Microwave displays F9 and may immediately stop any cooking attempt.

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

Corrupted EEPROM on control board, Failed microcontroller, Voltage spike damage, Manufacturing defect in PCB

Safety: Unplug the microwave before any work.

Steps:

1. Power reset: Unplug for 15 minutes to fully discharge internal supplies, then reconnect. If F9 returns, the board is likely faulty.
2. Check for moisture or contamination: Remove the control panel and inspect for liquid spills or corrosion. Clean lightly with isopropyl alcohol if minor contamination is present.
3. Replace control board: In most cases, F9 requires replacement of the main control PCB, as EEPROM is integrated.

Hard 4/5

Main Control Board

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