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

Safety first: Unplug the microwave before inspection.

Simple checks:

• Remove the glass tray and roller ring; clean and inspect for debris.
• Run the microwave briefly (10–15 seconds) with a cup of water and without the tray to see if the noise changes (do not run empty).
• If the noise disappears without the tray, the issue is likely with the tray, coupler, or roller ring.

Internal inspection (experienced users):

• Remove the outer cover.
• Check that the magnetron and transformer mounting bolts are tight.
• Inspect the cooling fan and turntable motor for foreign objects or signs of wear.

Note: A loud, deep buzzing often indicates a failing transformer or magnetron, which should be replaced by a professional due to high-voltage risks.