Freezer shows E9 and may run continuously without reaching set temperature, or may short-cycle frequently.

Safety: Disconnect mains power before touching the control board. Static discharge can damage electronics—ground yourself.

Steps:

• 1. Power reset: Unplug the freezer for at least 10–15 minutes to allow capacitors to discharge. Plug back in and check if E9 clears.
• 2. Inspect control board: Access the main PCB (often behind a rear cover or in the top control housing). Look for burnt components, bulging capacitors, or signs of moisture.
• 3. Check connectors: Reseat all multi-pin connectors to ensure good contact. Verify that no pins are bent or corroded.
• 4. Verify supply voltage: With appropriate safety precautions, confirm that the board receives correct mains input and outputs low-voltage supplies to sensors and display.
• 5. Replace control board: If E9 persists and no external wiring faults are found, replace the main control board with a Bomann-compatible module programmed for your model.

Note: Some models may require parameter setup after board replacement; refer to the service documentation or use a professional.