Safety first: Disconnect mains power before opening the control housing.

1. Remove control panel: Unclip or unscrew the front control panel to access the display PCB.
2. Check connectors: Reseat the display connector and any low-voltage harnesses. Ensure no pins are bent.
3. Inspect for damage: Look for burnt components, especially small transformers, regulators, or capacitors on the control board.
4. Test supply voltage: With the unit powered (only if you are competent and using insulated probes), measure the low-voltage output feeding the display (often 5V or 12V DC). If unstable or missing, the power supply section is faulty.
5. Replace display or PCB: If the supply is good but the display remains faulty, replace the display module. If the supply is bad, replace the main control PCB.
6. Reassemble and test: Refit the control panel and verify that F2 is cleared and the display is stable.

If you are not experienced with live electrical measurements, have a technician perform the voltage checks and board replacement.

F2 appears and the display backlight or segments flicker or go blank intermittently.

Possible Causes