MusicMan HD130 2100-130 Shuts off on "Hi-Power" Mode

[DominoTree]

Got a MusicMan HD130 here, it would shut off almost immediately after being powered on. Noticed the output transformer was getting REALLY hot and heard popping and crackling from the inside. Replaced it, and now the amp works in "low-power" mode, but as soon as you try "hi-power" mode, it will shut off.

Any ideas? AFAIK the low-power switch just taps the transformer in the middle of the coil, sending less voltage out. Is it possible one half of the coil in the transformer is shorted out, or should I be looking somewhere else?

[Prairie Dawg]

Shorted tube? Bad socket? Shorted flyback diode? Have you replaced every electrolytic in this thing and all the stuff on the bias board? I had a persistent intermittent red plater that got cured of its bad habits by this approach. New everything all the way back to the bias tap including driver transistors.