"Leonard Caillouet" bravely wrote to "All" (07 Nov 03 22:36:30)
--- on the heady topic of "FYI 2SC4834 Sony power supply Q601,Q602"

There might be a design issue with the horizontal driver circuit if the
gain of the hot is that critical. Is there some field service notes
issued about this problem? It just seems a shame to be burning up
expensive transistors when all along it was another problem...

LC Reply-To: "Leonard Caillouet"
LC Xref: aeinews sci.electronics.repair:10648

LC Heads up as per Jurb...hope this helps someone.

LC Just a few notes on these transistors and the results of some
LC experimenting. I had a KV27ts32 and a KV32s25 in the shop with the
LC classic HOT shorted and Q601,602 shorted. I had some 2SC4834M in stock
LC and ordered some plain 2SC4834 from Tritronics and some 2SC4834P from
LC Acme Enterprises (Orlando). I tried each type in both sets and found
LC that the higher rank (higher letter, higher gain) transistors ran
LC progressively cooler. The unranked versions ran almost 20 degrees F
LC hotter than the best, the P rank version. I matched the transistors
LC from batches of 10 by forward bias voltage on the junctions then in
LC circuit for nearest to 50% duty cycle. I have found that swapping
LC pairs or swapping the caps on Q601,602 can often improve the ratio to
LC closer to 50%.

.... Power is obtained by current meeting resistance