Blackface Vibrolux

[Grubey Doo]

I got one of these on the bench. I tried everything. It kills the output tube closest to the rectifier. I disconnected the .1 caps that feed the grids, injected a signal into the lifted ends of each cap and the side that has the problem the signal is louder than the ok side.
The grid resistors are right on also so I dunno, any ideas?

[stokes]

Is the bias voltage okay?Did you check to see if the caps are leaking excessive dc voltage to the grids?

[Amp Kat]

I've seen one of the 100k plate resistors of the PI on either side open up causing the signal on that side to drop way down.

[stokes]

Dont think losing the signal at the input would cause the tube to fry.Also dont think putting a signal into one side of a push pull out put is a very definitive test for a power tube failure.More likely you are losing bias voltage to that tube.Also if the input cap is leaking a lot of dc it would change the bias of that tube.