Microwave is very noisy during operation (loud humming, rattling, or vibration).

Steps:

• 1. Isolate noise source: Listen carefully to determine if the noise comes from the back, side, top, or cavity floor.
• 2. Check external items: Ensure the microwave is on a stable, level surface and not touching walls or other appliances that can resonate.
• 3. Inspect turntable: Remove the tray and roller ring and run a short test with a cup of water. If noise reduces, the issue is with the turntable system.
• 4. Tighten screws (for competent persons): With the unit unplugged, check and tighten accessible cabinet screws and internal brackets.
• 5. Fan or transformer noise: If the noise is a loud hum from the rear even without the turntable, the cooling fan or transformer may be failing and should be replaced by a technician.