Display shows E9 and the unit may shut down or fail to start; sometimes accompanied by beeping.

Warning: Work with electronics only when the unit is unplugged. If you are not comfortable with board-level work, contact a technician.

• Power reset: Unplug the cooler for at least 10 minutes to allow capacitors to discharge. Plug it back in and check if E9 clears.
• Check power quality: Ensure the cooler is plugged directly into a properly grounded outlet, not a power strip or extension cord. Avoid circuits shared with heavy appliances.
• Inspect main board: Remove the rear lower panel to access the main control board. Look for burnt components, bulging capacitors, or scorch marks.
• Reseat connectors: One by one, unplug and replug all harness connectors to the board to ensure solid contact.
• Replace main control board: If E9 persists and there is no visible wiring damage, replace the hOmeLabs main control board (PCB) with the exact part number for your model. Transfer any jumpers or configuration plugs from the old board.
• Test operation: After replacement, restore power and verify that the display initializes normally and E9 is gone.

Important: If E9 appears after a lightning storm or outage, a surge protector is recommended after repair.