Check the primary side of the HV transformer for voltage. Since this is a 240 vac microwave, I don't know if you should read 120 vac or 240 vac to the transformer. But, it should read one or the other. If no voltage, the problem is on the low voltage side; fuse, control board, tco or door switch. If there is voltage, the problem is on the high voltage side; HV transformer, HV capacitor, HV diode or magnetron.