Westinghouse No Heat – High Voltage System Failure

Microwave runs but does not heat; no error code displayed.

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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

Failed magnetron,Failed high-voltage diode,Failed high-voltage capacitor,Failed high-voltage transformer

How to Fix / Troubleshooting

Critical safety warning: The high-voltage section can be lethal. Do not attempt internal HV repairs unless you are trained. Most users should stop at basic checks and call a technician.

User-level checks:

  • 1. Confirm symptom: Heat a cup of water on HIGH for 1–2 minutes. If the turntable rotates and light is on but the water stays cold, heating has failed.
  • 2. Check door closure: Ensure the door is fully closed and latching properly; an interlock issue can sometimes prevent HV from engaging.
  • 3. Try different power levels and times: Verify that no settings (like low power or timer) are causing confusion.

Technician-level actions:

  • 4. Test magnetron, capacitor, diode, and transformer: With the unit unplugged and capacitor safely discharged, each HV component should be tested and replaced as needed.

Because of the danger, most no-heat conditions should be handled by a professional appliance technician.

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Repair Difficulty

Professional Required 5/5

Required Part

Magnetron
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