"Even Steven" wrote in message
m...
I'm working on a Hallicrafters SX-25 Super Defiant. It uses two 6F6
tubes in push pull in the audio
circuit. Boy do they get hot! Too hot to touch. If my finger lingers I'd
have an awful blister in less than a second. Is this normal? I've checked
the tube voltages and they seem to be where they should be...280 VDC on
plate, 6 volts on heater, 18 volts on cathode. Does anyone have any ideas
about how to help these things run cooler?

Steve
Steve,
Check the control grid voltages to make sure the bias is right. Sometimes a
leaky capacitor from the previous stage's plate will turn on the following
stage hard. Besides overheating the tubes, this can also burn out the power
transformer. If you haven't replaced all the electrolytic and paper
capacitors, I would suggest you do so before proceeding further.
Regards,
Bob AD3K