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MARKET CENTRE Cash in your surplus gear. Advertise it here in SILICON CHIP FOR SALE tronixlabs.com – Australia’s best prices on a growing range of hobbyist and enthusiast electronics from adafruit, DFRobot, Freetronics, Raspberry Pi, Seeedstudio and more, with same-day shipping. Audio + Video: Professional quality Quest AV brand equipment is made and sold in Australia exclusively by Quest Electronics. Ph 0431 920 667. sales<at>questronix.com.au PCB MANUFACTURE: single to multi­ layer. Bare board tested. One-offs to any quantity. 48 hour service. Artwork design. Excellent prices. Check out our specials: www.ldelectronics.com.au DIRECT FROM CHINA: Kinsten PCB, high-speed drill press, hookup wire. A$ prices www.kinsten.co; USD prices http://www.aliexpress.com/ store/130218 Low prices include postage. SUPERBRIGHT LEDs: Cree, Avago etc plus generic LEDs for non-critical applications. Also kits, power supplies, components etc. We can order almost anything in! www.ledsales.com.au PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics Phone 0434 781 191. sesame<at>sesame.com.au www.sesame.com.au PCBs & Micros: SILICON CHIP Publications can supply PCBs and programmed microcontrollers for all recent projects. Order from our Online Shop at www. siliconchip.com.au or phone (02) 9939 3295. SERVICES CONSULTING AND ENGINEERING SERVICES Pty Ltd specialises in the design and manufacture of electronic based products. We do volume manufacturing and reverse engineering. Contact 0247323310 or email nbsethna<at>gmail. com to discuss your requirements. KIT ASSEMBLY & REPAIR RF REPAIRS - Australia wide repair service of most two way radio equipment. Please contact us on (02) 4305 2301 or service<at>rfrepairs.com.au VINTAGE RADIO REPAIRS: electrical mechanical fitter with 36 years experience and extensive knowledge of valve and transistor radios. Professional and DOWNLOAD OUR CATALOG at www.iinet.net.au/~worcom WORLDWIDE ELECTRONIC COMPONENTS PO Box 631, Hillarys, WA 6923 Ph: (08) 9307 7305 Fax: (08) 9307 7309 Email: worcom<at>iinet.net.au reliable repairs. All workmanship guaranteed. $10 inspection fee plus charges for parts and labour as required. Labour fees $35 p/h. Pensioner discounts available on application. Contact Alan on 0425 122 415 or email bigalradioshack<at> gmail.com KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand; * Small production runs. Phone Keith 0409 662 794. keith.rippon<at>gmail.com WANTED WANTED: EARLY HIFIs, AMPLIFIERS, Speakers, Turntables, Valves, Books, Quad, Leak, Pye, Lowther, Ortofon, SME, Western Electric, Altec, Marantz, McIntosh, Tannoy, Goodmans, Wharfe­ dale, radio and wireless. Collector/ Hobbyist will pay cash. (07) 5471 1062. johnmurt<at>highprofile.com.au ADVERTISING IN MARKET CENTRE Classified Ad Rates: $32.00 for up to 20 words plus 95 cents for each additional word. Display ads in Market Centre (minimum 2cm deep, maximum 10cm deep): $82.50 per column centimetre per insertion. All prices include GST. Closing date: 5 weeks prior to month of sale. To book, email the text to silicon<at>siliconchip.com.au and include your name, address & credit card details, or phone Glyn (02) 9939 3295 or 0431 792 293. cooled 4-cylinder; a year before they went to fuel injection and sensors. The coils are Pertronix flame-thrower (2 x 45kV, epoxy core, 0.6Ω.) There are several points in its original vacuum advance system that could be used for the Sensym sensor. One is from the fuel manifold but I assume contamination would not be good for the sensor. • The open-circuit output voltage siliconchip.com.au from the Programmable Ignition System is 0-5V. It may be difficult to arrange a system whereby the unit’s output was directed to power separate coils, depending on the distributor position. Each coil driver would need to be connected immediately after the firing of the previous coil in order to maximise the dwell period. The Programmable Ignition System does not have facility to provide a dwell period that is greater than the period between each trigger. In addition, this period is reduced by the firing period minimum of 1ms. You will not gain any advantage from using separate coils unless you have each coil driver start to charge its coil immediately after its own firing. This extra dwell will cause heating in the coil once it is charged. A ballast continued page 104 August 2014  103 Preamplifier For A Yamaha Electric Piano I own a Yamaha piano (as distinct from a keyboard). The piano doesn’t have enough output amplitude from ‘Aux Out’ to drive an amplifier, hence the need for a stereo preamp such as that described in April 1994. In the kit, three alternatives are offered namely: magnetic cartridge, tape/cassette deck and microphone. I’m assuming that the RIAA curve would not be relevant and neither would the microphone option. I am intending to wire in the tape or cassette option. Am I correct or can you suggest another option for low output pianos? (D. V., via email). resistor may be required to limit the maximum current in each coil. The Sensym ASDX015A24R is hard to get. We recommend that you use an automotive MAP sensor. You can obtain new MAP sensors from: www.cyberspaceautoparts.com.au/contents/ en-uk/d3721_Holden_Map_Sensors. html or from similar suppliers. A secondhand MAP sensor can be obtained from a wreckers yard. We used a standard V6 MAP sensor in our prototype. 500W speed control for a 240V DC brush motor I have a 230-240V DC 500W brush motor that has been removed from a treadmill and I need to be able to vary its speed. Would the new 230VAC Speed Controller For Universal Motors (SILICON CHIP, February & March 2014) work on this motor? (A. C., via email). • Yes, this motor speed controller works with 240V DC motors. However, we suspect that your treadmill motor may be a standard universal AC motor. This is a series-wound brush/commutator motor which will run equally well on AC or DC. Extra slaves for Micromite Can you have more than one slave connected to a Master Micromite via the I2C connection, as in Fig.8 on page 73 of the June 2014 issue. If so, how? Also, have you considered modifying the 30A DC Relay project (No104  Silicon Chip • None of the suggested options in the article would be suitable. The RIAA and Tape options have frequency tailoring and high gain while the microphone option has too much gain. Your Auxiliary output should have 100mV or more and typically 250mV, so a gain of four would probably be the maximum you need. We suggest the same arrangement as the microphone option with R4 at 390Ω and R1 a wire link. The R2 value would only need to be 1kΩ for a gain of 3.56. If you need more gain, use a 2.2kΩ or 4.7kΩ resistor; for less gain, use an 820Ω resistor. Capacitor C2 can be 1nF. vember 2006) to have four or eight DPDT relays on one circuit board? The outputs could use header pins and/or screw terminals. A relay rating of 1A would be OK. I think this would be a useful to connect to a Micromite. (J. S., via email). • Yes, you can attach multiple slaves to the one master. The only limitation is the number of I2C addresses that are available (112 devices). We do not have plans to modify the November 2006 project but yours is a good idea for the future. The board could also have inputs as well as relay outputs and could be controlled over I2C. We will have a look at it to see if it’s feasible. Ultrasonic cleaner may be wired incorrectly I have purchased and assembled your Ultrasonic Cleaner (SILICON CHIP, August 2010) and have a few issues you might be able to help me with. After assembly, I did the first electrical check as per your instructions, removing fuse F1 and IC1 from circuit. The regulator voltage was within parameters of 4.85V and 5.15V DC. The power light comes on but the unit won’t activate when set to timer or start and the run LED won’t light. I have included some photos to assist. Your thoughts on solving this problem would be appreciated. (B. F., via email). • From the photos you supplied it seems that only two wires are connected on the PCB for the timer po- Advertising Index Altronics.................................. 72-75 Aust. Exhibitions & Events............ 47 Consulting & Eng. Services........ 103 Control Devices Pty Ltd.................. 5 Emona Instruments........................ 7 Harbuch Electronics....................... 6 Hare & Forbes.......................... OBC High Profile Communications..... 103 Icom Australia.............................. 31 Jaycar .............................. 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Components... 103 tentiometer. Depending on how this is wired to the potentiometer it will have an effect on the timer operation. It may be that the timer duration is so short that it finishes almost immediately after the Start button is pressed. Check that pin 4 of IC1 is at 5V normally and then is at 0V while the Start switch is pressed. Check also that all the IC pins are correctly inserted into the IC socket and not bent under SC the socket. siliconchip.com.au