H0
Galanz High-Voltage System Protection / HV Failure

Microwave displays H0 or HO and does not heat; fan and light may still operate.

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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

Shorted high-voltage diode, Failed high-voltage capacitor, Shorted magnetron, Blown internal line fuse due to HV fault

How to Fix / Troubleshooting

Extreme danger: The high-voltage section of a microwave can be lethal. Do not attempt to test or replace the HV capacitor, diode, or magnetron unless you are trained and have proper tools to discharge the capacitor safely.

What you can safely do:

  • 1. Basic reset: Unplug the microwave for 10 minutes, then plug back in. If H0 reappears and there is no heating, internal HV service is required.
  • 2. External checks: Confirm that the outlet has correct voltage and that the microwave is not on an overloaded circuit.
  • 3. Professional diagnosis: A technician will test the HV diode, capacitor, transformer (or inverter), and magnetron. Typically, one or more of these parts must be replaced.
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Repair Difficulty

Professional Required 5/5

Required Part

High-Voltage Diode or High-Voltage Capacitor
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