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Advertising Index Altronics...................................... 80-83 Australian Robotics.......................... 19 Clarke & Severn Electronics............ 43 Element14........................................ 23 Emona Instruments.......................... 45 Geoff Coppa.................................. 103 Grantronics.................................... 103 Hare & Forbes.............................. OBC High Profile Communications......... 103 HK Wentworth.................................. 13 Instant PCBs.................................. 103 Circuit Ideas Wanted Do you have a good circuit idea? If so, sketch it out, write a brief description of its operation & send it to us. Provided your idea is workable & original, we’ll publish it in Circuit Notebook & you’ll make some money. We pay up to $100 for a good circuit so send your idea to: Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. 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 Jaycar ................................. IFC,49-56 Jimojo.............................................. 42 Keith Rippon.................................. 103 Kitstop.............................................. 42 LED Sales...................................... 103 LHP.NET.AU................................... IBC MEAN WELL Power Supplies On The Net www.radioandelectronics.com Ph: 1300 495 211 Fax 08 9402 1287 Email: sales<at>radioandelectronics.com PO Box 780, Hillarys, WA 6923 Little Bird Electronics....................... 17 Measurement Innovation................. 43 Microchip Technology......................... 3 Microzed Computers........................ 43 Mikroelectronika............................... 11 Ask SILICON CHIP . . . continued from p102 of a radio scanner but with an effective AVC (automatic volume control) action to smooth out the varying levels associated with such receivers? Treble boost would also be necessary. (P. M., via email). • No, but the Hearing Loop Signal Conditioner from our January 2011 issue can be used. This is a mono line signal conditioner with treble boost and an automatic volume control. In addition, an amplifier would be needed to drive a loudspeaker. You could use the stereo amplifier from the May 2010 issue (Jaycar KC5495) or the Champ from February 1994 (Jaycar KC5152). Solution for a motorcycle ignition I have a 1982 Honda CX500 motorcycle with a failing ignition system. As usual, the problem is not the CDI but the high-voltage source coil which is wound on the alternator stator and very expensive to replace. The coils fail due to excessive heat and no cool104  Silicon Chip ing. As the CDI is sound I thought it would be possible to build a solid-state high-voltage source such as the high voltage section of the “Multi-Spark Capacitor Discharge Ignition” kit (SILICON CHIP, September 1997). The only problem I can see is that the kit high-voltage section supplies 300V whereas the bike CDI SCR circuit only requires 100V DC. Do you think it would be possible for me to convert the high-voltage section of the kit to 100V instead of 300V? If it is possible, I know the information will help many owners of older bikes whose only problem with failing ignition is faulty and very expensive to replace source coils. (J. J., via email). • The high-voltage section of the Multi-Spark Ignition is not suited to connect to a motorbike CDI. They effectively short out the high voltage when firing. The high-voltage coil could be rewound instead of replaced. Motor rewinders or transformer manufacturers can do the job. Alternatively, you can do the rewind yourself as the winding wire can be purchased and the coil rewound in the same way as SC the original winding. Mouser Electronics............................ 5 Ocean Controls................................ 21 Prime Electronics............................. 10 Quest Electronics........................... 103 Radio & Electronics....................... 104 RKT Auctioneers.............................. 95 RF Modules................................... 104 RMS Parts....................................... 71 Rohde & Schwarz............................ 22 Sesame Electronics....................... 103 Silicon Chip Binders......................... 94 Silicon Chip Bookshop................ 96-97 Silicon Chip Order Form.................. 79 SC Performance Elect. For Cars...... 94 Silicon Chip PCBs..................... 69,103 Silicon Chip Subscriptions............... 12 Siomar Battery Engineering........ 7,103 Splat Controls................................ 103 Truscotts Electronic World............. 103 VAF Research.................................. 42 Wiltronics........................................... 9 Wireless Design............................... 42 Worldwide Elect. Components....... 104 siliconchip.com.au