MasterChef No Power – Primary Power Circuit Failure

Microwave does not start at all; display is blank and no lights or sounds when door is opened.

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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

Blown internal line fuse, Faulty power cord, Failed noise filter board, Open thermal fuse on cavity or magnetron

How to Fix / Troubleshooting

Safety first: Unplug the microwave before any inspection. Do not bypass fuses or thermal cut-outs.

Steps:

  • 1. Verify outlet power: Test the wall outlet with another appliance. Reset any tripped breaker or GFCI.
  • 2. Inspect power cord: Check for visible damage, cuts, or burn marks along the cord and plug.
  • 3. Internal fuse check (experienced DIYers): Remove the cabinet and locate the line fuse near the power cord entry. If blown, investigate for shorts before replacing.
  • 4. Check thermal fuses: Locate the cavity thermal fuse and magnetron thermal cut-out. Test for continuity with a multimeter; replace any that are open.

Note: If a new fuse blows immediately, there is a deeper fault (shorted HV component or wiring) that requires professional diagnosis.

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Repair Difficulty

Hard 4/5

Required Part

Thermal Fuse
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