JennAir
No Heat – High-Voltage System Failure
Microwave runs but does not heat food; turntable and light work, fan runs, but items remain cold.
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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, Open high-voltage capacitor, Failed high-voltage transformer
How to Fix / Troubleshooting
Safety First: Unplug the microwave. The high-voltage system stores lethal energy. Do not attempt to discharge or test the capacitor, transformer, or magnetron unless you are a trained technician.
- Confirm symptom: Place a microwave-safe cup of water inside and run for 1–2 minutes. If the water remains cold and the unit appears to run normally, the issue is in the high-voltage circuit.
- Basic checks: Ensure the door is closing properly and that no error codes are displayed. Verify the unit is not in a low-power test mode.
- Professional diagnosis: A technician will test the magnetron, HV diode, HV capacitor, and transformer with appropriate tools and safety procedures.
- Component replacement: Replace the failed high-voltage component(s). Magnetron replacement is common on older JennAir microwaves.
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Repair Difficulty
Professional Required
5/5
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