Microwave Making a Loud Humming Noise

A loud hum or buzz, especially with weak heating, often points to the magnetron or a failing fan motor.

By Priya RamanOctober 11, 20253 min read read

Written by Wade Holbrook, Lead Technician — True Fix Dallas. Factory-trained, EPA-certified, 9 years servicing Dallas–Fort Worth.

Microwaves hum normally, but a new, loud hum signals a component under strain.

Failing Magnetron

A magnetron near end of life often hums loudly and heats poorly.

Fix: A technician tests and replaces it.

A worn fan motor or turntable motor can buzz loudly.

Fix: These motors are replaceable parts.

A failing diode can cause a loud buzz with arcing.

Fix: This requires professional diagnosis and safe capacitor discharge.

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