Haier High-voltage system failure (magnetron / transformer / inverter)

Microwave runs but does not heat food at all

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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

Failed magnetron, Open high-voltage diode, Blown high-voltage capacitor, Failed high-voltage transformer or inverter board

How to Fix / Troubleshooting

Critical safety warning: The high-voltage section of a microwave can store lethal charge even when unplugged. Do not attempt to service the magnetron, capacitor, transformer, or inverter unless you are a trained technician.

  • Basic verification: Place a cup of water in the microwave and run it for 1–2 minutes. If the water remains cold but the light, fan, and turntable operate, the heating system has failed.
  • Check power and settings: Confirm you are not in a low-power or demo mode. Verify the timer and power level are set correctly.
  • Do not continue using: Operating a microwave that runs without heating can further damage internal components.
  • Professional diagnosis: A technician will test the magnetron, high-voltage diode, capacitor, and transformer/inverter and replace the failed component with Haier-compatible parts.
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Repair Difficulty

Professional Required 5/5

Required Part

Magnetron
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