Alarm; NSW 86 Class Electric Locomotives. September 1989: 2-Chip Portable AM Stereo Radio (Uses MC13024 and TX7376P) Pt.1; AlarmTriggered Telephone Dialler; High Or Low Fluid Level Detector; Simple DTMF Encoder; Studio Series 20-Band Stereo Equaliser, Pt.2; Auto-Zero Module for Audio Amplifiers (Uses LMC669). October 1989: Introducing Remote Control; FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 1Mb Printer Buffer; 2-Chip Portable AM Stereo Radio, Pt.2; Installing A Hard Disc In The PC. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); Sensitive FM Wireless Microphone; FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disc Drive Formats & Optioris; The Pilbara Iron Ore Railways. December 1989: Digital Voice Board (Records Up To Four Separate Messages); UHF Remote Switch; Balanced Input & Output Stages; Data For The LM831 Low Voltage Amplifier IC; Install A Clock Card In Your PC; Index to Volume 2. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Speeding Up Your PC; Phone Patch For Radio Amateurs; Ac- Use this handy form to order you,· back issues l - - - - - - - - - - - - - - - - - - - - - - -.- - - - - - - - - - - - Please send me a back issue for: O October 1988 0 November 1988 0 March 1989 0 April 1989 U September 1989 O October 1989 0 February 1990 0 March 1990 0 July 1990 0 August 1990 O December 1990 O January 1991 O May 1991 o June 1991 O October 1991 O November 1991 O March 1992 O April 1992 O August 1992 0 September 1992 O January 1993 O February 1993 0 July 1988 December 1988 0 May 1989 O November 1989 0 April 1990 O September 1990 O February 1991 0 July 1991 O December 1991 0 May 1992 O October 1992 o Enclosed is my cheque/money order for $_ _ _or please debit my: O August 1988 O January 1989 0 June 1989 O December 1989 O May 1990 o October 1990 O March 1991 O August 1991 O January 1992 0 June 1992 O November 1992 O Bankcard Card No. Signature _ _ _ _ _ _ __ __ _ _ _ Card expiry date_ _ /_ _ O Visa Card ---7 O September 1988 O February 1989 D July 1989 0 January 1990 O June 1990 o November 1990 0 April 1991 o September 1991 O February 1992 0 July 1992 O December 1992 O Master Card $5.00 each (includes p&p) . Overseas orders add $1 each for postage. NZ orders are sent air mail. Street _ __ __ _ _ _ __ _ __ __ _ _ __ _ _ _ __ _ Detach and mail to: SILICON CHIP PUBLICATIONS PO BOX 139 COLLAROY BEACH NSW 2097 Suburb/town _ _ _ _ _ __ __ _ _ _ _ _ Postcode _ _ _ _ __ Or call (02) 979 5644 & quote your credit card details. Fax (02) 979 6503. Name _ _ _ _ _ _ _ __ _ _ __ _ _ _ _ __ __ _ _ _ __ L----------------------------------- ---~--88 SILICON CHIP live Antenna Kit; Speed Controller For Ceiling Fans; Designing UHF Transmitter Stages. February 1990: 16-Channel Mixing Desk; High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs , Pt.2; PC Program Calculates Great Circle Bearings. March 1990: 6/12V Charger For Sealed LeadAcid Batteries; Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. April 1990: Dual Tracking ±50V Power Supply; VOX With Delayed Audio; Relative Field Strength Meter; 16-Channel Mixing Desk, Pt.3; Active CW Filter For Weak Signal Reception; How To Find Vintage Radio Receivers From The 1920s. May 1990: Build A 4-Digit Capacitance Meter; High Energy Ignition For Cars With Reluctor Distributors ; The Mozzie CW Transceiver; Waveform Generation Using A PC, Pt.3; 16-Channel Mixing Desk, Pt.4. June 1990: Multi-Sector Home Burglar Alarm ; Low-Noise Universal Stereo Preamplifier; Load Protection Switch For Power Supplies; A Speed Alarm For Your Car; Design Factors For Model Aircraft; Fitting A Fax Card To A Computer. July 1990: Digital Sine/Square Generator, Pt.1 (Covers 0-500kHz); Burglar Alarm Keypad & Combination Lock; Simple Electronic Die; Low-Cost Dual Power Supply; Inside A Coal Burning Power Station; Weather Fax Frequencies. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Wave Generator, Pt.2. September 1990: Music On Hold For Your Telephone; Remote Control Extender For VCRs ; Power Supply For Burglar Alarms; Low-Cost 3Digit Counter Module; Simple Shortwave Converter For The 2-Metre Band. October 1990: Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs ; The Dangers of Polychlorinated Biphenyls; Using The NE602 In Home-Brew Converter Circuits. November 1990: How To Connect Two TV Sets To One VCR; A Really Snazzy Egg Timer; LowCost Model Train Controller; Battery Powered Laser Pointer; 1.5V To 9V DC Converter; Introduction To Digital Electronics; Simple 6-Metre Amateur Transmitter. December 1990: DC-DC Converter For Car Amplifiers; The Big Escape -A Game Of Skill ; Wiper Pulser For Rear Windows; Versatile 4-Digit Combination Lock; 5W Power Amplifier For The 6Metre Amateur Transmitter; Index To Volume 3. January 1991: Fast Charger For Nicad Batteries, Pt.1; The Fruit Machine; Two-Tone Alarm Module; Laser Power Supply; LCD Readout For The Capacitance Meter; How Quartz Crystals Work; The Dangers When Servicing Microwave Ovens. February 1991: Synthesised Stereo AM Tuner, Pt.1; Three Inverters For Fluorescent Lights; LowCost Sinewave Oscillator; Fast Charger For Nicad Batteries, Pt.2; How To Design Amplifier Output Stages; Tasmania's Hydroelectric Power System. March 1991: Remote Controller For Garage Doors, Pt.1; Transistor Beta Tester Mk.2; Synthe- sised AM Stereo Tuner, Pt.2; Multi-Purpose 1/0 Board For PC-Compatibles; Universal Wideband RF Preamplifier For Amateurs & TV; A Look At The Config.Sys & Ansi.Sys Files. April 1991: Steam Sound Simulator For Model Railroads; Remote Controller For Garage Doors, Pt.2; Simple 12/24V Light Chaser; Synthesised AM Stereo Tuner, Pt.3; A Practical Approach To Amplifier Design, Pt.2; Playing With The Ansi.Sys File; FSK Indicator For HF Transmissions. May 1991: Build A DTMF Decoder; 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1; Setting Screen Colours On Your PC. June 1991: A Corner Reflector Antenna For UHF TV; 4-Channel Lighting Desk, Pt.1; 13.5V 25A Power Supply For Transceivers; Active Filter For CW Reception; Electric Vehicle Transmission Options; Tuning In To Satellite TV, Pt.1. July 1991: Battery Discharge Pacer For Electric Vehicles ; Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2 ; Tuning In To Satellite TV, Pt.2; PEP Monitor For Transceivers. August 1991: Build A Digital Tachometer; Masthead Amplifier For TV & FM; PC Voice Recorder; Tuning In To Satellite TV, Pt.3; Installing Windows On Your PC; Step-By-Step Vintage Radio Repairs. September 1991: Studio 3-55L 3-Way Loudspeaker System ; Digital Altimeter For Gliders & Ultralights, Pt.1 ; Build A Fax/Modem For Your Computer; The Basics Of AID & DIA Conversion ; Windows 3 Swapfiles, Program Groups & Icons. October 1991: Build A Talking Voltmeter For Your PC, Pt.1; SteamSound Simu latorMk.II; Magnetic Field Strength Meter; Digital Altimeter For Gliders & Ultralights, Pt.2; Getting To Know The Windows PIF Editor. November 1991: Colour TV Pattern Generator, Pt.1 ; Battery Charger For Solar Panels; Flashing Alarm Light For Cars; Digital Altimeter For Gliders & Ultralights, Pt.3; Build A Talking Voltmeter For Your PC, Pt.2; Error Analyser For CD Players Pt.3; Modifying The Windows INI Files. December 1991: TV Transmitter For VCRs With UHF Modulators; lnfrared Light Beam Relay; SolidState Laser Pointer; Colour TV Pattern Generator, Pt.2; Windows 3 & The Dreaded Unrecoverable Application Error; Index To Volume 4. January 1992: 4-Channel Guitar Mixer; Adjustable 0-45V 8A Power Supply, Pt.1 ; Baby Room Monitor/FM Transmitter; Automatic Controller For Car Headlights; Experiments For Your Games Card ; Restoring An AWA Radiolette Receiver. February 1992: Compact Digital Voice Recorder; SO-Watt/Channel Stereo Power Amplifier; 12VDC/ 240VAC 40-Watt Inverter; Adjustable 0-45V 8A Power Supply, Pt.2; Designing A Speed Controller For Electric Models. March 1992: TV Transmitter For VHF VCRs; Studio Twin Fifty Stereo Amp lifier, Pt.1'; Thermostatic Switch For Car Radiator Fans; Telephone Call Timer; Coping With Damaged Computer Directories; Valve Substitution In Vintage Radios; The AR-1500 & AR-2800 Scanning Receivers. April 1992: lnfrared Remote Control For Model Railroads; Differential Input Buffer For CROs; Studio Twin Fifty Stereo Amplifier, Pt.2; Understand- ing Computer Memory; Switching Frequencies in Model Speed Controllers; Aligning Vintage Radio Receivers, Pt.1. May 1992: Build A Telephone Intercom; LowCost Electronic Doorbell; Battery Eliminator For Personal Players; lnfrared Remote Control For Model Railroads , Pt.2; A Look At Large Screen High Resolution Monitors; OS2 Is Really Here; Aligning Vintage Radio Receivers, Pt.2. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; lnfrared Remote Control For Model Railroads, Pt.3; 15Watt 12-240V Inverter; What's New In Oscilloscopes?; A Look At Hard Disc Drives. July 1992: Build A Nicad Battery Discharger; 8Station Automatic Sprinkler Timer; Portable 12V SLA Battery Charger; Off-Hook Timer For Telephones; Multi-Station Headset Intercom , Pt.2; Understanding The World Of CB Radio; Electronics Workbench For Home Or Lab. August 1992: Build An Automatic SLA Battery Charger; Miniature 1.5V To 9V DC Converter; The lnterphone Digital Telephone Exchange, Pt.1 ; Dummy Load Box For Large Audio Amplifiers ; Internal Combustion Engines For Model Aircraft; Troubleshooting Vintage Radio Receivers. September 1992: Multi-Sector Home Burglar Alarm; The lnterphone Digital Telephone Exchange , Pt.2; General-Purpose 3½-Digit LCD Panel Meter; Track Tester For Model Railroads ; Build A Relative Field Strength Meter; Internal Combustion Engines For Model Aircraft, Pt.2. October 1992: 2kW 24VDC To 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm , Pt.2; Mini Amplifier For Personal Stereos; Electronically Regulated Battery Charger (Charges 6V, 12V & 24V Lead-Acid Batteries); Internal Com bustion Engines Fo.r Model Aircraft, Pt.2. November 1992: MAL-4 Microcontroller Board, Pt.1; Simple FM Radio Receiver; lnfrared Night Viewer; Speed Controller For Electric Models, Pt.1; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.2 ; Automatic Nicad Battery Discharger; Modifications To The Drill Speed Controller. December 1992: Diesel Sound Simulator For Model Railroads; Easy-To-Build UHF Remote Switch; MAL-4 Microcontroller Board, Pt.2 ; Speed Controller For Electric Models, Pt.2; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.3; High Voltage Probes - Beware The Dangers ; Index To Volume 5. January ·1993: Peerless PSK60/2 2-Way Hifi Loudspeakers; Flea-Power AM Radio Transmitter; High Intensity LED Flasher For Bicycles ; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.4; Speed Controller For Electric Models, Pt.3; Restoring A 1920s t(it Radio February 1993: Three Simple Projects For Model Railroads; A Low Fuel Indicator For Your Car; Audio Level/VU Meter With LED Readout; Build An Electronic Cockroach; MAL-4 Microcontroller Board, Pt.3; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5; File Backups With LHA & PKZIP. PLEASE NOTE: All issues from November 1987 to June 1988 plus the August 1989 issue are now sold out. All other issues are presently in stock. For readers wanting articles from sold-out issues, we can supply photostat copies (or tearsheets) at $5.00 per article, including postage. When supplying photostat articles or back copies , we automatically supply any relevant Notes & Errata at no extra charge. MARCH 1993 89 ASK SILICON CIIlP 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. Problems with Discolight project I am having difficulties in chasing down a problem with one of your older designs, the Discolight (SILICON CHIP, July 1988). The project kit had a fair few missing parts. I have a good soldering technique and I am reasonably experienced with project construction. When the Display switch is set to Modulated, all four channels work correctly (obviously the Beat switch is set to Music). When the Display switch is set to Unmodulated, all three patterns work on Chaser, Strobe and Alternate, with the Beat switch set to Oscillator or Music. But when the Display switch is set to Mod (Modulated), the Beat switch to Music and the Pattern switch to Chaser, only two channels operate. Normally, these are channels 2 & 4, but if I turn the power switch off and then back on again, sometimes channels 1 & 3 are the only ones that work. dccasionally none of the channels light. If the Pattern switch is changed to Alternate, normally only channels 1 & 2 work but sometimes only channels 3 & 4 work. If the Beat switch is set to Oscillator, none of the above problems appear: All four channels How to combine · two TV antennas I live in an area where only two _television channels ·are available. Cha.onel 2 is easily received using g 2 or 3-elernent antenna, but channel 9 requtres a very high gain · antenna and a masthead amplifier. I need a means of combining these two inputs (750 each) to a common downlead (75.Q). The ·commercially available diplexers ,only offer onlll VHF and one UHF input; the latter attenuates either .· :Channel too much. 90 SILICON CHIP modulate the pattern set by the Pattern switch. Any suggestions as to the problem, or where to look, would be much appreciated. (P. M., Caringbah, NSW). • Your problem of incorrect patterns is a side effect of using all three settings together. The reason is that the source of modulation also causes movement in the pattern. The result is that the modulation signal will tend to dominate the beat pattern and so some lights will go out from time to time. This can be checked by noting that all four channels work properly when the Beat switch is set to Oscillator. Horace won't shut up I have a problem with Horace the Cricket, as described in the August 1990 issue of SILICON CHIP. I have assembled and tested him , only to find that he will not stop chirping when there is silence. I have checked my work against the diagram on numerous occasions to make sure it is right. My teacher and I have been all over it with a multimeter and found that one of the capacitors wasn't releasing electricity. The capacitor I refer to is the one on the Would you please provide a circuit for a diplexer specifically fOT these two channels, with an AC~ only path to channel 2 and an AC + DC path to channel 9? fA. $., Denmark, WA), • Unfortunately we don't have such a circuit and the desjgn procedure: for such circuit$ is rathe,r specialised. Perhaps one of our readers can provide a design. In the mean:time, the most effeclive means of coupling the two signals may be to use a simple changeover switch which would have no losses at all . lefthand side looking from the front directly behind the piezo transducer. My teacher suggested soldering in a larger capacitor but I still have the same problem. Could you please give me some advice on how to make Horace fully functional? (D. S., Murtoa, Vic). • There am two possible reasons for the circuit failing to operate correctly. One is that you have the diode in the wrong way around. The other is that the two 0.ZZµF capacitors are not low leakage types. Another possible reason for the malfunction is an incorrect resistor value. Problem with plasma display After more than four years, I have finally got around to building the plasma display in the August 1988 issue of SILICON CHIP. I elected to go it alone, rather than buy a kit, but I have run into a problem: the glass jar with the inert gas inside. But it's not what you think. I know a glass blower who can make the glass baUfor me (see below), and my brother has access to the chemistry laboratory at RMIT to evacuate the glass and introduce some inert gas. My problem is the insertion of the electrode into the glass. How is that achieved? In the second last paragraph of the article (page 12) it says " ... but keep your hands and fingers away from the lid of the container. If your hands stray too close you may get a nasty shock directly from the lid". Does this mean that the lid is metal rather than plastic? If so, is the high voltage electrode insulated from the lid and how is it done? Maybe I'm wrong but if the high voltage electrode was connected to a metal lid, the current path would be directly to the glass and to the plastic pipe and thus the display wouldn't work. Could you please give me some advice on the insertion of the electrode and what type of sealant may be re- quired to do this; eg, plaster, car body filler, silicone, etc. (R. H., Glen Iris, Vic). • The project in question did have a conventional jar lid which meant that the lid was live. You could use a high voltage electrode inserted into a plastic lid but then you may have more problems with sealing. We can assure you that, with a metal lid, the plasma display works quite well and there is no question of the current somehow shorting from the metal lid to the glass. Consider that · the current is high frequency AC and, therefore, the outer surface of the glass could be considered to be a high impedance electrode, with the return path back via the air or your body, if you happen to touch the glass. We am not sure as to what type of sealant was used in the original plasma display but if you are going to use a silicone sealant, it would be best to use one that has virtually no outgassing. It might be a good idea to contact Selleys or one of the other manufacturers for their recommendations. Protecting a power supply I have a query regarding a power supply I recently built. It is a fairly conventional design, 20A at 13.8V, to power my FT 757 on our periodic caravan trips. It works extremely well. The caravan also has its own battery, charged by the aforementioned supply when we are connected to the power mains. This is also OK when the mains are connected but look at the situation when the mains power goes off for any reason. The emitters of the four 2N3055 transistors still have a nominal +12V applied to them but their collectors will effectively be at ground, through the bleeder resistor. This would seem like reverse polarity of the pass transistors and may destroy them. Is this supposition correct? I have built other power supplies in the past, for a similar type of service, without any difficulties, but it seems to me that I am pushing my luck. I had intended to connect a relay in series with output of the supply and energise it from the output of the bridge rectifier. This would disconnect the supply from the battery as soon as the mains power is removed. Restoring the zap to ignition systems I may have experienced a simila:i; fault to that encountered by G. L. of Emerald, Vic, as mentioned on page 100 in the January 1993 edition ("Ford Telstar Ignition Loses Its Spark"). Although the ignition system I put together had a photodiode/LED pickup, I would say that the problem in the output would be sfmilar. Quite simply, I think the problem is that the high back-EMF from the primary winding of the ignition coil has arced through the insulating washer under the output transistor. Ignition system reliability is so important that I changed the single insulator to a stack of four and took the added Am I correct in my supposition? It has been suggested that I use a large series diode at the supply's output but I am not all that enamoured with diodes in this situation - I feel it would upset the supply's regulation, which is now very good. (R. G., Mount Bryan, SA). • It is possible that with mains voltage not applied, the power transistor in your power supply could be damaged by reverse voltage. The simple solution to this may be to place a power diode capable of carrying more than 6A in series with each power transistor emitter. Because these diodes will be inside the feedback loop of the power supply, they will not affect the regulation performance. The alternative of one large series diode will w9rk but it will reduce the regulation. Relay isolation will work too. Flickering problem with Touch-Lamp Dimmer I have some problems with the Touch-Lamp Dimmer which was described in the June 1989 issue of SILICON CHIP. I have built two, one installed in my bathroom and the other in a zippy box that operates a bedside reading lamp. There seems to an intermittent flickering problem that is at an irritating level (rather than just noticeable) precaution of insulating the die- ,I cast case from earth. A very healthy spark and trouble-free operation has been enjoyed since. If I make any more of these (and they are well worth it), a plastic zippy box with an aluminium top is a better choice than a diecast box. Mount the transistor hard on the top, all above earth potential, and mount the box into the engine compartment via the plastic portion. Precious little heatsinking of the output transistor is required. (G. H., Doubleview, WA). • We think that using four insulating washers is going over the top and you may find the transistor failing because its heat cannot pass through all the washers. Use two washers by all means but no more than that. when trying to read by the light. Quite likely, this is caused by the SEQEB controlled tariff pulses that periodically appear on the power lines to operate domestic hot water equipment. Can the filter in this circuit be modified to minimise this interference? (I guess that the meter pulses would be lkHz in frequency). I have also had problems using this device in close proximity to a multistation headset intercom system similar to that described in the June 1992 issue of SILICON CHIP (when plugged into the same GPO as the intercom power supply). Interference generated by the dimmer rendered the intercom unusable and so it had to be disconnected during the concert production). The wall-mounted version seems less sensitive to power line variations (perhaps a subjective assessment) but has another problem in that the higher than normal moisture content of the room is causing significant false triggering. This results in sporadic operation when the room is in use and ghostly operation at other times, where the light will come on in the middle of the day or night for no reason. The operation with the touchplate installed varies from continuous cycling of the dimmer through to uncontrollable flashing and cycling, especially in the winter months when condensation on the walls is signifiMARCH 1993 91 Autoranging DMM has only three digits I have an autoranging DMM that only gives a display of three digits, even though it covers from 450VDCdown to 0.lmV in five ranges. My question to you is could you help to make my meter read six digits, even if it has to do so slowly and in a number of steps. I don't imagine that you would suggest any modifications to the internal workings of the meter but I hope you can supply me with a method cant. I have got around this false triggering by removing the touchplate, which means the device will only operate by touching directly the protruding screw. Is it possible to reduce the sensitivity to the touchplate without compromising safety, or is the circuit just not suited to working in a high humidity area? (C. T., Brisbane, Qld) . • To improve the circuit's immunity to control tones on the mains, increase the .0068µF capacitor at pin 4 to a maximum of .033µF. This should solve the flickering problem when mains tones are present but it also has the effect of increasing the minimum brightness level. The capacitor at pin 4 is a compromise between the minimum brightness setting and immunity to mains tones. You can also obtain more immunity by changing the integrator component at pin 3. Replace the 680kQ resistor and .0022µF capacitor with a or perhaps even an external circuit that would do the trick. I enclose a copy of the instruction booklet ofmy meter. Any help would be appreciated. (H. G., Dickson, ACT). • As far as we can see from the specifications you have enclosed, your meter should display four digits rather than three at any time. It is not possible to add extra digits to the unit, although it is possible to increase the effective resolution by providing a fixe<J_ DC offset at a given measurement. lOOkQ resistor and a 0.lµF capacitor. Audio interference generated by the dimmer should be minimal when it is powered from a separate mains circuit. Extra filtering by way of a second lO0uH inductor and 0. lµF capacitor will be necessary when the dimmer is powered from the same mains circuit as sensitive audio equipment. False triggering can be caused by a film of dirt or condensation on the plastic surround of the touchplate. Wiping the plastic plate periodically should minimise this. If this fails, the sensitivity can be reduced by reducing the value of the lMQ resistor at pin 5 to 470kQ. UHF remote switch for a PC I wish to comment on the design of the UHF Remote Switch that was published in the December 1992 issue of Silicon Chip Binders * High quality with heavy board covers; will look great on your bookshelf. *(or Each binder holds up to 14 issues 12 issues plus 2 catalogs). * logo printed in goldcoloured lettering on spine & cover. SILICON CHIP Price: $A 11.95 plus $3 p&p each (NZ $6 p&p). Just fill in & mail the order form in this issue; or fax (02) 979 6503; or ring (02) 979 5644 & quote your credit card number; or buy a 12-month subscription & get the binder at a discount. 92 SILICON CHIP SILICON CHIP. The pre-built front-end is what I have been after for a long time. However, . it appears that this design is just like all others in that the receiver has a single output instead of delivering the full transmitted code in parallel. What I am seeking to do is connect such a receiver to a PC via the parallel port. However, the address lines are not necessary on the receiver although they are on the transmitter. Would you be able to assist me in finding the appropriate 12-bit encoder and the necessary interface components. To minimise redundant data to the XT/ AT, is there such a decoder able to provide a data ready pulse to ensure handshaking is installed? Is there an inductance meter or adapter for multimeters available? Regarding the 386 upgrade, I believe that upgrades are questionable. Surely it is senseless to spend so much money on ridiculously expensive upgrades when a new 386 40MHz system can be purchased for $1,600 from Ritronics. If anyone has a 286 system that they can't sell for $600 then the system isn't worth upgrading. Question ... the Number Cruncher. What age group are you aiming at? I think that kids would find little pleasure in playing with this "toy" when nothing comes close to their Sega or Gameboy. (N. H., Longreach Qld). • You are not alone in wanting a device which has parallel outputs. However, at present we do not know of any device or circuit which will provide a parallel link to a computer. An inductance meter adaptor kit is available from Jaycar Electronics. Regarding the 386 upgrade, we agree that pricing can make the whole concept questionable and that is why we made a comment along those lines at the end of the article. However, due to the fact that computer prices are dropping all the time, you may find it quite difficult to obtain $600 or more for a 286 system which is more than a few years old. The Number Cruncher is certainly not aimed at little kids. It is aimed at older readers who wish to build a project for fun and learning. Notes & Errata LED Flasher For Bicycles, January 1993: the circuit on page 41 shows pins 1 & 4 of ICl swapped. The PC board & wiring diagram are correct. ORDER -FORM BACK ISSUES* MONTH YEAR YEAR MONTH MONTH YEAR MONTH YEAR *Back issues are $AS each (incl. postage). Overseas orders add $A1 per issue for postage. BINDERS Please send me _ _ SILICON CHIP binder(s) at $A14.95 each (incl. postage). Overseas orders please add $A3.00 each for postage. TOTAL PRICE $A SUBSCRIPTIONS D New subscription - month to start D Renewal - Sub. No. r------------, D RATES (please tick one) 2 years (24 issues) D D D D D Australia Australia with binder(s)* NZ & PNG (airmail) Overseas surface mail Overseas airmail I I I I I I I I I I Gift subscription l<at>f' 1 year (12 issues) $A84 D $A42 $A105 0 D D D $A53 $A130 $A130 $A240 $A65 $A65 $A120 *1 binder with 1-year subscription; 2 binders with 2-year subscription I I YOUR DETAILS Your Name (PLEASE PRINT) Address Postcode Daytime telephone number I GIFT SUBSCRIPTION DETAILS Month to start Message Gift for: Name I I I I I I I I I I ~ (PLEASE PRINT) I Address I I I I I I I Postcode I State I IL _ _ _ _ _ _ _ _ _ _ _ _ ...JI Signature o Cheque/Money Order D Bankcard D Visa Card D Master Card '' Card No. I I I I II I I I II I I I II I I I I Phone (02) 979 5644 Fax (02) 979 6503 9am-5pm Mon-Fri. Please have your credit card details ready Fax the coupon with you r credit card details 24 hours 7 days a week Card expiry date I Mail coupon to : Freepost 25 Silicon Chip Publications PO Box 139, Collaroy Beach 2097 No pc stage stamp required in Australia MARCH 1993 93 . . . . . T CENIRE Cash in your surplus gear. Advertise it here in Silicon Chip. ANTIQUE RADIO ANTIQUE RADIO restorations. Your one-stop radio repair shop. Specialising in restoring vintage radios, including chassis rewiring, re-condensing, quality new parts, valves, valve sockets, speakers, power & audio transformers. Secondhand radio dials & parts for most brands & models. About 400 radios in stock for sale, restoration & parts. Every restored wireless is covered by a 2year warranty on parts & labour. We restore damaged woodwork & cabinets & French polish (approx. 40 coats). Vintage car radios available for sale or restoration. Repairs done on tape decks. r-------------------------, CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $10.00 for up to 15 words plus 40 cents for each additional word. Display ads (casual rate): $20 per column centimetre (Max. 10cm). Closing date: five weeks prior to month of sale. To run your classified ad, print it clearly in the space below or on a separate sheet of paper & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy Beach, NSW 2097. Or fax the details to (02) 979 6503. Open Sat. 10am-5pm; Sun. 12.30-5pm. 109 Cann St, Bass Hill, NSW 2197. Phone (02) 645 3173 BH or (02) 726 1613AH. FOR SALE WEATHER FAX programs for IBM X,T/ ATs *** "RADFAX2" $35 is a high resolution, shortwave fax, Morse & RTTY receiving program. Suitable for CGA, EGA, VGA and Hercules cards (state which). Needs SSS HF radio & Radfax decoder. *** "SATFAX" $45 is a NOAA, Meteor & GMS weather satellite picture receiving program. Needs EGA or VGA plus "WEATHER FAX" PC card. *** "MAXISAT" $75 is similar to SATFAX but needs 2Mb expanded memory (EMS 3.6 or 4.0) and 1024 x 768 SVGA card. All programs are on 5.25-inch or 3.5-inch disks (state which) & include documentation. Add $3 postage . Only from M. Delahunty, 42 Villiers St, New Farm, Old 4005. Phone (07) 358 2785. AN INTERFACE to control the outside world from a PC parallel port. 32 bits in, 32 bits out. Units can be cascaded. Short form kit includes software examples. $35 or send $2 for my 3.5-inch promo disk. Don McKenzie, 29 Ellesmere Crescent, Tullamarine 3043. Phone (03) 338 6286. Enclosed is my cheque/money order for $_ _ __ O Bankcard L 94 O Visa Card O Master Card or please debit my x I Card No. I I Signature_ _ _ _ _ _ __ _ ___ Card expiry date_ _~ /_ __ I I Name _ _ _ __ __ _ __ _ _ __ _ _ _ _ _ _ __ __ I I Street _ _ _ _ _ __ __ _ _ _ __ __ _ _ __ _ __ _ I I Suburb/town _ _ _ _ __ _ _ _ _ _ _ Postcode_ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ JI SILICON CHIP 40 MOTOROLA VOLTAIC PANELS: 6.5V 15W 60cm sq. System 26V 25A (650W). 200UB frame mount with sliding protective cover. Array complete $4250.00 ono. Further info PO Box 501, Mudgee2850. Phone(063)726118. UNUSUAL BOOKS: electronic devices, fireworks, locksmithing, radar invisibility, surveillance, self-protection, unusual chemistry and more. For a complete catalog send 95c in stamps to: Vector Press, Dept S, PO Box 434, Brighton SA 5048. VINTAGE RADIO PARTS and valves: we stock many new receiving and transmitting valve types, spare parts, complete radios and sundry items. Send 45c stamp for price list to Airwave Ra- SURPLUS COMPONENT SALE STOCK QTYS LIMITED, NO BACK ORDERS 2N3055 $1.20 RESISTORS TIP30C $0.50 MOST VALUES AVAIL. TIP122 $1.20 1/4WM/FILM $3/100 2N7000 $1.50 1/3W CARBON · $2/100 2SC2240 $0.60 1/2W CARBON $41100 VN88 $2.00 1W CARBON $51100 3N170 $1.50 2WCARBON $81100 2N5954 $1.50 5W WIREWOUND $0.30 2N3440 $1.20 1OW RESISTORS $0.60 7906C $0.50 100uF10VTANT $1.50 LM3900 $0.50 C&K 1201 SW $0.50 27C41 $1.00 8W DIL SW $2.00 68681 $7.00 CD22100 IC $2.50 747CJ $0.80 78l12, 79L12 $0.50 8251 $3.00 8259 $4.00 VALVES A25 THERMISTOR $3.00 3A4 $8.00 MCT275 OPTO $1.20 417A $8.00 MOC3020 OPTO $2.00 5651 $8.00 MOC8050 OPTO $1.50 5R4GY $8.00 74C161 $2.00 EL32 $8.00 74HC74 $0.70 ONE ONLY TBL 12/30 TRANSMIT TUBE $2500.00 PHONE OR MAIL ORDERS, CREDIT CARDS ACCEPTED FOR ORDERS $20 & OVER, DISCOUNTS FOR QUANTITY ORDERS SECONTRONICS PO BOX 2215, BROOKSIDE, OLD 4053, PHONE (07) 3551314 143 GRAYS RD, ENOGGERA, OLD 4051, FAX (07) 8551014 SHOP OPEN SATURDAY 9AM · 4PM AH (07) 8551880 dio Restoration, PO Box 333, North Hobart, Tas 7000. WE HAVE THE following items for sale, following completion of various contracts. HP 141 T spectrum analyser systems with various plug-ins, R1200 service monitors, AWA noise and distortion meters, signal generators, Tektronix 7000 series oscilloscopes, other items too numerous to mention. Call, write or fax Av-Comm Pty Ltd, PO Box 225, Balgowlah 2093 . Phone (02) 949 7417 or 948 2667. Fax (02) 949 7095. SPRINKLER CONTROLLER KITS: standard and enhanced versions have new PCB layout with optional program A/program B operation. Very reliable and versatile designs control eight stations and have 32 programmable start and run times. Can be used to control just about anything (refer SILICON CHIP, July 92). All settings stored in EEPROM. Kits come complete with LCD and case. Standard version: $135 . Enhanced version uses 60708U3 and has built in calendar, allowing day Qf fortnight watering (ie, SA. SU, MO, etc), externally triggerable cycles and rain switch capability: $175. Requires 24V AC to run. Relays extra at $3.75 each (requires 9 for full kit) . JOCKEY PCB UPGRADE KIT: upgrade your present version (PCB SPV3 or SPV4) to the features of the enhanced version. $49. SIMPLE 68705P3/U3 PROGRAMMER PCB: needs a programmed EPROM or use it with a ROM emulator: $27. All prices include p&p. Kits and further info available from Graham Blowes, 38 Garnet I MEMORY & DRIVES ICL 286 Board PRICES AT JAN. 18TH, 1993 All in one board with two serial, printer, IBM keyboard, high den· sity floppy & IDE mono video interface. Up to 4Mb RAM, 80286-16cpu, MS-DOS compatible, 130 page manual, small size 170mm x 255mm. Laptop power supply 240V 5Vf 3A 12V/3A $89 $299 lnfrared sets, 1 each IR LED, diode & IDC header $1 Ampro little PC Audio IC hybrids STK043-25 or STK058-40W $9.95 SIMM 1Mb x 9, 1Mbx3 4Mb x 9 4Mb x 8 70ns 70ns 70ns sons $54 $52 $205 $182 DRAM DIP 1 x 1Mb 256 X 4 41256 1Mb x 4 70ns 70ns sons Zor D $5.80 $6.00 $2 $24 DRIVES SEAG 42Mb SEAG 89Mb SEAG 107Mb SEAG 130Mb SEAG 245Mb 28ms 14ms 15ms 16ms 12ms $255 $350 $385 $415 $635 IBM PS.2 50/55/70 70135 90/95 2Mb 4Mb 4Mb $130 $220 $220 TOSHIBA T3200SX T44/6400 T5200 4Mb 4Mb 2Mb $240 $_240 $150 MAC 2MbSI & LC 4Mb P'Book $108 $270 CO-PROCESSORS 387SX 20I25 IIT $13015 387DX All Inlet $140 EPROMS 27C 4Mb15 $16 Sales tax 20%. Overnight delivery. Credit cards welcome. All in one NEC V40 CPU board, MS-DOS compatible, high density floppy. SCSI hard disk, 2 senal, printer, solid stale hard disk, IBM keyboard intertace, (4W), CMOS single +5V rail, up to 768Kb RAM, 384Kb ROM, 145mm x 250mm , 98-page manual. $299 Ring for Latest Prices 1st Floor, 100 Yarrara Rd, PO Box 382, Pennant HIiis, 2120. Tel:(02)9806988 Fax: (02) 9B0 6991 A lK .11...LY.l p► DTH' nL TRANSFORMER REWINDS Fujitsu 40Mb hard disks $269 Microbyte-PC230 v30 CPU board, 1Mb RAM installed, 2 serial, printer, 720Kb floppy, SCS1 hard disk, EGA video, IBM kb intertace, made in Australia, surplus $185 ea 720Kb Floppy Drives $55 TRANSFORMER REWINDS 1.44Mb Floppy Drives $89 St, Niddrie, 3042. Phone (03) 337 1917 (a/h); (03) 575 3349 (b/h); fax (03) 575 3369. THE HOMEBUILT DYNAMO: (plans) brushless, 1000 watt at 740 revs. $A85 postpaid airmail from Al Forbes, PO Box 3919 - SC, Auckland, New Zealand. Phone Auckland (09) 818 8967 anytime. KIT REPAIRS· & Construction Service. Fixed price servicing for all kits . No job too small. Ph (02) 649 2134 after 5pm. MUSIC ON HOLD KIT: SC Sept.1990. This unit is simply connected across the existing telephone line. Press the "Hold" button and your caller will have music on hold, press the release button to restore the conversation. Captures the line when activated and an inbuilt INTELSTAT - International S9tellite (Television) Receiving System (movies, sport, news). Commercial 4.8-metre solid dish plus system electronics package. Can see operating. $3995 .00 ono. Phone Rod (08) 387 0372. We buy surplus computer & electronic products, bankrupt stock and components. p C Computers " ' Taped components by the metre app 200pcs, tants, caps, zeners, diodes, resistors $5.95/metre 600-600 ohm audio output transformers PCB mount 18Hz38kHz. $9.95 Kits Max 110 kit for PCs, 7 relays, ADC, DAC, stepper driver, TTL inputs, with sof~vare $169 PC 110 card with 8255 chip 24 110 lines programmable as inputs or outputs $69 ALL TYPES OF TRANSFORMER REWINDS Reply Paid No.2, PO Box 438, Singleton, NSW 2330. Ph: (065) 76 1291. Fax: (D65) 76 1 DD3. Bargains 1.5 watt AM broadcast transmitter XTAL locked $49 2.5 watt FM broadcast transmitter 88-108MHz. $49 Digi-125 audio power amp (over 19,000 sold since 1987) 50 watV8 $14 125 watV4 $19 New 200 watV2 version $29 lnfrared relay kit $9 Remote control tester $4 36 Regent s1, Kensington, SA. Phone (08) 332 6513. FIX-A-KIT KIT REPAIR & CONSTRUCTION 3 MONTHS WARRANTY ON REPAIRS 12 MONTHS WARRANTY ON CONSTRUCTION TECHNICAL ASSISTANCE HVCAL ELECTRONICS Design. Manufacture & Repair of Electronic Equipment (02) 633 5477 pulser and a flashing LED remind you that the hold function is activated. Will even release the line after a few minutes in case you forget that you left somebody on hold. Just add an inexpensive radio for a complete system. The radio is switched by this unit to 1 conserve its batteries. On special at $30. For the complete kit without the case, 12V DC plugpack: $12.00. Cat No GK116. * 16 CHANNEL UHF REMOTE CONTROL: see EA Nov 88-Jan 89. One transmitter kit, one receiver kit, & one 4-channel relay driver kit, priced to clear at a total price of $90 . Ref XXFEB9401 . * 1-inch CRO TUBE: new 1-inch CRO tube, plus a connecting diagram, plus a simple experimental circuit. Very limited quantities: $30. Ref MARCH 1993 95 LOCAL TRADES & SERVICES JV Tuners - Repairs * Tuner repairs for TVs & VCRs * • • • • Shorted Turns Tester High Voltage Probe Degaussing Wand Remote Control Tester Altronics ............................... . 54-56 Transformer Re.winds For all types of transformer rewinds. (02) 7741154 Fax (02) 7741154 (065) 761291 Fax (065) 761003 Ian J Truscott's Electronic World EEM Electronics Antique Radio Restorations .... ... 94 A-One Electronics ....... ........ . 12-15 Autotron Australia ..... .. ... .. .. ....... . 46 Av-Comm ............................ ....... 67 David Reid Electronics ........ ...... 19 Mail or credit card facilities Printed circuit board assemhl)·, switch mode power supplies repaired. Design work from start to finish. Ring anytimc 9am-9pm Mon-Sun. (03) 7233344 Fax (03) 4192808 (03) 4011393 For service & repair work Advertising Index Dick Smith Electronics .. ........ 68-71 EEM Electronics ... ..... ..... ..... ... ... 96 Electronic World .. ....... .... ...... 53,96 Harbuch Electronics .... ....... ....... 73 Hycal Instruments .... .. ................ 96 Jaycar .. ... ............. ...... .... .... ... 48-49 Silicon Chip T.A. Mowles To advertise your products or services, please call Sharon on Printed circuit boards for· the hobbyist. For service & enquiries contact: (02)9795644(018)285532 (08) 3265590 JV Tuners .. ..... .. .. ........... ... ......... 96 Oatley Electronics .... .... ..... 3,39,96 PC Computers ... ..... .... ....... .. ...... 96 Pelham ............................... ... .... 95 Peter C. Lacey Services ............ 42 Philips Test & Measurement .... IFC XXFEB9402. * FIBRE OPTIC CABLE: high quality fibre optic cable, single fibre <at> $2/metre or 10 metres for $15, dual fibre <at> $4/metre or 10 metres for $30. Ref XXFEB9403. * SWITCHED MODE POWER SUPPLIES: compact enclosed ex-Telecom supplies. Dimensions: 300 x 90 x 180mm. Unregu lated input: 30-50V, regulated input of 12V<at> 6A or 5V <at> 40A; two different units. Limited stocks <at> $28 ea. P&P $7 (Heavy!). Specify type when ordering. Ref XXFEB9404. * SOLAR LIGHTING BARGAIN: (EA Nov. 92). This kit has three separate sections that are contained on one PCB but can be separated: (1) a crystal locked ultrasonic movement detector, (2) a fluorescent tube inverter (4-20W) with logic circuitry, (3) a solar battery charging regulator & an incandescent lamp switcher-pulser, which employs a Mosfet switch . As a package special , we are offering the complete kit for the three sections plus six 6V/1 W solar panels for a total cost of only $99! Ref XXJAN93104. * SWITCHES: high quality miniature enclosed, Italian (FEME) 1, 2, 3 & 5pole, 12-position switches: $2.80 ea or 10 for $20. Ref XXJAN93105 . Major 96 SILICON CHIP cards accepted with phone & fax orders. Total cost of certified p&p: Australia'$5, NZ (airmail) $10. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. Fax (02) 570 7910. WANTED SCULPTOR NEEDS AMATEUR electronics buff, digitally competent, to help with projects Adelaide area. No remuneration . 2B Trennery St, West Richmond. RCS Radio ... ..... ..... ..... .... ... ...... . 96 Resurrection Radio .............. ..... . 87 Rod Irving Electronics ..... ... .. 26-31 Sanyo Australia ... ... ..... .......... OBC Silicon Chip Binders .................. 79 Silicon Chip Back Issues ...... 88-89 T. A. Mowles ..... ... ..... .... ..... ........ 96 Tektronix .. ....... ............ ............. IBC Transformer Rewinds ... ...... ..... 104 RC§ RADIO PTY ILTD ~i~1,~ 0°i6if\!...ol Ill :;=J I RCS Radio Pty Ltd is the only company that manufactures and sells every PC board and front panel published in SILICON CHIP, ETI and EA. RCS Radio Pty Ltd, 651 Forest Rd, Bexley 2207. Phone (02) 587 3491 PC Boards Printed circuit boards for SILICON CHIP projects are made by: • Jemal Products, 5 Forge St, Welshpool, WA 6106. Phone (09) 350 5555. • Marday Services, PO Box 19-189, Avondale, Auckland, NZ. Phone (09) 828 5730. • RCS Radio Pty Ltd, 651 Forest Rd, Bexley, NSW 2207. Phone (02) 587 3491. INNOVATIVE COMPREHENSIVE RELIABLE The New TAS 400 Series from ll'Ktronix Tektronix Analog Scopes set new standards in user operations based on the success of the INNOVATIVE TDS Family of Digital Storage Oscilloscopes. Two or Four Channels, Autoset, dual time base, on-screen cursors, readout, save and recall of settings are part of the COMPREHENSIVE standard features. Enhanced TV Trigger mode makes the TAS family ideal for video applications. The TAS series are very RELIABLE. Should a scope fail during the 3 year standard warranty, it will be replaced at no charge. With prices from around $2500* you can afford the best! Call now for details and specifications. FREE CALL (008) 023 342 T EKTRONIX A NALOG ScoPEs Tektronix / ' Price does not incl ude Sa les Tax