Re: Sony 2SD625 line output transistor
Got the BU807 (high voltage fast darlington) today. Decided to give it a try, despite no longer being sure the 2SD625 has an hfe of 120. The BU807 is quoted as hfe of >100.
BIG surprise, it works. It gets very modestly warm and the overall current drawn by the set is down to 2.2A which is exactly as when the 2SD625 is fitted. The base waveform shows no signs of the parasitic ringing I've seen with all the other darlingtons I've tried.
So thanks to all for help and suggestions. Looks like a BU807 is a very good replacement for 2SD625, at least in my KV9000.
All this has been done on a previously working set. Now I'm going back to the non-working set and will fit a BU807. I have swapped the line output transformer on the non-working set with the working one so now I know both transformers are OK.
The non-working set has a field timebase fault. Both frame transistors get hot and the oscillator isn't running.
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