Robot vacuum reports F3 and refuses to start; may occur immediately after pressing Start or when placed on the dock.

Safety first: Unplug the charging station from the wall before cleaning contacts or moving it. Turn the robot OFF before inspecting the underside.

Steps:

• 1. Inspect and clean contacts: Turn the robot upside down on a soft surface. Locate the metal charging pads. Clean them and the dock contacts with a dry cloth. If there is visible oxidation, use a cloth lightly moistened with isopropyl alcohol, then dry thoroughly.
• 2. Check dock placement: Ensure the dock is on a flat, hard surface with at least 0.5 m of free space on each side and 1.5 m in front. Avoid thick carpets under the dock that can misalign the contacts.
• 3. Test power to dock: Plug the dock directly into a wall outlet (no power strip). Confirm the dock’s indicator light is on. If not, try another outlet. If still off, the dock may be defective.
• 4. Reseat robot on dock: Place the robot manually onto the dock, ensuring the front is aligned and the contacts touch. Watch for the charging indicator on the robot. If it does not show charging, gently rock the robot to ensure contact.

When to call a technician: If F3 persists and the dock has power, the internal charging harness or charge detection circuit on the main PCB may be faulty. Professional diagnosis and replacement of the charging station or internal wiring/PCB is recommended.