[Chuck Schwark]

You say the set you measured "seems" fine, but have you replaced all the filter block caps and other wax-paper bypass caps?

• Excessive leaky B+ bypass and filter caps can cause excessive current draw and warmup your transformer and ultimately kill it and the 80.
  
  
• Check for winding to winding or winding to case shorts in the audio output transformer. Bad shorted output tube(s).
  
  
• Check for carbon burns bewtween pins on the 80 socket.
  
  
• Check for shorted filter chokes. #3422 = 200 ohms, #3472 = 1,350 ohms.
  
  
• Check for shorted field coil - should be approx. 3,200 ohms.
  
  
• The filter block caps can be replaced with like-value film caps. They don't need to be electrolytic.
  
  
• It's a good idea to replace any resistors that are more than +/-20% off value as well. Imprpper audio tube biasing can make them draw excessive current. Check resistor #35, a three section wire-wound. The cathode bias section should be approx. 640 ohms.