Peavey Butcher Trouble

[apehead]

Hello,

I have a Peavey Butcher which, suddenly and without warning, has failed. As I turned on the standby control, there was an audible hissing/"shorting" sound, after which I completely turned off and unplugged power to the amp. I opened it up, performed visual component inspection. Finding no obviously failed components, I re-energized the amp. Only one tube in the power section began cherry-plating. Replaced that tube. The new tube in that socket is still cherry-plating. Did another visual inspect around socket for shorted components, found none. Can get small signal through amp, but it must be turned up, and the tube begins to cherry-plate rather quickly at that volume (it doesn't seem to cherry-plate when the volume is turned down, but this may just be due to an intermittent short). I included the stock schematic, but the amp has been modded for adjustable bias (can't find modded schematics) Recommended next course of action?

[Enzo]

Yeah. Pull ALL the power tubes. Turn the amp on and check the voltage son ALL the power tube sockets. Is there B+ on pins 3 AND 4 of each? is there -50 more or less at pin 5 of ALL?

[apehead]

Thanks, Enzo. I'll try that tonight. I forgot to mention, I had a bass plugged into the amp during testing. I had one hand on the bass strings, and I put the other on another amp chassis, and I was shocked. Not sure if this helps.

[Ronsonic]

That's another problem and could be either amp.