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

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

• Step 1 – Remove metal objects: Ensure you are not using metal containers, foil, or dishes with metallic trim.
• Step 2 – Clean the cavity: Thoroughly clean the interior with warm soapy water, focusing on the area where arcing occurred. Remove all burnt food deposits and grease. Dry completely.
• Step 3 – Inspect waveguide cover: Locate the mica waveguide cover (usually on the side wall). If it is burnt, cracked, or has holes, it must be replaced.
• Step 4 – Check cavity coating: Look for chipped enamel or exposed metal where arcing occurred. Small chips can sometimes be touched up with microwave‑safe cavity paint; larger damage may require cavity repair by a professional.
• Step 5 – Replace waveguide cover: Fit a new Indesit‑specified mica cover, ensuring it sits flat and fully covers the waveguide opening.

Note: Continued use with a damaged waveguide cover can destroy the magnetron.