So yes, I have removed the hum, and to a large degree the amp appears to be working well, but I noticed that bass notes got kind of farty sometimes and some specific notes would warble all over.
Weird… I’ll be putting the output section up on the scope again soon to see if I can figure out whats up.. I’m betting on a blown speaker, but I suppose the OT could be gone too.
One of the problems with an amp this old is that I don’t know what the primary impedance is meant to be. I can look for a short easy enough, but some shorts only appear at high power.
The speaker ought to be easy to test, I’ll plug in the good amp to that speaker.
Film at 11.
According to the guys at Mercury Magnetics, the OT is 8k/8 ohm
FYI