Insignia No Heat – High Voltage Circuit Failure

Microwave runs but does not heat food; turntable rotates and light is on, but food remains 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,Defective high-voltage diode,Open high-voltage capacitor,Failed high-voltage transformer

How to Fix / Troubleshooting

Safety Warning: A non-heating microwave almost always involves the high-voltage system, which is extremely dangerous. Do not attempt internal repairs unless you are trained and can safely discharge the capacitor.

User-level checks:

  • Verify that you are using microwave-safe cookware (no metal, no gold/silver trim).
  • Try heating a cup of water for 1–2 minutes. If there is no noticeable warming, the unit is not heating.
  • Unplug the microwave and do not continue to run it without heat, as this can further damage components.

Technician-level outline:

  • Remove the cabinet and discharge the capacitor.
  • Test the high-voltage diode, capacitor, and transformer for proper operation.
  • Test the magnetron for shorts and continuity; replace if defective.

Because of the risk of electric shock, most homeowners should contact an authorized Insignia service center for a no-heat condition.

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Repair Difficulty

Professional Required 5/5

Required Part

Magnetron
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