February 2004 - Silicon Chip Online

Outer Front Cover
Contents
Publisher's Letter: Electronic corrosion control is a fraud
Feature: Hands-On PC Board Design For Beginners; Pt.1 by Peter Smith
Project: Simple Supply Rail Monitor For PCs by Jim Rowe
Project: Studio 350 Power Amplifier Module; Pt.2 by Leo Simpson & Peter Smith
Project: Using The Valve Preamp In A Hifi System by Jim Rowe
Feature: Twenty-Five Years Of Automotive ABS by Julian Edgar
Project: Our Fantastic Human-Powered LED Torches by Julian Edgar
Project: Shorted Turns Tester For Line Output Transformers by Bob Parker
Project: PICAXE-18X 4-Channel Datalogger; Pt.2 by Clive Seager
Feature: Breaking The Gigapixel Barrier by Max Lyons
Vintage Radio: The HMV 660 console of 1940 by Rodney Champness
Back Issues
Advertising Index
Book Store
Outer Back Cover

This is only a preview of the February 2004 issue of Silicon Chip.

You can view 35 of the 96 pages in the full issue, including the advertisments.

For full access, purchase the issue for $10.00 or subscribe for access to the latest issues.

Purchase a printed copy of this issue for $10.00.

www.siliconchip.com.au February 2004 1 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Contents Vol.17, No.2; February 2004 www.siliconchip.com.au FEATURES 8 Hands-On PC Board Design For Beginners; Pt.1 A practical guide to downloading, installing and configuring the free Autotrax PC board design software – by Peter Smith 36 Twenty-Five Years Of Automotive ABS Anti-Lock Braking Systems have now been around for 25 years and have saved many lives. Here’s a brief look at their development – by Julian Edgar 76 Breaking The Gigapixel Barrier It’s claimed to be the biggest digital photo ever but it’s not done by simply pointing and clicking a camera – by Max Lyons Supply Rail Monitor For PCs – Page 12. PROJECTS TO BUILD 12 Simple Supply Rail Monitor For PCs It clips into your PC and has three LED bargraphs to indicate the health of the PC’s supply rails – by Jim Rowe 22 Studio 350 Power Amplifier Module; Pt.2 The construction details for this new high-power audio amplifier plus the circuit and wiring details for a matching power supply – by Leo Simpson & Peter Smith 32 Using The Valve Preamp In A Hifi System Here’s how to add a volume control and modify the November 2003 Valve Audio Preamplifier for use with line level signals – by Jim Rowe 56 Our Fantastic Human-Powered LED Torches Sure you’ve seen LED torches before but not like these. There are no batteries; you just crank the handle to generate light – by Julian Edgar 63 Shorted Turns Tester For Line Output Transformers No TV or monitor technician should be without this unit. Build it and you’ll wonder how you ever got along without it – by Bob Parker 73 PICAXE-18X 4-Channel Datalogger; Pt.2 Building The Studio 350 Power Amplifier Module – Page 22. Fantastic HumanPowered LED Torches – Page 56. Adding a real-time clock (RTC) to the datalogger and putting it to use – by Clive Seager SPECIAL COLUMNS 40 Serviceman’s Log A tale of four Philips TVs – by the TV Serviceman 70 Circuit Notebook (1) Cable Tester Uses A Quad Latch; (2) Phantom Supply For Lapel Microphone Adaptor; (3) Frequency Multiplier For LF Measurements; (4) LED Chaser Provides Three Game Functions 80 Vintage Radio The HMV 660 console of 1940 – by Rodney Champness DEPARTMENTS 2 4 31 53 55 Publisher’s Letter Mailbag Book Review Product Showcase Silicon Chip Weblink www.siliconchip.com.au 88 91 92 93 Shorted Turns Tester For Line Output Transformers – Page 63. Ask Silicon Chip Notes & Errata Order Form Market Centre/Ad Index February 2004 1 PUBLISHER’S LETTER www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Peter Smith Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Reader Services Ann Jenkinson Advertising Enquiries Leo Simpson Phone (02) 9979 5644 Fax (02) 9979 6503 Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Julian Edgar, Dip.T.(Sec.), B.Ed Mike Sheriff, B.Sc, VK2YFK Stan Swan SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $76.00 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: Unit 8, 101 Darley St, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silchip<at>siliconchip.com.au ISSN 1030-2662 * Recommended and maximum price only. 2 Silicon Chip Electronic corrosion control is a fraud Among all the email and other correspondence we receive at SILICON CHIP, there are many common requests which are quite understandable, especially as they tend to come from readers who are new to the magazine. But there are others which we find frustrating because they indicate that people are still being conned by peddlers of technical sounding rubbish. Under this heading come requests for us to do a project for electronic corrosion control for cars. A recent email is typical. Here the person quotes from the glowing testimonial on a website and asks could we do something similar, especially as there does not appear to be much electronics involved. In general, the principle of all these schemes is as follows: “A small pulsed DC power supply and control module about the size of a pack of cigarettes is the heart of our corrosion proofing systems. The power supply is all solid state circuitry embedded in electronics grade (UL 94V-0 flame retardant) epoxy encapsulant for long life and durability in any climate. On automobiles and light trucks it is typically installed in the engine bay or in the boot where it runs off the 12V from the vehicle battery, drawing less current than a typical digital clock. One or more unique “programmed capacitive couplers” which are attached to the painted metal surface with aircraft-grade adhesive, are charged by the power supply/control module and function as if they were the positive half of a capacitor. They are wired to the power supply in parallel (each on individual circuits) and meticulously engineered so that each serves to produce a measured and specific limited range of capacitance and thus deliver a measured and specific limited range electrostatic charge via capacitive coupling. These capacitive couplers are vital to the effectiveness of the system and the utmost care is exercised in their manufacture”. Well, there you go. They must be good. Such systems frequently appear to be protected by a patent and they have all been endorsed by “university tests” or “independent engineers”. Only the patent is never listed and details of the university or the “independent engineers” are never mentioned. Nor is there a warranty. Funny that. I always reply to these emails along the lines that I regard electronic corrosion control as a lot of hogwash and a fraud. How can such a system possibly work? There is no current flow through to the car body and there is no sacrificial anode (and even if there was, it could not work unless the car body was immersed in water!). Furthermore, if such a simple low-cost system was effective, why haven’t the world’s auto manufacturers all fitted it to their cars? The answer is that they don’t work and present measures employed by most car manufacturers are so effective that they typically give a 6-year warranty against paint failure and perforation corrosion (or words to that effect). In fact, some new cars in the USA (where they put salt on the roads in winter) come with a 10-year warranty. If you want further evidence of fraud, just log onto www.google.com and type in “RustEvader”. This US company was prosecuted by the Federal Trade Commission as long ago as 1996 and prevented from promoting its electronic corrosion protection system. Yet many other companies continue to promote virtually identical systems. The message is simple. They don’t work. They can’t work. It’s a con! Leo Simpson www.siliconchip.com.au Computer bits? We’ve got the lot! USB Converters Serial and Parallel PCI Addon USB Full Size ATA Flash Reader This new 6 in 1 memory card reader reads all the popular memory cards plus older style PCMCIA ATA flash cards. Also reads MMC, SD, SM, MS, MS Pro. Cat 6785-7 Mem Card Reader/Write 6 in 1 USB 2.0 $119 USB Net Phone This USB connected phone allows free calls across the internet using third party software. Just plug into a USB port, no drivers are needed. Operates with NetMeeting, MSN Messenger, Skype etc. Cat 10129-7 USB Net Phone $89 Includes two serial ports and one bi-directional printer port on the PCI BUS. Installation is simple with the Plug n Play BIOS support. Cat 2620-7 Serial/Parallel Card 2S/1P PnP PCI Switches Plug this card into a PCI slot and it will display the POST using LEDs. Perfect for trouble shooting PCs that will not boot. Cat 3422-7 Diagnostic Card - PCI $98 This auto switching box can be used either 4 in 1 out (4 PC’s share 1 printer) or 1 in 4 out (1 PC uses 4 printers). Cat 12016-7 Cat 12016 $75 UTP RJ45 Manual AB Switch between two UTP devices or share one UTP device on two computers. $35 Cat 12015 Serial/Par AB Manual DB25F Switch one printer between two computers or one computer between two printers. Suitable for parallel or serial printers, plotters etc. Cat 12009-7 Trackball $30 Manual VGA, AT Kb - Serial Mouse Sw Box 4 way This advanced 4D Dual Wheel Mouse has 100% Microsoft wheel functionality & superior performance and comfort. Middle button is programmable. Cat 8052-7 Trackball Cat 12041-7 $59 Connect your PC to mobile phones using these Infrared adapters or form a datalink from your PC to your laptop. Cat 8518-7 IR - M/B 115.2 Kbps $75 Cat 8421-7 IR - Serial 115.2 Kbps $59 Cat 8923-7 IR - USB 115.2 Kbps & 4Mbps $99 USB to Parallel Run printers or other devices that use a parallel port from your USB port using these handy adapters. Cat 2685-7 USB to Parallel - Cent36M $69 Cat 2697-7 USB to Parallel - DB25F $59 USB to ATAPI Allows ATAPI devices such as CD-ROMS to be connected to a USB port. Cat 15081-7 USB to ATAPI $129 Cat 2852 $55 VGA Monitor/PS/2 Kb & Mouse 4way S/box Manual switches to control up to four PCs using one console. Connect With Infrared Cat 8421 USB to RS232 These USB to Serial converters allow serial devices, such as a modem to be connected via the computers USB port. Cat 2801-7 USB to 1 RS232 - DB25M $79 Cat 2828-7 USB to 1 RS232 - DB9M $54 Cat 2852-7 USB to 2 RS232 - DB9M $119 Cat 2851-7 USB to 4 RS232 - DB9M $349 Auto Parallel 4 Way Bi Directional Cat 12015-7 Diagnostic Card - PCI $130 USB to RS-422/485 These devices provides native windows RS-422/485 COM ports which are compatible with Windows serial communication applications. Cat 2853-7 USB to 1 RS422/485 with Opto Isolation $249 Cat 2854-7 USB to 2 RS422/485 with Opto Isolation $499 Cat 2907-7 USB to 4 RS422/485 $560 Cat 12050-7 Cat 2851 Cat 2828 $61 KVM 2 PC Controller AT-PS/2 Serial Mouse These switches are active, so they keep the serial mouse alive when you switch Cat 11610-7 $259 USB video capture Easily capture a picture from your analogue video stream. Just plug the capture box into a USB port and load the included software. Cat 3393-7 Video Frame Capture - USB Port $139 Cat 8923 Cat 2685 Cat 2697 Front Access 5.25” Bay Never have to reach behind the computer again with this 5.25” front access bay. Reads & writes 6 Memory Cat 6765 cards, CF, SM, MMC, SD, MS and MD. Also has three USB 2.0 ports and two firewire ports. Plus audio in/out and 5volt/12volt out. It will operate with Win 98SE or later and Mac OS 8.6. Cat 6765-7 3 USB 2.0 & 2 FireWire ports $129 TV on your PC Cat 8518 LCD Monitor Arm Holds 14”, 15” & 17” LCD monitors. Supports up to 8kg. 3 in 1 design desktop, wall and clamp mounting. Standard VESA mounts. Cat 4666-7 Monitor Arm $99 Cat 4666 USB Port Extender Extends a USB 1.1 port up to 50m using Cat5 UTP cable. Ideal for setting up low cost web cams etc. Cat 11666-7 USB Extender $149 Cat 11666 Console Extender for PS/2 Computer via STP Allows one keyboard, monitor and mouse to be operated up to 150m from the PC. The connection between the sender and receiver unit is via Cat5 STP cable. Cat 11662-7 Console Extender PS/2 $469 Mouse Tablet A mouse which uses electromagnetic technology to provide high resolution input - there’s no ball to clog. It's also a stylus pen input device which has pinpoint accuracy with writing, drawing and painting capabilities. Cat 8676-7 Mouse Tablet Infrared Remote Control Signal Extender $179 Magnetic Card Readers Extend the range of your remote controls from one room to another. Cat 1008056-7 IR Remote Control Extender $129 Printer Extender to 400m Non Powered Microgram’s range of magnetic card readers cover all three tracks and come with either a serial or keyboard wedge style connection. Cat 8768-7 Track 1&2 KB PS/2 $259 Cat 8203-7 Track 1&2 Serial $259 Cat 8681-7 Track 2 KB Wedge PS/2 $219 Cat 8218-7 Track 2&3 KB AT Wedge $259 Cat 8968-7 Track 2 KB Wedge PS/2 Prog $259 Cat 1008056 A simple elegant solution to operate a printer at up to 400m from the computer. Cat 12020-7 Printer Extender $89 Video Extender Cat 8681 Use STP Cat5 cable to extend a VGA signal up to 130m from your PC. Cat 3441-7 Video (VGA) Extender $399 Cat 3441 Cat 3525 Receive Digital TV on your computer. As transmitted by the FTA stations eg Channels 7, 9, 10, ABC and SBS. Cat 3522-7 Digital TV Terrestial Card DVB-T $279 Use these external TV Tuner boxes to watch TV on your desktop or laptop. Cat 3523-7 TV Box USB 1.1 with FM Radio $179 Ideal for Notebooks! Cat 3525-7 TV Box Ext for LCD/CRT Monitor $239 Pentium 4 with ISA slots A Pentium 4 industrial motherboard, that is based on the Intel 845G chipset. It features an onboard watchdog timer, DiskOnChip socket and digital I/O (4 in/4 out). Comes Cat 17078 with 1 AGP slot 3 PCI slots, 3 ISA slots, 4 onboard COM’s ports and a MicroPCI socket. With ISA slots on board and a long life cycle, it is the platform of choice for industrial applications Cat 17078-7 P4 w 3xPCI/ISA Slots $699 Fast POS Thermal Printer A very fast thermal printer with extremely easy paper loading. It literally churns out the receipt at 180 mm/s. Comes with a parallel Interface. Gray or Black available. Cat 9177-7 POS Thermal Printer $799 Thin Client Terminals! We’ve got them for Serial, Ethernet, Windows Based and Linux applications MicroGram Computers Ph: (02) 4389 8444 FreeFax: 1800 625 777 Vamtest Pty Ltd trading as MicroGram Computers ABN 60 003 062 100, info<at>mgram.com.au 1/14 Bon Mace Close, Berkeley Vale NSW 2261 All prices subject to change without notice. For current pricing visit our website. Pictures are indicative only. SHOREAD/MGRM0204 Dealer inquiries welcome See all these products & more on our website...www.mgram.com.au www.siliconchip.com.au F 2004 3 ebruary MAILBAG Valve preamplifier won’t have “valve” sound Early valve amplifiers did produce a significant amount of distortion, as did transistor amplifiers of a similar vintage. But it is the type of distortion that these valve amplifiers produced that made them sound better. Simple valve amplifiers introduce even order harmonics so the distortion is similar to a musical chord. On the contrary, simple transistor amplifiers produce even and odd order harmonics. The odd order harmonics were introduced by the simple class B power section of these amplifiers. A human brain is good at noticing small amounts of odd-order distortion generated by transistor amplifiers but it will ignore even order distortion generated by valve amplifiers. So let’s forget about the history and think about why somebody would want to add a valve preamplifier to their relatively non-distorting transistor amplifier. One of the main reasons is to experience the added effect of even order harmonics. Notice that I called it an “effect” rather than distortion. In particular, it must be noted that valve guitar amplifiers were around before transistor amplifiers ever existed. The sound with this added effect is the sound expected from an electric guitar! The valve amplifier you published in the November 2003 issue employs negative feedback to remove some of the very effect that you were trying to generate. If you look at the Vintage Radio section of your magazine, you will find many examples of valve amplifier stages that employ little or no negative feedback. There is even one example of a stage with no negative feedback in the Vintage Radio section of the same issue that you published the valve preamplifier in! Our own valve preamplifier (K188) is based on a single subminiature pentode with flying leads. The pentode has a maximum plate voltage of 30V and needs 1.2V at 10mA to power the filament. The gain is adjustable from 0 to 4 times and the output impedance is about 10kΩ and the frequency response 4 Silicon Chip extends from 6Hz to 600kHz; perfect for inserting in-line with an amplifier system to simulate valve sound. Best of all, since no negative feedback was used you would get to experience true valve sound, as it used to be. Branko Justic, Oatley Electronics. Comment: while it is true that virtually all the circuits featured in Vintage Radio did not employ negative feedback, most good quality amplifiers produced at the end of the valve era did feature negative feedback, particularly in push-pull power amplifiers, and that includes virtually all guitar amplifiers. Sadly, no simple valve circuit, whether it features negative feedback or not, can hope to simulate the overall sound of a valve guitar amplifier, particularly when it is driven into overload. The controversy rolls on! Developing the valve theme Well, you said you would never do it but you did. Congratulations! As a keen hifi advocate and electronic DIYer, I believe that for a magazine such as SILICON CHIP this is a great opportunity to open up and maintain a new following of persons interested in hifi/guitar and also valves. As an instance, take a look at http://tubesall.hihome.com/ tube.htm which gives some idea of the interest in valve-based audio equipment, particularly for DIYers. Here are a couple of ideas for development. (1). Take your existing valve preamp design and the principles of your recent guitar effects unit to provide a guitar preamplifier based on valves that provides pre-distortion (that guitar players love) and combine this with your SC480 50W power amplifier to provide a valve sound with solid-state reliability in the output stage. (2). Develop your existing valve preamp design into a stereo RIAA equalised preamp for magnetic cartridges. Recent developments in valve quality, component tolerance and noise figures allow a very respectable amplifier to be built. Your existing power supply, properly screened, could be utilised and you already have DC for the heaters. I use three 12AX7s (ECC83) in my preamp and I am very happy with the performance/background noise compared to solid state designs. And it sounds better! (3). A valve power amplifier. Jaycar are selling EL34s (6CA7s) which are good for about 30W in push-pull mode and the 12AX7 could be an amplifier/phase splitter (OK, you may struggle with gain with only one per channel). Of course, the output and power supply transformers may be the “killer” of this idea – both the availability and the cost – which you note in your valve preamp article but perhaps there are some possibilities with existing manufacturers if there was enough interest from your readers. Looking forward to more “tubes” in SILICON CHIP. Dean Brookes, via email. Valve days long since gone Paul Rohde (Mailbag, January 2004) seems to have worked himself into a bit of a frenzy over your “valve philosophy”, if there is such a thing. Sound quality is a very elusive animal and, in spite of many advances, there is still not much really good quality sound available, due mainly to the difficulty and expense of producing really good loudspeakers. Since the advent of CDs, there is no technical reason for recorded sound not to be nigh on perfect although many sound recordists or the acoustics of the recording studio still manage to wreak www.siliconchip.com.au havoc on the final result. When transistors first became available, I was rather suspicious of these new-fangled devices which then had many limitations and, as I thought at the time, could never replace valves. However, when I built my first complete transistor amplifier in about 1968, I could not believe the absence of intermodulation distortion and the overall goodness of the sound. I might add that the valve amplifier I had been using was one of the better designs with a claimed distortion of 0.1%. I would never now consider the use of valve amplification for one moment. As you so rightly say, they “were great in the past (when there was no other choice) but their day is long since gone”. Loudspeakers still influence the final sound quality far more than source and amplifier and even very expensive speakers can be a disappointment. Most have colouration and most dealers seem to think that is what the buyers want. The attraction to valves is a bit like the attraction to “quack” medicines and other such fads. People are always attracted to off-beat solutions even though there is no cogent evidence of any advantage over scientifically proven procedures. I think your philosophy on valve amplifiers is quite clear and correct but you have a magazine to produce and you must consider the requirements of your readers no matter how misguided some of them may be! Alan March, via email. Miller effect was a problem Well, well! I thought that curiosity would finally persuade your design team, even if nothing else did, to have a go at valves! I have been making projects since the mid-1950s and I have to say that “FETs with lamps inside” haven’t entered the scheme of things for me since David Tillbrook produced his brilliant amplifier design using Mosfets in the early 1980s. On a more serious note, I recall that “Radio and Hobbies” struggled with the problems surrounding “Miller Effect” in triode stages, with some of their control units in the “Playmaster” series of the 1950s. This I think, www.siliconchip.com.au led them to concentrate on the EF86 pentode (which had a “coiled coil” filament for hum reduction), where gain and equalisation was the aim. This valve also had its problems, noise being the main one. In a low-noise application, one sometimes had to sample several valves before satisfaction was achieved. Where impedance conversion rather than pure stage gain was the aim, “Radio and Hobbies” chose on at least one occasion (I think it was a control unit for crystal and ceramic pickups in the early days of domestic stereo) to use a 12AU7 twin triode. “Miller Effect” with high input impedances was a lesser problem with this valve, although I believe the stage gain achievable was much less than with the 12AX7 or the 12AT7. Bruce Bowman, via email. Comment: the biggest problem with EF86 valves was their tendency to become microphonic, after which the slightest tap would make them “sing”. Multi-element TV antennas can be fakes It was interesting to read about your Penrith reader’s experiences with hail-damaged TV antennas in Mailbag in the December 2003 issue. I live in Riverstone which probably copped the worst of that same storm. My backyard went from English Country Garden to Arctic Wilderness in about five minutes! I had a similar antenna arrangement, with a VHF/ UHF job pointed at Artarmon and a 96-element UHF antenna pointed at Woolongong, but I didn’t get any sort of picture afterwards; not surprising with the masthead amplifier lying on the ground in four pieces and buried under six inches of solid ice! The UHF antenna was reduced to a single piece of aluminium box section sitting forlornly at the top of the pole, and the VHF antenna looked like someone had attacked it with a meat cleaver. Well, a new antenna system, complete with a brand-new masthead amplifier has just been installed and works a treat. I’ve now got the most common replacement out here: a Band III VHF antenna pointed at Artarmon February 2004 5 Solar cells not viable Mailbag: continued and the ABC and SBS on UHF from Wollongong. VHF I ABC reception has always been marginal at best out here, with a ghost from the Blue Mountains and violent Doppler flutter when a big Hercules comes in for a landing at the Richmond Air Force Base. Plus I no longer have those huge rear elements that seem to be so attractive to big birds! The thing that’s intrigued me is that, while as far as I can see the new 96-element UHF antenna looks pretty much like my old one, this one pulls in the Wollongong UHF channels like you wouldn’t believe! Running the signal through my household 8-outlet system without the amplifier still gives a pretty passable picture. The other antenna would give a barely visible picture under the same conditions. I actually asked the guy fixing a neighbour’s antenna about this and he confirmed what your Penrith correspondent suspected: there are antennas that have been carefully engineered using strict scientific principles which perform their tasks as well as is possible for a structure of those dimensions. There are also antennas which have been “reverse engineered” (ie, copied) from a working design (how accurately being anybody’s guess), and then there are “counterfeit” antennas which are simply rubbish, basically flung together to resemble a proper antenna. They do work, sort of, but so does an ordinary piece of wire under good conditions. The stupid thing is that in many cases the same materials could have been used to make an antenna that really did work! Keith Walters, via email. Hybrid computers not quite dead Rod Cripps, “Mailbag” December 2003, was interested in hearing from people with information on surviving examples of analog/hybrid computers. Well, the technology might not be as dead as he thinks. A series of construction articles to build a hybrid computer ran in “Eve6 Silicon Chip ryday Practical Electronics Online” towards the end of 2002. Currently, the December 2002 issue is offered as a free sample and a PDF version can be downloaded from the EPE Online website at www.epemag.com This issue contains Pt.2 in the construction series, which describes the “programming” of the computer together with using it with PC-based software to do calculations for a flight simulator. Paul Gittings, Russell Lea, NSW. Running SC480 modules at higher voltage The letters about the SC480 amplifier (from R. C. and J. W.) in the November issue caught my attention. I have been using three of the 1987 modules for some time with a 30V-0-30V transformer without problems. The DC voltage to the modules is ±43.2V. It is true that the BC639s and BC640 run hot but only at 50-60°C and this appears to be within the operating specs of the transistors (ON data sheets). Do you think I have a disaster waiting to happen here? RC’s transformer must be unusual if the rectified DC voltage is 47V. Just for your information, two of the 1987 modules were built using MJ802/ MJ4502 output pairs (since I had these available) and they work perfectly without any other modifications and (to my ears) sound better than when using the 3055/2955 pairs. Incidentally, concerning the valve preamp, I have used two 240VAC mains transformers back-to-back to generate HT voltages for valves. This maintains isolation from the mains and need not be too expensive since the current involved is usually low. If the input transformer has dual secondary windings, one winding can be used for the heater supply. Of course, size and space may be a problem. David Allen, Aspley, Qld. Comment: your amplifier modules should be OK with the higher voltage, especially as you are using the MJ802, etc. We would expect them to sound better too. I want to comment on the editorial regarding solar or gas fired power stations in the December 2003 issue. Firstly, I think you may have glossed over the issues of solar power somewhat. For years, conventional solar power (using solar cells) has seemed to be a reasonably viable way of generating electricity that is friendly to the environment, however a lot of people seem to only concentrate on how much power they can output and forget about how much power (and pollution) it actually costs to make them. Unless a solar cell is capable of generating more energy than the manufacturing process takes, then there is little point in using them other than to make people buy them because they believe they are helping the environment or saving money. Also there is the issue of disposal, given that in my experience solar cells only work efficiently for about 10 years or so and eventually degrade due to the effects of the weather (sun, rain, hail, etc). I can’t help but think that as a country we have chosen the certainty of environmental damage through greenhouse-gas emissions for electricity generation as opposed to taking the route of nuclear generation. Whilst I will admit that yes nuclear accidents are possible, I still believe that it is also possible to reduce the risks so as to be almost negligible. Anyway, it is good to see that the Editorials still keep touching on fairly controversial topics. Thanks for a great magazine, keep it up. David Peters, Bathurst, NSW. Comment: the subject of solar payback has been well researched. Have a look at http://www.ecotopia.com/apollo2/ pvepbtcsi.htm. There are plenty of other sites which give similar information. We really don’t think nuclear power will ever be a viable or ethical solution. The problems of decommissioning power stations and reprocessing or long-term disposal of fuel rods is extremely difficult. Nuclear power stations also cause far more “thermal” pollution than coal fired stations because they must run with lower steam temperatures – they are simply nowhere near as efficient. SC www.siliconchip.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au Hands-On PC Board Design For Beginners; Pt.1 Want to get started in PC board design? Here’s how to download, install and configure the free Autotrax design software. By PETER SMITH O VER THE PAST FEW months, our PC Board Design Tutorial series has provided a good look at the technologies and processes involved in PC board design and manufacture. Along the way, we’ve also recommended a number of guidelines applicable to actual board design, such as grid spacings, track widths, and much more. Many of our readers have indicated that they are now ready to “have a go” at their first design but are not sure where to start. Over the next month or two, we hope to provide enough “hands on” information for you to bring your first design into reality. Which software? Undoubtedly the most common question we’re asked is “which PC board design software should I use?” There’s simply no universal answer to this question; there are literally dozens Fig.1: run ATX161ND.EXE at a DOS prompt to extract the Autotrax installation files. 8 Silicon Chip of products on the market, with varying features and price tags. However, we strongly believe that you should “try before you buy”. All reputable products are available in shareware or demonstration versions, allowing you to make sure that you’re getting exactly what you need before reaching for your wallet. However, if you’re a beginner to PC board design, then it’s difficult to know precisely what you need. In addition, if you don’t plan to produce many boards, then you probably don’t want to pay much (if anything!) for the software anyway. Well, the EDA software experts Altium (formerly Protel Technology) have come to the rescue. They’ve recently made the most popular DOS-based PC board design software available free! Autotrax for gratis! Autotrax and its earlier cousin Easytrax are two of the most widely known EDA software packages on the planet. After all, they were among the first EDA applications written for the IBM PC. This popularity brings with it a host of benefits. For a start, designs produced in Autotrax will be accepted in their native format by most PC board manufacturers, particularly here in Australia. It also means that many professional designers as well as experienced amateurs cut their teeth on this product, so finding help when you need it is usually not too difficult! www.siliconchip.com.au Although DOS-based, Autotrax can be made to work on all versions of Windows without too much difficulty. Despite the fact that the user interface is definitely not like Windows, the uncluttered menus and keyboard shortcuts make it quite easy to master. In fact, many users swear by the product (and hey, the price is right!). Although Autotrax doesn’t have some of the bells and whistles available on high-priced Windows-based alternatives, it can handle all but the most complex designs. It includes features like 8-layer design, component library editing and simple autorouting. Getting your copy Autotrax can be obtained from Altium’s software download page at www.protel.com.au/resources/ downloads. Scroll down towards the bottom of the page until you find the section headed “Freeware”. When you click on the “Autotrax” link, you will be presented with Altium’s license agreement. Right click on the link at the foot of this page and select “Save Target As…” to download the Autotrax file (ATX161ND.EXE). While you’re there, grab a copy of the “EasyAuto” utility. This will enable you to quickly convert PC boards designs created in Easytrax to Autotrax format. Fig.2: the first screen of the simple installation program. All you have to change here is the “Source Drive” entry, which should be “C” rather than “A”. Fig.3: the final step in the installer is to select the desired graphics driver. Use the down-arrow key to highlight the “VGA 640x480” entry and press Enter. Installation Being a DOS-based application, Autotrax does not include the usual “point & click” installation program. Nevertheless, installation is quite straightforward if you follow the steps presented below. To begin, place a copy of the downloaded file in the root directory (\) of your hard disk drive. We put ours in C:\ for the following examples. ATX161ND.EXE is a self-extracting zip file; all you need to do is execute it and the contents will be automatically extracted into the root directory. To do this, open a Command Prompt and type in the following commands: C: CD\ ATX161ND.EXE Eight new files will be created in the root directory, as shown in Fig.1. Still at the Command Prompt, type www.siliconchip.com.au in INSTALL.EXE and press the <Enter> key to launch the installer program (Fig.2). In the menu that appears, change the “Source Drive” entry from “A” to “C” and press the <Enter> key three times, accepting the remaining defaults. This will install all the main PC board design (Traxedit) files in the C:\AUTOTRAX directory. Following the first menu, three similar menus allow you install the utilities, printing/plotting program (Traxplot) and associated drivers, as well as the graphics drivers. Accept the suggested defaults in all of these menus. The final menu allows you to choose a graphics driver to suit your video card and monitor (Fig.3). Select the “VGA 640 x 480” entry from the list for now; we’ll describe how to use higher screen resolutions a little further on. Once you’ve done that, you’ll see an “Installation Completed” message. As indicated by the message, a little “fine tuning” is required before launching Autotrax for the first time, so let’s do that next. Configuration During the installation, a directory called GRAPHDRV was created to contain all of the supported graphics drivers. Of these, only the basic VGA driver is required, along with the simple GRAPHSET utility used to switch display modes. Let’s tidy things up at little! Using Windows Explorer, open the C:\GRAPHDRV directory and copy the following files from there into the C:\AUTOTRAX directory: GRAPH.DRV VGA640.DRV GRAPHSET.EXE After you’ve copied the files, delete the entire C:\GRAPHDRV directory. The next job is to modify the DOS February 2004 9 Hands-On PC Board Design – continued Fig.4: the path variable is modified via the System icon in Control Panel under Windows 2000 & XP. Remember to click on the “OK” button to save your changes. search path so that it includes our remaining two directories. For Windows 95/98 & Me, this can be achieved by editing the C:\AUTOEXEC.BAT file. To do this, right-click on the AUTOEXEC.BAT in Windows Explorer and choose “Edit” from the context menu. This automatically opens the file in Notepad for editing. The contents will vary according to your PC’s configuration. However, all you need to do is add the following line so that it appears after any existing lines beginning with the “PATH” statement: PATH=%PATH%;C:\ AUTOTRAX;C:\TRAXPLOT Experienced DOS users will know that you can also add these two paths to the existing “PATH” statement. Either method will work OK. Remember to save the changes using File -> Save before closing Notepad. To modify the path in Windows 2000 and XP, open Control Panel from the Start menu and double-click on the “System” icon. Next, click on the “Advanced” tab and then the “Environment Variables” button. The “Environment Variables” dialog box appears (Fig.4). Highlight the PATH variable and click on the Edit button. Now add the following string to the end of the existing variable value: ;C:\AUTOTRAX;C:\TRAXPLOT 10 Silicon Chip To check that your path modification was successful, restart Windows (not required for 2000 & XP), open a Command Prompt, type in “PATH” and press <Enter>. On our Windows XP system, the result looked like this (yours may differ, but you get the idea): C:\>path PATH=C:\WINDOWS\System32;C:\ WINDOWS\System32\Wbem;C:\ AUTOTRAX;C:\TRAXPLOT Important: none of the paths in the “PATH” statement should exceed 56 characters in length. If they do, Autotrax could behave erroneously. For more information on this limitation, check out the Airborn Electronics web site page www.airborn.com.au/layout/ ntvdm.html Desktop icons The Autotrax package consists of two main applications, namely “Traxedit” and “Traxplot”. Traxedit is used for creating your PC board design, whereas Traxplot is used to print out the design and generate files for manufacturing. It’s quite a simple matter to add icons to your desktop for both of these applications. To add an icon for Traxedit, start Windows Explorer and navigate to the C:\AUTOTRAX directory. Drag and drop the TRAXEDIT.EXE file from the Explorer window to your desktop or right click on the file and choose “Create Shortcut”. With the latter method, you’ll need to cut and paste the new shortcut onto your desktop. Next, right-click on the shortcut and choose “Properties”. Select the “Screen” tab and under the “Usage” field, click on the “Full-screen” option (see Fig.5). All the remaining (default) settings are generally fine, so click on the OK button to close the Properties box. Repeat the above procedure to create a shortcut for TRAXPLOT.EXE in the C:\TRAXPLOT directory. Test time! OK, you’re all set to go! Double-click on the Traxedit icon and the Windows desktop should disappear, replaced with the “Protel Autotrax” opening screen. Hit any key to get to the main screen, where you’ll be prompted to open a file for editing. The default file name is shown as *.PCB. If you simply hit <Enter>, you’ll get a list of the demo designs included in the TRAXEDIT directory. The main menu can be displayed at any time by hitting <Enter>. If that doesn’t work, you may be in edit mode – simply hit the <Esc> key to exit edit mode first. Many commands within Traxedit can be actioned with just a single keystroke. Where possible, this is the first letter of the command. For example, to close Traxedit, you can either select File -> Quit from the main menu or press <F> followed by <Q>. As with other MS-DOS programs, you can suspend Traxedit and switch to Windows to perform other tasks. To do this, hold down <Alt> and press <Enter>, or use <Alt + Tab> to switch between active tasks. You can also use the “Windows” key if your keyboard has one. Display resolution If you plan to do a lot of work in Autotrax, then increasing the screen resolution to something higher than the standard 640x480 pixels can make life a lot easier. With higher resolutions, you can see more of your board at any one time; there’s a lot less need to continually zoom and pan around. The higher resolution drivers included with Autotrax were intended for use with specific video cards, the majority of which have long-since www.siliconchip.com.au resolutions up to 1600 x 1200 pixels. You can download these free of charge from www.airborn.com.au/layout/ easytrax.html Unzipping the drivers Fig.5: after creating a shortcut icon to Traxedit, you need to go to the Screen tab in the Traxedit shortcut properties dialog and select “Full-screen” usage. You then repeat this procedure for the Traxplot shortcut. been recycled (we hope!). However, help is at hand! Steven Murray of Airborn Electronics has made available a complete set of drivers for All the drivers are contained in a single file named EASYVIDEO.ZIP. Simply unzip the contents of this file into your C:\AUTOTRAX directory and run the GRAPHSET.EXE utility to switch resolutions. In the unlikely event that you experience problems with the drivers, you’ll find a host of useful information on Steve’s site. Well, that’s about all we have room for this month. We hope to bring you more on Autotrax in upcoming issues, including how to create your own components libraries, design a simple PC board and print out the results from Windows. Credits Our thanks to Steven Murray of Airborn Electronics for making his updated Easytrax/Autotrax video drivers freely available. You’ll also find a plethora of common-sense information on the RCS Radio web site at www.rcsradio.com.au, courtesy of SC Bob Barnes. Silicon Chip Binders REAL VALUE AT $12.95 PLUS P & P H Each binder holds up to 12 issues H S ILICON C HIP logo printed on spine & cover H Heavy board covers with mottled dark green vinyl covering Price: $A12.95 plus $A5 p&p each (available only in Australia). Buy five and get them postage free. Just fill in the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. New From SILICON C HIP Car Projects, Volume 2 THE PROJECTS: High-Energy Universal Ignition System; High-Energy Multispark CDI System;Programmable Ignition Timing Module; Digital Speed Alarm & Speedometer; Digital Tachometer With LED Display; Digital Voltmeter (12V or 24V); Blocked Filter Alarm; Simple Mixture Display For Fuel-Injected Cars; Motorbike Alarm; Headlight Reminder; Engine Immobiliser Mk.2; Engine Rev Limiter; 4-Channel UHF Remote Control; LED Lighting For Cars; The Booze Buster Breath Tester; Little Dynamite Subwoofer; Neon Tube Modulator. Available from SILICON CHIP Mail order prices: Aust: $14.95 (incl. GST & P&P) NZ/Asia Pacific: $18.00 via airmail Rest of World: $21.50 via airmail Order by phoning (02) 9979 5644 & quoting your credit card number; or fax the details to (02) 9979 6503; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. www.siliconchip.com.au February 2004 11 PC Power Monitor By JIM ROWE Does your PC crash intermittently? Maybe the hard disk or something else within the machine is not getting the right rail voltage but how would you know? This unit lets you easily monitor the main power rails – it clips into your PC and has three LED bargraphs and an alarm to indicate if any of the supply rails swings too high or too low. A S WELL AS HAVING to provide a number of different DC voltages, your PC’s power supply has to deliver an appreciable amount of power – hundreds of watts. This is the main reason why switchmode power supplies are used, because they’re much more efficient than the older “linear” type of power supply. However, they’re also more complex and this tends to make them slightly less reliable. 12 Silicon Chip Also, some PC power supplies really do have trouble supplying all that current and sometimes they fail to deliver just the right voltage at critical times – like when you are in middle of a big download off the Internet. If you build this unit, it will give you a visual and audible warning of the problem so that you can have it fixed. Of course, apart from data loss, if a PC’s power supply does happen to develop a fault, this can have quite disastrous (and costly) consequences. Replacing a blown CPU chip can involve many hundreds of dollars, while replacing blown DIMM modules can be almost as costly. Fortunately, many of the latest PC power supplies incorporate special circuitry to detect when any of the main power rail voltages fail or go high and shut down the supply if such a fault occurs. However, such protection circuitry does not always do the job, so this monitoring circuit can still be a worthwhile addition. It’s good to know that if a fault develops, you’ll be warned straight away so you can “pull the plug” before much damage is done. So that’s the idea of this project. It’s a low-cost, easy-to-build circuit which can continuously monitor the main power rails in a PC and display their status via columns of LEDs. At the same time, whenever it senses that any of the rail voltages has moved out of the safe operating range (too high or too low), it sounds a small piezo www.siliconchip.com.au buzzer to draw your attention to a possible problem. How many supply rails does it monitor? The answer is “just three” but they are the three that are now the most important. These are the +12V line (used for the motors on most disk drives), the +5V line (used for most of the logic on drives and plug-in cards) and the +3.3V line (used to power the memory modules, the chipset and motherboard logic and the CPU). By the way, as you can see from Table 1, PC processor voltages have varied a great deal in recent years. In most cases, the processor supply voltage(s) are derived from the +3.3V line from the power supply, either directly or via a DC-DC converter, which has its output voltage(s) set either manually by jumper shunts on the motherboard or automatically via “VID” (voltage identification) coding pins on the processor itself. So in most cases, it’s sufficient to monitor the +3.3V line in order to keep an eye on processor voltage. The only exception to this is with the latest generation of PCs using very fast P4 processors, where the chip’s DC-DC converter is run from the motherboard’s auxiliary +12V line (rather than the +3.3V line) in order to be able to supply the extra power. In these cases, monitoring the +12V line is probably sufficient to keep an eye on processor voltage, although you’d still be advised to monitor the +3.3V line as well because this is used for the memory modules and the chipset. Forget -5V and -12V It isn’t really necessary to monitor the -5V line any more, because this was actually only used by a few of the older ISA bus cards (like RS-232C serial port and modem cards). Similarly, it’s no longer necessary to monitor the -12V line, because this too is rarely used in most PCs made in the last 10 years or so. So by monitoring just the +12V, +5V and +3.3V lines, we’re likely to be able to detect just about any fault in a PC power supply that could result in data loss or damage to critical circuitry or components. It’s very easy to monitor the +12V and +5V lines, because these are available from any disk drive cable connector – and there’s usually at least one of these spare. The +3.3V line is a little more awkward, though. You generally www.siliconchip.com.au Fig.1: the circuit is based on three LM3914 dot/bar display driver ICs (IC1-IC3) – one to monitor the +12V rail, one for the +5V rail and one for the +3.3V rail. Each IC drives five LEDs which indicate the status of each supply rail at a glance. have to run one or two wires connecting directly to the motherboard at the main power connector. We’ll give you the details of this later in the article. How it works To keep the project as simple as pos- sible, each of the three power lines is monitored by an expanded-scale LED voltmeter circuit based on an LM3914 dot/bar display driver IC. As you can see from the circuit diagram (Fig.1), IC1 is used to monitor the +12V line while IC2 and IC3 monitor the +5V February 2004 13 Fig.2: install the parts on the PC board as shown here, taking care to ensure that all polarised parts are oriented correctly. Note that trimpots VR1-VR3 are mounted on the copper side of the board. and +3.3V lines respectively. Although each LM3914 has 10 output lines, designed to drive 10 LEDs in a normal dot or bar type display, 14 Silicon Chip here we use only nine of the outputs to drive a total of five LEDs per chip. Output O6 in the centre of each chip’s voltage range is used to drive the green “OK” LED for that power line, while the remaining eight outputs are connected as four tandem pairs to power the “HIGH”, “TOO HIGH”, “LOW” and “TOO LOW” LEDs for each supply line. All three ICs are actually powered from the PC’s +12V line and the LEDs are all connected to this line as well. This means, of course, that if the PC’s +12V line fails completely, the complete monitoring circuit will go dead as well. But as this in itself will be a clear indication that your PC’s power supply has a serious problem, we don’t see it as a disadvantage. As you can see, the inputs of IC2 and IC3 are connected directly to the +5V and +3.3V rails of the PC. However, to allow IC1 to correctly monitor the +12V rail, we use a simple 2:1 resistive voltage divider to allow it to monitor half the voltage – ie, a nominal +6V rail which is directly proportional to the +12V rail. The reference voltage and sensing range of each IC are tailored using the resistors connected to pins 4, 6, 7 & 8 to give the correct “centre voltage” and measuring range for each of the three voltage rails. But each IC also has a trimpot (VR1, VR2 and VR3), so that each monitor can be calibrated independently for correct indication and alarm sensing. By the way, calibration trimpot VR3 has a higher value than the other two so that the centre of IC3’s sensing range can be adjusted to suit whatever voltage is used in the PC for running the CPU. So you’re not forced to monitor just the motherboard’s +3.3V line; you can monitor the actual CPU supply voltage if you prefer. We recommend that you do monitor the +3.3V line though, because it’s easier to do this and therefore less risky. How do we do the alarm sensing? Ah, that’s easier than you’d think. As you can see, the three LEDs which are used to indicate “OK”, “HIGH” and “LOW” in each monitor are all connected directly to the +12V line. So when any of these LEDs is illuminated (because there’s no serious problem), nothing else happens. On the other hand, the LEDs at the top and bottom of each monitoring range (ie, LED1 and LED5, etc) are not connected directly to +12V but instead to an “alarm sense” rail which in turn connects to the +12V rail via the baseemitter junction of transistor Q1. This means that if any of the ICs happens to detect a “TOO HIGH” or “TOO LOW” condition and lights one of these LEDs, this draws base current through Q1 and turns the transistor on. As a result, it conducts collector current and turns on the piezo buzzer. Nifty, don’t you think? Construction All the components for the power monitor are mounted on a compact PC board measuring 146 x 38mm and coded 07102041. This board is designed so that it can be mounted directly behind a 5.25-inch drive blanking plate, with the status indicator LEDs protruding via matching 3.5mm holes. An array of even smaller holes at one end of the panel allows the sound from the piezo buzzer to emerge. Fig.2 shows the parts layout. All parts are mounted on the top side of the PC board except for the three calibration trimpots (VR1-VR3) and the PC board terminal pins, which are used for the power input connections. www.siliconchip.com.au The location and orientation of all of the components can be seen clearly in the board overlay diagram. As usual, fit the wire links first, so that you don’t forget them. The three short vertical links can be made from tinned copper wire or resistor lead offcuts, while the two longer horizontal links (near the bottom edge of the board) should be made from insulated hookup wire. Once the links are in, fit the six PC board terminal pins that are used for the input connections. As mentioned earlier, these are fitted from the rear of the board and soldered on that side as well. The fixed resistors can go in next, making sure that you fit each one in the correct position. That done, install the three 2.2µF tantalum capacitors – they all mount with their positive leads towards the top of Fig.2. The last capacitor to fit is the 100µF electrolytic but note that although it mounts on the front of the board as usual, it is mounted on its side to provide clearance when the board is mounted behind a blanking plate or box panel. This capacitor is also mounted with its positive lead uppermost. The next components to fit are transistor Q1 and the three LM3914 ICs. Note that the ICs all mount with their notched (pin 1) ends facing downwards, as shown in Fig.2. Fitting the LEDs You’re now ready to fit the 15 LEDs. These are all 3mm-diameter types and there are three green LEDs, six orange LEDs and six red LEDs as shown. They should all be mounted with 10mm lead lengths (ie, the bottom of each LED should be 10mm above the board), so they they’ll later all protrude evenly through the holes in the front panel when the board is mounted behind it. The easiest was to do this is to cut a short strip of cardboard 10mm wide and then fit each column of LEDs with their leads straddling the cardboard strip. That way, they’ll all be automatically set to the correct height before their leads are soldered. It’s a simple trick but it works well. By the way, notice that each LED is fitted with its cathode (flat side) towards the right. The last component to fit to the front of the board is the small piezo buzzer. This mounts directly to the board via two pins. Because there are several different types of buzzers available, with different pin spacings, we’ve provided extra pads and holes on the board for flexibility. Note that the buzzer’s negative pin should always go through the bottom hole. Installing the trimpots The final components to fit are the three trimpots, which mount on the back (ie, copper side) of the PC board. This is done so that they’re easy to adjust from the back when the board is mounted on a blanking plate or panel. Make sure you use the 1kΩ trimpots for VR1 and VR2, and the 5kΩ trimpot for VR3. Once the board is fully assembled, you can place it aside for a few minutes while you drill the holes in the blanking plate or box panel. You can use a photocopy of the front panel artwork (Fig.5) as a drilling guide and template. Note that the holes for the LEDs and the four board mounting holes (in the corners) are all 3.5mm diameter, while those for the buzzer “grille” are 2mm in diameter. Once the holes in the blanking plate have all been drilled and deburred, you might want to attach another photocopy of the artwork to the front Table 1: Resistor Colour Codes o o o o o o o o o o No. 1 1 1 3 1 1 1 2 1 www.siliconchip.com.au Value 10kΩ 4.7kΩ 3.9kΩ 1.5kΩ 1.2kΩ 1kΩ 470Ω 270Ω 220Ω 4-Band Code (1%) brown black orange brown yellow violet red brown orange white red brown brown green red brown brown red red brown brown black red brown yellow violet brown brown red violet brown brown red red brown brown Fig.3: this diagram shows how the PC board is secured to the rear of the blanking plate using 12mm spacers and M3 x 6mm machine screws. The LEDs protrude through matching holes in the blanking plate – see text. Fig.4: here are the pin connections for a 20-pin ATX motherboard power connector and for a 6-pin ATX auxiliary power connector which is sometimes used on older motherboards. 5-Band Code (1%) brown black black red brown yellow violet black brown brown orange white black brown brown brown green black brown brown brown red black brown brown brown black black brown brown yellow violet black black brown red violet black black brown red red black black brown February 2004 15 VR3 Fig.5: here are the full size artworks for the PC board and front panel. Check your board carefully for defects by comparing it against the above pattern before installing any of the parts. using double-sided tape, so it will dress the panel up and give a professional look. Alternatively, you may be able to buy a kit of parts that includes a professionally made “sticker” for the front panel. The PC board assembly can now be mounted behind the panel on four 12mm-long M3 tapped spacers and secured using 6mm-long M3 machine screws. Fig.3 shows the details. We suggest that you also fit a star lockwasher under each of the rear mount- ing screws, to ensure that they don’t loosen with vibration. Connecting it up The easiest way to connect the +12V, +5V and earth (ground) inputs of the monitor board to the corresponding power rails of the PC is by cannibalising the 4-pin plug and one set of wires from a disk drive “Y adaptor” power cable. These are readily available from computer stores and electronics suppliers. The free ends of the wires are The completed PC Power Rail Monitor simply clips in the front of the PC’s case, in place of an existing drive blanking plate. 16 Silicon Chip then soldered to the four main input pins on the monitor board but make sure you connect them correctly: the red wire goes to the +5V input, the yellow wire to the +12V input and the two black wires to the centre ground pins. The 4-pin plug can then be mated with one of the power connectors in the PC, to make all these connections. The connections to the PC’s +3.3V rail are a little trickier but simple and safe enough if you’re careful. To do this, solder a pair of insulated hookup leads about 500mm long to the two remaining pins on the monitor board, using wire with orange insulation for the +3.3V lead and wire with black insulation for the ground lead. That done, remove the cover from your PC so you can gain access to the underside of the motherboard, just below the main power connectors. In most PCs made in recent years, you should find that the main DC power lead from the power supply mates with the motherboard using a 20-pin Molex type plug and socket (called the ATX power connector). If that’s the case with your PC, you can connect the +3.3V and ground wires from the monitor to the underside of the 20-pin motherboard connector, to pins 1, 2 or 11 (orange wire) and 3 (black wire) respectively. Fig.4 shows www.siliconchip.com.au VR2 VR1 The above view show the completed PC board from the top, while the inset shows how the three trimpots (VR1-VR3) are mounted on the copper side. how to identify the pins on the motherboard ATX connector. On some earlier model PCs, you may find that this 20-pin ATX connector is “missing”. Instead, there will be a pair of 6-pin in-line main power connectors (P1 and P2), together with a third 6-pin in-line connector providing the +3.3V power and an additional +5V line. This is known as the 6-pin ATX auxiliary power connector (see Fig.4) If your PC has this arrangement, the +3.3V lead from the monitor board (orange) should be connected to either pin 4 or pin 5 of the auxiliary connector (under the motherboard), while the remaining ground wire (black) can be connected to either pin 2 or pin 3. If your PC is even older and doesn’t even have the ATX auxiliary connector but just the P1 and P2 connectors, this means that it doesn’t have a +3.3V rail. In that case, you won’t need to worry about monitoring the nonexistent +3.3V rail, so simply remove the orange and black wires from the monitor board pins and ignore the third column of LEDs (which won’t light anyway). Calibration Calibrating the monitor is quite easy but you’ll need a reliable digital voltmeter. The basic idea is that you will be adjusting the relevant trimpot www.siliconchip.com.au for each of the monitor’s three LED voltmeters so that the green LED glows when the input voltage is at the correct nominal value for that power line. When this is done, the other LEDs will glow for the correct higher and lower voltage levels. Step one is to measure the +12V line with your DVM. If it’s very close to the correct reading (say within ±100mV of +12V), all that you then need to do is adjust trimpot VR1 until the green LED glows steadily in the first column of LEDs. In fact, you should set VR1 to the centre of the small adjustment range over which the green LED glows. What if the PC’s +12V rail actually measures a little below 11.9V, or a little above 12.1V? That’s no great problem but it does mean that you should adjust VR1 so that one of the two orange LEDs glows instead – ie, adjust VR1 so that either the lower orange LED is just glowing if the voltage is just below 11.9V, or the upper orange LED is glowing if it’s just above 12.1V. Calibration of the +5V and +3.3V monitors is done in exactly the same way. You simply measure the actual voltage of these power rails first with your DVM, then adjust each trimpot so that either the green LED or one of the orange LEDs for that monitor is glowing, depending on the reading on the DVM. Parts List 1 PC board, code 07102041, 146 x 38mm 1 piezo buzzer, PC mount 6 1mm PC board terminal pins 4 12mm x M3 tapped spacers 8 M3 x 6mm machine screws 4 M3 star lockwashers 2 1kΩ horizontal trimpots (VR1, VR2) 1 5kΩ horizontal trimpot (VR3) Semiconductors 3 LM3914 display drivers (IC1IC3) 1 PN200 PNP transistor (Q1) 3 3mm green LEDs (LEDs 3, 8, 13) 6 3mm orange LEDs (LEDs 2, 4, 7, 9, 12, 14) 6 3mm red LEDs (LEDs 1, 5, 6, 10, 11, 15) Capacitors 1 100µF 16V RB electrolytic 3 2.2µF 35V TAG tantalum Resistors (0.25W, 1%) 1 10kΩ 1 1kΩ 1 4.7kΩ 1 470Ω 1 3.9kΩ 2 270Ω 3 1.5kΩ 1 220Ω 1 1.2kΩ Once you’ve set all three trimpots in this way, your PC Power Rail Monitor SC is calibrated and ready for use. February 2004 17 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au Pt.2: By LEO SIMPSON & PETER SMITH Building the: Studio 350 Power Amplifier Module Last month, we introduced our rugged new 350W power amplifier module and gave the circuit details. This month, we show you how to build it and describe a matching power supply. T O HELP ENSURE that everything goes together without a hitch, it’s a good idea to read the following information in its entirety before reaching for your soldering iron! 22 Silicon Chip Referring to the overlay diagram in Fig.1, begin by installing all the wire links. There are 15 links in total, 11 of which must be formed from 1mm tinned copper wire. Use 0.7mm wire for the remaining four links. The over- lay diagram shows the larger (1mm) links in red. Set aside all of the heatsink-mounted transistors (Q4-Q17), the two 470µF electrolytic capacitors, choke (L1) and 6.3mm spade lugs for the moment. We’ll deal with these in more detail shortly. All other components can now be installed, progressing from smallest to largest. The 1W and 5W resistors should be mounted about 1mm proud of the PC board to aid heat dissipation. Also, be sure to orient the cathode (banded) ends of diodes D1-D5 as shown. www.siliconchip.com.au When installing the fuse clips, note that the small retaining lug on each clip must be positioned to the outer (fuse end) side, otherwise fuse installation will be impossible. If you intend mounting the output transistors horizontally, then it’s also necessary to install 3-pin header strips in the mounting positions for Q8 & Q9. As we’ll see shortly, these are required because the transistor leads are too short to extend all the way through the PC board holes. TO-220 heatsinks Transistors Q4, Q5 & Q6 must be attached to TO-220 heatsinks before fitting them to the PC board. First, smear a thin film of heatsink compound to both the rear (metal) area of each transistor as well as the mating areas of the heatsinks. That done, fasten them to the heatsinks using M3 screws, nuts and washers (see Fig.2) but don’t fully tighten the screws just yet. Note that insulating pads are not required here. Now slip each assembly into place in its PC board holes, taking care not to mix up the BF469 and BF470 types. The tabs of the heatsinks should fully engage the holes in the PC board, such that all of the heatsink edge contacts the PC board surface. Finally, push the transistors all the way down the slots in the heatsinks and then tighten up the screws. The transistor leads can now be soldered, taking care that the assemblies remain in place when the board is turned over. Winding the choke If you’ve building your amplifier module from a kit, the 6.8µH choke may have been supplied pre-wound. If so, all you’ll need to do is scrape the enamel insulation off the wire ends, tin them and solder the part in place. Alternatively, it’s a relatively simple matter to wind the choke yourself. You’ll need a 13mm I.D. plastic former (bobbin) and about three metres of 1mm enamelled copper wire. Begin by bending the wire at right angles, about 10mm from one end. This will be the starting end. Slip it into the bobbin and position the end in one of the slots. Now wind on 23.5 turns as evenly and tightly as possible, then pass the remaining wire length out through the opposite slot and cut off any excess, leaving about 10mm protruding. Finally, wind on a couple of turns of www.siliconchip.com.au Parts List 1 PC board coded 01102041, 136mm x 241mm 1 6.8µH air-wound choke (L1) (see text) 1 2-way 2.54mm terminal block (CON1) 2 3-way 2.54mm pitch SIL headers (for Q8 & Q9) 3 TO-220 heatsinks, 25mm x 12.5mm with PC board tabs 1 diecast heatsink, 300 x 75mm, 35mm shelf (0.4°C/W or better) 8 TO-3P or TO-264 siliconebased insulating pads 2 TO-220 silicone-based insulating pads & washers 1 TO-126 silicone-based insulating pad 350mm (approx.) 1.0mm tinned copper wire for links 70mm (approx.) 0.7mm tinned copper wire for links 4 M205 PC-mount fuse clips (F1, F2) 2 M205 5A slow-blow fuses 5 6.3mm chassis-mount spade lugs Semiconductors 1 BC556 PNP transistor (Q1) 2 2SA1084 PNP low-noise transistors (Q2,Q3) 2 BF469 NPN transistors (Q4, Q5) 1 BF470 PNP transistor (Q6) 1 MJE340 NPN transistor (Q7) 1 MJE15030 NPN transistor (Q8) 1 MJE15031 PNP transistor (Q9) 4 MJL21194 NPN transistors (Q10, Q12, Q14, Q16) 4 MJL21193 PNP transistors (Q11, Q13, Q15, Q17) 3 1N4148 small-signal diodes (D1-D3) 2 1N4936 fast-recovery diodes (D4, D5) Capacitors 2 470µF 100V PC electrolytic (Farnell 319-9149) 1 47µF 16V non-polarised PC electrolytic 1 1µF 16V non-polarised PC electrolytic insulation tape to hold everything in place. You can now test-fit the assembly in position, bending the leads as nec- 10 220nF 100V MKT polyester 1 150nF 250V MKT polyester 1 100nF 63V MKT polyester 1 12nF 100V MKT polyester 1 330pF ceramic disc 1 68pF 250V ceramic disc (or mica) (Farnell 867-871) 1 10pF ceramic disc Resistors (0.25W 1%) 2 22kΩ 1 1kΩ 1 18kΩ 1 680Ω 1 15kΩ 1W 1 470Ω 1 6.8kΩ 1W 10 100Ω 2 4.7kΩ 1 10Ω 1 2.2kΩ Wirewound resistors 2 470Ω 10W wirewound (for setup) 1 6.8Ω 5W wirewound 8 0.47Ω 5W wirewound Trimpots 1 200Ω 25-turn miniature horizontal trimpot (VR2) 1 100Ω 25-turn miniature horizontal trimpot (VR1) Screws & nuts 8 M3 x 20mm pan-head screws 3 M3 x 15mm pan-head screws 3 M3 x 10mm pan-head screws 14 M3 nuts 28 M3 flat washers 5 M4 or 3BA x 10mm pan-head brass screws 5 M4 or 3BA brass nuts 10 M4 or 3BA internal star washers (brass or stainless steel) Power supply 1 50V+50V 500VA toroidal mains transformer (Altronics Cat. M-5750) 1 35A 400V chassis-mount bridge rectifier 6 8000µF 75V chassis-mount electrolytic capacitors (Altronics Cat. R-6722) 2 470nF 100V MKT polyester capacitors 4 15kΩ 1W resistors essary to get the bobbin to sit down on the PC board surface. That done, scrape the enamel insulation off the wire ends with a scalpel blade or February 2004 23 24 Silicon Chip www.siliconchip.com.au Fig.1: use this diagram when assembling and wiring the amplifier module. The ±70V wiring is routed underneath the board and attached to it with cable ties once testing is complete. yet to be installed are the two 470µF electrolytic capacitors. These can go in now, with an eye to correct orientation. Take particular care here, as they’re oriented differently to one another. If you get one the wrong way around, it will be damaged at power up and may even explode! Horizontal heatsink mounting The amplifier module was designed for mounting to the horizontal shelf of a diecast heatsink. However, a verticalmounting configuration is also possible – see the panel entitled “Using Different Heatsinks” for a discussion of this alternative method. We recommend an Altronics 300mm diecast heatsink with 35mm shelf (Cat. H-0452), as used on the prototype. So let’s look at how the PC board and transistors are attached to this heatsink. The only guaranteed way of getting all the heatsink holes in the right places is to use the PC board as a drilling template. First, find the smoothest side of the heatsink shelf and place it upwards. That done, position the PC board on the top of the shelf and butt it right up against the main body of the heatsink, centred left to right within the available space. Next, making sure that nothing moves (clamp the board to the shelf if necessary), use a sharp pencil to mark through all 11 transistor mounting holes. Be sure to mark a clean circle around the circumference of each hole, so that you’ll easily be able to find the centre. Remove the PC board and gently centre-punch your marks before drilling. A strip of cardboard cut to the correct width (7mm) makes a handy bending guide for the leads of the heatsinkmounted transistors. similar and tin them before soldering the choke permanently in position. Lug terminations Except for the audio line input, all connections to the PC board are made via 6.3mm spade lugs. If the lugs are double-ended, then cut off one end using electrician’s sidecutters. Position each lug as shown on the overlay diagram and fasten it securely to the PC board using the method depicted in Fig.3. We recommended raw brass (rather than nickel-plated) screws and nuts for securing the lugs. As noted in several of our recent high-power amplifier designs, these return a slightly lower distortion figure at the high-power end of the spectrum. Apart from the main heatsinkmounted transistors, the only parts Fig.2: transistors Q4-Q6 must be attached to TO-220 heatsinks as shown here. Insulating pads are not necessary, but you should apply heatsink compound to the mating surfaces. Fig.3: here’s how to bolt up the spade lugs. If you have doublesided lugs, cut off one side with heavy-duty sidecutters first. Tighten them up enough so that they don’t move around when the receptacles are pushed on. Initially, drill a pilot hole at each mark, using a 1mm bit. Finish with a 3.3mm bit, then deburr the holes by hand using a much larger drill size. Both sides of the shelf must be completely free of swarf and sharp edges. Table 1: Resistor Colour Codes o o o o o o o o o o o o o o o No. 2 1 1 1 2 1 1 1 1 10 1 2 1 8 www.siliconchip.com.au Value 22kΩ 18kΩ 15kΩ 6.8kΩ 4.7kΩ 2.2kΩ 1kΩ 680Ω 470Ω 100Ω 10Ω 470Ω 10W 6.8Ω 5W 0.47Ω 5W 4-Band Code (1%) red red orange brown brown grey orange brown brown green orange brown blue grey red brown yellow violet red brown red red red brown brown black red brown blue grey brown brown yellow violet brown brown brown black brown brown brown black black brown not applicable not applicable not applicable 5-Band Code (1%) red red black red brown brown grey black red brown brown green black red brown blue grey black brown brown yellow violet black brown brown red red black brown brown brown black black brown brown blue grey black black brown yellow violet black black brown brown black black black brown brown black black gold brown not applicable not applicable not applicable February 2004 25 Fig.4: the mounting details for the TO-126 (Q7) and TO-264 (Q10-Q17) transistors. Don’t solder the leads until the screws have been tightened to their final torque. Fig.5: the leads of the TO-220 (Q8 & Q9) packages are too short to reach all the way through the PC board. Simply bend the leads so that they touch the header pins instead. Again, don’t solder the leads until the mounting screws have been tightened. Insulated TO126 Packages Transistor Q7 (an MJE340) is supplied in a “plastic” TO-126 package. These packages usually include a small rectangular metal area on the rear. This area is electrically connected to the collector and therefore must be isolated from the heatsink with an insulating washer (see Fig.4). However, some TO-126 packages do not have this metal area – they’re “plastic” on both sides. This isolated type package should be mounted without an insulating washer. Simply smear its mating surface with a small amount of heatsink compound and bolt it directly to the heatsink. By the way, a drill press is mandatory for this job, as drilling accurate holes in thick aluminium with a hand drill is extremely difficult. Attaching the transistors Now position the PC board beneath the heatsink shelf and insert two M3 x 20mm screws in the extreme left and righthand holes. Fit M3 washers and nuts (on the PC board side) and wind them up barely finger tight. The idea here is not to clamp the board against the heatsink shelf too tightly; it must be allowed to move at this stage. These screws are temporary placeholders 26 Silicon Chip and can be removed when necessary. All transistors must be insulated from the heatsink with silicone-based pads. The TO-220 devices (Q8 & Q9) also require insulating bushes for the screws. Figs.4 & 5 shows how to mount each transistor type. As you can see, the leads of each transistor must be bent at right angles before installation. The position of the bend should be placed so that the leads slip easily into the PC board holes while the mounting holes line up with the holes in the heatsink and the PC board underneath. A strip of cardboard cut to the appropriate width makes a handy bending guide (see photo). Mount the TO-126 package (Q7) first, then progress outwards in left and right pairs (Q8 & Q9, Q10 & Q11, etc). The two TO-220 transistors (Q8 & Q9) present a special case. Their leads are not long enough to reach all the way through the PC board holes, so instead must be soldered to the 3-pin headers installed earlier. However, do not solder to the header pins just yet. Simply bend the device leads so that they just make contact with the rear of the header pins. You’ll probably find that you need to trim a little off the leads so that they don’t interfere with the plastic base of the header strips. Wind up the nuts only finger tight during installation. Once they’re all in place, go back and tighten each one to the final torque, starting in the middle and working towards the sides. Don’t overtighten – about one click of the elbow is more than enough! That done, set your meter to read Ohms and measure between the heatsink and the centre lead (collector) of Although featuring a different amplifier module, this picture shows the vertical mounting method for the output and driver transistors. www.siliconchip.com.au Fig.6: the power supply wiring is quite straightforward. Take particular care that you have the positive (+) and negative (-) terminals of the capacitors connected as shown. The same goes for the bridge rectifier, also noting that it must be bolted firmly to a metal surface for heatsinking. Note the safety warning. each device. You should get an open circuit reading in all cases. If everything checks out, then solder all transistor leads to complete the assembly. Note that the mounting screws must be tightened up before soldering the leads. If this is done in reverse order, then stress will eventually crack the solder joints and perhaps even delaminate the PC board copper. DANGER: HIGH VOLTAGE! The 100VAC from the transformer secondaries (2 x 50VAC) and the 140V DC supply across the filter capacitor bank and the amplifier supply rails is potentially lethal! After the power supply wiring is complete and before you apply power, mount a clear Perspex sheet over the capacitor bank to protect against inadvertent contact – now or in the future! Note also that the capacitors take some time to discharge after the power is switched off (check the voltage with a multimeter). Vertical heatsink mounting Details for vertical mounting will vary according to the style of heatsink. However, we’ve included a rough guide to get you started. Of course, you must have already modified the PC board as described in the “Using Different Heatsinks” panel! To begin, use what ever you have on hand to raise the PC board to the required mounting height. A pair of 3mm holes is provided at the rear of the board for tapped spacers but you’ll also need to place something under the front of the board to bring it back to the horizontal position. Next, fit the 11 transistors (Q7Q17) into their respective mounting holes but don’t solder or cut any of their leads just yet! That done, butt the assembly up against your chosen heatsink and centre it roughly within the available space. Note that the transistors should be mounted as close to the centre of the heatsink as practical although this will be affected by the www.siliconchip.com.au available transistor lead length. If possible, line up the transistors so that the mounting holes will fall between the heatsink’s cooling fins. This way, you can avoid the additional task of thread tapping. Once you’re happy with the positioning, mark through each transistor mounting hole with a sharp pencil. Now centre-punch each mark and drill 1mm pilot holes. Redrill to 3.3mm if you’ll be using screws with nuts, or use a smaller, 2.5mm bit size in preparation for M3 thread tapping. After drilling, deburr the holes by hand using a much larger drill size so that the mating surface is entirely smooth. Attaching the transistors Loosely attach the transistors to the heatsink using insulating pads and bushes where necessary. The requirements here are similar to those shown for horizontal mounting as shown in Figs.4 & 5. Be sure to check that the PC board is sitting horizontal and at right angles to the heatsink before tightening up the screws. It’s then just a matter of turning the assembly over and soldering all transistors in place. Finally, it’s a good idea to make sure that all transistor collectors are indeed isolated from the heatsink. To do this, set your meter to read Ohms and measure between the heatsink and the centre lead (collector) of each Table 2: Capacitor Codes Value 220nF 150nF 100nF 12nF 330pF 68pF 10pF μF Code 0.22µF 0.15µF 0.1µF 0.012µF – – – EIA Code 224 154 104 123 331 68 10 IEC Code 220n 150n 100n 12n 330p 68p 10p February 2004 27 Using Different Heatsinks As shown in the various photos, the transistors on our prototype are mounted horizontally, on the shelf of a large diecast heatsink. This method of mounting is mechanically robust and relatively easy to assemble but obviously unsuitable for heatsinks without a shelf. Suppose, for example, that you’ve decided to build a stereo unit, utilising a pair of Jaycar’s fan-cooled tunnel heatsinks (Cat HH-8532). In this case, the transistors must be mounted vertically along the edge of the PC board, allowing them to be bolted directly to the heatsink faces. With just one modification, the PC board can accommodate this alternative, vertical mounting style. This modification involves cutting off a portion of the PC board so that the transistors are just a few millimetres from the PC board edge. This must be done before any components are mounted on the PC board! A thin broken track has been included on the PC board as a cutting guide. Note that there should be about 0.5mm of space between the pads/tracks and the board edge. This ensures that once the unit is assembled, the bare copper tracks can not short out on the face of the heatsink. For this reason, we suggest cutting along the device. You should get an open circuit reading in all cases. Power supply assembly Due to the weight of the mains transformer, the power supply components must be mounted on a substantial metal baseplate. Typically, this will be the base of a rack-mount case or similar. If deemed necessary, the base can be strengthened with an additional plate to achieve sufficient rigidity. The suggested wiring for the bridge rectifier (BR1) and capacitor bank is shown in Fig.6. The bridge rectifier Fig.7: the mains earth should be securely attached to the base of the metal chassis as shown here. Tighten the first nut very firmly before winding on the second “locknut”. The earth wire from the capacitor bank also connects to this point. 28 Silicon Chip Fig.8: to enable vertical transistor mounting, cut off the entire front section of the PC board as shown here. You do not need to do this for the horizontal mounting style shown in the various photographs! outside of the line, to allow for the width of the cut and any subsequent filing (see Fig.8). must be attached directly to a flat area of the metal chassis for heatsinking. Smear the face of the rectifier and the contact area with a thin film of heatsink compound before assembly. The 8000µF capacitors are attached to the baseplate using circular clamps. They should be positioned as close together as practical, with their terminals in line to allow hookup with lengths of solid-core wire. Use two strands of 0.7mm tinned copper wire or similar for a total wire diameter of at least 1.4mm for each connection. If you only ever intend driving 8Ω speakers, the filter capacitor count can be reduced by two for a worthwhile saving. For 4Ω speakers, the full complement of six capacitors is required to achieve the listed power and distortion figures. Connections to and from the capacitor bank should be made with extraheavy duty (10A) multi-strand cable. The +70V, -70V and 0V wires leading away from the bank should be twisted tightly together to minimise radiated noise and improve appearance. Safety precautions Before applying mains power, the capacitor bank must be covered with a rigid, non-conductive shield. A section of clear perspex is ideal for the Where To Get The Parts Kits for this amplifier project will be available from Altronics and from Jaycar Electronics. Check out their websites at www.altronics.com. au and www.jaycar.com.au for further details. Individual items can be obtained from the usual kit suppliers, including DSE, Altronics and Jaycar. The 2SA1084 low-noise transistors are available from WES Components, on the Internet at www. wescomponents.com or phone (02) 9797 9866. Parts shown with a Farnell catalog number can be ordered on-line at www.farnellinone.com.au or phone 1300 361 005. job. This step is very important, as simultaneous contact with the +70V & -70V rails could easily kill you (or someone else)! Note also that the 100VAC produced by the transformer secondaries (2 x 50VAC) is also potentially lethal, so don’t get across these windings. As shown on the wiring diagram, four 15kΩ 1W resistors must be inwww.siliconchip.com.au stalled across the ±70V rails. These will gradually discharge the capacitors after power is switched off. However, before working on any part of the circuit, always measure the supply rails with a multimeter first to make sure that it is safe to do so. Wiring Housing and wiring of the amplifier modules is totally up to you. However, we’ve outlined a few points below that will help you to get the most from your amplifier. First, never take shortcuts with mains wiring. Always use mains-rated cable and be sure to insulate all exposed connections. This includes the use of rubber boots (or equivalent) on the rear of IEC sockets, switches and fuseholders. The mains earth must be connected to the metal chassis using the arrangement shown in Fig.7. Return all earth wires to this point to eliminate potential earth loops. Use extra heavy-duty (10A) multi-strand cable (or larger) for all power and speaker connections. The wire ends need to be terminated with 6.3mm push-on receptacles to suit the board-mounted lugs. These are available in insulated and noninsulated varieties. For the insulated type receptacles, you’ll need a ratchet-driven crimping tool, such as the Altronics T-1552, Jaycar TH-1829 or DSE T-3535. Don’t be tempted to use a cheaper (non-ratchet style) crimper, as they’re just not up to the job. If you don’t want to cop the expense of a new crimper, then you can use the non-insulated style receptacles and solder them on instead. These are available from DSE (Cat. H-5012) and most electrical wholesalers. While you’re at it, get some terminal covers to suit (Cat. H-5022). Supply wiring The +70V, -70V and 0V connections to the amplifier module should be twisted tightly together and positioned as shown on the overlay diagram. Note how the www.siliconchip.com.au February 2004 29 This is what the completed amplifier module looks like. Be sure to mount the 5W wirewound resistors about 1mm proud of the PC board, to allow the air to circulate beneath them for cooling. The spare holes in the PC board allow the supply power wiring to be secured in position using cable ties. 0V wire connects to the centre lug, whereas the ±70V wires continue beneath the PC board. Small cable ties are then used to secure the wires in place underneath the PC board. Positioning the wires as shown helps to cancel the fields resulting from currents flowing in the PC board tracks. This produces the lowest possible signal distortion. Setup & testing With nothing connected to the power supply output, apply mains power and measure the positive and negative rails. Both readings should be close to the 70V mark, depending on mains fluctuations. The next task is to zero the amplifier’s input offset voltage and set the quiescent current in the output transistors. To protect the amplifier in case of faults and to simplify adjustment, remove both fuses from the board and solder a 470Ω 10W resistor across each 30 Silicon Chip fuseclip pair. Alternatively, you may find it easier to tack solder the resistors on the rear (copper) side of the PC board. Note that nothing should be connected to the input or output terminals until these checks are complete. Set VR2 fully anticlockwise and then apply power. With your multimeter set to read millivolts, measure the voltage across the output (speaker) terminals. Adjust VR1 for a reading of 0V ±2mV. That done, set your meter to read 70V or more and measure the voltage across one of the 470Ω 10W resistors. It’s not important which one you choose. Rotate VR2 clockwise until you get a reading of 47V. This gives a total quiescent current of 100mA. Now give the amplifier about 10 minutes to warm up, then readjust VR2 if necessary. It’s normal for this reading to vary by a few volts as circuit temperature varies. To check that each output transistor is doing its job, you can measure the voltages across the 0.47Ω emitter resistors. With about 25mA flowing in the emitter legs, you should get a reading near 11mV across each of these resistors. Note that the innermost pair of resistors also carry the driver transistor (Q8 & Q9) emitter current, so these two will read a few millivolts higher. Problems? If you’re unable to adjust VR1 or VR2 for the specified readings, then there is a fault somewhere on the board. We’ve provided voltage readings for various points on the circuit that may help you to track down the problem (see Fig.7, Pt.1). Your readings should fall within ±10% of our listed values. If everything checks out OK, switch off the power, remove the 470Ω resistors and install the fuses. That’s it – your Studio 350 Amplifier is now SC ready for use! www.siliconchip.com.au BOOK REVIEW DVD Players and Drives, by K. F. Ibrahim. First edition published 2003 by Newnes. Soft covers, 155 x 232mm, 319 pages. ISBN 0 7506 5736 7. $79.00 including GST. DVD players in homes and PCs are rapidly becoming commonplace and will soon be almost universal but books and magazine articles on the topic are very rare. But now there is this very useful book on the subject from Fawzi Ibrahim. It will be of interest to anyone working with DVD signals or the hardware and those who want to understand the technology. At the outset, we should say that this book will be of limited use to anyone attempting to do repairs and maintenance on DVD players or drives, even though there is a chapter on this very subject. For anything other than fairly basic trouble-shooting you really need manufacturers’ service manuals and sadly, for many of the cheaper models such manuals are virtually unobtainable. Of course, many models are now so cheap that anything other than the most basic repair is likely to be uneconomic. All told, there are 13 chapters and five appendices. Chapter 1 is a general introduction to the topic, covering the various DVD formats. Constant linear velocity (CLV) and constant angular velocity (CAV) discs are explained, a well as their advantages and disadvantages. Chapter 2 is on digital and microprocessor applications, covering from binary coding to error control techniques. Chapter 3 is on analog and digital video signals, covering topics such as raster scanning, pixels, colour difference signals (R-Y etc), video sampling, video formats (4:3, 16:9 etc). Chapter 4 is on DVD encoding and discusses topics such as temporal and spatial data compression, multi-channel audio formats, MPEG and AC-3 audio encoding, linear PCM and the sub-picture stream. Chapter 5 covers Framing & Forward Error Correction while chapter 6 is on the Optical Pickup Unit. Chapter 7 is on Signal Processing & Control during DVD playback. It discusses the processing of the signal as it comes from the optical pickup. Chapter 8 is on Video & Audio Decoding and discusses how the signal from the RF processor is encoded into PAL or NTSC signals on the video side and multichannel audio, with up to 7 channels provided for in MPEG2 (or six in Dolby Digital). Chapter 9 is on Power Supply & the User Interface. The latter is controlled by the front panel buttons or the IR remote control. Not surprisingly, the power supply ends up being just as complicated as that for a PC, with just as many supply rails. Chapter 10 is on Servicing DVD players, and as indicated above, this is mainly a guide to general fault diagnosis. There are some useful sample scope waveforms such as chrominance, luminance and CVBS (composite video, blanking & sync) signals. Chapter 11 is on Data Flow while Chapter 12 is on DVD Production although this involves the planning and processing before the production of stampers and so on. Finally, Chapter 13 is on DVD Drives as featured in PCs. Again this is not about the drive itself but how it is controlled and installed in the PC – quite useful. There is also quite a comprehensive DVD glossary and five appendices, on Integrated Circuits, Functions of a DVD Player, DVD Copyright Protection, Units & Specifications and Self-test Questions & Answers. Perhaps a little surprisingly, there is very little about Region coding (apart from the above listed appendix) and how to circumvent it (many DVD players now play all Region DVDs). Nor is there anything about Macrovision – a major issue with new release DVDs and compatibility with older TV sets, some only a few years old. Apart from those minor negative comments, this book is very welcome, especially since it is clearly laid out and easy to read. It will be available from the SILICON CHIP Bookshop service at $79 plus postage. (L.D.S.) Digital Oscilloscope Logic Analyzer + from 5 $59 ANALOG = DIGITAL Convert your PC into a powerful Scope and Logic Analyzer! Now you can analyze electronic circuits in the analog and digital domains at the same time. BitScope lets you see both analog AND digital logic signals to find those elusive bugs. USB and Ethernet connectivity means you can take BitScope anywhere there is a PC or Network. BitScope Hardware • 100MHz Input BW • 40MS/s Sample Rate • Dual 32K Buffers • 4 Analog Inputs • 8 Digital Inputs • Waveform Generator • SMART POD Probes www.siliconchip.com.au BitScope Software • Windows or Linux • TCP/IP Networking • Advanced DSP • Digital Scope • Analog Scope • Logic Analyzer • Spectrum Analyzer Applications • Electronics Labs • Remote data logging • Engineering students • Scientific research • Robotics and control www.bitscope.com USB or Network connection to Windows and Linux PCs! February 2004 31 Following our description of the 12AX7 valve preamp in the November 2003 issue, we’ve had quite a few letters from readers asking if it can be adapted for use in a hifi preamplifier. It certainly can, and here are the details. Using the Valve Preamp in a hifi system Fig.1: the frequency response features a slight rise in the low bass region and is just -1dB down at 180kHz. By JIM ROWE This is the original 12AX7 valve preamplifier, as described in the November 2003 issue of SILICON CHIP. It’s easy to modify for use as a hifi preamp. 32 Silicon Chip www.siliconchip.com.au Fig.2: total harmonic distortion (THD) vs signal output. It’s almost an order of magnitude better than before. T HE 12AX7 VALVE audio preamplifier in the November 2003 issue was “the project that we swore we would never do”. This may have been a tad embarrassing but the project has proved to be surprisingly popular. It looks like quite a few more people than we expected did want to try out “valve sound” for themselves! The November 2003 design was intended for use mainly with electric guitars and musical instruments, which is why we gave it a gain of about 60 times. But not long after the November issue appeared, we started to get letters and emails from people wanting to use two or more of the preamps with their hifi sound systems. They wanted to know how to adapt the basic preamp design for this kind of application. As it stands, the original design has far more gain than is necessary and would be seriously overloaded by the signals from a CD player, tuner, cassette deck or whatever. To make it suitable for these “line level” signals, we need to lower the overall gain to about four times. As well, we needed to show how to fit a volume control, as the original preamp didn’t provide one. Fig.3: THD vs frequency at 2V output. Again, it’s almost an order of magnitude better than the original circuit. response curve is shown in Fig.1 and this also has a very slight rise in the low bass region. Again, this is largely academic. The biggest changes come about in the harmonic distortion and since the feedback in the modified circuit is much greater (ie, we increased the feedback to reduce the gain), we would expect to the harmonic distortion to be considerably lower. And indeed it is. Fig.2 shows the total harmonic distortion (THD) plotted against signal amplitude and this demonstrates that is almost an order of magnitude better (ie, one tenth) than before. On the downside, the circuit can now only deliver just over 8V before clipping sets in (demonstrated by the vertically rising curve) and this is due to the increased loading of the feedback network on the plate circuit of the second triode. Fig.3 shows THD versus frequency at a signal output level of 2V and again, it is almost an order of magnitude better than the original circuit. Signal to noise ratio is also improved, to -99dB unweighted (22Hz to 22kHz) with respect to 2V output. Circuit changes In talking about the new design, we will assume that readers have access Performance As you would expect, the changes to the circuit do bring about significant changes to the performance and these are all to the better. The frequency response is now even more extended, with the -1dB point now being 180kHz rather than 160kHz, although this is really academic. The new frequency www.siliconchip.com.au Fig.4: the circuit changes are straightforward and involve changing six resistors and increasing the value of the feedback coupling capacitor to 680nF. A 50kΩ log pot has also been added for volume control. February 2004 33 Table 1: Capacitor Codes Value 680nF 220nF 100nF µF Code EIA Code IEC Code 0.68µF 684 680n 0.22µF 224 220n 0.1µF 104 100n to the full November 2003 article. Fortunately, it wasn’t too difficult to modify the preamp design to lower the overall gain. As you can see from the modified circuit in Fig.4, we’ve mainly lowered the division ratio in the negative feedback voltage divider, to give a ratio of about 4:1 ((5.6kΩ + 4.7kΩ + 3.3kΩ)/3.3kΩ = 4.12) instead of the original 60:1. In order to do this, we had to increase the value of the first triode’s (V1a) cathode bias resistor to 3.3kΩ (from 1kΩ), so that the overall divider resistance wouldn’t be too low – which would have provided excessive loading on the plate of the second triode (V1b). But because increasing the Fig.5: here’s how to install the parts on the PC board and wire up the volume control. Make sure that the high-voltage components are covered with neutral-cure silicone sealant. value of V1a’s cathode resistor reduces that valve’s plate current, we also had to increase the value of its plate load resistor, to bring its quiescent plate voltage back to around half the HT supply. So that’s why the plate load resistor for V1a is now 270kΩ, rather than the original 100kΩ. Even with these changes, the negative feedback divider still has a somewhat lower resistance than in the original design (ie, 13.6kΩ rather than 67kΩ). To compensate for this additional loading on V1b, we’ve increased the quiescent plate current of that triode stage by reducing its cathode bias resistor to 560Ω (from 1kΩ) and also reduced the value of its plate load resistor to 68kΩ (from 100kΩ) to again bring the quiescent plate voltage back to around half the HT supply. Performance Frequency Response: +0.5dB at 16Hz and -1dB at 180kHz (see Fig.1) Harmonic Distortion: 0.2% for output levels up to 6V RMS (see Figs.2 & 3) Signal-to-noise Ratio: -99dB unweighted (22Hz to 22kHz) with respect to 2V RMS output Voltage Gain: 4 Input Impedance: 1MΩ Output Impedance: 600Ω approx. (before volume control) 34 Silicon Chip The only other circuit change has been to increase the value of the coupling capacitor between the plate of V1b and the negative feedback divider, to compensate for the lower divider resistance and ensure that the preamp’s bass response is not degraded. The capacitor value has been increased to 680nF (from 220nF). Volume control What about the volume control? This is simply a 50kΩ log pot connected to the output of the preamp, as you can see from the circuit. Of course, if you intend building two of these valve preamps for stereo, you’d use one half of a dual 50kΩ log pot for each channel. We should also mention that although the plate current of both triode stages has been changed in this version of the preamp, the total HT current drain is almost exactly the same as that of the November 2003 version. So the HT power supply described in the November article is quite capable of running two of the modified preamps, for stereo operation. In fact, it could be used to drive quite a few other valve stages, if that was ever required. Construction The modified preamp can be built up on the original PC board, because only the component values have changed. Almost all of the changed component www.siliconchip.com.au values have the same physical size as those in the original preamp, too, so in most cases it’s simply a matter of fitting the different value parts into the board using the new overlay diagram as a guide. The only exception to this is the 680nF 630V feedback coupling capacitor, which you’ll find is somewhat larger than the original value of 220nF. You may have to bend the leads of this capacitor inwards so they’ll go through the board holes, and you may even have to mount the capacitor “leaning over” so it will fit between the surrounding components. As shown in the overlay diagram, the output RCA socket is no longer on the PC board, since in this version, the preamp output connects only to www.siliconchip.com.au the volume control pot. You can then connect the output from the pot using a short length of screened audio cable to an RCA socket. If you’re building up dual preamps Is It Really Necessary? If your power amplifier has an input sensitivity of 1V RMS or less, for full power output, then strictly speaking, you don’t really need a preamplifier of any sort for line level signals. All you need is a volume control. However, since so many people have asked for this circuit, we have gone ahead and shown what needs to be done. for stereo, they can be mounted side by side on the lid of a diecast metal box like the Jaycar HB-5046 (171 x 121 x 55mm), with the HT power supply and the dual volume control pot inside the box. The output cables from the volume controls could be terminated at insulated single-hole-mounting RCA sockets fitted into the end of the box remote from the +12V power input, ready for a standard stereo lead to a stereo power amplifier. This would make quite a neat arrangement, while still allowing the preamp valves to be “on display”. Finally, note that the high-voltage components must be covered with neutral-cure silicone sealant, to guard against electric shock – see Fig.5. SC February 2004 35 25 YEARS OF AUTOMOTIVE ABS by Julian Edgar Anti-Lock Braking Systems (ABS) are now a quarter of a century old. In that time the systems have saved countless dollars in panel damage, a huge number of injuries and prevented many deaths. German company Bosch has been instrumental in developing the technology and seeing it widely adopted by car manufacturers around the world. Here we take a look at the development. 36 Silicon Chip www.siliconchip.com.au Bosch ABS Milestones 1936: Bosch registers a patent for a “mechanism to prevent locking of the wheels of a motor vehicle”. 1970: ABS 1 models perform all required functions; but reliability of the control unit is not yet adequate. 1978: First fitting of ABS 2 as option at Mercedes-Benz and shortly thereafter at BMW. As the first ‘active’ car control system with major implications for safety, ABS required extensive development prior to its release. Here early vehicle testing by Bosch is shown. 1981: 100,000th ABS system supplied; ABS now also in commercial vehicles. 1985: Bosch ABS fitted for the first time in U.S. vehicles. In the 25 years since Bosch ABS went into production, the mass of the control system has dropped from 6.3 to 1.6kg, the number of components in the Electronic Control Unit has dropped from 140 to 16, and the amount of memory has risen from 2 to 128kB! 1986: One million Bosch ABS delivered. 1987: Production of Traction Control System (TCS) for passenger cars starts. 1989: With the ABS 2E, the control unit is attached directly to the hydraulic unit. 1992: 10 million ABS systems from Bosch. 1993: Start of production of ABS 5.0 from Bosch. 1995: Production of Bosch ABS 5.3 starts (with attached microhybrid control unit); production start of Electronic Stability Control. While slow to gather momentum, the proportion of new cars sold worldwide with ABS as standard has skyrocketed over the last 15 years. Just under 70 per cent of all new cars now have ABS as standard. www.siliconchip.com.au 1998: Bosch begins volume production of ABS 5.7 1999: 50 million Bosch ABS systems. 2001: Bosch ABS version 8 launched. 2003: 25 years of series production of Bosch ABS February 2004 37 CONTROL UNIT HISTORY 1970 Bosch subsidiary Teldix started working on ABS in 1964 and by 1970 had developed a system controlled entirely by electronics. The basic structure of this design, named ABS 1, is still to be found in nearly all ABS systems. But the reliability and durability of the electronic control unit - with its roughly 1000 analog components and the safety switches - were not good enough for volume production. 1978 The advent of digital technology and integrated control circuits allowed the number of electronic components to be reduced to 140. After 14 long years of development, everything was finally in place in 1978: the second generation of Bosch’s ABS – ABS 2 – began to be fitted as optional equipment, at first in Mercedes-Benz’s ‘S’-class cars and shortly afterwards in BMW’s 7-series vehicles. 1983 Based on the first ABS, the following 1983 generation 2S was more compact and efficient. However still only 0.3 per cent of new vehicles worldwide were then being fitted with ABS. 1987 In 1987, Bosch produced the first traction control system (TCS) for passenger vehicles. It was based on ABS2S and was upgraded with the required hydraulics and electronic elements. TCS helps to improve acceleration on smooth or slippery surfaces, and also increases stability by reducing engine power when corners are taken too fast. 1989 In 1989, Bosch started the mass production of ABS 2E. For the first time, developers succeeded in integrating a control unit ECU manufactured in hybrid technology. Bosch Not the First 1993 More compact and powerful solenoid valves are characteristic of the 1993 generation 5 ABS. The integrated electronic control unit ECU also had more functions. 38 Silicon Chip Despite Bosch developing the technology that has allows ABS to be implemented in millions of cars, it was not the first company to be involved in fitting ABS to a passenger car. The first car with ABS was the 1966-71 Jensen Interceptor FF, which used Dunlop Maxaret antilock brakes originally developed for fighter aircraft landing on aircraft carriers. www.siliconchip.com.au 1995 The 1995 ABS 5.3 was the first to be fitted with an ECU in micro hybrid technology. Total weight and size were further reduced. 1998 2001 1978 The brake control system of the 1998 generation 5.7 is optimised for the use in Electronic Stability Control systems. 2001 The direct comparison of hydraulic and electronic control units in the ABS2 from 1978 (left) and the integrated ABS8 of the latest generation show how the latter is much more compact. ABS 8 – the current generation – first appeared in 2001. It uses a modular design, which allows various degrees of complexity of the brake control system – ABS, Traction Control and Electronic Stability – to be manufactured in very similar ways. How ABS Works The hydraulic unit is the central component of an ABS system. Each of the four wheels has a speed sensor, which measures the rotational speed of the wheel. This information is monitored by an electronic control unit, which opens and closes the magnetic valves in the hydraulic unit at the right time. If a wheel is about to lock under heavy braking, the system reduces the hydraulic pressure on that particular wheel until the threat of locking is past. Once the wheel is turning freely again, the hydraulic pressure is increased. This variation in pressure continues until the driver reduces the force on the brake pedal or until the tendency to lock is overcome – when there is more grip on the road surface, for instance. Depending on the particular system, there is a certain amount of feedback movement at the brake pedal. www.siliconchip.com.au sc February 2004 39 SERVICEMAN'S LOG A tale of four Philips TVs TV servicing these days involves coping with both hardware and software faults. Fortunately, in-built software diagnostics can often make the job easier by pointing directly to faulty hardware. I’ve written before at length on the Philips 33FL1880/75R (FL1.1S chassis), a set I am not impressed with when it comes to servicing. Recently, I had one come in to the workshop that really baffled me. After a power surge, Mr Phelps’ set would no longer show a picture on any channel or input. However, the sound was still present, along with the on-screen displays and the Teletext (Supertext on Channel 7). And, strictly speaking, there was a picture but only in the small PIP (Picture-In-Picture) mode – it wouldn’t transfer to the main picture. The brightness and contrast controls all worked. After removing the back, I could just reach service pins S23, S24 and S25 but there were no error codes displayed on the SDM mode. I had a couple of 29FL1880/75R sets in the workshop at the time and I swapped as many modules as I could but the few that were compatible made absolutely no difference. Next, I hooked up a colour bar generator to the AUX AV SCART input and fired up the oscilloscope. I then had to balance the chassis very precariously on its front edge before starting to trace the video signal. I followed the signal from pin 18 of IC7219 (TEA6414) to pin 15 of IC7365 (TDA4650), where it splits into Y, R-Y and B-Y signals before going into IC7366 (TDA4660). From there, the signals are fed into video control IC7395 (TDA8443A) but that’s as far as they went. There was no output on pins 19, 20 or 21 to the “100Hz High End Box” (the 100Hz High End Box steps up the 50Hz field rate to 40 Silicon Chip 100Hz and includes noise reduction circuitry). This seemed like a good start and so I proceeded to analyse this IC in depth. I checked all the voltages to all the pins and every one except the three outputs was spot on. Next, I checked the sandcastle input to pin 24, then checked the SCL and SDA lines to pins 13 and 14 for digital noise before moving on to check the Frame Blanking to pin 3. Thus far, I was drawing a total blank but I couldn’t find any signal so I spent a great deal of time following this back via Q7183 to IC7258 (HEF4094), which is an 8-bit shift resistor and output latch. Eventually, I worked out that the blanking pulse was used to switch this IC from RGB input to colour difference. In disgust, I then replaced IC7395 but it made no difference. Well, if it wasn’t the IC, perhaps it was the load. The output goes via a limiting resistor into the 100Hz High End Box module, where it feeds a series of surface-mounted transistors. These are biased on and off by IC7210, Items Covered This Month • Philips 33FL1880/75R FL1.1S TV set. • Philips Series 900 KR684 KL9A3 TV set. • Philips 29PT6231 (A8.0A chassis) TV set. Philips 34PT6361/79R (A10A chassis) TV set. Fender Hot Rod Deluxe guitar amplifier. • • an HEF4066 quad bilateral switch. I replaced this IC but that didn’t help and I couldn’t fault the circuit. I then tried running the set without this module plugged in but it wouldn’t work. Next, I tried heating and freezing around this area and noticed that when it got very hot, a very faint picture appeared. However, all this achieved in the end was to damage the components on the module itself. By this time, Mr Phelps was impatient for a report on the set’s progress and what it meant for him. I wasn’t in really much of a position to advise accurately, so I could only advise him that, in terms of labour and parts, it was going to be expensive. At his insistence, I gave him an approximate figure for the repair and this enabled him to go back to his insurers and make a claim (this was not the only appliance to be damaged by the power surge). The figure I supplied, along with a note about parts availability, was enough for Mr Phelps to get a new set. And in the process, I scored the old one. A break at last All I was really interested in was finding the cause of the fault. I put the set aside and started asking around. I interrogated the web, Philips and other service centres but I was getting nowhere until a competitor offered to lend me a similar set which was in his workshop for repair. It was giving a very dull picture and he thought that the picture tube might be going “flat”. Perhaps this was the break I needed! I soon found that the cause of the problem in his set was due to the wrong flyback transformer having been fitted, the incorrect part giving low EHT and low heater filament voltages (a 29xxx version had been used). I also replaced C2523 (8.2nF) and C2504 (470pF) just in case. The fact is, the confusion surrounding these sets is due to the poor service manuals that are made www.siliconchip.com.au available. Nothing in them is clear, especially the differences between models, a lot of information is missing and there are outright errors in some places. Once his set was going, I could start swapping large chunks of it without worry. (Swapping many boards with the 29xxxx version just didn’t work as there are just too many differences). I had already swapped some of the smaller modules, along with the microprocessor and several ICs (after mounting IC sockets), especially the suspect video control ICs. Nothing made any difference until I swapped the EEPROM (IC7137, X24CO4P1) and High End Box module together, when suddenly there was a main picture. At last! Next, I went into the Service Mode (by shorting S23 and S24) to check the option codes. Option Code 1 was 010 (= FQ816/MS Multi-system type of tuner and PIP module fitted) and Option code 2 was 005 (= NTSC(1) and 100Hz high-end box(4) fitted). The option codes for these sets are not published as far as I am aware and the lists of options are difficult to comprehend. I then refitted the old EEPROM which I had already tested in a 29FL1880 set (FL1.0S chassis Option 1 = 010, Option 2 = 017 – I think). That done, I punched in the new option code numbers before storing them into memory with the “Personal Preference Store” key on the front panel of the set. This too restored the picture. My problem in relating this story is that the repair was done in dribs and drabs over many months and I can’t remember exactly what the original option codes were when the set came in. However, I think they were 026 and 001, which in the absence of definitive data might have been correct. The additional “4” for the 100Hz High End Box would account for why the video control IC was switched off and gave no output. As mentioned before, the original 100Hz High End Box had been damwww.siliconchip.com.au aged due to the excessive heat I had subjected it to. This double-sided board was hardly a delight to fix – the metal work plus the location of the module make access extremely difficult. Anyway, I eventually discovered that R3210 (22Ω) was burnt up because of a short in IC7400 (TDA2579B) and surface-mount transistor 7104, which feed off the 13V rail. The latter fault gives a no-colour symptom. Still in the woods Unfortunately, I am still not completely out of the woods, as the set is now showing (a few months later) intermittent error codes at switch-on from cold only – and sometimes not even showing a picture. The new error numbers include 15 and 10, neither of which are listed in the service manual, and also error 09, which is IC7430 (TDA4680) which has already been replaced. In addition, there is error 05 which is IC740 (the SDA9088 PIP processor) and error 08 which is IC7324 (TDA4670), both of which appear to work properly. I checked the +5V V START and reset rails and changed C2071 from 33µF to 330µF but unfortunately the problem still remains unresolved. It all goes to show that we now have to cope more and more with both hardware and software faults. Another Philips set In total contrast, I also had a 1986 Philips Series 900 KR684 KL9A3 TV come into the workshop. It too had no picture – the raster and sound were OK but the set actually came in for a completely different reason. In fact, the complaint was that the focus was intermittent and I found that the arcing tripler needed replacing. The set had always been used with the remote and otherwise left in the standby position. However, switching the mains power off highlighted another problem. The backup battery (1675) had dropped from 2.4V to just 0.4V. Replacing that fixed the memory backup, after which and the picture tuning and sound all had to be reset. Fortunately, I still have a few spares for this set and so I started off by swapping the modules. When I fitted the chrominance-luminance module, it fixed the “no-picture” problem and so I naturally figured that the problem lay there. I checked the luminance delay line and the voltages but was finally forced to dredge up the oscilloscope. It took a long time for the penny to drop that the module that worked was somewhat different from the one February 2004 41 Serviceman’s Log – continued as the +8V rail also fed the IO switching circuits. The seaside Philips that didn’t. The latter had an extra two sockets (N4 and N5) and the former had a link from 1N4 to 3N4. When I fitted this extra link, the set once again performed correctly and so I followed the N4 lead to the switches – both physical and an HEF4066 (IC706P) – on the SCART interface panel. However, this wasn’t the problem area and it wasn’t until I followed the video switch line (1N5) into the dusty bowels of the set under the CRT that I found the problem – the RGB buffer wasn’t switching and so no RGB signal was coming from the SCART socket either. By measuring the voltages on this module, I soon discovered that none of the transistors were being biased on, even though there was +13V and -24V supply rails to the board. Finally, I discovered that a single 10kΩ resistor (R3616) fed all the eight transistors and 42 Silicon Chip this was open circuit. A new one soon fixed the problem. The third Philips A 1999 Philips 29PT6231 (A8.0A chassis) came in with no sound and no monitor output. This turned out to be a classic textbook repair which demonstrated just how diagnostic software should work. The error code was 014 which points to IC7430 (MSP3410D). A few quick voltage checks around this IC showed that the +8V on pin 39 had gone “missing”, although the +5V on pin 7 was OK. Tracing back from pin 39 to Q7431 showed that there was no voltage on the collector of this transistor (BC337-25). However, there was 13V on the other side of R3464 and this 15Ω fusible resistor proved to be open circuit. Replacing it fixed both symptoms, I had to attend to a 2000 Philips 34PT6361/79R (A10A chassis) which was on the top floor of a block of units that overlooked the beach. The view was fantastic but the 3-year old TV was already rusty due to the saltladen air. Mrs Allenby was complaining that the remote wouldn’t work “after a while” and that the set would go dead after a few hours. If she then let the set cool down for about three hours, it would work normally again. When I arrived, the set was working but not the remote control and when I switched it off, it wouldn’t restart. This was a blow as it meant that I couldn’t access the error codes. The Small Signal Panel (SSP) board can cause problems in these sets and, as service centre, we are now expected to repair it ourselves – including changing the 100-pin sub-miniature surface-mounted microprocessor ICs! I can cope with the 8-pin EEPROM but change the other ICs on the off chance that this would fix the fault without compounding it? – not me! Even the exchange boards sometimes have problems and I need the confidence of the warranty. In this case, I took the SSP with me to send off to Philips and left a loan set. Ten days later, another board arrived and I went back and fitted it. Because I never saw the on-screen displays in the SDM mode, I just had to assume that the correct option codes were in the replacement. I realigned the geometry and adjusted the tuning of the set and left, but not before giving a lecture on the disastrous location of the set and the dangers of on-shore winds corroding the set to pieces. In fact, I strongly advised that they cover the set over when not watching it. I noted the error codes as 16, 13, 17. A week later, a distraught Mrs Allenby called me back, saying the set was doing exactly the same thing as before. Oops! I returned as soon as possible to witness the same story and this time I removed the entire chassis and shipped it off to Philips. It looked as though it would take longer this time to get it back as they had run out of SSPs! But initially I was informed no fault could be found, although after soak testing it the sympwww.siliconchip.com.au toms began to show again. Finally, they found the cause of the problem – one of the 5-pin 5V IC regulators (IC7967, SI-3050C) was failing when it got hot, damaging the SSP. I returned the set, realigned it again and noted that the error numbers that were still there after clearing the buffer were 16, 13 and 17. I am assured these are normal. When I left this time, I emphasised that they were not to cover the back of the set when they were watching it – only when they weren’t! After all, the back cover doesn’t have ventilation slots purely for decoration. I haven’t heard from them for three months now so – cross fingers – it’s still going OK. And now for a change of scene, here is a contributed story from A. P. of Kuranda, Qld. I’ll let him tell it in his own words. Fender guitar amplifier Dave brought his circa 1996 Fender Hot Rod Deluxe 30W valve guitar amplifier to me saying that it hadn’t sounded quite right for some time. He demonstrated the problem by playing his electric guitar through it. The high and middle range notes sounded fine but the bass was quite distorted. I also noticed that, even without any input signal, there was a strange rustling noise coming from the loudspeaker. This noise remained constant, regardless of the settings of the volume and tone controls. Dave said that the amplifier sometimes produced this rustling sound when he used it at home but never when he was playing at a gig. He blamed it on “dirty power” at home but I thought that the amplifier might be oscillating supersonically. Not having worked much with valve equipment, the first thing I did when I was alone was to turn it on and cup my hand over one of the valves to feel its warmth. However, I was disappointed – the valve I had picked was cold! It was V4, one of two 6L6GC output valves and the other valves were all glowing nicely. Well, that explained the distortion. Could V4 have a blown heater? I tried putting the other output valve, V5, in the V4 position. It came up with the heater on. On the strength of this test I ordered two 6L6GC equivalents. My plan was to replace both valves to ensure that they remained a matched pair. www.siliconchip.com.au When the new valves arrived, I installed one in the V4 position and turned the amplifier on. Its heater stayed dark but then suddenly came on when I touched the valve! I took the back off and this revealed a large vertical PC board with most of the components on it. In addition, there was a long, narrow PC board mounted horizontally, copper side up, and this carried the power amplifier and one of the preamplifier valves. The solder side of the power amplifier board was readily accessible and I quickly found that two pins of the V4 socket moved in their holes when I wiggled the valve. Closer inspection showed that the solder on these pins had cracked. It was easily fixed and for good measure, I remelted the solder on the pins of all the valve sockets. A few of the pins moved with a slight click when I did this, relieving tensions that had been built in during manufacture. This solved the problem with the distorted bass response but the rustling sound was still there. Because the rustling didn’t change with the setting of the volume control, I suspected that the problem was in the power amplifier. I tested this by plugging my signal tracer into the PREAMP OUT socket – there was no rustling. Conversely, when I put a 6.5mm plug into the POWER AMP IN socket, the main speaker continued to rustle. That cleared the preamplifier and also exonerated the switch in the POWER AMP IN socket that disconnects the preamplifier from the power amplifier. Next, I tried replacing V5 with the other new valve but this made no difference. Up to this point, I had been working without the circuit diagram but now I’d tried all the easy things and it was ELAN Audio The Leading Australian Manufacturer of Professional Broadcast Audio Equipment essential to have it. Fortunately, when I phoned Dave to bring him up to date on progress, he said he had the user manual and it had a circuit diagram. Now non-technical people sometimes confuse block diagrams with circuit diagrams, so I wasn’t hoping too hard. However, a couple of days later, Dave dropped by with the manual and I found that it did indeed have a clear circuit diagram, which included test voltages at many points. There was also a comprehensive layout diagram. The power amplifier has just one other “bottle” apart from the output 2 Steel Court South Guildford Western Australia 6055 Phone 08 9277 3500 Fax 08 9478 2266 email poulkirk<at>elan.com.au www.elan.com.au RMA-02 Studio Quality High Power Stereo Monitor Amplifier Designed for Professional Audio Monitoring during Recording and Mastering Sessions The Perfect Power Amplifier for the 'Ultimate' Home Stereo System For Details and Price of the RMA-02 and other Products, Please contact Elan Audio February 2004 43 valves: V3, a 12AX7A dual triode, connected as a phase splitter for the pushpull output stage. Because it was easy, I swapped V3 with another 12AX7A (V1 from the preamplifier section). The rustling noise remained, so I installed a plug in the POWER AMP IN socket to isolate the preamplifier from the power amplifier, in case the original V3 was still causing problems. However, the rustling noise persisted. The power amplifier has feedback from the centre tap of the secondary of the output transformer to the grid of V3B via a resistor/capacitor network. I needed to disable this feedback if I was to pinpoint the source of the rustling and it occurred to me that I could do this safely without having to remove any PC boards from the chassis by simply removing both output valves. I did this, and found that although the signal at the grid of V3A was clean, there was rustling at the anode. There was also rustling at the anode of V3B. V3A’s anode connects to the +392V Y supply via R5 (82kΩ 0.5W), while V3B’s anode connects to Y via R58 (100kΩ 0.5W). I now suspected that the fault was in one of these resistors or in the Y supply itself. Unfortunately, I couldn’t connect my signal tracer directly to the Y supply because the voltage exceeds its 44 Silicon Chip maximum DC rating, so I looked for an indirect method. Reference to the circuit showed that this amplifier has a standby switch, S5, which disconnects the high voltage supplies at the secondary of the transformer. This allows you to turn on the sound cleanly after the heaters have brought the cathodes up to operating temperature. However, it also allowed me to do a rough test of the Y supply. With my signal tracer connected to the anode of V3A and the rustling sound in full evidence, I threw S5 to standby. The rustling continued for about a second or two, then faded as the reservoir capacitor discharged. The fact that the rustling didn’t stop dead when I switched to standby exonerated the power transformer. I now felt – admittedly without very much justification – that the rest of the Y supply was probably also OK. Now for those two resistors. I began by discharging the four high-voltage filter capacitors before measuring R57 and R58 with an ohmmeter. Frankly, I wasn’t really expecting to see anything. Instead, I suspected that the resistors would look fine on the meter but that one or the other was breaking down under the strain of about 200V across it. I was already trying to think of ways to test for this but I needn’t have both- ered: R58 was spot on at 100kΩ but R57, which is marked on the circuit as 82kΩ, came in at 220kΩ! At this stage, I still hadn’t actually seen R57. Instead, I was measuring it from the copper side of the board, courtesy of the detailed layout diagram, and the resistor itself was obscured by V3’s socket. Of course, it was possible that R57 was supposed to be a 220kΩ resistor but, due to a design change or printing error, was shown differently on the circuit diagram. Anyway, I removed the narrow board and examined R57. It was indeed marked as 82kΩ and looked to be perfectly OK, with no charring or cracks. I replaced it and the rustling sound ceased! I don’t know why Dave thought that the rustling noise only occurred when he used the amplifier at home, since it would have been present all the time. Perhaps the crowd noise at a live gig was masking out the problem? I also don’t know whether the rustling noise was generated in the resistor itself, perhaps due to high voltage stress, or whether the noise was a result of V3A being incorrectly biased. Of course, I could have tried replacing R57 with a genuine 220kΩ resistor to see whether this was the case but by this time I just wanted to SC declare the job done. www.siliconchip.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au PRODUCT SHOWCASE Working Fuel Cell Experimenter’s Kit from Jaycar With more and more manufacturers looking towards fuel cells as the future of motor vehicle propulsion, Jaycar Electronics have released an experimenter’s kit which will help provide an understanding of how fuel cells work. It would also make the basis of a superb science or school project. The kit contains a working fuel cell, forming the basis of 30 experiments in fuel cell application and operation. The kit includes a small model car and the equipment to make (by electrolysis) the oxygen and hydrogen that the fuel cell uses to make electricity to power the car. The package comes with a wellillustrated 90+ page manual containing suggestions for all 30 experiments. The book also gives background information and an explanation of fuel cell mechanics. All theory is covered in a simple and informative manner. The $299 kit (Cat No. KT-25000 includes a digital multimeter (needed for the experimental work), a 130 x 120mm solar panel, electric motor, axles, car chassis, wheels, etc. Thames & Kosmos kits are avail- able exclusively in Australia from Jaycar Electronics. Contact: Jaycar Electronics (all stores) PO Box 6424, Silverwater NSW 1811. Tel: (02) 9741 8555 Fax: (02) 9741 8500 Website: www.jaycar.com.au Digital Photo Colour Correction with SPYDER With record sales of digital cameras and photo-printers, many consumers are in for a rude awakening when it comes to viewing and printing those digital camera images. That decidedly chartreuse wedding gown or your green-skinned grandmother are not going to make it to the family scrapbook, without crucial colour corrections…on the screen or at your printer.    At last month’s Consumer Electronics Show in Las Vegas, ColorVision Inc launched its new “SPYDER” product suites to make those corrections, with very little effort, putting quality in the hands of the creator. The new SPYDER Suites offer solutions for home hobbyists, graphic designers, amateur and professional photographers, as well as desktop professionals labouring over crucial PowerPoint presentations. Because attributes of a display monitor slowly change over time, recalibrating and profiling is a constant concern when it comes to accurate images as well as desktop graphics and www.siliconchip.com.au software and also includes a free Adobe Photoshop Album. SPYDERPRO is for the advanced hobbyist and is the professional’s choice for monitor calibration. It includes the Spyder colorimeter, OptiCAL™ software, as well as a free Adobe Photoshop Album. AUDIO MODULES broadcast quality design. With the SPYDER technology every monitor in the home or office can show “true” colours. SPYDER is for the hobbyist, serious amateur or desktop designer and is highly desirable for anyone working with digital images. The suite includes the Spyder colorimeter, PhotoCAL Contact: ColorVision 5 Princess Rd Lawrenceville, NJ 08648 Tel: 0111 1 609 895 7430 Fax: 0011 1 609 895 7447 Website: www.colorvision.com Manufactured in Australia Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 9476-5854 Fx (02) 9476-3231 February 2004 53 Wireless Analysis Package from Tektronix Tektronix’ new WCA11G Analysis Package speeds design and validation of wireless local area network (WLAN) products complying with any of today’s prevailing WLAN standards. WLAN technology is providing users with wireless access to the Internet and email in airports, office buildings and coffee shops. However, engineers must contend with a host of complex modulation and signal formats in addition to the separate IEEE 802.11a, 802.11b and 802.11g WLAN standards. The new WCA11G Signal Analysis software package is a comprehensive solution that automates key measurements, interprets erratic or incomplete data, and delivers multi-domain analysis tools for solving complex design problems. The software is now available with the Tektronix WCA330 and WCA380 Wireless Communications Analyzers, part of the company’s real-time spectrum analyser portfolio. Contact: NewTek Sales 11 Lyon Park Rd, North Ryde NSW 2113 Tel: (02) 8888 0100 Fax: (02) 8888 0125 Website: www.newteksales.com Metal-bender software eliminates trial and error Easily operated Windows-based software which eliminates trial and error from the process of calculating where to bend steel tubing for maximum cost-efficiency has been introduced by metal fabrication specialist Swadesir International. The new Bend-Tech EZ and Bend Techsoftware packages are designed to minimise waste of steel in manufacturing and fabrication operations by eliminating offcuts and errors associated with hit-or-miss manual calculations. Bend-Tech EZ is used for two-dimensional bends, providing the ideal cut length, weight and bend location information for manufacturing. Bend Techsoftware is a more sophisticated product that applies to three-dimensional calculations, removing the need for expensive CAD packages. It includes multiple document interface for simultaneous viewing, creation and changes to parts and manufacturing instructions are available on-screen with printed backup. Parts settings selections (including tooling and materials) are based on individually established inventory. Display settings include decimal or fractional output and bend dimension locations. A shaded view window provides a true representation of part design instructions. 54 Silicon Chip Bend-Techsoftware: Can create true 3D parts, shaded models of which can be rotated dynamically on-screen. It can produce prints of the dimensioned model, shaded model, flat layout and title block. The software allows easy design input with pick points for dimensional placement, parametric style interface and CLR or inside radius (adjustable for each bend). It also incorporates parts and material databases with graphic parts recall and recognition of the difference between tube and pipe. Contact: Swade-Sir International Pty Ltd 5-7 Strong Ave, Thomastown, Vic 3074 Tel: (03) 9460 3444 Fax: (03) 9460 8777 Website: www.swadesir.com.au Latest AV Receivers from Marantz Marantz has added two new AV 6.1 channel receivers to its Home Theatre range. The SR-5400 and SR-4400 digital surround receivers are designed to provide the frequency response demanded by Super Audio CD and DVD-Audio. The SR-4400 offers 80W RMS into 8Ω per channel and is ideal for high performance 6.1 channel home theatres. The SR-5400 has 90W per channel. The SR-4400 includes the latest generation Cirrus Logic DSP to decode DTS ES and is compatible with Dolby Digital EX, Dolby ProLogic II and Circle Surround II. It has 24-bit DSP with 192kHz/24-bit D/A converters for all channels, four digital inputs, two digital outputs, S-video and composite video switching, source direct and pure direct. A pre-coded remote control is included. The higher-spec SR-5400 has 32-bit DSP with 192kHz/24-bit D/A converters, four assignable digital inputs, a variable crossover and is the world’s first home theatre receiver to incorporate SSR TruSurround Headphone. Both models feature oversize power transformers which ensure a minimum of 70% of the rated two-channel power when all channels are driven in surround stereo mode. They also feature the Marantz D-Bus system, which increases the flexibility of system integration by communicating commands to all elements on thebus. Recommended retail prices are $999 for the SR-4400 and $1399 for the SR-5400. Both models are currently available in silver (pictured) or black finishes. Contact: Qualifi Pty Ltd 24 Lionel Rd, Mt Waverley, Vic 3149 Tel: 1800 24 24 26 Website: www.qualifi.com.au www.siliconchip.com.au SILICON CHIP WebLINK How many times have you wanted to access a company’s website but cannot remember their site name? Here's an exciting new concept from SILICON CHIP: you can access any of these organisations instantly by going to the SILICON CHIP website (www.siliconchip.com.au), clicking on WebLINK and then on the website graphic of the company you’re looking for. It’s that simple. No longer do you have to wade through search engines or look through pages of indexes – just point’n’click and the site you want will open! Your company or business can be a part of SILICON CHIP’s WebLINK . For one low rate you receive a printed entry each month on the SILICON CHIP WebLINK page with your home page graphic, company name, phone, fax and site details plus up to 50 words of description– and this is repeated on the WebLINK page on the SILICON CHIP website with the link of your choice active. Get those extra hits on your site from the right people in the electronics industry – the people who make decisions to buy your products. Call SILICON CHIP today on (02) 9979 5644 BitScope is an Open Design Digital Oscilloscope and Logic Analyser. PC software drives BitScope via USB, Ethernet or RS232 to create a powerful Virtual Instrument. BitScope is available built and tested or in kit form. Extensive technical details are available on the website. Great for hobbyists, university labs and industry. BitScope Designs Designs BitScope Contact: sales<at>bitscope.com Contact: sales<at>bitscope.com WebLINK: bitscope.com WebLINK: bitscope.com · Hifi upgrades & modification products - jitter reduction and output stage improvement. · Danish high-end hifi kits - including pre- amps, phono, power amps & accessories. · Speaker drivers including Danish Flex Units plus a range of accessories. · GPS,GSM,AM/FMindiv.&comb.aerials. Soundlabs Soundlabs Group Group Syd: (02) 4627-8766 Melb: (03) 9859-0388 Syd: (02) 9660-1228 Melb: (03) 9859-0388 WebLINK: WebLINK:soundlabsgroup.com.au soundlabsgroup.com.au We specialise in providing a range of Low Power Radio solutions for OEM’s to incorporate in their wireless technology based products. The innovative range includes products from Radiometrix, the World’s leading manufacturer. TeleLink Communications Tel:(07) 4934 0413 Fax: (07) 4934 0311 WebLINK: telelink.com.au A 100% Australian owned company supplying frequency control products to the highest international standards: filters, DIL’s, voltage, temperature compensated and oven controlled oscillators, monolithic and discrete filters and ceramic filters and resonators. Our website is updated daily, with over 5,500 products available through our secure online ordering facility. Features include semiconductor data sheets, media releases, software downloads, and much more. Hy-Q International Pty Ltd JAYCAR JAYCAR ELECTRONICS ELECTRONICS WebLINK: www.hy-q.com.au WebLINK: www.jaycar.com.au WebLINK: www.jaycar.com.au JED designs and manufactures a range of single board computers (based on Wilke Tiger and Atmel AVR), as well as LCD displays and analog and digital I/O for PCs and controllers. JED also makes a PC PROM programmer and RS232/RS485 converters. International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. Jed Microprocessors Pty Ltd Tel: (03) 9762 3588 Fax: (03) 9762 5499 www.siliconchip.com.au . complicated and more efficient by removing the need for writing scripts. PowerQuest now makes the process of migrating to Windows XP simpler and easier by providing this GUI interface that supports migrations in a WinPE environment. By leveraging PowerQuest’s imaging technology together with WinPE, IT professionals and service providers can eliminate the need to create DOS network boot floppies and leverage the efficiencies of the Av-COMM Pty Ltd Tel:(02) 9939 4377 Fax: (02) 9939 4376 Tel:(02) WebLINK: jedmicro.com.au Enhanced Windows XP Migrations ImageCenter32, from PowerQuest Corporation, is a streamlined 32-bit application that enables trouble-free configuration of image deployment under the Microsoft Windows Preinstallation Environment (WinPE). ImageCenter32 provides a straightforward graphical user interface (GUI) for PowerQuest DeployCenter Library, PowerQuest V2i Builder and the Deploy Toolkit – to make the process of creating and deploying images less Tel: Tel: 1800 1800 022 022 888 888 Tel:(03) 9562-8222 Fax: (03) 9562 9009 WebLINK: avcomm.com.au WebLINK: avcomm.com.au 32-bit Windows network environment for maximum deployment speeds. It is available immediately as a nocharge download to all licensed customers of PowerQuest DeployCenter Library, PowerQuest V2i Builder and the PowerQuest Deploy Toolkit at www.powerquest.com/easier Contact: PowerQuest Tel: (02) 9521 6466 Website: www.powerquest.com February 2004 55 Sure you’ve seen LED torches. But not like these! Our Fantastic HUMAN-POWERED LED TORCHES! by Julian Edgar Drum-roll, please! We’d like to introduce our new DIY humanpowered electric torches. Using a deceptively simple design, a slow turn the handle is enough to give a quite amazing output. D EPENDING ON how you choose to build the torch, you can have anything from a pencil beam with a range of at least 50 metres (and incredibly, it will light reflectors at well over five times that distance!) to a broad and diffuse light source perfect as a general purpose torch. Plus, you don’t need to turn the handle continuously; the light itself is ultra-white; and we would expect such a torch to last for, well, nearly ever. And, to top it all off, if you play your cards right, the torch can also cost you very, very little to put together… The Design Basics So what’s inside these humanpowered torches? Just four basic components: a stepper motor, which generates the power to run the thing; a rectifier, which converts the AC (alternating current) from the stepper 56 Silicon Chip motor into DC (direct current), which the LED needs; capacitors, which store the power; and finally the LED itself, which produces the light. Stepper Motor The driving force in any of the designs is a stepper motor, driven as an alternator. Stepper motors are used in electric typewriters, printers, photocopiers, faxes – a whole range of goods. They are most easily identified as a stepper because of the large number of wires that come out of the motor – usually six leads. When you turn the shaft, you’ll also feel a ‘cogging’ motion. The huge benefit of using a stepper motor to produce the power (rather than the conventional brushed DC generator) is that the rotational speed needed is much, much slower. In fact, a stepper motor can be turned 10-15 times slower than a conventional motor-turned-generator. So using a stepper motor in this application means that you can completely dispense with the gearbox – not only does that reduce noise and cost, it also decreases effort, as even a good gearbox has noticeable frictional losses. Longevity is also greatly enhanced. And you shouldn’t have to pay much for the stepper motor – not if you get it from inside a discarded printer, electric typewriter, fax, photocopier or similar. Scrounging the steppers The stepper motors used here came from laser printers and fax machines (each around $5 at jumble sales), while an old electric typewriter (for example, a daisy wheel design) can yield three or four suitable steppers. Steppers are available in many different sizes www.siliconchip.com.au – smaller motors will generally yield less power than larger motors. Rectification Either four diodes or two bridge rectifiers are used to turn the AC output of the stepper motor into the DC that the LED and storage capacitor pack need. Pretty well any small diodes can be used – they can be salvaged from equipment (the PC board from the aforementioned discarded electric typewriter had no less than 16 suitable diodes!) or they can be bought new for nearly nothing. The wiring approach that you use depends on the stepper motor that you have at hand – more on this below. Capacitor Storage The low current draw of the LED makes something else possible – shortterm energy storage. Using capacitors within the torch serves two functions: 1: it smoothes out the pulsing coming from the alternator, which otherwise causes the LED to flicker; and 2: it allows the LED to stay on for a short time after you stop cranking How long the LED stays on for depends on how much capacitance you can squeeze inside the box. For example, using four 4700µF 16V electrolytic caps (ie 18,800µF total), typically gives a usable beam for about three seconds after you stop cranking – and the LED beam will stay dimly glowing for much longer. The latter means that it’s easy to find the torch in the dark if you put it down. The heart of the hand-cranked LED torch is a stepper motor. Several different types are shown here – these can typically be obtained from discarded electric typewriters and printers, amongst other goods. However, if you decide to invest a little more money and use a supercapacitor (eg, the RS Components’ 339-6843 1 Farad designs), the torch will produce a dim beam all night without any further cranking! LEDs The torches use white LEDs rather than conventional bulbs. LEDs are starting to replace incandescent bulbs in many applications. Until very recently, even highintensity LEDs were really marginal in high-output torches – the amount of light produced was simply not great enough for any distant viewing. However, that limitation can now be Using Stepper Motors To Generate DC Stepper motors use a multi-pole alternator design with four phases. When used as a motor, the computer puts a pulse of current into each phase coil in turn, moving the shaft on one step. As with a DC permanent magnet motor, driving the motor’s shaft makes it work as a generator – in this case causing pulses of current to come out of the windings. The developed current is AC, going positive as a magnet pole approaches a coil and then negative as it goes away again. Usually there are four phases at 90-degree intervals so when one comes down to zero, the next one has reached maximum. This is a benefit as it means the output can be rectified to produce much smoother DC with hardly any gaps, but it means these www.siliconchip.com.au motors have a scarily large number of wires coming out. Luckily, it’s quite easy to figure out which way around they are by using a resistance meter (preferably digital), and getting them the wrong way around won’t do any damage. The most common type of stepper has six wires coming out. The six wire stepper is actually two motors on one shaft, so the six wires can immediately be separated into two groups of three. Each group will have some connection to each other, but no connection to any of the other group. In each group, one wire is the common and the other two are the opposite ends of a winding which will give out oppositely-phased AC. In terms of resistance, the reading from the common to either end will be half the reading across the two ends. Having found the common on one set, you can use the same process to find the common in the other one. All four windings will have almost exactly the same resistance. The majority of steppers are six wire, but there are other varieties. Five wire ones are easy; the two commons on the six wire have already been connected together for you, which makes things easier. Eight wire ones are just like a six wire but with all the windings separate, and four wire ones are half of an eight wire one (or half a six wire one with the two windings separate). Courtesy of www.c-realevents.demon.co.uk/steppers/stepmotor.htm - used with permission February 2004 57 Fig.1: most stepper motors that can be salvaged from old equipment use this type of wiring configuration. Finding out which wire is which can be done with a multimeter. overcome by (a) using very bright white LEDs, and (b) using first-class coated optics to develop a very well focused beam. The great advantage of using a LED is that its current draw is so low. The disadvantages (and of course, there are also disadvantages…) is that the LED costs more than an incandescent bulb, and in the final analysis, doesn’t produce as much light as a hard-driven filament lamp. However, we’re immensely pleased with how strong the beams of these torches are, especially considering that the effort put into turning the handle is really quite low. Focusing Lens A key ingredient in getting a good beam is the use of a focusing lens. High intensity LEDs are already very directional – some light comes out of the side of the LED but the vast majority is aimed straight out of the front. So while a reflector is good to channel the minor amounts of light scattering out the sides, it’s much more important to focus the beam that’s already being formed. The best lens that we have found is formed from some of the glass elements from an old standard 35mm SLR camera lens. These days, with the advent of digital cameras and with pretty well all SLR cameras being sold with zoom lenses, the standard lens is unloved and unwanted. In short, you can buy them secondhand for nearly nothing. For example, one of these torch designs uses a lens formed from the reversed rear section of a 50mm f2 Ricoh lens. (Note that the ‘speed’ of the lens – ie in this case a maximum aperture of f2 – is important as the ‘faster’ the lens, the larger will be its glass bits.) Using what was once a very good quality lens (ie, much better than a cheap plastic magnifying glass or 58 Silicon Chip Fig.2: the simplest way of getting DC out of a stepper motor is to link the two commons to the ‘minus’ terminal and then connect the four live phases through small diodes to provide the positive output. similar) gives plenty of light transmission and also allows for the focusing of a tight beam. After all, how many commercial torches use high quality, low dispersion, coated glass optics! Organising the Bits 1. Finding the Stepper The first step is to find a suitable stepper motor that can be used to generate the power the LED needs. Digging through discarded equipment, it’s not hard to come up with four or five steppers of different sizes and outputs. A quick way of sorting out the better ones for the torch application is to firstly go for the larger motors (but which are still small enough to fit in your designated box), and then select those which most easily light a white LED wired directly to two of the output wires. (Despite the stepper producing AC when wired like this, the LED will still light when the stepper is turned – it will just flicker a lot). You will need to find a stepper where even when the shaft is turned quite slowly (eg, 1-2 turns a second), the LED shines brightly. The experimentation that you do should be with a LED similar to that which you intend using in your final design – LEDs vary in their current requirements. For example, the Luxeon Star 1-watt models (available in Australia from Prime Electronics (www.primelectronics.com.au) or the Alternative Technology Association (www.ata.org.au/leds.htm) certainly can’t be brought to full illuminance by a small stepper but that same stepper can work quite well with a conventional white LED. The Jaycar ZD1780 6000mcd LED is suitable for use with many small steppers, for example. The physically larger the stepper, the more Fig.3: if you want to generate a higher voltage for the same cranking speed, you’re usually better off using this circuit which uses two bridge rectifiers. likely that you will be able to drive a high-current LED. 2. Wiring Approaches There are two wiring approaches that can be taken when building the torch – these are shown in Figs. 2&3 in the “Using Stepper Motors to Generate DC” breakout box. Fig.2 is the most common approach but Fig.3 has a distinct advantage in some applications – often it will increase the voltage available from the stepper. Deciding which approach is better for your application requires some further experimentation. First, use a multimeter to find out which wire is which, then wire the stepper to the LED as is shown in Fig.2. The next step is to turn the stepper as fast as you will ever be able to (you can use a bulldog clip to make a temporary clamp around the shaft of the motor to act as the attachment for a test handle) and measure the voltage being developed as the LED is powered up. In addition, turn the shaft more slowly (that is, at a comfortable speed) and view the LED brightness. The ideal www.siliconchip.com.au Step by Step: Making a Narrow Beam Torch We selected a rigid plastic box as Using a holesaw, a hole was then 1Electronics the enclosure for the design – Jaycar 11 cut in one end of the box. The two Cat. HB-6122 at $7.25. It halves of the box were then separated, is made from high impact ABS, uses a tongue-and-groove seal around the lid, and is dust and hoseproof. Importantly to hand-holding comfort, it has rounded edges and corners. first step was to mount the 2usingThe stepper motor in the lid of the box, the two screws that originally held the stepper in place inside the laser printer. Next, the lens/reflector package needed to 3disassembled be organised. This Ricoh camera lens was and it was found that the rear lens elements (mounted in a sub-assembly) gave good results when placed about 20mm from the LED. The assembly is reversed in orientation to that used in the original camera lens. torch was then disassembled, 4Athesmall reflector removed… …and the reflector 5 opening for the bulb carefully drilled out (jn small steps) until the LED was a tightish push-fit. (The reflector isn’t critical but it adds a ring of light around the main beam.) The pump-lid of a plastic 6having container of skin cream was then selected as a hole in one end about right for the reflector and a length about right for the LED-to-lens distance. The lid was disassembled 7opened-up and the hole in the cap a little with a round file so that the reflector sat nicely in it. 8 The threaded top of the skin-cream container was then cut off, cleaned-up and then screwed back down inside the lid, holding the reflector firmly and securely in place. The holder from the 9 camera lens was filed from its original semi-circular shape until it was about the same diameter as the reflector holder (that’s the former skin cream cap, remember!). Good quality elec10 trical tape was then wrapped around the lens/reflector assembly, holding the two pieces together. Large diameter heatshrink could also have been used for this purpose. www.siliconchip.com.au the lens/reflector assembly inserted, and the box temporarily re-assembled to check that the lens/reflector assembly was held firmly in place. It was. The capacitors were placed into 12 position next, being held in place inside the lid with double-sided tape. The diodes were soldered to the four 13 stepper motor outputs, making sure that all their bands were furthest from the stepper motor, then the wiring was completed. Note that the capacitors are polarised – their negative terminal is shown by a line of negative (-) symbols down the side of each of their bodies and they must be connected around the right way. The final design is quite a 14 tight fit – as you can see here, there’s only just enough room for all of the bits. The hand crank was made from 15 a piece of polypropylene plastic kitchen chopping board. This material has a distinct advantage in this application: if a carefully-sized hole is drilled in the material, it can then be forced over the stepper motor shaft giving a good non-slip fit. In the case of the stepper motor shown here, a small diameter cog was already in place on the shaft and so the push-fit of the crank is even more secure. At the other end of the crank, a 17 high quality knob was made by using two ball-bearing pulleys, previ- ously found inside an electric typewriter. Sandwiched together and with a couple of washers under them, they give an easily-grasped knob which has excellent quality bearings built right in. Note that the distance 18 centre-to-centre between the knob and the motor shaft (ie the working length of the crank) is very important to the ‘feel’ of the device: you should experiment with this distance until the leverage suits your preferences. February 2004 59 La Crème de la Crème – the big-buck design This torch is the big buck design – it uses an expensive 1-watt(!) Luxeon Star/O LED and super capacitor energy storage. As you’d expect, in operation it’s also the most impressive of the designs, able to light a room or create a swathe of light outside that – for example – is ideal for walking. Despite the fact that extra focusing optics would have given this torch an incredible beam reach, it was decided to use only the Luxeon built-in lens and reflector, resulting in a very even 20° beam. When held close to a digital light meter, a reading of over 34,000 lux can be recorded! In practice, when walking down a road at night, the full width of the road is illuminated with a range of six metres or so. The torch uses for its body a plastic housing that was originally one of the satellite speaker enclosures in a PC sound system. The knob is a ball-bearing equipped cog (with the teeth mostly sanded away) that was salvaged from an old fax machine. Both wiring approaches were tried and the simple diode rectification gave the best output for the least The output of a focused cranking effort. Inside, a 0.47µF beam or Luxeon Star electrolytic capacitor and a 1 farad LED torch is sufficient to super capacitor are used for energy storage. cause eye discomfort and This is an enormously impressive possibly eye damage. torch. In fact, the only downside Do not look directly into is that generating a full watt by a the torch, and don’t shine Warning! the beam into anyone else’s eyes at a close distance. hand-cranked mechanism is hard to do quietly – despite the direct drive, the stepper motor makes a whirring noise when being turned. The size of the required stepper also makes this torch the heaviest of the designs – it weighs 600 grams – but the sheer light output is just staggering. Very few people can believe that a simple turn of the handle can produce this much light – especially from a LED! If you want the best, you have to be prepared to pay for it. This torch uses the VERY bright LUXEON Star/O LED and a supercapacitor. But its performance is exceptional! 60 Silicon Chip www.siliconchip.com.au A Broad Beam Torch After my partner saw the results of the narrow beam torch, She-Who-Must-Be-Obeyed decided that when out walking she wanted a torch that would light up the area immediately in front of her – that is, producing a very broad, diffuse beam. This meant that a focusing lens was not required, so creating more room inside the box for storage capacitors – nine 4700µF capacitors were installed, giving a total capacitance of 42,300µF. Secondly, it was preferred that the torch weigh less than the first design, so in this model a smaller stepper motor was used. It was also decided to fit two of the high intensity LEDs, rather than just one. The stepper motor is easily able to drive two LEDs (and probably more as well), and without the dramas of trying to integrate multiple LEDs into a reflector-and-lens system, it was easy enough to use two. However, when wired with separate rectifying diodes, the smaller stepper proved to have a lower voltage output than the larger stepper used in the focus-beam torch. This meant that the crank had to be wound very fast to get a good light output, so a revision was made to the wiring. Two bridge rectifiers were then used (ie, Fig.3’s wiring approach). In practice this resulted in the voltage rising to 3.2V at an easy cranking speed – and peaking at 3.4V when the short handle was being turned as quickly as possible. While the effort in turning the handle rose when this alternative wiring configuration was adopted, it is still quite easy to turn. In some respects, the handle is actually easier to use when working against the slight resistance – before, it was almost free-wheeling. A very short handle was fitted (about 10mm centre-to-centre), with its knob formed by three sealed ball bearings from discarded video cassette recorder video heads. In a small room with a white ceiling and walls, the twoLED torch will dimly illuminate the whole room. Following outcome is a peak voltage of around 3.5V – that’s what is needed by the LED – and a ‘slow turn’ voltage as close to this as possible. (In fact, of course, it’s the peak current – rather than the voltage – that should be limited, but if the stepper being turned flat-out develops only around 3.5V, in real use the LED will be well within its ratings.) Matching the stepper motor to the LED in this way removes the need for a dropping resistor, saving valuable energy – energy, remember, that’s being put in by you! If the voltage that you see during the test is well below 3.5V, try the wiring approach shown in Fig.3. Often (but not always!), this will increase the www.siliconchip.com.au an outside path at night, the torch casts a soft white glow that extends about five metres ahead and a metre or so either side of the path. In fact, the light output is similar to a small fluorescent lantern. Interestingly, with the LEDs sticking out of the front of the torch, any light being produced by them is more easily seen than in the focusing torch design (where the LED is buried from view behind a lens). In fact, the LEDs in this torch stay faintly glowing for a very long time after the handle has stopped turning – in pitch darkness, they can be seen for over six hours – and that’s without using any expensive super capacitors! This characteristic, and the diffuse spread of light that it develops, makes this an ideal torch for moving around a house at night when the lights are off, walking down a dark footpath, or for use as an emergency torch during blackouts. voltage output of the stepper motor. If neither approach yields a high enough voltage when powering the LED of your choice, select another stepper and try again. In our testing of more than 50 stepper motors salvaged from used con- sumer goods, we’ve not seen a stepper motor that, when cranked in this way, produced well in excess of 3.5V – so your chances of overpowering the LED are slim. On the other hand, probably half of these motors had enough ‘oomph’ to drive a conventional white Emergency? These human-powered LED torches have some really good emergency applications. The light is visible from a very long distance (especially if you build it to have a narrow, focussed spot beam) and the torch will never get a flat battery. Because of the direct-drive system, the quality bearings used in stepper motors, and the LED light source, the torches should also have an almost unlimited life. February 2004 61 If the LED torch is constructed with precision focusing optics, a very intense, narrow beam is formed. This lens assembly uses elements from a discarded 50mm SLR camera lens and gives excellent long-range performance. LED to a high brightness. In short, a great many small salvageable steppers are ideal for white LED torches. 3. Optics Once you have found the right combination of LED and stepper, you will need to make some decisions about the optics. There are three basic choices: • A narrow, intense beam – this requires a series of lenses, preferably an optical assembly from a 35mm camera lens as described above. • A broad, bright beam – usually, a single lens can be used to achieve this – eg, a single element from a 35mm camera lens or a good standalone glass lens; eg, a quality magnifying glass. Alternatively, a very 62 Silicon Chip high quality LED lens-and-reflector combination (such as the Luxeon Star/O 1W white LED) can be used. • A diffused, relatively dim beam – in this case, one or two LEDs can be mounted ‘bare’; ie, without any optics at all. Think through the choice carefully – the utility of the final torch for the application that you have in mind is dramatically affected by the decision on optics. 4. Storage Capacitors The type and number of storage capacitors that you use depends on how much room you’ve got inside your box – and how much you want to pay. Electrolytic capacitors are the ones to go for and if you select those with a lower working voltage, the size of the capacitor becomes smaller for a given capacitance. In other words, a 1000µF 16V capacitor is physically much smaller than a 1000µF 63V capacitor. Since we’re working with only 3-4V, the lower voltage capacitor is fine. Basically, the more capacitance that you can squeeze in, the better – which brings us to super capacitors. While these mighty marvels are available from a variety of sources, extensive testing showed that the cheaper super caps give poor results – we recommend the RS Components 339-6843 1 Farad component. Note also that a super cap used on its own won’t work very well –you should always have a conventional electrolytic capacitor as well, of as high a capacitance as will fit in the box. You might be wondering how all these capacitors are connected – again it’s very easy, with the capacitors wired in parallel to both each other and the LED. No current limiting resistors, no zenor diodes, nothing. It works extremely well and wastes no energy. Conclusion Despite being very simple in design and construction, these torches really cut it. They’re effective and cheap, working well in both general-purpose and specialised applications. Not one of the many people who have seen the prototypes was unimpressed – in fact most people had to have the torch removed from them by force, so intent were they on winding the handle and shining the torch into SC dark places! www.siliconchip.com.au It has often been described as about the third-mostuseful piece of test gear in a TV service tech’s arsenal. It’s easy (and cheap!) to build, easy to use and you will wonder how you got along without one . . . Design by Bob Parker Shorted Turns Tester www.siliconchip.com.au February 2004 63 OK, so you’re already asking: if it’s number three, what are one and two? Few would argue that the multimeter (or more likely a DMM these days) and a ’scope well and truly take the first two spots. But if you’re into repairing TV sets and/or video monitors, a shorted turns tester in your tool box or on the bench can save you hours of wasted time – not to mention a lot of expense. However, we’re getting a bit ahead of ourselves. What does it do? Ummm – isn’t that blindingly obvious? Shorted turns tester? Tests for shorted turns? Yes, it does just that – but unless you ARE a TV or monitor technician, you’re probably still none the wiser. Let’s go back a few steps. In all traditional (ie, CRT-equipped) TV sets and video monitors there is a horizontal output stage (also called the line output stage). You could regard this as the “business end” of the TV set/monitor. It’s job is to supply appropriate signals and the extra high tension (around 20-30,000V) the picture tube needs to make it operate. Operating at high voltages, frequencies and power levels, the horizontal output stage is one of the most-stressed sections of the circuit and is responsible for more than a fair share of faults in TV sets and monitors. Unfortunately, faults in the horizontal output stage are often difficult to find – and many a technician has replaced the principal (and most expensive) component, the line output transformer, only to find the fault is somewhere else. Perhaps the fault is in the highspeed rectifier diodes connected to the transformer’s secondaries. Maybe the horizontal output transistors have failed due to the stresses they are under. Or it could be an insulation breakdown in the deflection yoke on the back of the tube. But the fault that most technicians dread is a shorted winding within the line output transformer. Without the right test gear, the easiest way to test a line output transformer is by substituting a known good one. But we have already mentioned the fact that they are expensive – and, unfortunately, they are commonly NOT interchangeable from one brand to another. Another minor dilemma for the This project was first described in Electronics Australia in August, 1998 and has proved to be a very popular and enduring design with thousands sold around the world. It is re-presented here, with cosmetic changes only, for the benefit of 21st century readers! Note that existing stocks of the Dick Smith Electronics kit (Cat K-7205; $49.80) will include the old panel and instructions until the next run of kits. technician is that this section of the set can bite – badly. Most repairers are slightly less than enthusiastic about digging around the horizontal output stage while it is powered up. They’d much rather find a way to test a less angry set! All things considered, a technician needs to be fairly confident that the line output transformer IS faulty before going to the trouble of obtaining a good’un then substituting it (which usually means a bit of set disassembly). How do you test it? Most test equipment, including the one described here, is based on the fact that nearly all serious faults in horizontal output stage will greatly increase the losses in the primary circuit. The components in the primary circuit form a reasonably low loss resonant circuit (also called high “Q”), especially at low voltage levels. Shorted turns or components in the output stage will lower that “Q”. Find a way to check low Q and you have a handy piece of test equipment. Ring testing When you apply a fast pulse to the primary of the line output transformer (LOPT), the total inductance and capacitance will produce a decaying oscillation in the secondary, which may have a dozen or more cycles before it dies away to a low value. This is known as “ringing” Incidentally, it is called that because it is very similar to the effect you get when you strike a bell. You get a note that gradually dies away. If the circuit has shorted turns These two ’scope shots demonstrate not only the principle of operation of the Shorted Turns Tester (and also a ringing oscillation!) but also its effectiveness. The first shot is that of a known good line output transformer; the second is the same transformer with a dead short across one of the secondary windings (eg, a crook rectifier diode). In the first shot, all LEDs were lit; in the second only four. 64 Silicon Chip www.siliconchip.com.au or other faulty components in the secondary, the oscillations die away very much faster. Continuing the bell analogy for a moment, if you place your hands around the bell to stop it resonating, the bell sounds for a much shorter time. This principle is the basis of our Shorted Turns Tester. A fast pulse is applied to the primary of the transformer and the number of “rings” (or oscillations) are counted. If all is well, the circuit lights up a number of LEDs. If all is not so well, less LEDs light. If there is catastrophic failure (for example, a collector/emitter short in the horizontal output transistor(s) or a capacitor short) there will probably be no ringing at all, with no LEDs lighting. We’ll look at this in more detail shortly. Before we move on to the circuit description, it is worth noting that this Shorted Turns Tester works at low voltage and is designed to check the line output stage “in situ” – very much more convenient than having to remove the transformer or other components. The circuit There are three sections to the Shorted Turns Tester circuit (Fig.1): the oscillator, which produces the low frequency but fast-rising pulse; the comparator, which compares the amplitude of the oscillations produced by the transformer; and the LED bar-graph driver and display. The low frequency pulse generator: IC1b, one half of a LM393 dual comparator, is set up as a low frequency oscillator, whose output (pin 7) is normally pulled up to essentially the positive supply rail by the two 1kΩ resistors. The output switches down to 0V for about 2ms every 100ms, with the timing set by the feedback components between the inverting input (pin 6) and the output. It is during these low-going 2ms pulses that each ring test occurs. When IC1 pin 7 goes low, Q1 is driven into saturation and its collector voltage rises almost to the +6V supply. This makes two things happen. First, the 100pF capacitor, between Q1’s collector and the reset pins of IC2, sends a positive pulse of about 5us duration to those resets, which drives all the outputs of the four-bit www.siliconchip.com.au February 2004 65 switches cleanly between its low and high voltage levels. The result of all this is that an inverted and squared-up version of the ringing waveform appears at the output of IC1a, until the ringing amplitude has decayed down to about 15% of its initial value. This pulse train is connected straight to the clock inputs of the two shift registers in IC2. 3. The LED bargraph display: IC2 consists of a pair of identical four-bit serial-in/parallel-out shift registers, connected to form a single eight-bit unit, with each output driving one LED in the ‘bargraph’ display via the 1kΩ resistors. The serial data input of the first stage (pin 15) is permanently connected to the positive supply, or logic 1. Fig.2: follow the PC board overlay above and the photo at right and you should have no problems in assembling the project. It should take less than an hour to do. Remember to leave the LEDs until last, as explained in the text. shift registers to a low state. This switches off all the LEDs, in readiness for a new ring test. At the same time, D2 is forward biased, resulting in a brief 650mV pulse across the diode. This is coupled via the 47nF capacitor to the test leads and the LOPT primary winding. As previously explained, this causes (hopefully!) the LOPT circuit to ‘ring’, a bit below its natural resonant frequency due to the presence of C3 (which functions as the resonating capacitor when testing an LOPT on its own). 2. The ring amplitude comparator: The ringing waveform is coupled by a 10nF capacitor to the inverting input of comparator IC1b, itself DC biased to about +490mV by the voltage divider across the supply (4.7kΩ, 33kΩ and 150kΩ resistors). At the same time, D3 is constantly forward-biased and its entire voltage drop of about 600mV is applied to IC1a’s non-inverting input as a reference voltage, via a 10kΩ resistor. The 1MΩ resistor between the non-inverting input and the output of IC1a produces a small amount of positive feedback, ensuring that its output Partially assembled Shorted Turns Tester shows the battery holder in place in the case bottom and the PC board ready to mount on its threaded spacers with the LEDs poking through the front panel. In the DSE kit these holes are pre-punched, saving you a lot of time and trouble (rectangular holes are a cow to drill . . .) 66 Silicon Chip One measurement For the first 5us after the commencement of a new 2ms measuring pulse, both shift registers are reset to zero on all outputs, as described And here it is fully assembled, ready to close up and use. You might like to put some foam rubber between the PC board and batteries, just in case. www.siliconchip.com.au best use. Their responses are shown below, giving a good idea of the usefulness (and the limitations) of this tester. Putting it together Fig.3: the wiring is pretty simple because almost everything mounts on the PC board. If you get a DPST (or even a DPDT) power switch in your kit (as ours was), simply use the centre pin and one of the outside pins. earlier. At the same time the initial positive pulse applied to the LOPT drives IC1a’s output, connected to both shift registers’ clock inputs, to a low (logic 0) level - unless the test leads are shorted. If the LOPT primary circuit is OK, it will ring during the next several hundred microseconds. For each ring above about 15% of its initial value, it will cause a high-going pulse to be applied to the shift register clock inputs, resulting in the logic 1 on IC2 pin 15 being moved one shift register stage further along. It doesn’t matter if the LOPT rings more than eight times – all LEDs will still remain illuminated. So the overall result is that one LED illuminates for each LOPT ring cycle above 15% of the initial level, and this condition remains until the start of the next 2ms measuring pulse. Usage & limitations In order to assess the usefulness of this design, we gave several prototype Shorted Turns Testers to technician friends to evaluate for many months, then asked for their comments and thoughts on how to put the tester to Before soldering anything to the PC board, hold it up to a bright light and examine the copper side carefully for fine track breaks and, especially, whiskers or bridges - particularly where tracks pass close to component solder pads. Referring to the board overlay in Fig.2, begin installing the components, starting with the low-height components – the resistors and diodes - working your way up to the tall ones including the four PCB pins for `GND’, `HOT’ and `+6V’ terminal connections. Leave the LEDs off the board for now. Take care with the orientation of the polarised components, including the IC sockets. With everything but the LEDs installed on the PCB, once again illuminate it from the top, then check for and correct any solder bridges or other problems. Now turn your attention to the front panel, mounting the banana sockets and the power switch in their respective holes. Attach the tapped spacers to the corners of the board using plain 3mm screws and solder long component lead offcuts to the `GND’, `HOT Collector’ and `+’ solder pads, followed by the battery snap’s black wire to the `-’ pad. Next, without soldering them, poke the leads of all the LEDs through their respective holes in the board. Make sure the coloured LEDs are in their correct places, and that all the (long) anode and (short) cathode leads are correctly oriented as shown in Fig.??. Using black countersunk 3mm screws, Fig.4: this drawing should give you a pretty good idea of how it all goes together. Only the battery holder mounts in the case itself – everything else “hangs” off the front panel. www.siliconchip.com.au February 2004 67 Comments from the field: the Shorted Turns Tester under test! Our sincere thanks to Larry Sabo, Michael Caplan and Wayne Scicluna for their assistance in completing this project. We couldn’t have done it without you! Larry Sabo is an experienced monitor technician in Ottawa, Canada: One of the first things I do to check out a monitor is connect the tester between the HOT collector and ground. If no or only a few LEDs light, I check the HOT, damper diodes and tuning caps for shorts using a DMM. If these are OK, I check for an open fusible resistor in the circuit feeding B+ to the LOPT, and for shorts/ leakage in diodes on the LOPT secondaries. I also check the bypass capacitor on the DC supply to the LOPT primary for excessive ESR. If these check OK, I ring the horizontal yoke with its connector unplugged. It will normally ring seven times on its own. If the yoke rings OK, I unsolder all but the LOPT primary winding and ground pins, and ring the primary. If the primary still rings low with everything else disconnected, the LOPT is probably defective. Most LOPTs on their own will ring 8+ times, but some ring only four or five, even when they are perfectly normal. So it is prudent to confirm the diagnosis by ringing an identical known-good LOPT, if at all possible. Sometimes an LOPT is defective, but still rings normally with the tester, eg, due to leakage or arcing that only occurs at full operating voltage. The problem will sometimes be manifest by heavy loading of the B+ supply, spurious ringing and/or reduced voltages on the HOT collector, or excessively high EHT resulting in HV shut-down. Because this tester uses impulses of only 650mV to minimise the forward biasing of semiconductors, such defects will not be reflected in the ring count. In these circumstances, I check for measurable leakage resistance between the EHT cap and the other LOPT pins. It should be unmeasurable, otherwise the LOPT is defective. If I have gone through the above tests and have 68 Silicon Chip these symptoms and a normal ring count on the tester, the diagnosis can usually be confirmed only by substituting a known-good identical LOPT, or by testing with a chopper similar to the one described in Sam Goldwasser’s Electronics Repair FAQ, located on the Internet at http://www.repairfaq.org/ sam/flytest.htm. Something else I do when testing a LOPT is to supply it with a reduced B+ to enable scoping the HOT and measuring EHT (in situations where the monitor goes into HV shutdown). To reduce the B+, I use two light bulbs in series, one end to B+ supply, centre-tap to LOPT B+ connection, other end to ground. One bulb is 60 watts, the other is 100, so I can reverse the end leads and increase or decrease the B+ value used in testing. At the outset, when I have power supply cycling but have confirmed there are no shorts from HOT-C to ground, I substitute a dummy load (60W bulb) for the LOPT where the B+ enters, to see if the power supply works with the LOPT out of the equation. Overall, the LOPT tester can identify about 80% of LOPT failures. When trying to solve a puzzle, if someone offers information that is right 80% of the time, it’s a lot better than having to guess 100% of the time, especially if the ante is the price of a LOPT and wasted, valuable time. Michael Caplan does general electronic servicing in Ottawa, and added the following useful points in relation to TVs: It’s pretty straightforward to use, with the usual precautions of ensuring that the under-test unit power is off and any caps are discharged. When testing an LOPT in circuit, it might be necessary to disconnect some of the LOPT terminals, and/or yoke plugs that could load it down and upset the readings. The tester will often not detect bad HV diodes in integrated split-diode LOPT units, nor shorts/arcing that is voltage dependent - but then no other passive tester does either. I have found it useful for checking TV deflection yokes, both horizontal and vertical. A good yoke lights at least five and typically the full eight LEDs. However, many yokes have built-in parallel or series damping resistors, and these must be temporarily disconnected. Otherwise the reading will be low, even though the winding itself is fine. The tester can be used for checking high-Q transformers such as those used in SMPS’s. However, my experience has shown that it will not provide more than a two or three LED indication for good TV horizontal drive transformers. It can be used for these, however – to indicate shorts (no LEDs lit). On the other hand the ESR Meter (Dick Smith catalog number K-7204) can do much the same with these low resistance transformers. Wayne Scicluna services TVs in Sydney, and is the technician who talked me into developing the tester in the first place. Here are his hints: If you’ve already checked for the more obvious leaky and shorted semiconductors and capacitors etc., and are still getting a low reading on the tester, there are some other traps to avoid. You need to get a good connection with the test leads, because contact resistance can cause a low reading. The same applies to defective solder joints in the horizontal output stage, especially on the LOPT itself and HOT. In fact connecting the tester with clip leads, flexing the board and wiggling components is a good way to show up bad solder joints in this area. Body conductivity can also cause a lower than normal reading if you’re touching the test leads and your skin is damp. Low readings can also be caused by having the test leads reversed, i.e., connecting ‘HOT Collector’ to chassis, and by faults in an external voltage tripler. www.siliconchip.com.au Parts List – Shorted Turns Tester 1 PC Board, code ZA1137 (51 x 76mm) 1 plastic case, 130 x 68 x 41mm (DSE H-2853); 1 front panel to suit (prepunched and screened) 4 PC pins 1 red 4mm banana socket 1 black 4mm banana socket 1 set red/black test leads with 4mm banana plugs 1 4x AAA flat battery holder 1 battery snap 1 SPST power switch, push on/off 1 8-pin DIP IC socket 1 16-pin DIP IC socket 4 M3 tapped spacers, 15mm; 4 M3 x 6mm screws (zinc plated) 4 x countersunk M3 x 6mm screws (black) 4 x countersunk No4 x 6mm screws (black) double-sided adhesive tape Semiconductors 1 LM393 dual comparator (IC1) 1 4015 / MC14015 / CD4015 dual 4-bit shift register (IC2) 1 BC328 / 2N5819 PNP silicon transistor (Q1) 3 1N914 / 1N4148 silicon diode (D1-3) 3 Rectangular red LEDs (LED 1-3) 2 Rectangular yellow LEDs (LED 4,5) 3 Rectangular green LEDs (LED 6-8) Capacitors 1 100µF 16/6VW RB electrolytic 4 47nF MKT polyester (code 473 or 47n) 1 10nF MKT polyester (code 103 or 10n) 1 100pF disc ceramic (code 101 or 100p) Resistors (All 5% 0.25W carbon or better) 1 2.2MΩ 4 1MΩ 1 150kΩ 2 47kΩ 1 33kΩ 1 10kΩ 3 4.7kΩ 11 1kΩ 1 270Ω TEST COIL: 1 Balun core (DSE Cat. R-5440) 2 metre length 0.25mm enamelled copper wire attach the front panel to the board assembly and place the whole thing face-down on a soft flat surface. Manoeuvre all of the LEDs into their cutouts in the front panel, and push each LED down slightly to ensure its face is level with the front of the panel. In the unlikely event that a LED won’t fit, use a small file or similar to remove the excess powder coating inside the hole. Now solder all the LEDs into place, then connect the test lead sockets and the closest terminal of the power switch to their respective wires from the board, and finally the red battery snap wire to the free switch contact (refer to Fig.3, the wiring diagram). Snip off the battery holder’s PCB mounting pins, then install four ‘AAA’ cells into it. Connect the battery snap to the terminals, and switch the unit on. If everything’s OK then the bottom red (‘1’) LED will illuminate and shorting the test leads will cause it to go off. An effective way to test the unit is to connect the test leads to the primary winding of a known good LOPT out of circuit, which should bring all eight LEDs on. Then thread a loop of solder around the ferrite core of the LOPT (simulating a single shorted turn), and the LED count should drop to 1-3 as the loop is closed. If everything’s OK, use double-sided adhesive tape to stick the battery holder into the bottom of the case, with the cells aligned in a “north-south’ direction for easiest access. All that remains to be done now is to screw the front panel into place and try out your tester on some LOPTs and their associated circuitry. Winding a Test Coil In order for constructors to test the unit once assembled we have provided details and parts to construct a simple transformer coil which enables the circuit to light all ‘8’ LEDs. Your Dick Smith Electronics kit should include a Balun core (R 5440) and about two metres of 30B&S (0.25mm) enamelled copper wire. Construction is very simple. Using the balun core provided, wind around 45 turns (tightly wound) through the two centre holes. Once completed trim the wires to approximately 50mm and clean the enamel from each end so that a positive connection can be made. Now test the coil in the Shorted Turns Tester. It should display all eight LEDs. Feeding through an additional winding and shorting the ends (remember to remove the enamel!) will reduce the “rings” to either one or two LEDs, giving a good indication that the unit is working correctly. SC Resistor Colour Codes o o o o o o o o o No. 1 11 3 1 1 2 1 4 1 Value 270Ω 1KΩ 4.7kΩ 10kΩ 33kΩ 47kΩ 150kΩ 1MΩ 2.2MΩ www.siliconchip.com.au 4 Band (5%) red violet brown gold brown black red gold yellow violet red gold brown black orange gold orange orange orange gold yellow violet orange gold brown green yellow gold brown black green gold red red green gold 4 Band (1%) red violet brown brown brown black red brown yellow violet red brown brown black orange brown orange orange orange brown yellow violet orange brown brown green yellow brown brown black green brown red red green brown 5 Band (1%) red violet black black brown brown black black brown brown yellow violet black brown brown brown black black red brown orange orange black red brown yellow violet black red brown brown green black orange brown brown black black yellow brown red red black yellow brown February 2004 69 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. Cable tester uses quad latch This circuit was designed to allow microphone cables or other cables to be easily tested for intermittent breaks that can often be difficult to find using a multimeter. The circuit can test cables with up to four cores. Both switches used in the circuit are momentary contact pushbuttons and it can run from a 9V battery, in which case the 7805 regulator can be omitted. To test a cable, connect it between the two sockets and press switch S2 which resets all four latches in IC1, setting them low. This turns on all four LEDs. A good connection for each core of the cable will mean that the relevant Set inputs of the latches (pins 3, 7, 11 & 15) will be pulled high and the appropriate LED will remain on. A broken connection in the cable will result in the relevant Set input being pulled low by the associated 10kΩ resistor and the so the LED will be off. Because the circuit latches, it is easy to pinpoint even the smallest breaks by simply flexing and twisting the cable up and down its length until one of the LEDs turns off. To test different types of cables, simply connect appropriate sockets in parallel with or in place of the XLR sockets. Ashley Dawson, Warrandye, Vic. ($35) Phantom supply for lapel mic adaptor This modification to the Lapel Microphone Adapter for PA systems (January 2004) will allow the unit to operate with the standard 48V phantom supply available on some audio mixers. Resistors R1-R4 form a simple voltage divider network to reduce the standard 48V phantom supply to 9V to power the adaptor circuit. Zener diode ZD1 provides voltage regulation and capacitor C1 provides audio decoupling. 70 Silicon Chip www.siliconchip.com.au Frequency multiplier for LF measurements When designing bass reflex loudspeaker cabinets, it is necessary to measure the resonance of the speaker to an accuracy of about 1%. To do this, you need an audio oscillator and a frequency counter. However, the typical accuracy and resolution of a frequency counter when measuring frequencies below 50Hz can lead to errors of several percent. The solution to this problem is to use a frequency multiplier and The original normally-open (NO) relays are replaced with changeover (DPDT) types to protect the phantom supply from a short circuit. The two original 6.8kΩ audio balancing resistors have been changed to 22kΩ each to prevent excessive current being drawn from the phantom supply. Both the output and input connectors can be changed to mini XLR sockets for convenience but the stereo phone jacks can still be used. Alan Morrow. Reservoir, Vic. ($30) www.siliconchip.com.au the circuit presented here can be switched to multiply by 10 or 100. It uses a 4046 phase locked loop (PLL) and a 4518 connected as a dual divide-by-10 counter. As shown, the oscillator signal is fed into the comparator formed by IC1a and its output drives the SIGin input, pin 14, of the 4046 PLL (IC2). The PLL’s output is fed to IC3 and divided by 10 or 100, depending on the setting of switch S1. The divided signal is then fed to the COMPin input (pin 3) of IC2. In this way, the PLL is forced to multiply the input frequency by 10 or 100 and this multiplied frequency can be read out with much im- J. B is this megg winner onth’s Peak At of the las L Meter CR proved accuracy by a typical digital frequency meter. However, you must then divide the displayed reading by the selected multiplication ratio to get the true frequency. The limitation in this circuit is that the 4046 can only run up to 20kHz so that the input frequency is limited to 200Hz or 2kHz, depending on the multiplication ratio. This is quite adequate for measuring bass reflex cabinets. J. Begg, Heidelberg, Vic. Silicon Chip Binders REAL VALUE AT $12.95 PLUS P & P H Heavy board covers with mottled dark green vinyl covering H Each binder holds up to 12 issues H SILICON CHIP logo printed on spine & cover. Price: $A12.95 plus $A5 p&p each (Australia only; not available elsewhere). Buy five and get them postage free. Just fill in & mail the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. February 2004 71 Circuit Notebook – continued LED chaser provides three game functions This circuit is essentially a light chaser but it can also be set to provides heads or tails (Two Up) or a Dice (die). It also has a speaker to simulate the sound of a spinning roulette wheel. Note that the dice and heads/tails features can be deleted if required and rules for the games created to suit individuals; eg, betting can be used or the numbers recorded and then totalled to get the highest score per game. CONTRIBUTE AND WIN! As you can see, we pay good money for each of the “Circuit Notebook” contributions published in SILICON CHIP. But now there’s an even better reason to send in your circuit idea: each month, the best contribution 72 Silicon Chip IC1 is a 4046 phase locked loop (PLL) but only the voltage controlled oscillator (VCO) portion of the chip is used to provide the clock pulse for IC2, a 4017 decade counter/divider. In roulette wheel mode, switch S3 is pushed to start the game. This charges the 10µF capacitor at pin 9 and as the capacitor discharges, the output frequency is slowly reduced to slow the rate of the chaser LEDs driven by IC2. In chaser mode, switch S2 is closed to provide a fixed frequency output from IC1. This can be varied over a wide range with potentiome- ter VR1. Transistor Q1 is also driven by the oscillator output of IC1 and it drives the speaker. Trimpot VR2 varies the sound level while switch S4 turns it off. Switch S5 selects Die or other (chaser/roulette). In Die mode, pin 6 is connected to the reset, pin 15, so that the circuit only counts to 6 whereas in the other modes it counts to 10 and displays all LEDs. Pin 12 drives transistor Q2 and two LEDs to provide the Heads/ Tails function. John McCuaig, Caloundra, Qld. ($40) published will win a superb Peak Atlas LCR Meter valued at $195.00. So don’t keep that brilliant circuit secret any more: sketch it out, write a brief description and send it to SILICON CHIP and you could be a winner! You can either email your idea to silchip<at>siliconchip. com.au or post is to PO Box 139, Collaroy, NSW 2097. www.siliconchip.com.au PICAXE-18X 4-channel datalogger Pt.2: adding a real-time clock Last month, we examined the datalogger circuit, described how to build the basic module and detailed a basic datalogging mission using the light and temperature sensors. This month, we add a real-time clock to the datalogger and show you how to use it. By CLIVE SEAGER U SING THE BASIC datalogger hardware, logging can be carried out at regularly spaced intervals (up to several hours) using simple programmed time delays. For example, the datalogger program presented last month used the “Pause” instruction to generate a 60,000ms (1 minute) sampling interval. However, time delays generated in this way are not entirely accurate, due mainly to manufacturing tolerances within the PICAXE micro’s internal resonator. This becomes particularly evident when longer sampling periods are called for. To avoid this problem, you can add a real-time clock (RTC) IC to the basic datalogger module. DS1307 Real-Time Clock chip The Maxim/Dallas Semiconductor DS1307 is an accurate real-time clock in an 8-pin DIP package. It automatically maintains the current time and date, including corrections for leap years and months with less than 31 days. A standard low-cost 32.768kHz watch crystal connects between pins 1 & 2 to provide an accurate time base. An optional 3V lithium coin cell can also be connected to pin 3, ensuring that the device keeps functioning even when main circuit power is removed. The IC automatically detects removal of the main power source and switches to the lithium cell when required. Less than 1µA of current is consumed by the chip in this mode, meaning a cell life of 10 years or more. The DS1307 has two additional features of interest. Pin 7 is an open collector output that can be programmed to flash at a 1Hz rate. This allows an LED to be attached as a seconds indicator in clock applications. The IC also contains 56 bytes of general-purpose RAM, which can be used as extra memory by the PICAXE micro. Fig.1: this diagram shows how the DS1307 real-time clock chip is connected to the PICAXE-18X 4-Channel Datalogger circuit. www.siliconchip.com.au Installing the RTC Installation of the RTC upgrade on the datalogger PC board is very straightforward February 2004 73 Table 1: DS1307 Registers time/date data is in BCD (binary-coded decimal) format, which makes it very easy to interpret using normal hex notation. For example, 11:35am will contain $11 in the hours register and $35 in the minutes register. Address Register (all BCD) 00 Seconds (00-59) 01 Minutes (00-59) Setting the Time/Date 02 Hours (00-23) 03 Day of Week (01-07) 04 Date (01-31) 05 Month (01-12) 06 Year (00-99) To initialise the chip after the circuit is first powered up, the current time must be written to the registers. The example program that follows sets the time to 11:59:00 on Thursday 25/12/03 using the “writei2c” command. This is carried out by loading the registers in order from address 00 upwards (seconds then minutes, hours, etc.) 07 Control (set to $10) 08-$3F General-purpose RAM and should take you less than a minute! First, insert the DS1307 IC into the empty 8-pin IC socket (IC2), making sure that you have the pin 1 (notched) end oriented correctly. Next, slip the CR2032 lithium cell into its holder with the positive (+) side facing up. That’s it! Note however that the chip will not operate until the current time/date is set. I2C Slave Parameters The following I2C slave details can be found in the DS1307 datasheet (available from www.maxim-ic.com): slave address address size bus speed 1101000x 1 byte 100kHz This means that the PICAXE i2cslave command is as follows (see last months article for further explanation): i2cslave %11010000, i2cslow, i2cbyte The DS1307 registers are defined in Table 1. All the 74 Silicon Chip i2cslave %11010000, i2cslow, i2cbyte writei2c 0, ($00, $59, $11, $03, $25, $12, $03, $10) end After this program is downloaded, the green LED (LED1) should flash once every second. Using the DS1307 Reading the time and date from the DS1307 is best shown by example. The program given in Fig.5 acts as an “alarm clock” datalogger, checking the time every 23 seconds. When the time is exactly 07:00, the temperature and light sensors are read and stored in EEPROM. The program runs for 30 days, after which the red LED comes on to show that the mission is complete. Datalogger Wizard Of course, this is a relatively simple example. ProFig.2: the pinouts for the DS1307 real-time clock chip. A 3V lithium cell connected to pin 3 will keep the device functioning even when main circuit power is removed. www.siliconchip.com.au Fig.5: Datalogger Program Fig.3: installing the RTC upgrade on the Datalogger PC board is easy – just plug DS1307 IC into the empty 8-pin IC socket (IC2) and slip the CR2032 lithium cell into its holder. grams that make full use of the datalogger’s resources are considerably more complicated. However, the PICAXE Programming Editor software includes a “Wizard” which will automatically generate the more complex BASIC code for you with just a few mouse clicks! To use the Wizard: (1). Start the Programming Editor software (v3.5.1 or later). (2). Select View -> Options and choose PICAXE-18X mode. Click OK. (3). Select PICAXE -> Wizards -> AXE110 Datalogger -> Start New Datalogger Mission. (4). Chose the desired options and click on the “OK” button. The Datalogger Wizard dialog is shown in Fig.4. Most of the Wizard’s options are self-explanatory and as you can see, two timing options make use of the DS1307 clock upgrade. One sets an accurate timing interval while the other sets an alarm clock style time/date for logging. Once the “OK” button is clicked, the Wizard gener- main: high 5 let b13 = 0 ‘write protect EEPROM ‘reset address counter loop: i2cslave %11010000, i2cslow, i2cbyte sleep 10 readi2c 0, (b0, b1, b2) if b2 <> $07 then loop if b1 <> $00 then loop ‘set DS1307 slave ‘wait 23 sec ‘read sec, min, hour ‘if hour not 07 loop ‘if min not 00 loop high 3 low 5 ‘LED green ‘write enable readadc 0,b3 i2cslave %10100000, i2cfast, i2cbyte writei2c b13,(b3) pause 10 ‘read light value from 0 ‘set block 0 parameters ‘write the value ‘wait EEPROM write time readtemp 7,b4 i2cslave %10100110, i2cfast, i2cbyte writei2c b13,(b4) pause 10 ‘read temp value from 7 ‘set block 4 parameters ‘write the value ‘wait EEPROM write time high 5 low 3 ‘write protect EEPROM ‘LED off pause 60000 ‘wait 1 minute let b13 = b13 + 1 if b13 > 30 then stop goto loop ‘increment address ‘30 days up? ‘no so loop stop: high 2 goto stop ‘LED red ‘loop forever ates a BASIC program to perform a complete mission based on the options you have selected. This is displayed on-screen and can be edited just like any other BASIC program if desired. Note that once a datalogger program is downloaded, the mission starts immediately. It’s not possible to restart a mission by pressing the RESET button. Instead, you must download the program again. Summary The DS1307 is an easy-to-use real-time clock that can be used to add long-term accuracy to your datalogging missions. It is a low-cost versatile addition to your PICAXE datalogger system. The DS1307 real-time clock and CR2032 lithium cell can be purchased together (Part No. AXE034) from www.microzed.com.au. The full datalogger kit is available as Part No. AXE110. Next month: expanding your datalogger’s memory, displaying information on an LCD and adding a humidSC ity sensor. About the Author Fig.4: the Datalogger Wizard does all the hard work for you – just select the options you want and click the OK button to load the code. www.siliconchip.com.au Clive Seager is the Technical Director of Revolution Education Ltd, the developers of the PICAXE system. February 2004 75 by Max Lyons Late last year, an image was posted on the internet which was claimed to be the largest digital“photograph” ever. Here the photographer explains how he did it. And what‘s more, you can download the shareware used to create it! T he photo at right is a view from Bryce Point in Bryce Canyon National Park in Utah. Nice, huh? But we haven’t shown you the photo just because of its scenic beauty. This image is believed to be the largest digital photograph ever. If SILICON CHIP pages were five metres wide, this image could be printed at high resolution! The original contains 40,784 x 26,800 pixels – 1,093,011,200 pixels in total, or a little more than one gigapixel. Now you might think that it would be a rather impressive digital camera to take such a photo – and you’d be half right. In fact, such a camera hasn’t yet been invented. This image actually consists of 196 separate photographs shot with a garden-variety Canon D1, then stitched together into one seamless composite. I have been unable to find any record of a higher resolution photographic (ie non-scientific) digital image that has been created without resizing a smaller, lower resolution image or using an interpolated image. Here’s another way to think about it. Given that the resolving power of the human eye (under ideal conditions at the centre of the retina) is about one arcminute (1/60th of one degree). This image captures considerably more detail than I (or any other normal sighted human) was able to see with my eye when standing on the overlook at Bryce Point. Assuming one pixel per arcminute, an image with dimensions of 3780 x 2485 would suffice to capture the amount of detail that the naked eye could resolve. This image has more than 100 times this detail. Looking at the full sized digital image, one is able to see things that might have been difficult or impossible to spot, even when using binoculars. Below are some crops to simulate the amount of detail that would be captured using cameras of different resolutions (I don’t own any of these higher resolution cameras, so the crops below are simulated. Due to the resizing algorithm used to create these crops, they may over-estimate the amount of detail actually captured by these cameras). How was it created? The first step in the creation of the image was to choose an appropriate subject. There were a number of technical issues that I had to consider that are not normally encountered when taking single images. For example, it took me 13 minutes simply to take all the photographs and I was shooting as fast as my camera could write images to its memory card. So I needed a subject that was relatively static. Secondly, I knew that I would have to use a very long focal length lens to take the image, otherwise the final composite would end up with an extremely wide field of view. . . some- RESOLUTION: What does it mean? Each of these simulations shows the amount of detail captured shooting the same scene at different resolutions. While they are simulations, achieved by resizing the 1GB image) they probably err on the good side (actual results would probably be worse.) 76 Silicon Chip Unresized (1.09GB) 140 megapixel camera. 50 megapixel camera. www.siliconchip.com.au We obviously can’t do the image justice printed on a magazine page. In true life, it would be five metres wide . . . thing I didn’t want. This also presented challenges due to the extremely short depth of field when using very long lenses. The second step was to assemble the images. This was a complex and lengthy process. My normal procedure (using “PTAssembler” [see “About the software”]), Panorama Tools and Photoshop) was not sufficient in this case for a number of reasons because of the size and number of images I was working with. For example, the version of Photoshop that I use cannot work with images with pixel dimensions of more than 30,000. So, my solution was to 22 megapixel camera. www.siliconchip.com.au modify some of the existing programs in my workflow and write a number of new software programs to create this image. Why Bother? Good question. The short answer is “why not?” As digital camera resolutions have increased and the hardware, techniques and software for stitching multiple images into composites have improved, there has been specualtion about when gigapixel images would become possible. This seemed like an interesting challenge to me. (I still think that it will be a long time before true gigapixel 11 megapixel camera. 6 megapixel camera. cameras will become available.) However, this isn’t the only reason. I’ve been producing and printing stitched images consisting of 20-150 megapixels for several years. I’ve become addicted to the amazing detail that is visible in large prints from these images! Gigapixel images present the possibility of producing some of the most amazingly detailed prints at sizes of 10-15 feet wide. A 300ppi print of this image would measure about 3.3m wide, while a 240 ppi print would be close to 5m wide. Even printed at this size, the image would appear very sharp upon close inspection. 3 megapixel camera. February 2004 77 Another advantage to an image this size is the ability to crop very small portions of this image in a number of different ways and still produce extremely high resolution large prints. How do you print It? Another good question. The short answer to this is that there appear to be a number of alternatives, but none that I’ve discovered I’m completely happy with. So, I’m still thinking about it! However, I’m interested in hearing from anyone who would like to partner with me on printing this image. I think it would be an excellent match for (and an excellent demonstration of) large format printing technology. If you have an idea or a proposal, please let me know! About the software With time and patience, anyone can achieve the results seen on these pages. Basically, two programs are used: PTAssembler and Panorama Tools. In fact, you could use just Panorama Tools but PTAssembler will dramatically help you. PTAssembler is a Windows “helper” program for Panorama Tools, Helmut Dersch’s powerful panoramic image stitching software. Despite (perhaps because of) its numerous features and capabilities, Panorama Tools can be challenging to use. It requires a lot of time and effort to create the “scripts” needed by Panorama Tools to stitch multiple images into a larger panorama. PTAssembler is designed to make this task as easy as possible. No knowledge of Panorama Tools or its script syntax is needed in order to operate PTAssembler. I’ve been using Panorama Tools This shows the 196 individual digital photographs before they were stitched together to achieve the single 1 gigapixel photograph shown earlier. It took some thirteen minutes to shoot the series, as fast as the Canon 1D camera would allow. for a few years to create my high resolution images and continue to be impressed by its abilities. However, many people (myself included) find it extremely difficult to learn and use. I decided to write PTAssembler to make it easier to use Panorama Tools. Even with a “helper” program like PTAssembler, Panorama Tools is complicated and requires more input from the user to create a final panorama than many popular “automatic” stitching programs. But the results are worth it. With a little time, perfectly stitched panoramas can be created every time. Overview of panorama creation Stitching images together using Panorama Tools is a little different from most “automatic” stitching programs. For example, the user is required to set “control points” on each image marking features that appear in the overlap region between adjacent images. Unlike automatic programs, Panorama Tools does not know (and will not guess) how images should be aligned without these control points. Another aspect of using Panorama Tools that may seem strange to users who are used to automatic programs is its “optimiser”. The optimiser uses the control points to determine the best positioning for individual images in the final panorama. The optimiser also uses the control points to detect and correct any lens distortions (e.g. Here’s how it works, with (in this case) four overlapping photographs. digitally “stitched” together to produce one composite picture that would defy even the experts to pick! There are several fully automatic programs around which will do this simple task; none could possibly hope to handle a 1GB final image nor do it anywhere near as well! 78 Silicon Chip www.siliconchip.com.au barrel or pincushion) that can cause misalignments between images. PTAssembler allows the user to optimise all parameters necessary to create a panorama without having to write and/or modify scripts. Although Panorama Tools can output a final image in JPEG, TIFF (and other) formats, one of its greatest strengths is its ability to output a “layered” image file that allows the user to perform the final blending between adjacent images manually. Panorama Tools takes care of warping, aligning and positioning the images so that they line up correctly. However, you can choose to perform the final blending (i.e. decide the exact position of the “seam” between images) in your favorite image editor. For a beginners guide to creating a stitched image using PTAssembler, please refer to the on-line PTAssembler Tutorial at www.tawbaware.com/ptasmblr_tutorial.htm Also, complete documentation is included with PTAssembler but is also available on-line. Where from, how much Both Panorama Tools and PTAssembler are shareware; that is, they can be downloaded free of charge but a small registration fee applies. Some features may not work fully without registration. All necessary links for the software along with a large amount of documentation, examples, tutorials and further links (and much more besides!) may be accessed via the author’s website, www.tawbaware.com SC About the author/photographer . . . This is me. . . Max Lyons. So is the guy on my left, and the one on his left, and the... (not forgetting the one peeking in from the edge of the photo!) As you can see, I have a lot of fun “doing things” with digital photography. I’m the author of the software and photographs in this article. This isn’t my “day job” but I do spend a lot of time at it! I became interested in progamming and digital photography around 1996, after buying a “Teach yourself Visual Basic” book and a fantastically over-priced digital camera. The programs on my website (see below) are the product of a few years of work and far too many late nights... I have some other stuff on the web. There is the digital camera software (www.tawbaware.com), and some of my better photographs (www.tawbaware.com/maxlyons/ index.html). If you are moved to do so, you can email me at maxlyons<at>tawbaware.com. I promise I will read them all but as you might imagine, I get a lot of them so I can’t guarantee I will answer every one! www.siliconchip.com.au February 2004 79 VINTAGE RADIO By RODNEY CHAMPNESS, VK3UG The HMV 660 console of 1940 Housed in a stylish cabinet and boasting performance to match, the HMV 660 was undoubtedly one of the better console receivers from the early 1940s. It is a 5-valve dual-wave receiver that’s well-made and easy to service. These days, our homes are crowded with electronics equipment, including VCRs, DVD players, large-screen colour TV sets, audio and home-theatre equipment and of course, transistor radios. However, in the early days of electronics, the average home of the 1930s was lucky to have just one radio receiver. At the start of the 1930s, this would probably have been a TRF receiver of mediocre performance coupled to a large outside antenna and earth system. Later, when superheterodyne receivers became established, large mantel and table sets became more common, while the more affluent lashed out and purchased a console receiver costing many “guineas”. What’s a “guinea”? The large, easy-to-read dial was an impressive feature of the HMV 660 console. 80 Silicon Chip For those born after the abolition of pounds, shillings and pence, a guinea was equal to one pound and one shilling (a pound was equal to two dollars when decimal conversion was introduced at the start of 1966). So why was the term “guineas” used? Well, it always sounded so much more upmarket (or “toffy”) than pounds and shillings and it also had the advantage, at least from a salesman’s point of view, of making the price sound less that it really was. Racehorses were always sold in guineas, for example, so why not upmarket radio receivers? The console receiver held pride of place in the lounge room right through the 1940s but waned in popularity in the 1950s when radiograms took over. In turn, radiograms were relegated to second place when TV was introduced. During the heyday of the console receiver, many fine examples were manufactured. Recently, I was given the opportunity to closely examine a www.siliconchip.com.au “His Master’s Voice” logo is still on the top of the cabinet. This particular cabinet is in very good condition and has not been stripped back. However, a few marks are visible and they will be polished out in due course. In fact, Laurie prefers to keep the cabinets looking as original as possible and a few minor blemishes are allowed to remain. This brings us back to the old argument as to whether a receiver should be restored to “as new” condition or simply made look to respectable and restored to good working order, while keeping it as original as possible. Much depends on the sets themselves, some of which may be 70 years or more old. And, of course, individual restorers will have their own ideas. A glance inside the back of the cabinet reveals the battleship-grey chassis and chassis-mounted components that were typical of HMV sets. Everything looks solid and neatly laid out. The loudspeaker is a 12-inch (305mm) HMV electrodynamic unit attached to the substantial baffle board in the lower section of the cabinet. Guarantees and instructions This view inside the cabinet shows the quality of the construction. The envelope to the left of the chassis contained the original instructions and the guarantee. An interesting aspect of this old HMV 660 is that the installation and operating information, along with the guarantee card, were still with the set when Laurie obtained it. This is very HMV 660 owned by one of my friends, Laurie Tilley. Cabinet style The HMV 660 was one of the better quality units available on the Australian market around the start of the World War II. It is an extremely solid (heavy) unit made from high-quality plywood and has an attractive veneer on the outside surfaces. The half-round dial-scale on these receivers always impressed me, perhaps because I liked seeing my grandfather’s HMV 660 set. I used to be fascinated by the colourful lighting of the dial which, to an 11 year old boy, was very impressive. This model is claimed by some to be the best console made by HMV and probably one of the best of any makes for that matter. The cabinet has a walnut finish with figured walnut inlays on the front and is a well-made, quality item. The original HMV decal with the familiar www.siliconchip.com.au This view shows the partially-restored chassis. The power cord (far right) had badly perished and was still awaiting replacement when this photo was taken. February 2004 81 unusual, as most of these “extraneous” bits and pieces never survived more than a few years. Today, these items and the packing cartons are often considered to be more valuable than the sets themselves. The accompanying photographs give will you some idea of the contents of these documents, which make fascinating reading. If you are fortunate enough to obtain a receiver with any (or all) of the literature and accessories, be sure to keep them, as they too are part of our radio heritage. Fig.1: the HMV 660 is a fairly conventional 5-valve superhet receiver. Note that this set has three IF transformers – two before the 6U7G IF amplifier valve and one after it. Dismantling the set 82 Silicon Chip Dismantling the set is a straightforward task. First, the four knobs are removed and all except the tuning knob have screws which go through a slit in the control shaft. HMV appeared to be the only manufacturer that did this at the time. It has the advantage of placing minimal pressure on the bakelite knobs while still retaining good rotational ability. In fact, I haven’t seen a single broken knob where this technique has been used. Once the knobs are off, the celluloid strip labelled with the control functions, is removed from the shafts, along with the felt shaft washers. The two long (6mm diameter) bolts that attach the chassis to the chassis shelf are then removed, after which the speaker lead can be unplugged and the chassis slid out from the back of the cabinet. Once it’s out, the chassis can sit on one end quite comfortably for servicing or you can use a servicing jig such as the one described in the October 2000 issue of SILICON CHIP. Laurie has not found it necessary to replace many components at this stage, apart from the electrolytic capacitors and the power cord. If you want to keep old sets looking original, by the way, 3-core (brown) fabric-covered power lead is available from Direct Components, PO Box 437, Welshpool, 6986 (phone 08 9479 4850); and from Elizabeth Trading, 15 Station St (PO Box 374), East Kew, 3102 (phone 03 9859 8799). In addition, one bypass capacitor earth lead has come adrift from its mounting lug but everything else was in quite reasonable condition. The remaining components will be checked further at a later date, with emphasis on the critical audio coupler and AGC bypass capacitors. The speaker cloth was replaced with a plain brown cloth www.siliconchip.com.au and although it doesn’t have the same pattern as the original, it doesn’t look out of place. The dial system still works well, with no slipping. As mentioned earlier, this is an impressive set to look at from the front and equally impressive in its build quality when viewed from the rear. Circuit details HMV receivers of this era have always impressed me with their attention to circuit detail. The HMV 660 is a 5-valve set with a 6J8G converter. This is followed by a 6U7G IF amplifier on 457.5kHz, a 6B8G as a combined diode detector, AGC diode and pentode audio amplifier, and then a 6V6G as the audio output stage. The power supply uses a 5Y3G as the rectifier. Let’s first take a look at the front end. This radio is a dual-wave unit, covering 550-1600kHz on the broadcast band and approximately 6.4-21.6MHz on the shortwave band. Due to the smooth dial-drive system, shortwave stations are fairly easy to tune in. The dial-scale is illuminated by four lamps but only two at a time are used, depending on whether the broadcast or shortwave band is selected. As a result, only the appropriate section of the dial scale is illuminated. The connections to the antenna system are rather unusual. As shown on the circuit diagram (Fig.1), the “earthy” end of the antenna coil goes to an unearthed antenna terminal (A1). This manual was also inside the large envelope. It describes how to install and operate the receiver and covers both the 660 and 550 models. www.siliconchip.com.au The HMV 660’s original guarantee form and registration card were inside the large envelope that was adjacent to the chassis. It’s rather unusual for this type of printed material to survive intact, This is normally bridged to the earth terminal, so why have this terminal at all if it is earthed out anyway? The answer is that for normal operation, the additional terminal is superfluous. However, on shortwave, the performance can be considerably enhanced if the A and A1 terminals are connected to a balanced 75-ohm transmission line which terminates on a horizontal dipole antenna. Note that, for best performance, the dipoles need to be cut to suit the particular bands of interest. Apart from the unusual antenna input circuit, the antenna coils are quite standard for the time. The primary windings of both antenna coils are in series with each other, which saves one switch position. L5 has so little inductance that it doesn’t affect the operation of L1 and, in fact, acts as a small loading coil to slightly improve broadcast band performance. Conversely, L1 looks like a large RF choke in series with L5 when the set is tuned to shortwave. However, this has no effect as the shortwave signals are passed through capacitor C1 with very little attenuation. L1 and C1 together form a resonant circuit which resonates at a frequency just below the broadcast band. This increases the performance at the lowfrequency end of the dial and the loop at the top of L1 improves the coupling at the high-frequency end. The IF (intermediate frequency) amplifier stage is more elaborate that in most sets of the era. As shown on Fig.1, there are two IF transformers at the input of the IF amplifier and one after it. The type of coupling used is called “shunt capacitance coupling” or “bottom coupling”. The two transformers at the amplifier input are designed to give a response KALEX • High Speed PCB Drills • PCB Guillotine Laser Labels • PCB Material – Negative or Positive Acting • Light Boxes – Single or Double Sided; Large or Small • Etching Tanks – Bubble • Electronic Components and Equipment for TAFEs, Colleges and Schools • Prompt Delivery We now stock Hawera Carbide Tool Bits 718 High Street Rd, Glen Waverley 3150 Ph (03) 9802 0788 FAX (03) 9802 0700 Website: www.users.bigpond.net.au/kalex Email: kalexpcb<at>bigpond.net.au ALL MAJOR CREDIT CARDS ACCEPTED February 2004 83 This under-chassis view shows the open layout around the wave-change switch and the coils. Other sections of the receiver follow in a logical circuit progression from the top righthand corner, down the side and along the bottom, with the power supply down the lefthand side. The chassis was designed for more than one model, judging by the plates used to cover several spare holes. curve that has a slight dip in the centre at 457.5kHz and a reasonably sharp cut-off outside the pass-band. Taken together, the IF transformers give a substantially flat response right across the pass-band. This added complexity results in an audio frequency range out to 8-9kHz, as compared to around 4-5kHz in most other sets. So the HMV 660 was indeed a quality receiver! A comment in Vol.4 of the “Australian Official Radio Service Manual” (AORSM) stated that one of the tone control positions was designed to boost the high-frequency audio output to make up for the sloping response of the IF amplifier. So it appears that HMV made every effort to produce high-fidelity audio output from their receiver. And although we may not consider 8-9kHz as hifi today, it certainly was back in 1940! 84 Silicon Chip The circuitry following the 6U7G IF amplifier is conventional, with the 6B8G providing delayed AGC and diode detection. AGC is applied to the 6J8G converter stage and the 6U7G IF amplifier, while around half this amount is applied to the audio amplifier. This is designed to ensure that the set produces an audio output that’s at the same volume for both strong and weak stations. An undesirable byproduct of AGC can be a high level of noise when tuning between stations. This could have been overcome by using extra circuitry to partially mute the receiver between stations. However, because this increases the complexity and therefore the cost, it was rarely done. The audio amplifier The detected audio output is applied to a tapping on the secondary of the final IF transformer (IFT3). From there, it is then fed through an IF filter network (C21, R11 & C23) and a volume control to the grid of the 6G8G first audio amplifier stage. The resulting signal is then applied to the 6V6G, which in turn drives the 12-inch 2-ohm loudspeaker via output transformer T1. Note the resistive divider consisting of R22 and R23 across the secondary of the speaker transformer. This applies a feedback signal via the switched tone control network to a tap on the volume control. This was a very effective method of tone control and provided good quality sound with minimal distortion (for those times). The chassis is also wired so that a record player pick-up can be connected to the audio output stages, just ahead of the volume control (ie, at P.U.). In practice, the pick-up leads were plugged into two banana type sockets on the rear apron of the chassis. Note that the earth socket is split so that when the plug is inserted, the junction of R11 and C21 is earthed, www.siliconchip.com.au thereby shorting out the audio from the receiver’s detector stage. This was a neat system that obviated the use of an additional switch section to switch off the HT voltage to the converter and IF stages. However, it didn’t remove the AGC voltage from the 6G8G, so variations in volume could be expected if the set was tuned to a station that was fading and causing the AGC voltage on the 6G8G to change. In practice, this really wasn’t much of a problem as most people listened to local broadcast band stations where fading didn’t occur. The pick-up inputs were probably a selling point but you have to wonder how many people actually took advantage of them by connecting a turntable. Probably very few! The power supply The power supply is quite conventional, the only minor variation being that the field coil (filter choke) in the electrodynamic speaker is placed in the negative lead. This meant that the coil winding and the earthed frame had very little voltage between them, ensuring very little insulation stress. The back bias and delayed AGC voltage is obtained by tapping off part of the voltage developed across the field coil via a voltage divider network. Under the chassis The view under the chassis shows a neatly laid out set using small groups of components which are mostly soldered onto insulated mounting boards. Access is quite good and restoration is not a problem. It really is a pleasure to work on such a well laid out set. Alignment Unfortunately, the AORSM does not give any information on aligning this receiver. However, the procedure for aligning the signal input and oscillator circuits will be quite conventional, as described in the article in the February 2003 issue of SILICON CHIP. The alignment of the IF amplifier stage may require a different technique to that commonly used. I have not had an opportunity to align this set and Laurie hasn’t found it necessary to do so either, as the set is already performing quite well. Should alignment be required, the secondary of IFT1 should be loaded with a 10kΩ resistor when its primary and IFT2 are being adjusted. Similarly, www.siliconchip.com.au The HMV 660’s manual is well written and contains detailed notes on both the installation and operation of the receiver. It even explains the procedure for connecting an external loudspeaker. remove the 10kΩ load and place it across IFT2 when adjusting the secondary of IFT1. By using this method, you should have a good chance of successfully obtaining the correct IF transformer response shape. IFT3 can be aligned in the usual manner, as discussed in the articles in the December 2002 and January 2003 issues. Summary In summary, the HMV 660 is an impressive 5-valve dual-wave receiver with better than average performance. To match this performance, it is in- stalled in a solid, well-made console cabinet. Despite its age, Laurie found that it required very little work on the circuitry to restore it to good working order. The dial is particularly impressive, both in terms of looks and performance. It’s a well-made unit with little sign of wear in the mechanism, despite its age. Finally, this is an easy set to service, particularly when compared to many other sets. The only thing you have to watch out for is the method of aligning the IF transformers, to get the correct SC pass-band response. February 2004 85 Silicon Chip Back Issues August 1994: High-Power Dimmer For Incandescent Lights; Dual Diversity Tuner For FM Microphones, Pt.1; Nicad Zapper (For Resurrecting Nicad Batteries); Electronic Engine Management, Pt.11. September 1994: Automatic Discharger For Nicad Batteries; MiniVox Voice Operated Relay; AM Radio For Weather Beacons; Dual Diversity Tuner For FM Mics, Pt.2; Electronic Engine Management, Pt.12. April 1989: Auxiliary Brake Light Flasher; What You Need to Know About Capacitors; 32-Band Graphic Equaliser, Pt.2. December 1991: TV Transmitter For VCRs With UHF Modulators; IR Light Beam Relay; Colour TV Pattern Generator, Pt.2; Index To Vol.4. May 1989: Build A Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference. March 1992: TV Transmitter For VHF VCRs; Thermostatic Switch For Car Radiator Fans; Valve Substitution In Vintage Radios. July 1989: Exhaust Gas Monitor; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; The NSW 86 Class Electrics. April 1992: IR Remote Control For Model Railroads; Differential Input Buffer For CROs; Understanding Computer Memory; Aligning Vintage Radio Receivers, Pt.1. September 1989: 2-Chip Portable AM Stereo Radio Pt.1; High Or Low Fluid Level Detector; Studio Series 20-Band Stereo Equaliser, Pt.2. October 1989: FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 2-Chip Portable AM Stereo Radio, Pt.2. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disk Drive Formats & Options. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; IR Remote Control For Model Railroads, Pt.3; 15-Watt 12-240V Inverter; A Look At Hard Disk Drives. October 1992: 2kW 24VDC - 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm, Pt.2; Mini Amplifier For Personal Stereos; A Regulated Lead-Acid Battery Charger. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Active Antenna Kit; Designing UHF Transmitter Stages. February 1993: Three Projects For Model Railroads; Low Fuel Indicator For Cars; Audio Level/VU Meter (LED Readout); An Electronic Cockroach; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5. February 1990: A 16-Channel Mixing Desk; Build A High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2. March 1993: Solar Charger For 12V Batteries; Alarm-Triggered Security Camera; Reaction Trainer; Audio Mixer for Camcorders; A 24-Hour Sidereal Clock For Astronomers. March 1990: Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16-Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. April 1993: Solar-Powered Electric Fence; Audio Power Meter; ThreeFunction Home Weather Station; 12VDC To 70VDC Converter; Digital Clock With Battery Back-Up. April 1990: Dual Tracking ±50V Power Supply; Voice-Operated Switch With Delayed Audio; 16-Channel Mixing Desk, Pt.3; Active CW Filter. June 1993: AM Radio Trainer, Pt.1; Remote Control For The Woofer Stopper; Digital Voltmeter For Cars. June 1990: Multi-Sector Home Burglar Alarm; Build A Low-Noise Universal Stereo Preamplifier; Load Protector For Power Supplies. July 1993: Single Chip Message Recorder; Light Beam Relay Extender; AM Radio Trainer, Pt.2; Quiz Game Adjudicator; Antenna Tuners – Why They Are Useful. July 1990: Digital Sine/Square Generator, Pt.1 (0-500kHz); Burglar Alarm Keypad & Combination Lock; Build A Simple Electronic Die; A Low-Cost Dual Power Supply. October 1994: How Dolby Surround Sound Works; Dual Rail Variable Power Supply; Talking Headlight Reminder; Electronic Ballast For Fluorescent Lights; Electronic Engine Management, Pt.13. November 1994: Dry Cell Battery Rejuvenator; Novel Alphanumeric Clock; 80-M DSB Amateur Transmitter; 2-Cell Nicad Discharger. December 1994: Car Burglar Alarm; Three-Spot Low Distortion Sinewave Oscillator; Clifford – A Pesky Electronic Cricket; Remote Control System for Models, Pt.1; Index to Vol.7. January 1995: Sun Tracker For Solar Panels; Battery Saver For Torches; Dual Channel UHF Remote Control; Stereo Microphone Preamplifier. February 1995: 2 x 50W Stereo Amplifier Module; Digital Effects Unit For Musicians; 6-Channel Thermometer With LCD Readout; Wide Range Electrostatic Loudspeakers, Pt.1; Oil Change Timer For Cars; Remote Control System For Models, Pt.2. March 1995: 2 x 50W Stereo Amplifier, Pt.1; Subcarrier Decoder For FM Receivers; Wide Range Electrostatic Loudspeakers, Pt.2; IR Illuminator For CCD Cameras; Remote Control System For Models, Pt.3. April 1995: FM Radio Trainer, Pt.1; Balanced Mic Preamp & Line Filter; 50W/Channel Stereo Amplifier, Pt.2; Wide Range Electrostatic Loudspeakers, Pt.3; 8-Channel Decoder For Radio Remote Control. May 1995: Guitar Headphone Amplifier; FM Radio Trainer, Pt.2; Transistor/Mosfet Tester For DMMs; A 16-Channel Decoder For Radio Remote Control; Introduction to Satellite TV. June 1995: Build A Satellite TV Receiver; Train Detector For Model Railways; 1W Audio Amplifier Trainer; Low-Cost Video Security System; Multi-Channel Radio Control Transmitter For Models, Pt.1. August 1993: Low-Cost Colour Video Fader; 60-LED Brake Light Array; Microprocessor-Based Sidereal Clock; Satellites & Their Orbits. July 1995: Electric Fence Controller; How To Run Two Trains On A Single Track (Incl. Lights & Sound); Setting Up A Satellite TV Ground Station; Build A Reliable Door Minder. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Generator, Pt.2. September 1993: Automatic Nicad Battery Charger/Discharger; Stereo Preamplifier With IR Remote Control, Pt.1; In-Circuit Transistor Tester; +5V to ±15V DC Converter; Remote-Controlled Cockroach. August 1995: Fuel Injector Monitor For Cars; Gain Controlled Microphone Preamp; Audio Lab PC-Controlled Test Instrument, Pt.1; How To Identify IDE Hard Disk Drive Parameters. September 1990: 3-Digit Counter Module; Build A Simple Shortwave Converter For The 2-Metre Band; Taking Care Of Nicad Battery Packs. October 1993: Courtesy Light Switch-Off Timer For Cars; Wireless Microphone For Musicians; Stereo Preamplifier With IR Remote Control, Pt.2; Electronic Engine Management, Pt.1. September 1995: Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.1; Keypad Combination Lock; The Vader Voice; Jacob’s Ladder Display; Audio Lab PC-Controlled Test Instrument, Pt.2. October 1990: The Dangers of PCBs; Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; NE602 Converter Circuits. November 1993: High Efficiency Inverter For Fluorescent Tubes; Stereo Preamplifier With IR Remote Control, Pt.3; Siren Sound Generator; Engine Management, Pt.2; Experiments For Games Cards. October 1995: 3-Way Loudspeaker System; Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.2; Fast Charger For Nicad Batteries. November 1990: Connecting Two TV Sets To One VCR; Build An Egg Timer; Low-Cost Model Train Controller; 1.5V To 9V DC Converter; Introduction To Digital Electronics; A 6-Metre Amateur Transmitter. December 1993: Remote Controller For Garage Doors; LED Stroboscope; 25W Audio Amplifier Module; A 1-Chip Melody Generator; Engine Management, Pt.3; Index To Volume 6. November 1995: Mixture Display For Fuel Injected Cars; CB Transverter For The 80M Amateur Band, Pt.1; PIR Movement Detector. January 1991: Fast Charger For Nicad Batteries, Pt.1; Have Fun With The Fruit Machine (Simple Poker Machine); Two-Tone Alarm Module; The Dangers of Servicing Microwave Ovens. January 1994: 3A 40V Variable Power Supply; Solar Panel Switching Regulator; Printer Status Indicator; Mini Drill Speed Controller; Stepper Motor Controller; Active Filter Design; Engine Management, Pt.4. March 1991: Transistor Beta Tester Mk.2; A Synthesised AM Stereo Tuner, Pt.2; Multi-Purpose I/O Board For PC-Compatibles; Wideband RF Preamplifier For Amateur Radio & TV. February 1994:90-Second Message Recorder; 12-240VAC 200W Inverter; 0.5W Audio Amplifier; 3A 40V Adjustable Power Supply; Engine Management, Pt.5; Airbags In Cars – How They Work. May 1991: 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1. March 1994: Intelligent IR Remote Controller; 50W (LM3876) Audio Amplifier Module; Level Crossing Detector For Model Railways; Voice Activated Switch For FM Microphones; Engine Management, Pt.6. July 1991: Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2; Tuning In To Satellite TV, Pt.2. April 1994: Sound & Lights For Model Railway Level Crossings; Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. September 1991: Digital Altimeter For Gliders & Ultralights; Ultrasonic Switch For Mains Appliances; The Basics Of A/D & D/A Conversion; Plotting The Course Of Thunderstorms. May 1994: Fast Charger For Nicad Batteries; Induction Balance Metal Locator; Multi-Channel Infrared Remote Control; Dual Electronic Dice; Simple Servo Driver Circuits; Engine Management, Pt.8. July 1996: VGA Digital Oscilloscope, Pt.1; Remote Control Extender For VCRs; 2A SLA Battery Charger; 3-Band Parametric Equaliser; Single Channel 8-Bit Data Logger. October 1991: A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator For Model Railways Mk.II; Magnetic Field Strength Meter; Digital Altimeter For Gliders, Pt.2; Military Applications Of R/C Aircraft. June 1994: A Coolant Level Alarm For Your Car; 80-Metre AM/CW Transmitter For Amateurs; Converting Phono Inputs To Line Inputs; PC-Based Nicad Battery Monitor; Engine Management, Pt.9. August 1996: Introduction to IGBTs; Electronic Starter For Fluorescent Lamps; VGA Oscilloscope, Pt.2; 350W Amplifier Module; Masthead Amplifier For TV & FM; Cathode Ray Oscilloscopes, Pt.4. November 1991: Build A Colour TV Pattern Generator, Pt.1; A Junkbox 2-Valve Receiver; Flashing Alarm Light For Cars; Digital Altimeter For Gliders, Pt.3; A Talking Voltmeter For Your PC, Pt.2. July 1994: Build A 4-Bay Bow-Tie UHF TV Antenna; PreChamp 2-Transistor Preamplifier; Steam Train Whistle & Diesel Horn Simulator; 6V SLA Battery Charger; Electronic Engine Management, Pt.10. September 1996: VGA Oscilloscope, Pt.3; IR Stereo Headphone Link, Pt.1; High Quality PA Loudspeaker; 3-Band HF Amateur Radio Receiver; Cathode Ray Oscilloscopes, Pt.5. ORDER FORM December 1995: Engine Immobiliser; 5-Band Equaliser; CB Transverter For The 80M Amateur Band, Pt.2; Subwoofer Controller; Knock Sensing In Cars; Index To Volume 8. January 1996: Surround Sound Mixer & Decoder, Pt.1; Magnetic Card Reader; Automatic Sprinkler Controller; IR Remote Control For The Railpower Mk.2; Recharging Nicad Batteries For Long Life. April 1996: 125W Audio Amplifier Module; Knock Indicator For Leaded Petrol Engines; Multi-Channel Radio Control Transmitter; Pt.3. May 1996: High Voltage Insulation Tester; Knightrider LED Chaser; Simple Intercom Uses Optical Cable; Cathode Ray Oscilloscopes, Pt.3. June 1996: Stereo Simulator (uses delay chip); Rope Light Chaser; Low Ohms Tester For Your DMM; Automatic 10A Battery Charger. Please send the following back issues:________________________________________ Enclosed is my cheque/money order for $______or please debit my:  Bankcard  Visa Card  Master Card Card No. Signature ___________________________ Card expiry date_____ /______ Name ______________________________ Phone No (___) ____________ PLEASE PRINT Street ______________________________________________________ Suburb/town _______________________________ Postcode ___________ 86 Silicon Chip 10% OF SUBSCR F TO IB OR IF Y ERS OU 10 OR M BUY ORE Note: prices include postage & packing Australia ............................... $A8.80 (incl. GST) Overseas (airmail) ..................................... $A10 Detach and mail to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Or call (02) 9979 5644 & quote your credit card details or fax the details to (02) 9979 6503. Email: silchip<at>siliconchip.com.au www.siliconchip.com.au October 1996: Send Video Signals Over Twisted Pair Cable; 600W DC-DC Converter For Car Hifi Systems, Pt.1; IR Stereo Headphone Link, Pt.2; Multi-Channel Radio Control Transmitter, Pt.8. June 1999: FM Radio Tuner Card For PCs; X-Y Table With Stepper Motor Control, Pt.2; Programmable Ignition Timing Module For Cars, Pt.1; Hard Disk Drive Upgrades Without Reinstalling Software? November 1996: 8-Channel Stereo Mixer, Pt.1; Low-Cost Fluorescent Light Inverter; Repairing Domestic Light Dimmers; 600W DC-DC Converter For Car Hifi Systems, Pt.2. July 1999: Build A Dog Silencer; 10µH to 19.99mH Inductance Meter; Audio-Video Transmitter; Programmable Ignition Timing Module For Cars, Pt.2; XYZ Table With Stepper Motor Control, Pt.3. December 1996: Active Filter For CW Reception; Fast Clock For Railway Modellers; Laser Pistol & Electronic Target; Build A Sound Level Meter; 8-Channel Stereo Mixer, Pt.2; Index To Vol.9. August 1999: Remote Modem Controller; Daytime Running Lights For Cars; Build A PC Monitor Checker; Switching Temperature Controller; XYZ Table With Stepper Motor Control, Pt.4; Electric Lighting, Pt.14. January 1997: How To Network Your PC; Control Panel For Multiple Smoke Alarms, Pt.1; Build A Pink Noise Source; Computer Controlled Dual Power Supply, Pt.1; Digi-Temp Monitors Eight Temperatures. September 1999: Autonomouse The Robot, Pt.1; Voice Direct Speech Recognition Module; Digital Electrolytic Capacitance Meter; XYZ Table With Stepper Motor Control, Pt.5; Peltier-Powered Can Cooler. February 1997: PC-Controlled Moving Message Display; Computer Controlled Dual Power Supply, Pt.2; Alert-A-Phone Loud Sounding Telephone Alarm; Control Panel For Multiple Smoke Alarms, Pt.2. October 1999: Build The Railpower Model Train Controller, Pt.1; Semiconductor Curve Tracer; Autonomouse The Robot, Pt.2; XYZ Table With Stepper Motor Control, Pt.6; Introducing Home Theatre. March 1997: Driving A Computer By Remote Control; Plastic Power PA Amplifier (175W); Signalling & Lighting For Model Railways; Build A Jumbo LED Clock; Cathode Ray Oscilloscopes, Pt.7. November 1999: Setting Up An Email Server; Speed Alarm For Cars, Pt.1; LED Christmas Tree; Intercom Station Expander; Foldback Loudspeaker System; Railpower Model Train Controller, Pt.2. April 1997: Simple Timer With No ICs; Digital Voltmeter For Cars; Loudspeaker Protector For Stereo Amplifiers; Model Train Controller; A Look At Signal Tracing; Pt.1; Cathode Ray Oscilloscopes, Pt.8. December 1999: Solar Panel Regulator; PC Powerhouse (gives +12V, +9V, +6V & +5V rails); Fortune Finder Metal Locator; Speed Alarm For Cars, Pt.2; Railpower Model Train Controller, Pt.3; Index To Vol.12. May 1997: Neon Tube Modulator For Light Systems; Traffic Lights For A Model Intersection; The Spacewriter – It Writes Messages In Thin Air; A Look At Signal Tracing; Pt.2; Cathode Ray Oscilloscopes, Pt.9. January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Picman Programmable Robot; Parallel Port Interface Card; Off-Hook Indicator For Telephones. June 1997: PC-Controlled Thermometer/Thermostat; TV Pattern Generator, Pt.1; Audio/RF Signal Tracer; High-Current Speed Controller For 12V/24V Motors; Manual Control Circuit For Stepper Motors. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; An Ultrasonic Parking Radar; Safety Switch Checker; Sine/Square Wave Oscillator. July 1997: Infrared Remote Volume Control; A Flexible Interface Card For PCs; Points Controller For Model Railways; Colour TV Pattern Generator, Pt.2; An In-Line Mixer For Radio Control Receivers. March 2000: Resurrecting An Old Computer; Low Distortion 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Glowplug Driver For Powered Models; The OzTrip Car Computer, Pt.1. August 1997: The Bass Barrel Subwoofer; 500 Watt Audio Power Amplifier Module; A TENs Unit For Pain Relief; Addressable PC Card For Stepper Motor Control; Remote Controlled Gates For Your Home. May 2000: Ultra-LD Stereo Amplifier, Pt.2; LED Dice (With PIC Microcontroller); Low-Cost AT Keyboard Translator (Converts IBM Scan-Codes To ASCII); 50A Motor Speed Controller For Models. October 1997: 5-Digit Tachometer; Central Locking For Your Car; PCControlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3; Customising The Windows 95 Start Menu. June 2000: Automatic Rain Gauge; Parallel Port VHF FM Receiver; Switchmode Power Supply (1.23V to 40V) Pt.1; CD Compressor. November 1997: Heavy Duty 10A 240VAC Motor Speed Controller; Easy-To-Use Cable & Wiring Tester; Build A Musical Doorbell; Replacing Foam Speaker Surrounds; Understanding Electric Lighting Pt.1. December 1997: Speed Alarm For Cars; 2-Axis Robot With Gripper; Stepper Motor Driver With Onboard Buffer; Power Supply For Stepper Motor Cards; Understanding Electric Lighting Pt.2; Index To Vol.10. January 1998: Build Your Own 4-Channel Lightshow, Pt.1 (runs off 12VDC or 12VAC); Command Control System For Model Railways, Pt.1; Pan Controller For CCD Cameras. July 2000: Moving Message Display; Compact Fluorescent Lamp Driver; Musicians’ Lead Tester; Switchmode Power Supply, Pt.2. August 2000: Theremin; Spinner (writes messages in “thin-air”); Proximity Switch; Structured Cabling For Computer Networks. September 2000: Swimming Pool Alarm; 8-Channel PC Relay Board; Fuel Mixture Display For Cars, Pt.1; Protoboards – The Easy Way Into Electronics, Pt.1; Cybug The Solar Fly. October 2000: Guitar Jammer; Breath Tester; Wand-Mounted Inspection Camera; Subwoofer For Cars; Fuel Mixture Display, Pt.2. February 2002: 10-Channel IR Remote Control Receiver; 2.4GHz HighPower Audio-Video Link; Assemble Your Own 2-Way Tower Speakers; Touch And/Or Remote-Controlled Light Dimmer, Pt.2; Booting A PC Without A Keyboard; 4-Way Event Timer. March 2002: Mighty Midget Audio Amplifier Module; The Itsy-Bitsy USB Lamp; 6-Channel IR Remote Volume Control, Pt.1; RIAA Pre-Amplifier For Magnetic Cartridges; 12/24V Intelligent Solar Power Battery Charger; Generate Audio Tones Using Your PC’s Soundcard. April 2002:Automatic Single-Channel Light Dimmer; Pt.1; Water Level Indicator; Multiple-Output Bench Power Supply; Versatile Multi-Mode Timer; 6-Channel IR Remote Volume Control, Pt.2. May 2002: 32-LED Knightrider; The Battery Guardian (Cuts Power When the Battery Voltage Drops); Stereo Headphone Amplifier; Automatic Single-Channel Light Dimmer; Pt.2; Stepper Motor Controller. June 2002: Lock Out The Bad Guys with A Firewall; Remote Volume Control For Stereo Amplifiers; The “Matchless” Metal Locator; Compact 0-80A Automotive Ammeter; Constant High-Current Source. July 2002: Telephone Headset Adaptor; Rolling Code 4-Channel UHF Remote Control; Remote Volume Control For The Ultra-LD Stereo Amplifier; Direct Conversion Receiver For Radio Amateurs, Pt.1. August 2002: Digital Instrumentation Software For Your PC; Digital Storage Logic Probe; Digital Thermometer/Thermostat; Sound Card Interface For PC Test Instruments; Direct Conversion Receiver For Radio Amateurs, Pt.2; Spruce Up Your PC With XP-Style Icons. September 2002: 12V Fluorescent Lamp Inverter; 8-Channel Infrared Remote Control; 50-Watt DC Electronic Load; Driving Light & Accessory Protector For Cars; Spyware – An Update. October 2002: Speed Controller For Universal Motors; PC Parallel Port Wizard; Cable Tracer; AVR ISP Serial Programmer; 3D TV. November 2002: SuperCharger For NiCd/NiMH Batteries, Pt.1; Windows-Based EPROM Programmer, Pt.1; 4-Digit Crystal-Controlled Timing Module; Using Linux To Share An Optus Cable Modem, Pt.1. December 2002: Receiving TV From Satellites; Pt.1; The Micromitter Stereo FM Transmitter; Windows-Based EPROM Programmer, Pt.2; SuperCharger For NiCd/NiMH Batteries; Pt.2; Simple VHF FM/AM Radio; Using Linux To Share An Optus Cable Modem, Pt.2. January 2003: Receiving TV From Satellites, Pt 2; SC480 50W RMS Amplifier Module, Pt.1; Gear Indicator For Cars; Active 3-Way Crossover For Speakers; Using Linux To Share An Optus Cable Modem, Pt.3. February 2003: PortaPal Public Address System, Pt.1; 240V Mains Filter For HiFi Systems; SC480 50W RMS Amplifier Module, Pt.2; Windows-Based EPROM Programmer, Pt.3; Using Linux To Share An Optus Cable Modem, Pt.4; Fun With The PICAXE, Pt.1. March 2003: LED Lighting For Your Car; Peltier-Effect Tinnie Cooler; PortaPal Public Address System, Pt.2; 12V SLA Battery Float Charger; Little Dynamite Subwoofer; Fun With The PICAXE, Pt.2 (Shop Door Minder); SuperCharger Addendum; Emergency Beacons. February 1998: Multi-Purpose Fast Battery Charger, Pt.1; Telephone Exchange Simulator For Testing; Command Control System For Model Railways, Pt.2; Build Your Own 4-Channel Lightshow, Pt.2. November 2000: Santa & Rudolf Chrissie Display; 2-Channel Guitar Preamplifier, Pt.1; Message Bank & Missed Call Alert; Protoboards – The Easy Way Into Electronics, Pt.3. April 1998: Automatic Garage Door Opener, Pt.1; 40V 8A Adjustable Power Supply, Pt.1; PC-Controlled 0-30kHz Sinewave Generator; Build A Laser Light Show; Understanding Electric Lighting; Pt.6. December 2000: Home Networking For Shared Internet Access; White LED Torch; 2-Channel Guitar Preamplifier, Pt.2 (Digital Reverb); Driving An LCD From The Parallel Port; Index To Vol.13. May 1998: Troubleshooting Your PC, Pt.1; 3-LED Logic Probe; Automatic Garage Door Opener, Pt.2; Command Control For Model Railways, Pt.4; 40V 8A Adjustable Power Supply, Pt.2. January 2001: How To Transfer LPs & Tapes To CD; The LP Doctor – Clean Up Clicks & Pops, Pt.1; Arbitrary Waveform Generator; 2-Channel Guitar Preamplifier, Pt.3; PIC Programmer & TestBed. June 1998: Troubleshooting Your PC, Pt.2; Universal High Energy Ignition System; The Roadies’ Friend Cable Tester; Universal Stepper Motor Controller; Command Control For Model Railways, Pt.5. February 2001: An Easy Way To Make PC Boards; L’il Pulser Train Controller; A MIDI Interface For PCs; Build The Bass Blazer; 2-Metre Groundplane Antenna; The LP Doctor – Clean Up Clicks & Pops, Pt.2. July 1998: Troubleshooting Your PC, Pt.3; 15W/Ch Class-A Audio Amplifier, Pt.1; Simple Charger For 6V & 12V SLA Batteries; Auto matic Semiconductor Analyser; Understanding Electric Lighting, Pt.8. March 2001: Making Photo Resist PC Boards; Big-Digit 12/24 Hour Clock; Parallel Port PIC Programmer & Checkerboard; Protoboards – The Easy Way Into Electronics, Pt.5; A Simple MIDI Expansion Box. July 2003: Smart Card Reader & Programmer; Power-Up Auto Mains Switch; A “Smart” Slave Flash Trigger; Programmable Continuity Tester; PICAXE Pt.6 – Data Communications; Updating The PIC Programmer & Checkerboard; RFID Tags – How They Work. August 1998: Troubleshooting Your PC, Pt.4; I/O Card With Data Logging; Beat Triggered Strobe; 15W/Ch Class-A Stereo Amplifier, Pt.2. April 2001: A GPS Module For Your PC; Dr Video – An Easy-To-Build Video Stabiliser; Tremolo Unit For Musicians; Minimitter FM Stereo Transmitter; Intelligent Nicad Battery Charger. August 2003: PC Infrared Remote Receiver (Play DVDs & MP3s On Your PC Via Remote Control); Digital Instrument Display For Cars, Pt.1; Home-Brew Weatherproof 2.4GHz WiFi Antennas; PICAXE Pt.7; A Digital Timer For Less Than $20. September 1998: Troubleshooting Your PC, Pt.5; A Blocked Air-Filter Alarm; Waa-Waa Pedal For Guitars; Jacob’s Ladder; Gear Change Indicator For Cars; Capacity Indicator For Rechargeable Batteries. October 1998: AC Millivoltmeter, Pt.1; PC-Controlled Stress-O-Meter; Versatile Electronic Guitar Limiter; 12V Trickle Charger For Float Conditions; Adding An External Battery Pack To Your Flashgun. November 1998: The Christmas Star; A Turbo Timer For Cars; Build A Poker Machine, Pt.1; FM Transmitter For Musicians; Lab Quality AC Millivoltmeter, Pt.2; Improving AM Radio Reception, Pt.1. December 1998: Engine Immobiliser Mk.2; Thermocouple Adaptor For DMMs; Regulated 12V DC Plugpack; Build A Poker Machine, Pt.2; Improving AM Radio Reception, Pt.2; Mixer Module For F3B Gliders. January 1999: High-Voltage Megohm Tester; Getting Started With BASIC Stamp; LED Bargraph Ammeter For Cars; Keypad Engine Immobiliser; Improving AM Radio Reception, Pt.3. March 1999: Getting Started With Linux; Pt.1; Build A Digital Anemometer; Simple DIY PIC Programmer; Easy-To-Build Audio Compressor; Low Distortion Audio Signal Generator, Pt.2. April 1999: Getting Started With Linux; Pt.2; High-Power Electric Fence Controller; Bass Cube Subwoofer; Programmable Thermostat/ Thermometer; Build An Infrared Sentry; Rev Limiter For Cars. May 1999: The Line Dancer Robot; An X-Y Table With Stepper Motor Control, Pt.1; Three Electric Fence Testers; Heart Of LEDs; Build A Carbon Monoxide Alarm; Getting Started With Linux; Pt.3. www.siliconchip.com.au May 2001: 12V Mini Stereo Amplifier; Two White-LED Torches To Build; PowerPak – A Multi-Voltage Power Supply; Using Linux To Share An Internet Connection, Pt.1; Tweaking Windows With TweakUI. June 2001: Universal Battery Charger, Pt.1; Phonome – Call, Listen In & Switch Devices On & Off; Low-Cost Automatic Camera Switcher; Using Linux To Share An Internet Connection, Pt.2; A PC To Die For, Pt.1. July 2001: The HeartMate Heart Rate Monitor; Do Not Disturb Telephone Timer; Pic-Toc – A Simple Alarm Clock; Fast Universal Battery Charger, Pt.2; A PC To Die For, Pt.2; Backing Up Your Email. August 2001: DI Box For Musicians; 200W Mosfet Amplifier Module; Headlight Reminder; 40MHz 6-Digit Frequency Counter Module; A PC To Die For, Pt.3; Using Linux To Share An Internet Connection, Pt.3. September 2001: Making MP3s; Build An MP3 Jukebox, Pt.1; PCControlled Mains Switch; Personal Noise Source For Tinnitus; Directional Microphone; Using Linux To Share An Internet Connection, Pt.4. November 2001: Ultra-LD 100W/Channel Stereo Amplifier, Pt.1; Neon Tube Modulator For Cars; Audio/Video Distribution Amplifier; Build A Short Message Recorder Player; Useful Tips For Your PC. December 2001: IR Transceiver For PCs; 100W/Ch Stereo Amplifier, Pt.2; Pardy Lights Colour Display; PIC Fun – Learning About Micros. January 2002: Touch And/Or Remote-Controlled Light Dimmer, Pt.1; A Cheap ’n’Easy Motorbike Alarm; 100W /Channel Stereo Amplifier, Pt.3; Build A Raucous Alarm; FAQs On The MP3 Jukebox. April 2003: Video-Audio Booster For Home Theatre Systems; Keypad Alarm; Telephone Dialler For Burglar Alarms; Three Do-It-Yourself PIC Programmer Kits; PICAXE, Pt.3 (Heartbeat Simulator); Electric Shutter Release For Cameras. May 2003: Widgybox Guitar Distortion Effects Unit; 10MHz Direct Digital Synthesis Generator; Big Blaster Subwoofer; Printer Port Simulator; PICAXE, Pt.4 (Motor Controller). June 2003: PICAXE, Pt.5; PICAXE-Controlled Telephone Intercom; PICAXE-08 Port Expansion; Sunset Switch For Security & Garden Lighting; Digital Reaction Timer; Adjustable DC-DC Converter For Cars; Long-Range 4-Channel UHF Remote Control. September 2003: Robot Wars; Krypton Bike Light; PIC Programmer; Current Clamp Meter Adapter For DMMs; PICAXE Pt.8 – A Data Logger; Digital Instrument Display For Cars, Pt.2. October 2003: PC Board Design, Pt.1; JV80 Loudspeaker System; A Dirt Cheap, High-Current Power Supply; Low-Cost 50MHz Frequency Meter; Long-Range 16-Channel Remote Control System. November 2003: Logging Your Every Driving Moment; PC Board Design, Pt.2; 12AX7 Valve Audio Preamplifier; Our Best Ever LED Torch; Smart Radio Modem For Microcontrollers; PICAXE Pt.9; Programmable PIC-Powered Timer. December 2003: How To Receive Weather Satellite Images; Self-Diagnostics Plug For Cars; PC Board Design, Pt.3; VHF Receiver For Weather Satellites; Linear Supply For Luxeon 1W Star LEDs; MiniCal 5V Meter Calibration Standard; PIC-Based Car Battery Monitor; PICAXE Pt.10. January 2004: Studio 350W Power Amplifier Module; High-Efficiency Power Supply For 1W Star LEDs; Antenna & RF Preamp For Weather Satellites; Lapel Microphone Adaptor FOR PA Systems; PICAXE-18X 4-Channel Datalogger; 2.4GHZ Audio/Video Link. PLEASE NOTE: Issues not listed have sold out. All other issues are in stock. We can supply photostat copies from sold-out issues for $8.80 per article (includes p&p). When supplying photostat articles or back copies, we automatically supply any relevant notes & errata at no extra charge. A complete index to all articles published to date can be downloaded free from our web site: www.siliconchip.com.au February 2004 87 ASK SILICON CHIP Got a technical problem? Can’t understand a piece of jargon or some technical principle? Drop us a line and we’ll answer your question. Write to: Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097; or send an email to silchip<at>siliconchip.com.au Help with LED bargraph ammeter Can I ask for your assistance with the Bargraph Ammeter published the January 1999 issue? This meter measures 25-0-25A. How can it be altered to read around 10-0-10A as I want to use it in my caravan to keep a check on the battery which will be connected to an 8A regulated charger. The only analog meters seem to be 60-0-60A which would be useless. (N. G., via email). • There are two things which affect the circuit sensitivity: the shunt resistance and the gain of IC1a. Provided you have a suitable shunt, you simply have to calibrate the circuit for 10A0-10A by adjusting trimpot VR1. Can Mighty Midget run from 24V? I was reading about the Mighty Midget power amplifier in the March 2002 issue and I was wondering if it can be adapted for 24V for my off-grid house. I could use a 24V to 12V stepdown inverter for every amplifier but this is inefficient and wish to use a 24V amplifier. The TDA1562Q chip in your design has an 18V (max) rating. Is there a substitute IC that has a higher rating? (G. M., via email). • Sorry. No can do. The best we can suggest is the 25W module using the National LM1875T featured in the December 1993 issue. Running from a 24V (nominal) supply, it should deliver around 14W into a 4-ohm load. High energy ignition current limit I have recently constructed one of your High Energy Ignition kits and came across a small problem. Once I had fitted the kit to the vehicle and made all of the required connections, I went about setting the current limiter. I set trimpot VR1 all the way clockwise, got a 12V supply and turned the ignition on, all as described in the instructions although the lowest reading I was able to get across the 0.1Ω resistor was 0.28V. This went up to over 0.34V. However, 0.25V was specified by the instructions and I’m not to sure how this came about. It should not be a problem though should it? This just means that the Windows-Based EPROM Programmer I’m having a bit of trouble with the Windows-Based EPROM Programmer software (SILICON CHIP, November/December 2002 & February 2003). It gives an error when I try to verify a write it has just done – it returns a run-time error 6 “overflow”. I’m using the latest version of software from your website and I’m trying to program an ST M27C512 chip using the packaged device configuration. The write to the chip is good and it works OK but I simply can’t verify the data written. Do you have any suggestions? (A. S., via email). 88 Silicon Chip • It seems that you may be getting “ringing” on the printer port interface, when the data is being read back during verify. You may need to change the printer port settings in BIOS or reduce the value of the pullup resistors on the programmer’s data line inputs. Another thought: are you using a good quality shielded DB25-DB25 data cable? If you’re not, all kinds of weird problems can be experienced with an unshielded ribbon type cable. This type of problem is very similar to the problems caused by a poor quality unshielded cable. coil might get a little more current than if the pot was set to 0.25V? The car seemed to run really well and the coil did not generate to much heat. (J. B., via email). • The 280mV limit is OK. This sets the maximum coil current to 5.6A. Since the coil doesn’t run hot it will be fine. PIC-based Speed Alert uses speedo signal I built the PIC-based Speedometer Alert (November & December 1999) project a while ago for a Ford Falcon XF. I have mounted the unit above the steering wheel column and it works fantastic. I was looking through the factory manual of the car and realised it has an electronic setup for the speedo that’s the same as your design, using the magnet and pickup coil. I successfully attached the factory pulse wire to your PIC speedo without any resistors between them. So now the two speedos share the same pulse wire. In doing this, it disables the factory speedo in the dash. As soon as I remove the PIC based speedo, the factory speedo works fine again. Would you be so kind as to tell me how can I run both your PIC Speedo and the factory speedo using the same factory pulse wire? (A. P., via email). • The 1kΩ resistor at the pin 2 input to IC2a should be increased in value to 10kΩ to prevent it loading the ECU speedometer signal. Also, remove the 0.1µF capacitor at pin 2 of IC2a. Electronic delay for tweeter Could you please advise whether the 20ms Digital Delay kit from the February 1996 issue is modifiable to allow different delay times, possibly as short as 1ms and how accurately? In addition, would the circuit have any effect on the signal? I’m considering another project where this will be used to delay the www.siliconchip.com.au signal to a tweeter but it has to be as transparent as possible to the sound, as it’ll be part of a high-sensitivity horn system, which is very intolerant of distortion. (P. S., via email). • The 20ms delay project uses an M65830P delay IC. This can be set for delays between 1ms and beyond 30ms using codes sent to the REQ, SCK and Data inputs. Accuracy is set using a crystal timebase. Note that filtering at the input and output of the delay IC will introduce phase delays. Total harmonic distortion through the delay is 0.3% at 1V and 1kHz and 3% at 10kHz. We have used this IC for a stereo simulator (June 1996), a digital reverb (December 2000 & January 2001) and the LP Doctor (January <at> February 2001). These each used a circuit to set the time delay using standard ICs. A microcontrolled unit was used in a Dolby Prologic Decoder (November & December 1995). Fast clock for model railways I would like to build a “fast” clock for my model railway. Have you ever featured one? I would like to use big digit displays. (K. S., via email). • We described a Fast Clock for Model Railways in the December 1996 issue. However, it was based on a standard 32kHz crystal-controlled clock movement so you can make an analog fast clock as small or as large as you want. Some people have even used a crystal watch movement and built it into a clock tower on their layout! We have not described a fast clock circuit using 7-segment displays. We can supply the December 1996 issue for $8.80 including postage. Winding inductor for battery charger I have a quick question regarding the winding of the inductor in the Fast Universal Battery Charger Mk II (June & July 2001). It states “20 turns bifilar wound” which I understand. However the former only holds about nine turns when wound bifilar. Should I wind left to right, bring the wire back to the left and continue in this fashion until I reach 20 turns or should I wind left to right, then right to left, etc until I reach 20 turns? (A. L., via email). • You wind on the first layer and www.siliconchip.com.au Tachometer for machine tools I’m looking to build a tacho for machine tool use; ie, lathes, milling machines, etc. However, this does not rule out an automotive tacho for the above purpose. The spindle speeds range from 10 - 10,000 RPM. I would like 10 RPM minimum resolution/increment or better still, actual real time RPM. I have searched the SILICON CHIP and EA websites and have found possibly nine tachos. The question is: which tacho is the right one to build? (S. D., via email). • The 5-Digit Tachometer pub- then continue winding with the turns returning back to the start end. Always continue winding in the same direction and do not bring the wires back to the start after each layer is made. Log and linear pots explained I’m fairly new to electronics and this may be a silly question but could you please tell me the difference between logarithmic and linear potentiometers? Where are they best used in applications? (A. D., via email). • That’s not a silly question. A linear pot has a linear increase in resistance between wiper and one end terminal as you turn the shaft. At half travel, you should have roughly equal resistance between the wiper and the end terminals. You can check this for yourself using your multimeter. A log pot has a logarithmic increase in resistance as you turn the shaft. Log pots are often used in amplifier volume controls where their response is more suitable for matching the logarithmic response of human ears. Hall sensor trigger for strobe light Could you please tell me how to connect a Hall Effect sensor to trigger the Strobe Light described in the August 1998 issue of SILICON CHIP? I want to trigger it in sync with a rotating shaft. The Hall Effect sensor will be positioned to within 0.030-inch of the projections (bolts) on the rotating lished in the October 1997 of SILICON CHIP is the only one which suits your application. It updates at 0.25s intervals (four times per second), has 1 RPM resolution and operates from 1 - 60,000 RPM. However, it only has a 100:1 range so if you want a 10,000 RPM reading, the lowest reading would be 100 RPM. If you set it at 10 RPM minimum, then the maximum would be 1000 RPM. You could incorporate a switch which selected the range for measurement (ie, 1-1000 RPM in position 1 and 100-10,000 RPM for position 2). This switch would change the capacitor on the phase lock loop oscillator. shaft and these projections will trigger a pulse in the Hall sensor. (P. G., via email). • The triggering will depend on the Hall sensor and what it gives as an output. If as you say it gives a pulse, presumably high when activated, then there is no reason why it cannot be used to drive a transistor in a similar manner to Q1 in the circuit. The collector of the extra transistor would connect to pin 2 of IC2. If the Hall sensor provides a low output when activated and an open circuit output when not activated (normally pulled high with a resistor), then the Hall output could be connected to the anode side of diode D2. In either case, the ground or negative supply for the Hall sensor would connect to the ground of the strobe circuit. Multiple neons for the sound modulator I would like to modify the neon tube Sound Modulator kit (SILICON CHIP, November 2001) so that it can power up to perhaps 10 30cm neon tubes. Which components would I have to change and what would their values be? (M. K., via email). • These neon tubes typically draw 250mA or 400mA at 12V so you could power 10 or 15 of the 250mA devices off the one neon modulator and you could probably run more than that if you fitted the Mosfets with a suitable heatsink. No other circuit changes would be required. February 2004 89 Erratic results from current clamp adaptor I have completed the Current Clamp from the September 2003 issue and on first test in my car with headlights switched on and off, the indication was OK. However, attempts to repeat this procedure produced erratic results. I could no longer null the meter reading with VR3 and the digital meter gave a range of false current readings. Having disassembled the 100-turn calibration coil, I could only readjust VR2 to obtain a zero on VR3. It seems to me that VR2 at 50kΩ is too big a range of resistance for such a small fixed pot. In fact, a 10-turn pot would have been better. The existing VR2 could change its resistance slightly if the device was accidentally knocked or due to vehicle vibration. The drifting readings of the clamp could be due to the sloppy operation of the battery clamp itself, poorly constructed for this role. Have you any suggestions? The idea is great and for a device that would be used infrequently, it could play a very useful role in trouble-shooting. I built it to check How to charge 11V Lithium batteries Is it possible to modify the Multi-Purpose Fast Battery Charger (SILICON CHIP, June & July 2001) so it can charge the latest Sanyo Lithium Polymer battery packs which have a nominal output of 11.1V? (M. W., via email). • The 12V position for switch S5 needs changing to cope with 11.1V batteries. This can be easily done by removing the 150kΩ resistor in parallel with the 12kΩ resistor. Re-label this position as 11.1V. Note that it will no longer be suitable for charging 12V Nicad or NiMH battery packs. Sidereal clock wanted Some years ago, your magazine had two articles of interest to me. One was a sidereal clock and the other an astronomical clock, made by a person 90 Silicon Chip the charge rate on a friend’s boat, when he uses a petrol generator to charge his batteries via a mains charger. There is no ammeter installed. (D. J., via email). • You can use a multi-turn pot but this would add to the expense. We used a better clamp available from Dick Smith Electronics. Some battery clamps are very poor, even for use as a battery clamp. The actual zeroing can really only be set to within ±0.1mV. Some multimeters can show better resolution than this. As mentioned, the core can become magnetised due to DC current. This can produce an offset in the reading. The zeroing range may not cater for this and the core will need to be demagnetised by reversing the clamp over the current carrying wire. For more critical measurements, a much larger core should be used which will not become magnetised as readily. The clamp would then need to be considerably larger to accommodate the core. For fixed current measurements, the clamp can be dispensed with and the core held in position over the wire with tape or cable ties or glue. who sold the PC board EPROM and switches as a kit. I would like to know whether the person is still doing the kit or failing that, whether the sidereal clock kit and parts are still available. (R. M., via email). • We have described two sidereal clocks, in March 1993 and August 1993. The March design had an LCD but did not use a micro to drive it. All the parts and the PC board should still be available. The August design used a Z80C micro and EPROM to drive a double clock display (7-segment LEDs). It is unlikely that it is still available as a kit. Problems with digital thermometer I have built the Digital Thermometer/ Thermostat (August 2002) to control an incubator but I have run into problems with the testing procedure and also the alarm adjustment side of things. The testing procedure starts off correctly with both TP1 and TP3 being able to be adjusted to +2.49V and -2.49V respectively. The problems start when it comes to measuring the offset voltage. With Sensor 1’s positive terminal, TP1 and TP4 shorted to ground, the multimeter reads -0.3mV to -0.2mV and counts up to 0.0mV where it stabilises. Continuing on with the testing procedure and taking the offset voltage to be 0.0mV, everything tests perfectly until step 9. Instead of the same reading on the display and the multimeter (reference thermometer), the temperature displayed on the unit is 4-6°C higher than that indicated by the multimeter. The other problem is that S2 doesn’t function correctly to set the alarm temperature. First, VR7 has no effect on the alarm temperature at all. Also, every time S2 is pressed, the display has a different reading. The most common reading it will give is to delete the decimal point, so if the unit is reading 27.3°C, pressing S2 causes it to read 273°C. If the unit is switched to the higher range, pushing S2 usually has no effect at all. This is the most usual outcome but it also just gives random readings and will sometimes begin to count up or down. I have been over the construction no less than four times and am positive that all the components are in their correct places and orientated correctly. The unit, although reading 4-6°C higher than it should, appears to display the temperature properly, with only a faint blow on the thermocouple causing it to increase temperature instantly. (M. H., Rylstone, NSW). • Most probably, switch S3 is incorrectly wired. Check the contacts of the switch and note that the (C) common terminals are not the centre pins but the outside pins. If the switch is upside down to the shown orientation, the wiring will be incorrect. One-way intercom for deaf driver A friend of mine suffers from agerelated deafness. He wears a hearing aid but it amplifies everything, including background noise. The problem is most noticeable when driving as he is unable to distinguish conversation from the ambient noise. Since he is www.siliconchip.com.au now retired and wishes to spend much of his time travelling, this has become a significant problem. I have looked through past projects in SILICON CHIP but none appear suitable. What I had in mind is some type of one way intercom which has a sound activated and noise cancelling microphone for the passenger and a headset for the driver. Do you have any suggestions? (I. C., Euroa, Vic). • Perhaps the most applicable project is the FM radio intercom for motorbikes, published in the October & November 1989 issues. This was an FM link and two of the chips used in the circuit are now superseded. However, it did feature a noise-cancelling microphone which you could still build and this could drive our Guitar Headphone Amplifier, as featured in the May 1995 issue. We can supply these issues for $8.80 each, including postage. Fish tank heater for etchant Do you know of a suitable heater for Jaycar’s etching tank? I would like to be able to heat up ammonium persulphate to the required temperature. Would a fish tank heater be hot enough, or would I need something bigger? (A. H., via email). • A fish tank heater will work fine but you need to set the thermostat as high as possible. Bike horn for bike alarm I have a question about the bike alarm featured in the January 2002 issue. Is it possible to wire it up to the bike’s horn instead of using a separate piezo horn? Or won’t this chirp properly as the kit is designed to do? (S. F., via email). Calibrating the reaction timer I recently assembled the reaction timer from the June 2003 issue but have never been capable of calibrating it as per the instruction schedule. The best I can get VR1 adjusted to is 608Hz (not 1kHz). Any suggestions? (K. • It sounds as if your 40106/74C14 chip has somewhat different switching thresholds compared with the chips used in our prototype timers, and this is lowering the clock oscillator frequency. That’s no big deal. To fix the problem, all you need to do is reduce the value of either • As far as the Bike Alarm is concerned, it is doubtful that the MJE3055 could handle the current of the bike’s standard horn. The problem is not the rating of the transistor itself; it is just not supplied with sufficient base current for it to handle high currents. the capacitor or the fixed resistor in oscillator IC1c, to allow the frequency to be raised to 1kHz. You could replace the 100nF capacitor with one of 56nF, for example, or replace the 15kΩ resistor with one of 10kΩ. You should also check the supply to IC4 at pin 16. This should be around 5.6V. Note that you should have some frequency output from pin 4 of IC4, even if it isn’t locked in phase with input. In addition, check for a short at pin 4 or check if pin 5 is at ground. Also, are the components connecting to IC4 correct and are there any shorts to adjacent pads or tracks? Maybe it would work if you substituted a high-gain Darlington power transistor (eg, BD649) and fitted it with a reasonable heatsink but even then it will only handle a current of 5A or so (and the bike battery will flatten SC quickly!). Notes & Errata Digital Tachometer, October 1997: Tables 3 & 4 on page 26 have some errors in the DIP switch settings. The multiplier for a 3-cylinder 4-stroke engine should be 320 (not 360). This requires the DIP settings to be 0010 0000 (not 00100100 as shown). Also the 5-cylinder 4-stroke multiplier of 192 should be 1100 0000 (not 1000 0000) as shown. Weather Satellite Receiver, December 2003: the circuit diagram should show the 1kΩ isolating resistor for the audio line output coming from the speaker side of the 330µF output coupling capacitor, not from the output of IC2a. The PC board overlay diagram is correct. High-Efficiency Power Supply For 1W Star LEDs, January 2004: the PC board number given in the parts list is incorrect. The correct board number is 11101041. Studio 350 Power Amplifier Module, January 2004: the 470µF 100V electrolytic capacitor connected to the -70V rail (adjacent to fuse F2) is shown reversed on the circuit diagram SC (Fig.7). WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. www.siliconchip.com.au February 2004 91 SILICON CHIP siliconchip.com.au YOUR DETAILS NEED PCBs? Order Form/Tax Invoice You can get the latest PCBs and micros direct from SILICON CHIP! See p100 for full details . . . Your Name_________________________________________________________ Silicon Chip Publications Pty Ltd ABN 49 003 205 490 PO BOX 139, COLLAROY NSW 2097 email: silicon<at>siliconchip.com.au Phone (02) 9939 3295 Fax (02) 9939 2648 This form may be photocopied without infringing copyright. (PLEASE PRINT) Address____________________________________________________________________________________________________ Postcode__________ Daytime Phone No. ( )____________________ Email address ________________________________ Method of Payment: q EFT (ring or email for details) q Cheque/Money Order q PayPal q Visa Card q Master Card Card No. Card expiry date: Signature_________________________________________________ YOUR ORDER SILICON CHIP PRINTED EDITION SUBSCRIBERS# QUALIFY FOR 10% DISCOUNT (except on subscriptions!) SIMPLY TICK THE ITEMS REQUIRED – DON'T FORGET TO FILL IN DETAILS ABOVE. WE'LL WORK THE TOTAL OUT FOR YOU AND SEND YOU A RECEIPT WITH YOUR ORDER SILICON CHIP SUBSCRIPTIONS (all prices include P&P) SILICON CHIP BOOKSHOP (P&P additional – See below) q AUSTRALIA 6 MONTHS (INC. GST) ...................................................................$52.00 q AUSTRALIA 12 MONTHS (INC. GST)..................................................................$97.50 q AUSTRALIA 12 MONTHS WITH BINDER (INC. GST) .......................................$115.00 q AUSTRALIA 24 MONTHS (INC. GST)................................................................$188.00 q AUSTRALIA 24 MONTHS WITH 2 BINDERS (INC. GST) .................................$222.00 q NEW ZEALAND 6 MONTHS (AIR MAIL) ........................................................ $AU55.00 q NEW ZEALAND 12 MONTHS (AIR MAIL)....................................................... $AU99.00 q NEW ZEALAND 24 MONTHS (AIR MAIL) ................................................... $AU196.00 q OVERSEAS (EXCEPT NZ) 6 MONTHS (AIR MAIL) ......................................... $AU80.00 q OVERSEAS (EXCEPT NZ) 12 MONTHS (AIR MAIL)...................................... $AU140.00 q OVERSEAS (EXCEPT NZ) 24 MONTHS (AIR MAIL) .................................... $AU265.00 NEW! CONVENIENT AUTOMATIC SUBSCRIPTION RENEWAL: q PERFORM. ELECT. FOR CARS PLUS ELECTRONIC PROJECTS FOR CARS (2003) – last few, some may be shop-soiled, – BOTH BOOKS .... $21.95 now only $15.00 Embossed "SILICON CHIP", securely holds 12 months+ of issues Available in Australia only.......................................................................................$14.95 q q q q q q q q q q q q q q q q q q q q q q q PCBs, PANELS, PROGRAMMED MICROS #10% discount offer does not apply to online edition subscribers nor to website orders q Tick here if you'd like us to automatically renew your subscription when it elapses (ie, 6 month, 12 month or 24 month). We'll renew until you tell us to stop! SILICON CHIP BACK ISSUES/ARTICLE PHOTOCOPIES q SILICON CHIP BACK ISSUES*; SC/EA/ETI PHOTOCOPIES – includes P&P – $12.00 within Australia; $15.00 overseas *where in stock - photocopy of article supplied where issue is out of stock. EA/ETI: no back issues left, only photocopies available. Price is for each back issue or each article photocopy. Nominate issue and article required: Month:...................................... Year:......................... Article required:.................................................................................................................... Please attach list if more than one back issue or photocopy required. There is a 10% discount for ten or more back issues and/or photocopies (no further discount applies). SILICON CHIP MAGAZINE BINDERS q OR FAX (24/7) This form (or a photocopy) to (02) 9939 2648 with all details AMATEUR SCIENTIST CD NEWEST Version 4.0............................................. $62.00 AUDIO POWER AMPLIFIER DESIGN – SELF ................................................. $81.00 BUILD YOUR OWN ELECTRIC MOTORCYCLE ... ............................................ $40.00 DVD PLAYERS AND DRIVES ........................................................................ $71.00 ELECTRIC MOTORS AND DRIVES.................................................................. $51.00 NEWNES GUIDE TV & VIDEO TECHNOLOGY................................................. $49.00 OP AMPS FOR EVERYONE.......................................................................... $100. 00 PIC IN PRACTICE........................................................................................... $60.00 PIC MICROCONTROLLERS - KNOW IT ALL................................................. $83.00 PIC MICROCONTROLLER - PERSONAL INTRO COURSE............................... $60.00 PRACT. GUIDE TO SATELLITE TV (7th edition)............................................. $49.00 PRACTICAL RF HANDBOOK .......................................................................... $61.00 PRACT. VAR. SPEED DRIVES/POWER ELECT................................................. $73.00 PROG. 32-BIT MICROCONTROLLERS IN C ..................................................... $79.00 PROGRAMMING AND CUSTOMIZING THE PICAXE ................................... $65.00 RADIO, TV AND HOBBIES ON DVD-ROM ...................................................... $62.00 RF CIRCUIT DESIGN...................................................................................... $63.00 SELF ON AUDIO (2nd edition)........................................................................ $69.00 SMALL SIGNAL AUDIO DESIGN.................................................................... $88.00 SWITCH. POWER SUPPLIES A-Z (inc CD-ROM)............................................ $91.00 TV ACROSS AUSTRALIA ............SUPER SPECIAL – LAST FEW! $39.95...... $29.95 USING UBUNTU LINUX.................................................................................. $27.00 P&P RATES: Many PCBs and panels, along with some pre-programmed microprocessors and microcontrollers are now available direct from SILICON CHIP. See the separate page listing those currently available on page 100. To eMAIL (24/7) Place silicon<at>siliconchip.com.au Your with order & credit card details Order: 92 Silicon Chip AC MACHINES................................................................................................ $66.00 Subscriptions, back issues and project reprints: P&P included Binders (available Australia only): $10.00 per order; for 5 or more P&P is free. Books: Aust. $10 per order; NZ: $AU12 per book; Elsewhere $AU18 per book OR PAYPAL (24/7) OR Use PayPal to pay silicon<at>siliconchip.com.au PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with your credit card details OR MAIL This form to PO Box 139, Collaroy NSW 2097 www.siliconchip.com.au *ALL ITEMS SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES IN AUSTRALIAN DOLLARS AND INCLUDE GST WHERE APPLICABLE. 2/04 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $20.00 (incl. GST) for up to 20 words plus 66 cents for each additional word. Display ads: $33.00 (incl. GST) per column centimetre (max. 10cm). Closing date: five weeks prior to month of sale. To run your classified ad, print it clearly in the space below or on a separate sheet of paper, fill out the form & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy, NSW 2097. Alternatively, fax the details to (02) 9979 6503 or send an email to silchip<at>siliconchip.com.au Taxation Invoice ABN 49 003 205 490 _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $__________ or please debit my  Bankcard  Visa Card  Master Card Card No. Signature__________________________ Card expiry date______/______ Name _____________________________________________________ Street _____________________________________________________ Suburb/town ___________________________ Postcode______________ Phone:_____________ Fax:_____________ Email:__________________ www.siliconchip.com.au FOR SALE UNIVERSAL DEVICE PROGRAMMER: Low cost, high performance, 48-pin, works in DOS or Windows incl. NT/2000. $1364. Universal EPROM programmer $467.50. Also adaptors, (E)EPROM, PIC, 8051 programmers, EPROM simulator and eraser. Dunfield C Compilers: Everything you need to develop C and ASM software for 68HC08, 6809, 68HC11, 68HC12, 68HC16, 8051/52, 8080/85, 8086, 8096 or AVR: $198 each. Demo disk available. ImageCraft C Compilers: 32-bit Windows IDE and compiler. For AVR, 68HC08, 68HC11, 68HC12, 68HC16. $385.00 Atmel Flash CPU Programmer: Handles the 89Cx051, 89C5x, 89Sxx in both DIP and PLCC44 and some AVR’s, most 8-pin EEPROMS. Includes socket for serial ISP cable. $220, $11 p&p. SOIC adaptors: 20 pin $132.00, 14 pin $126.50, 8 pin $121.00. Full details on web site. Credit cards accepted. GRANTRONICS PTY LTD, PO Box 275, Wentworthville 2145. (02) 9896 7150 or http://www.grantronics.com.au PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics (02) 9593 1025. sesame777<at>optusnet.com.au http://sesame_elec.tripod.com USB KITS: Stepper Motor Controller, USB PIO Interface, DTMF Transceiver, Thermometer, DDS HF Generator, Compass, 4-Channel Voltmeter, I/O Relay Card. Also available: Digital Oscilloscope, Temperature Loggers, VHF Receivers and USB Active X (and USBDOS.exe file) to control our kits from your application. www.ar.com.au/~softmark WEATHER STATIONS: Windspeed & direction, inside temperature, outside temperature & windchill. Records highs & lows with time and date as they occur. Optional rainfall and PC interface. Used February 2004 93 New New New Mark22-SM Slimline Mini FM R/C Receiver Cygnus Logic Systems  Industrial High Speed Automation  Electronic System Design  Custom Software Design  Consultancy  Troubleshooting  Project Management Tel: (02) 9904 3991 Fax: (02) 9904 3993 Mob: 0402 985 574 Foam surrounds,voice coils,cones and more Original parts for Dynaudio,Tannoy and others Expert speaker repairs – 20 years experience Australian agents for products Trade welcome – email for your user ID Phone (03) 9682 2487 speakerbits.com.au cygnuslogic<at>iprimus.com.au • • • • • 6 Channels 10kHz frequency separation Size: 55 x 23 x 20mm Weight: 25gm Modular Construction Price: $A129.50 with crystal TAIG MACHINERY Micro Mini Lathes and Mills From $489.00 Electronics PO Box 580, Riverwood, NSW 2210. Ph/Fax (02) 9533 3517 email: youngbob<at>silvertone.com.au Website: www.silvertone.com.au Coax Cable & Connectors       Type Cable OD (mm) dB/m 150 MHz 2400 MHz $/m N-Type RPSMA or RGTNC Pigtails Web: Email: Tel: CFD-200 5 0.130 0.550 $2.50 ($1.50 *) CFD-400 10 0.050 0.220 $4.00 ($2.00 *) Connectors $7.00 $7.00 ($3.00 *) ($4.00 *) $10.00 n/a ($5.00 *) email * = bulk price www.freenet-antennas.com sales<at>freenet-antennas.com +61 (8) 9319 1720 by Government Departments, farmers, pilots, and weather enthusiasts. Other models with barometric pressure, humidity, dew point, solar radiation, UV, leaf wetness, etc. Just phone, fax or write for our FREE catalogue and price list. Eco Watch phone: (03) 9761 7040; fax: (03) 9761 7050; Unit 5, 17 Southfork 94 Silicon Chip JACKSON BROS JACKSON OF THE UK IS BACK Highest quality products made by UK Craftsmen Variable and trimmer capacitors, reduction drives, dials, ceramic stand-offs Stepper motors: 200 oz in $89.00, 330 oz in $110.00 Digital verniers: 150mm $55.00, 200mm $65.00 59 Gilmore Crescent (02) 6281 5660 Garran ACT 2605 0412269707 Need prototype PC boards? We have the solutions – we print electronics! Four-day turnaround, less if urgent; Artwork from your own positive or file; Through hole plating; Prompt postal service; 29 years technical experience; Inexpensive; Superb quality. Printed Electronics, 12A Aristoc Rd, Glen Waverley, Vic 3150. Phone: 1300 132 251; Fax: (03) 9561 5529 Call Mike Lynch and check us out! We are the best for low cost, small runs. Drive, Kilsyth, Vic. 3137. ABN 63 006 399 480. S-Video . . . Video . . . Audio . . . VGA distribution amps, splitters, standards converters, tbc’s, switchers, cables, etc, & price list: www.questronix.com.au sPlan Windows electronic schematic software and Sprint Layout Windows PCB layout software are feature packed but low in price. Pixel Programmable Controller with 4 analog inputs, 8 digital inputs and 8 relay outputs. Can use a 28A or 28X Picaxe. Programmed in Basic or Flow chart. Labjack USB Data Acquisition Module features 8 12bit analog inputs, 20 digital I/O, 2 analog outputs and high speed counter. Free software, Labview driver and ActiveX component. DAS005 Parallel Port Data Acquisition Module features 8 12bit Analog inputs, 4 Digital I/Ps & 4 Digital O/Ps. Full range now available off the shelf in Australia CATALOGUES AND PRICE LISTS NOW AVAILABLE CHARLES I COOKSON PTY LTD GPO BOX 812, ADELAIDE, SA 5001 Tel: (08) 8235 0744 Fax: (08) 8356 3652 FreeFax: 1800 673355 (Within Australia) Email: jackson<at>homeplanet.com.au ALL MAJOR CREDIT CARDS ACCEPTED SOLE AGENTS FOR AUSTRALIA AND NEW ZEALAND & MADE TO ORDER PCBs For more details: www.acetronics.com.au Phone (02) 9600 6832 email: acetronics<at>acetronics.com.au Free windows software and source code. Dual Relay Modules suitable for TTL and Open Collector Outputs. Programmers for Atmel and PIC microcontrollers. Stepper Motor and Servo Motor controller kits. Switch Mode and Linear Power Supplies and DC-DC convertors. Full details and credit card ordering available at: www.oceancontrols.com.au KITS KITS AND MORE KITS! Check ’em out at www.ozitronics.com CENTRAL COAST FIELD DAY, Sunday 29th Feb. Don’t miss Australia’s biggest Amateur Radio exhibition and sale of new and used radio and communication equipment at Wyong Race Course, just 1 hour north from Sydney. Gates open 8.30 a.m. Special Field Day bargains from traders and tons of disposals gear in the flea market. Exhibits by clubs www.siliconchip.com.au Do You Eat, Breathe and Sleep Technology? Management & Sales Positions We are a rapidly growing, Australian-owned international retailer with more than 30 stores in Australia and we have a growing expansion program to open many more, so we need dedicated individuals to join our team to help achieve our goals. If you are customer focused, have an eye for detail, empathy for the products we sell and have recently completed a TAFE of University degree in electronics, we want to meet you. Career opportunities with full training are available now if you have the drive and ambition to make your future with Jaycar. We offer a competitive salary, sales commission and many other benefits. To apply for these positions please send your C.V. indicating the role you are interested in to the address shown below. Retail Operations Manager Jaycar Electronics Pty. Ltd. P.O. Box 6424 Silverwater NSW 1811 Fax: (02) 9741-8500 Email: jobs<at>jaycar.com.au Jaycar Electronics is an equal opportunity employer and actively promotes staff from within the organisation. Advertising Index Acetronics....................................94 Altronics.........................................7 BitScope Designs....................31,55 Carba-Tec Tools...........................95 Cygnus Logic Systems.................94 Dick Smith Electronics........... 18-21 Eco Watch....................................93 Elan Audio....................................43 FreeNet Antennas........................94 Gadget Central...........................IFC Grantronics...................................93 Harbuch Electronics.....................53 Instant PCBs................................95 Development / Training Board For the PIC Micro Jackson Bros................................94 Hy-Q International........................55 Jaycar .......................... 45-52,55,95 JED Microprocessors................5,55 Kalex............................................83 MicroByte Electronics...................95 The Most Flexible Development board around. Based on the PIC16F877. The development board can be used with a wide variety of PIC Micros including the PIC18F452. Adaptors avaliable to use the 8, 18, 28-pin PIC Micros. ICD 2 connector allows In-circuit programming / Debugging with Microchip’s ICD2. Uncommited I/O ports allow for your own connection configuration to each device and also to external circuits. Onboard parallel port programmer allows programming of the PIC while still connected to the circuits. Other optional extras available.Connection to each circuit module or extrenal circuit is made via 10-way IDC cables provided. The possibilities are endless. Student/School discounts available. For more information . . . Visit: www.microbyte.com.au Phone: (03) 9378 4288 Email: info<at>microbyte.com.au and groups with interests ranging from vintage radio, packet radio, scanning, amateur TV and satellite. www.ccarc. org.au. Ph (02) 4340 2500. LEDs: 5mm RGB LEDs $1.25 each. 4-chip (80mA) 8mm superbright LEDs $2 each. CR123A lithium batteries $4 each. www.ledsales.com.au RCS RADIO/DESIGN is at 41 Arlewis St, Chester Hill 2162, NSW Australia, www.siliconchip.com.au Building speaker boxes? Mounting electrical components onto solid timber? You may need the Carba–tecTOOLS FOR WOOD catalogue!! We have Australia’s largest range of woodworking handtools & machinery. Please contact us for your FREE 220 page colour catalogue or come in & see us at: 32 PERCY ST, AUBURN 2144 9649 5077 www.carbatec.com.au and has all the published PC boards from SC, EA, ETI, HE & AEM and others. Tel (02) 9738 0330. sales<at>rcsradio.com.au, www.rcsradio.com.au KIT ASSEMBLY NEVILLE WALKER KIT ASSEMBLY & REPAIR: • Australia wide service • Small production runs • Specialist “one-off” applications Phone Neville Walker (07) 3857 2752 Email: flashdog<at>optusnet.com.au WANTED VALVE TESTER IN GOOD CONDITION. Silicon Chip back issues: ALL 1987; ALL 1988; January, February, March, June, August 1989; May 1990; June, August 1991; February, November 1992; March 1996; March 1998; February 1999. Will pay reasonable prices. Please contact Alan (03) 9460 3091. Microgram Computers....................3 MicroZed Computers....................74 Ozitronics.....................................43 Prime Electronics.........................35 Printed Electronics.......................94 Quest Electronics....................55,95 RCS Radio...................................95 RF Probes....................................83 Silicon Chip Back Issues..............86 Silicon Chip Binders.....................71 Silicon Chip Bookshop..........96,IBC SC Car Projects Book.........11,OBC Silicon Chip Subscriptions...........92 Silvertone Electronics..................94 Soundlabs Group.........................55 Speakerbits..................................94 SPLat Controls.............................79 Taig Machinery.............................94 Telelink Communications.............55 ____________________________ PC Boards Printed circuit boards for SILICON CHIP projects are made by: RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. February 2004 95 ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE PRACTICAL RF HANDBOOK by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* A guide to RF design for engineers, technicians, students and enthusiasts. Covers key topics in RF: analog design principles, transmission lines, couplers, transformers, amplifiers, oscillators, modulation, transmitters and receivers, propagation and antennas. 279 pages in paperback. Alternative fuel expert Carl Vogel gives you a hands-on guide with the latest technical information and easy-to-follow instructions for building a two-wheeled electric vehicle – from a streamlined scooter to a full-sized motorcycle. 384 pages in soft cover. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE PRACTICAL RF HANDBOOK by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* A guide to RF design for engineers, technicians, students and enthusiasts. Covers key topics in RF: analog design principles, transmission lines, couplers, transformers, amplifiers, oscillators, modulation, transmitters and receivers, propagation and antennas. 279 pages in paperback. Alternative fuel expert Carl Vogel gives you a hands-on guide with the latest technical information and easy-to-follow instructions for building a two-wheeled electric vehicle – from a streamlined scooter to a full-sized motorcycle. 384 pages in soft cover. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST