Microwave interior shows arcing (sparks) during cooking, often near the waveguide cover or walls.

Safety first: Stop the microwave immediately if you see sparks. Unplug the unit and allow it to cool.

• Remove metal objects: Ensure no metal utensils, foil, or twist ties are inside the cavity.
• Clean cavity thoroughly: Wipe the interior with a mild detergent solution and a soft cloth. Pay special attention to the area around the waveguide cover.
• Inspect waveguide cover: The waveguide cover (often a mica or plastic panel on the side or top) should be smooth and intact. If it is burned, cracked, or has holes, replace it with the correct Fisher & Paykel part.
• Check cavity paint: Look for chipped paint exposing bare metal. Small chips can sometimes be touched up with microwave-safe cavity paint; larger damage may require professional repair.
• Test with water load: After cleaning and replacing damaged parts, test the microwave with a cup of water. If arcing persists, discontinue use and contact a technician.