F4
Tristar
Cooling System / Fan Feedback Error
Microwave shows F4 and may shut down unexpectedly; display and clock remain on.
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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 cooling fan motor, Blocked airflow, Faulty fan feedback sensor (if equipped), Control PCB fan monitoring circuit failure
How to Fix / Troubleshooting
Safety: Unplug the microwave before removing the cabinet.
Steps to address F4:
- 1. Check vents: Ensure all vents are clear and not blocked by cabinets or objects. Clean dust and grease buildup.
- 2. Listen for fan: During operation, confirm that the cooling fan runs. If silent, suspect a fan issue.
- 3. Inspect fan assembly: Remove the cabinet and locate the cooling fan. Check for obstructions and verify that the blades spin freely.
- 4. Test fan motor: Disconnect the fan and test for continuity. Replace if open or seized.
- 5. Feedback sensor (if present): Some Tristar models use a tach or feedback wire from the fan. Ensure this connection is secure. If the fan runs but F4 persists, the feedback sensor or control PCB may be faulty.
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Repair Difficulty
Medium
3/5
Required Part
Cooling Fan Motor
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