Microwave runs but makes loud buzzing, humming, or grinding noises during operation.

Safety first: Unplug the microwave before removing any covers. Loud electrical buzzing can indicate a dangerous fault.

• Step 1 – Isolate the source: Listen carefully to determine if the noise comes from the bottom (turntable motor), rear (transformer/fan), or side (fan).
• Step 2 – Check turntable components: Remove the glass tray and roller ring. Clean and inspect them. Run the microwave with a cup of water and the tray removed; if the noise disappears, the issue may be with the tray, ring, or coupler.
• Step 3 – Inspect fan and mounts (advanced): Remove the outer cabinet and check that the cooling fan and magnetron are securely mounted. Tighten any loose screws and ensure no wires are touching the fan blades.
• Step 4 – Transformer or magnetron noise: A deep, loud hum often indicates a failing transformer or magnetron. These components should be tested and replaced by a professional.

Note: Do not continue to use the microwave if the noise is accompanied by a burning smell or smoke.