How to Fix LG Microwave Error F1

Error Code: F1 Difficulty: Hard

Problem: Indicates a mainboard failure.

How to Fix F1 Error (Step-by-Step)

1. Unplug the microwave from the wall outlet to completely cut off power.
2. Remove the outer cabinet screws, typically located on the back and sides, and slide the cabinet off.
3. Before touching any internal components, locate the large high-voltage capacitor and safely discharge it using a screwdriver with an insulated handle to short the terminals.
4. Identify the main control board (mainboard), which is the central circuit board with numerous wire connectors.
5. Carefully disconnect all wire harnesses attached to the board, taking a photo beforehand for reference.
6. Unscrew the old mainboard and gently remove it from its mounting points.
7. Install the new mainboard, secure it with the screws, and reconnect all wire harnesses exactly as they were before.
8. Turn the appliance off, wait about 2 minutes, then turn it back on.

Still Not Working?
If the replacement part didn’t fix the issue, you may have a wiring problem or main board failure.