Microwave shows F9 and will not operate; sometimes occurs after a door slam or impact.

Safety first: Unplug the microwave. Door switch circuits are tied to high-voltage safety; improper repair can be hazardous.

• Check door operation: Open and close the door slowly. It should close smoothly and latch firmly without excessive force.
• Listen for clicks: As you open and close the door, you should hear distinct clicks from the interlock switches. Missing or weak clicks suggest a faulty or misaligned switch.
• Inspect latch and hooks: Look at the plastic latch hooks on the door and the latch bracket inside the cabinet. Replace if cracked or bent.
• Access door switches: Remove the outer cabinet and control panel to access the door interlock switch assembly. Check each switch for secure mounting and proper actuator contact.
• Test and replace switches: If you have a multimeter, test each switch for proper open/closed operation. Replace any defective door interlock switches as a set if possible.
• Adjust latch bracket: Slightly loosen the latch bracket screws and adjust position so the door closes firmly and all switches actuate correctly, then retighten.