Ever since I used one for the first time at W8AV's station in the CQ WW CW, I've been in love with the Kenwood TS-930S. Available in the $450-$700 range, is quite possibly the best buy in used amateur radio transceivers, especially when combined with the PIEXX TS-930SE microprocessor board and cascaded Inrad IF filters. Broken radios can be obtained for even less. Despite having an awesome receiver and outstanding transmit audio on phone, it suffers from poor thermal design in the power supply and power amplifier. Older radios with 2 and 3 million serial numbers also suffer from numerous problems due to poor construction techniques in the Digital, PLL, and PA circuit boards. Most of these are discussed in the Kenwood service bulletins.
A number of helpful fixes and improvements are described in W6NL's article [available at www.kkn.net/~k5tr/ts930fix.html]. Since even the newest '930's are 20 years old, repair is a matter of when, not if. If you have not performed these fixes, I strongly recommend that you do, even if nothing is wrong with your radio. However, Leeson fails to address the most serious failures commonly found in the TS-930S in great detail. I have compiled my repair notes in HTML format for the interested as a sort of addendum to Leeson's already fantastic document. If you were linked directly to this page, please read the Introduction to Repair Notes before trying anything. I also expect some familiarity with the Leeson mods and repairs in addition to the service manual. If enough interest is shown, I'll consider repeating important sections of the service manual here.
- 28.5-volt line reads in the ~40-volt range
- Dead MRF-485 PA drivers [as a result of #1 above]
Local radio trading and refurbishing afficionado KF9Z suggested that I consider making available kits of parts associated with each of the repairs outline above. Since most of the components are available from the same source, I don't really feel that this is necessary. Although, if the people clamor, I'll oblige.
In further discussion with KF9Z, I mentioned that I'd thought of designing a more robust 13ish-amp 28-volt switching supply. He agreed that this would be a good idea. Unfortunately, I know very little about switching power supplies. So, if anyone would like to take this project on or give me a hand, please drop me a note. Alternatively, Jameco and other electronics distributors offer a variety of switching power supplies. I know for sure that a 13-amp 27-volt supply is available in the $200-range for single quantities with substantial discounts for quantities of 25 or more. Of course, I have not checked the dimensions or RFI (giving or receiving) compatability of this unit.