Guy H Humble , TX July 06, 2016 Blowing primary power fuses The interlock circuit on the microwave door was shorted through the failed micro switch. An ohm reading from the input power to neutral followed by disconnecting various loads identified the failed switch. The part was ordered and replaced and the microwave was reinstalled and went back to work. 8 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes