オリジナル投稿者： rcordova ,
The cheap switch is only part of the problem. Microwave ovens are meant to be shutoff before opening the door. This is not a problem on smaller ovens as the smaller amperage discharge across the switch when you open the door does not harm it. There are two interlock switches one for each leg of the transformer that powers the magnetron, one switch completes the circuit to send power to the relay which then sends power to one leg of the transformer, the other door interlock switch is directly connected to the other leg of the transformer. This is the switch that goes bad when you open the door with the unit on. Transformers work by magnetic charge, when you open the interlock switch the voltage in the transformer will jump the switch eventually destroying it. The relay on the other leg of the transformer can handle the on/off amperage. Go with a better switch. The manufacturer could put in a heavier switch as they use the same switch for small and large ovens but it is unintentional planned obsolescence. The third interlock switch is called the monitor switch and it shorts the power to the transformer blowing the fuse if the other interlock switch gets its contacts locked together or is bypassed.