Microwave produces sparks or arcing inside the cavity during cooking.

Safety First: Press Cancel and open the door immediately if you see sparks. Unplug the microwave before cleaning or inspection.

• Remove metal objects: Ensure no metal utensils, twist ties, or foil are in the cavity unless specifically allowed by the manual.
• Clean cavity: Thoroughly clean the interior with mild detergent and water, paying special attention to areas where arcing occurred.
• Inspect waveguide cover: Check the mica or plastic waveguide cover (usually on a side wall) for burns, cracks, or holes. Replace if damaged.
• Touch-up paint: If interior paint is chipped down to bare metal, use microwave-safe cavity touch-up paint to cover exposed metal after cleaning and drying.
• Do not use if arcing continues: Persistent arcing may indicate deeper damage to the waveguide or magnetron and requires professional service.