Replaced the magnetron, capacitor and diode. Symptoms of failure were change in tone/noise put out by the microwave and no heat in the item being microwaved. Could have been a failure of either the diode, capacitor or the magnetron, but I believe it was the magnetron that failed. Replaced all three. The right hand side of the housing needs to be removed to access these parts. Take lots of pictures for reference as it all comes apart, wiring, placement of the various screws, etc. Not an easy job. Took me about 2.5 hours to complete including removal/re-install of the microwave in the kitchen cabinetry. Works great now.