Daewoo No Heat – High-Voltage System Failure

Microwave runs (light on, turntable turning, fan running) but does not heat food

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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, Failed high-voltage diode, Failed high-voltage capacitor, Failed high-voltage transformer

How to Fix / Troubleshooting

Critical safety warning: The high-voltage system in Daewoo microwaves is extremely dangerous. Do not attempt to test or replace HV components unless you are trained and know how to safely discharge the capacitor.

User-level checks:

  • 1. Confirm symptom: Heat a cup of water for 1–2 minutes. If it remains cold while the unit appears to run normally, heating has failed.
  • 2. Check power and settings: Ensure you are not in a low-power or defrost mode. Set to 100% power and test again.
  • 3. Listen for abnormal noises: A loud buzzing or humming can indicate a failing transformer or magnetron.

Recommendation: For no-heat conditions with normal operation, contact a Daewoo service technician. Magnetron, transformer, capacitor, and diode replacement are not DIY-safe repairs.

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Repair Difficulty

Professional Required 5/5

Required Part

Magnetron
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