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

Safety First: Unplug the microwave before inspection. Do not operate the unit with covers removed.

• Isolate noise source: Run the microwave briefly and listen carefully to locate the area of the noise (top, side, bottom). Then unplug and inspect that area.
• Check turntable system: Remove the glass tray and roller ring. Run a short test (with no food) to see if the noise disappears. If so, inspect and replace the roller ring or turntable motor as needed.
• Inspect fan: Access the cooling fan motor and exhaust fan (for OTR models). Remove any debris and ensure blades are not rubbing against housing. Replace the fan motor if bearings are noisy.
• Magnetron hum: A deep, loud hum accompanied by poor heating can indicate a failing magnetron or high-voltage component. This should be diagnosed and repaired by a qualified technician.