Microwave runs but makes a rattling, scraping, or grinding noise from inside the cabinet.

Safety first: Unplug the microwave before opening the cabinet.

Step-by-step checks:

• 1. Isolate the source: Listen carefully during operation (before unplugging) to determine if the noise is from the top, side, or bottom.
• 2. Inspect turntable system: Remove the glass tray and roller ring. Run briefly with a cup of water to see if the noise disappears. If so, the issue is with the tray, ring, or coupler.
• 3. Access fans: Remove the cabinet and inspect the cooling fan and any convection fan. Remove debris and tighten loose screws.
• 4. Replace worn parts: If the fan blade is cracked or the motor shaft is loose, replace the fan assembly. If the turntable motor is noisy, replace it.