Microwave makes loud buzzing or humming noise while running, louder than normal, sometimes accompanied by a burning smell.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety: If you smell burning or see smoke or sparks, stop the microwave immediately, unplug it, and do not use it again until inspected.
User-level steps:
- 1. Check cookware: Remove any metal objects, foil, or dishes with metallic trim. These can cause arcing and loud buzzing.
- 2. Inspect cavity: Look for burn marks, chipped paint, or exposed metal inside the cavity or on the waveguide cover (a small panel on the side or ceiling).
- 3. Clean thoroughly: Wipe away grease and food splatter, especially near the waveguide cover and ceiling.
- 4. Test with water: After cleaning, heat a cup of water. If the loud buzzing persists, stop use.
Persistent loud buzzing usually indicates a failing magnetron or transformer or arcing in the waveguide. These require professional diagnosis and repair.