Microwave makes loud buzzing, humming, or crackling noises during operation, louder than normal fan noise.

Safety: Stop the microwave immediately if you hear crackling or see sparks.

Steps:

• 1. Inspect interior: Remove the glass tray and roller ring. Check for metal objects, foil, or utensils left inside.
• 2. Check waveguide cover: Inspect the mica or plastic waveguide cover (usually on the side wall) for burn marks, cracks, or food splatter. Clean gently with a damp cloth; if burned through, it must be replaced.
• 3. Turntable hardware: Ensure the roller ring is seated correctly and the coupler is not cracked.

If loud buzzing persists with a clean cavity and intact waveguide cover, the magnetron or high-voltage components may be failing. Discontinue use and contact a technician.