[Chuck Schwark]

You may have an electrolytic wired with incorrect polarity causing excess current draw.
There is at least one filter cap on the audio output grid bias circuit that has POS to ground.
IIRC, there is another that has its NEG side connected to the HV center tap and NOT ground.
(Working from memory here...)

Also, it may be partially shorted internally, making it a much smaller resistance value than it should be causing excess current draw.
Check DC resistance against schematic/service bulletin to compare.

Chuck