Sharp Short Circuit or 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: Do not repeatedly reset the breaker and retry; this can cause further damage or fire. Unplug the microwave.

User checks:

  • 1. Inspect power cord: Look for visible damage, cuts, or burn marks. If damaged, the cord must be replaced.
  • 2. Try a different outlet: If safe, plug into another properly grounded outlet on a different circuit to rule out a bad breaker (do this only once).

Advanced: A technician should test the high-voltage capacitor, diode, magnetron, and line filter for shorts. Internal fuses on the Sharp power input board may also be blown and must be replaced with the exact type and rating.

Recommendation: This fault requires professional service due to high-voltage and fire risk.

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Repair Difficulty

Professional Required 5/5

Required Part

High-Voltage Capacitor
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