Oster High-voltage component noise / impending failure

Microwave interior light, fan, and turntable run, but there is a loud buzzing or humming noise during operation.

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, Shorted high-voltage diode, Magnetron internal arcing, Loose mounting of transformer or magnetron

Safety first: Unplug the microwave. Loud buzzing from the high-voltage section can indicate a serious fault.

Do not continue use: Stop using the microwave until inspected. Continued operation can cause further damage or fire risk.
Check mounting screws (external): If accessible without entering the high-voltage area, ensure the transformer and magnetron mounting screws are tight. Do not touch electrical terminals.
Professional diagnosis: A technician will test the transformer, diode, capacitor, and magnetron and replace the faulty component.

Professional Required 5/5

High-Voltage Transformer

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