Most have 5 year warranty on magnetron. If it made a horrible smell and buzzing noise before blowing it could be the high voltage diode (relatively cheap). There's 5000 Volts back there so unplug and discarge the capacitor first.
If it blew when door was closed it is most likely a door switch.
If it's the magnetron it's not worth fixing. Last time I checked the're around $100.
Moonpie, October 2009
