I wonder if that amp was ever wired for 220. It does sound like it could be a bad transformer. If it is wired for 120 and is connected to something on a different phase in your power panel, strange things can happen. (IE Radio or computer in your shack on a different circuit) I would take Carl's advice. "As for the current discovery: Each socket has three 200pf caps, one from each grid pin to ground. There is also a 1 mH choke to ground to provide a DC path for the grid. The older rectangular caps are very prone to develop leakage, heat up and split the seams. An open choke will render the tube in that socket inoperative unless there is a sufficient path thru a bad cap; it opens during a tube short and tends to protect other components such as in the bias supply. " The amp just keying make no sense if you have no radio connected to it. That sound like another problem, that may have smoked something else. Good Luck. .