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MAILBAG Feedback on radio kits Enclosed is payment for the renewal of my subscription for another year. Keep up the good work. I wish to bring to your attention a problem I have observed in the PCB artwork for the mini stereo transmitter published in the October 1988 issue of SILICON CHIP. If one end is not cut off correctly, the antenna output is shorted. It's always the simple things in life that make life frustrating, to misquote the Kelloggs ad. The transmitter sounds quite good and it's amazing that the whole thing runs on only 1. 5 volts. Another very good kit of yours is the AM Stereo Radio. The whole thing went together so easily, and it worked first go. However, it sounded even better after I aligned it. It's a pity that the radio stations in Sydney can't improve the music they transmit! The sensitivity of this radio is also something fantastic. It will pick up stations in Wollongong and Gosford during the day. Mark Allen, Gore Hill, NSW. Specialty chips are difficult to get These days, more and more project designs are including specialty chips not carried by our turnover conscious electronics stores. Consequently, construction of such projects is made more difficult, as the specialty supplier ring around begins. The problem raised itself recently when l was trying to source a "doorbell" chip. I remembered your UHF doorbell of August 1988, and eventually dug up the relevant article. It uses the SAB0602, yet doesn't mention any more about that particular IC. I realised that it was a Siemens chip from the similarity to the dreadful SAB0600. One wonders what went through the minds of the Comeng engineers when they decided to put this horrific sounding creature inside the NSW Railway's Tangaras. I'm still sure it was a joke that went wrong! Might I suggest that when presen- ting projects using non-standard components, a "shoparound" column should be included. Better still, why not a feature article on ·semiconductors, their labelling, identification, and supply? Accompanying the article could be a table of suppliers for each of the state capitals. I for one would benefit from a further understanding of IC labelling in particular and I'm sure many other readers are in a similar position. Thanks for the magazine. Keep it up! Greig Sheridan, Ashfield, NSW. The story of electrical energy Congratulations on the Bryan Maher series describing electrical energy. The man is not only clever but thoroughly readable and informative. The conclusion of his mammoth series on electric railways left, for me, a large hole in SILICON CHIP. This series had captured my interest from the jump and was always the first article to which I'd turn upon receiving each issue. Thankfully, that hole is now filled by a writer I enjoy on a subject in which I have much interest. By starting this new series, you have given me yet another reason to be glad that I subscribe to SILICON CHIP. Julie Kentwell, VKZXBR, Springwood, NSW. Listing for computer clubs The secretaries of user groups and computer clubs who read your magazine will be interested to know that it is now possible for them to arrange, through Telecom Business Offices, an entry in the Yellow Pages under the new classification: "Clubs - Computer". A charge is made for a white pages entry; eg, the secretary's private number and address preceded by the name of the group/club and this is a pre-requisite for the free Yellow Pages entry as above. We in Canberra, with its rather mobile population, have been conscious of the need for this for some SILICON CHIP, PO Box 139, Collaroy Beach 2097. years and we think that others will want to take advantage of it too. We are informed that the first cab off the rank will be the 1991 Sydney Directory, entries for which will close in a few months time. K. W. Shands, Secretary, Commodore User Group, Curtin, ACT. How about a reprint of earlier issues? I am one of the many readers who would like a copy of the November 1987, December 1987 and January 1988 issues of SILICON CHIP but they are sold out. Why don't you see how many people are interested in a copy? It may be economically viable to print another edition. Jason Semple, Preston, Vic Extended guarantee on boards with VLSI chips In the July issue of SILICON CHIP, Mr R. Hobson of Glenreagh, NSW wrote about the boards supplied by Electronic Solutions which have surface mounted VLSI chips. I would like to answer his concerns as follows. First, he says that if the boards had chip carriers to hold the VLSI chips, this would solve the "repairability" of the boards. The reason that manufacturers are moving away from chip carriers is that because of the large number of connections (and this number is increasing as larger scale integration is being achieved), the chip carriers themselves are unreliable and are tending to fail after a period of time. Second, special tools are required to remove and replace VLSI chips. Third, VLSI chips are extremely reliable. This makes products that have a small chip count due to the use of VLSI chips very reliable as well. Therefore, as Mr Hobson has brought this to our notice, from July 1990, all boards with VLSI chips that are supplied by Electronics Solutions will carry a full 12 months parts and · labour warranty. Ian Hardwick, Managing Director, Electronic Solutions, Lane Cove, NSW. SEPTEMBER 1990 9