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Making Loud Hum When Not On But Plugged In Troubleshooting Guides

Published FixGraph guidance for diagnosing and responding to making loud hum when not on but plugged in.

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Microwave Makes a Loud Hum While Plugged In but Off

A slight standby hum can be normal on some microwave models, but a loud or new hum while the controls are off is not enough to diagnose a transformer, fan, magnetron, or another internal part. Unplug the microwave if the sound is accompanied by heat, burning odor, sparks, smoke, a display or interior light turning on, a turntable moving, or any apparent heating.

Microwave · Appliance Repair