I don't know if these outputs are just shorting out on me during this process but your question about 506 caused me to revisit it. I discovered it shorted between all 3 legs. I know it wasn't in that condition before. The previous testing had Q504 unpopulated and all others populated. I replaced Q506 and inserted a replacement into Q504 and retested.
Q500/501 5.4v
Q502/503 4.0v
Q504/505 5.3v
Q506/507 4.0v
Q500/501 5.4v
Q502/503 4.0v
Q504/505 5.3v
Q506/507 4.0v
That looks much better. If you don't see any other problems, reinstall the two capacitors and clamp all FETs and see if it will power up.
Reassembled and it powered up. Getting 115v at the bus bars near the outputs and 58v at the output terminal. Tested for audio at a low level and it is playing clean so far. There was some sparking that came from the ends of the resistors in between the 2 rows of capacitors, the 4R7 and 2R7 resistors, so I resoldered the ends as best as I could reach with the soldering iron. I will order some and change them. Also one of the capacitors next to them appears to have a bulging top so I will change that also. I will still insert an insulator under the green transformer winding.
Is there anything else I need to do to make sure the amplifier is fully repaired and reliable?
Is there anything else I need to do to make sure the amplifier is fully repaired and reliable?
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