Originally Posted by harp

Update,
I just took this amp to a tech. He looked over the work I had done in converting to el34's (changing screen resistors and one bias resistor.) He confirmed everything looked good there. He looked over both boards with a magnifying glass and found nothing amiss. He checked the output transformer and found one side to be putting out almost no current, around 5-6 mA and, and jumping around a lot, while the other side was just fine. He said the OT was shot and this would definitely cause the tube heating problems. Does this make sense? I'm trying to understand how lack of current could cause heating.

BTW thanks for all the very helpful inputs!