Daewoo Noisy High-Voltage Transformer or Magnetron

Microwave makes a loud buzzing or humming noise during operation, louder than usual.

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

Failing high-voltage transformer, magnetron internal damage, loose mounting bolts on transformer or magnetron, high-voltage arcing

How to Fix / Troubleshooting

Safety warning: Loud buzzing from the high-voltage (HV) area can indicate dangerous arcing. If you smell burning or see smoke, unplug immediately and do not use the microwave.

User-level checks:

1. Confirm noise source: Remove any rattling items from on top of or around the microwave. Run it briefly with a cup of water to confirm the noise is internal.
2. Stop using if severe: If the noise is very loud or accompanied by a burning smell, discontinue use and contact a technician.

Technician-level checks:

Inspect transformer and magnetron mounts for looseness.
Check for burn marks or arcing in the waveguide and high-voltage (HV) wiring.
Test the transformer and magnetron and replace as needed.

Repair Difficulty

Professional Required 5/5

Required Part

High-Voltage Transformer

Check Price on Amazon

We may earn a commission from links on this page.