White countertop microwave on a kitchen counter
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Microwave keeps blowing the line fuse when the door is opened or closed

The monitor switch is designed to short the line and blow the fuse if the door switches do not open in the right order. Worn latches, a misaligned door or a failed switch cause this. Replace the failed switch(es), check latch alignment, then replace the fuse with the exact rating.

Cross-checked ~45 min advancedBrands: All

Before you start

  • DANGER: the high-voltage capacitor can hold a lethal charge even when unplugged
  • Inexperienced users should NOT open the cabinet
  • Never bypass, jumper or remove a door interlock or monitor switch: it protects against microwave exposure

Diagnostic steps

Unlock all 4 steps with expected values

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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Microwave keeps blowing the line fuse when the door is opened or closed · OnCall Tech