Microwave makes loud buzzing, crackling, or popping noises during operation, sometimes with visible sparks inside.

Safety: Stop the microwave immediately if you see sparks. Unplug before inspection.

Steps:

• 1. Remove metal objects: Ensure there is no metal cookware, foil, or twist ties inside.
• 2. Inspect waveguide cover: Locate the small rectangular mica cover on the side or top wall. If it is burned, cracked, or heavily stained with grease, it must be replaced.
• 3. Clean the cavity: Use a mild detergent and soft cloth to remove grease and food splatter, especially near the waveguide cover.
• 4. Check cavity coating: Look for chipped paint or exposed metal. Small chips can be touched up with microwave-safe cavity paint.

Resolution: Replace the waveguide cover and repair any damaged cavity coating with appropriate materials. If arcing persists, have a technician inspect the waveguide and magnetron.