Microwave makes loud buzzing, humming, or grinding noises during operation, louder than normal.

Safety first: Unplug the microwave before inspection.

• Isolate noise source: Run the microwave briefly with a cup of water and listen carefully (door closed). Note whether the noise seems to come from the top, side, or bottom.
• Check turntable system: Remove the glass tray and roller ring, then run the unit briefly. If the noise disappears, the issue is with the tray, ring, or coupler. Clean and replace worn parts.
• Inspect fan: Access the cooling fan and check for debris in the blades or bent blades rubbing against the housing. Clean and straighten as needed.
• Check for loose panels: Tighten any loose screws on the outer cover, mounting brackets, or internal shields that may vibrate.
• Magnetron noise: A loud, deep buzzing often indicates a failing magnetron or high-voltage component. This should be diagnosed and replaced by a professional.