Amica Abnormal Magnetron or Transformer Noise

Microwave runs but makes loud buzzing or humming noises, louder than normal, especially when heating.

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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.

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Possible Causes

Failing magnetron, Loose high-voltage transformer mounting, Saturated transformer due to shorted diode, Metal object arcing inside cavity

How to Fix / Troubleshooting

Safety: Unplug before internal inspection.

  • Check cavity: Remove any metal objects, damaged waveguide covers, or arcing marks inside the cavity. Do not operate with an empty cavity for long periods.
  • Waveguide cover: Inspect the mica waveguide cover on the side wall for burns or holes. Replace if damaged.
  • Mounting check: With power disconnected, check that the transformer and magnetron mounting bolts are tight.
  • Persistent loud buzz: If the noise is accompanied by no heating or burning smell, stop using the microwave and arrange professional service. The magnetron or transformer may be failing.
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Repair Difficulty

Hard 4/5

Required Part

High-Voltage Transformer
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