Microwave shows E9 and will not start, sometimes accompanied by unusual humming
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.
Possible Causes
How to Fix / Troubleshooting
Critical safety warning: This error involves the high-voltage system. Do not attempt to test or replace HV components unless you are trained. The capacitor can retain lethal charge.
User-level actions:
- 1. Power reset: Unplug the microwave for at least 10 minutes. Plug back in and test. If E9 returns immediately, internal HV faults are likely.
- 2. Do not repeatedly restart: Repeated attempts can worsen damage or cause fire if a component is shorted.
Technician-level actions (summary):
- Discharge the HV capacitor safely.
- Test transformer primary and secondary windings for shorts.
- Check capacitor and diode for shorts.
- Test magnetron for continuity and shorts to ground.
Recommendation: Contact a qualified Daewoo service technician for E9 faults. Component-level HV repair is not recommended for untrained users.
Repair Difficulty
Required Part
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