Quote:
Originally Posted by simpsons
Unless I've missed something, why are you changing capacitors willy nilly?
The first check must be if there is any DC on the grid of V6 it should not be positive. If it is hook in anything from 0.01uF to whatever @ 300vdc working.
Move then onto HT, then V5a and V6 anodes. The schematic will tell you what should be there. If there little or no hum from the speaker and the HT is OK, the main smoothing is probably OK. No need to stuff anything.
Should these be within spec, the cathode bypass C3 would be my next choice.
The loudness capacitors are unlikely to be short circuit
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Will nilly, capacitors that are 70 odd years old, I don't think so, as already stated they measure ok, but are probably leaky at this stage, and for the sake of the cost of 4 film capacitors, it's a safe bet to do, for not only safety reasons, but for preventing future failures. I think the main power filter cap is OK and I will leave this be for now, there is no hum or buzzing. When the caps have been replaced, then I will safely take voltage readings without damaging any further components, i.e valves. " The schematic will tell you what should be there" not the one I am looking at, no voltages given. "The loudness capacitors are unlikely to be short circuit" as already stated if you read through the thread, none are shorted or open circuit for that matter. But possibly leaky.