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December 14, 2020

Microwave Oven Repair: Another Interlock Switch Failure

Filed under: Uncategorized — admin @ 7:39 pm

the failed switch -note the depressed button

Over the past several years at Campbell River Repair Cafe events and elsewhere I’ve seen at least a dozen microwave ovens need repair because of failure of a specific component -one that is inexpensive and easy to source and replace: a door interlock switch. In the hopes of saving a few more microwave ovens from becoming landfill or other waste, here’s the repair that I recently did to our own GE microwave oven that failed the same way.

Basically, most microwave ovens made in at least the past 15 or so years tend to have 3 or 4 small spring-loaded switches mechanically coupled to the door latches, such that the microwave power shuts off and the interior light comes on when the door opens, plus some safety interlocks. These switches often fail. They are relatively easy to source (just look up the part number e.g. on ebay) and replace, and tend to cost less than a dollar.

Safety first: unplug the power and wait at least 30 seconds for big capacitor discharge before getting to work on yours.

Typically, per my pictures, you’ll need to remove the sheet metal top cover of the oven (might need a Torx Security screwdriver bit for some), and then the switches are located inside adjacent to the door latch insertion points. They typically have NO (normally open) and NC (normally closed) states that you can check easily with an ohmmeter, but especially note that the failure mode tends to be happen such that the switch button is stuck down in depressed state. That observation is a good way to find out which switch has failed without doing excess disassembly.

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