Well, since I mentioned Midwest did a cap overhaul.

I read right through that. Sorry. And 'roger' all.

Unless they 'cooked' it before returning it, a slow changing resistor may not
show up

Also, I wonder if the B+ is decreasing? Sometimes a resistor instead of a choke
is used in a power supply's pi filter.

Also, if there is a C- source for an audio stage grid's bias, that voltage
DEcreasing may reduce gain. The stage will drop to a lower gain type A instead
of, say, a type AB1 amp.

Just some thoughts.

Bill. K5BY