On Oct 15, 12:02*pm, mynick wrote:
no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Loud hum sometimes means something is shorted. The increased load on
the transformer makes it hum more. You can't always detect a short in
a high voltage component with an ohm meter. You can measure the
heating element voltage with an multi-meter but you really ned to be
careful. There is probably a diode and capacitor in the high voltage
circuit as well. If the diode has shorted the ac load will go through
the capacitor and that can also cause the high hum. I tried to fix
one once that had a bad magnitron but the magnitron was about half the
cost of a whole new microwave,