Microwave makes loud buzzing, humming, or grinding noises during operation

Safety: Unplug the microwave before inspecting moving parts.

• Isolate noise source: Run the microwave briefly with a cup of water and listen carefully to locate the noise (bottom, back, side, or top).
• Check turntable system: Remove the glass tray and roller ring. Clean both and the cavity floor. Run briefly without the tray to see if the noise changes. Replace a noisy turntable motor or worn roller ring.
• Inspect fan: On over-the-range models, check the vent fan and blower wheel for debris or looseness. Tighten mounting screws and remove obstructions.
• Magnetron hum: A deep, loud hum often indicates a failing magnetron or high-voltage component. This requires professional diagnosis and replacement.