Westinghouse Short Circuit / Overcurrent on Startup

Microwave trips the household circuit breaker or blows a fuse when starting.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Shorted high-voltage capacitor,Shorted high-voltage diode,Shorted magnetron,Shorted line filter or power cord

How to Fix / Troubleshooting

Safety warning: Repeatedly resetting breakers can be dangerous. Unplug the microwave and do not continue trying to run it.

User-level checks:

  • 1. Try a different outlet: Use a dedicated circuit if possible to rule out overloaded circuits (do not use extension cords).
  • 2. Observe when it trips: If the breaker trips immediately upon pressing START, an internal short is likely.

Technician-level steps:

  • 3. Inspect line filter and cord: Check for burnt marks or melted insulation.
  • 4. Test HV components: Safely discharge the capacitor and test the capacitor, diode, magnetron, and transformer for shorts.

Due to high voltage and risk of fire, this repair should be done by a professional.

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Repair Difficulty

Professional Required 5/5

Required Part

High-Voltage Capacitor
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