H0
Russell Hobbs
Magnetron / High Voltage System Failure
Microwave shows H0 or HO and does not heat, but light and fan may run
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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,Open high-voltage transformer winding,Blown high-voltage capacitor or diode,Faulty high-voltage wiring connections
How to Fix / Troubleshooting
Critical safety warning: The high-voltage section of a microwave is extremely dangerous. Do not attempt to service the magnetron, transformer, capacitor, or HV diode unless you are trained and have proper tools.
- 1. Confirm symptom: Place a microwave-safe cup of water inside and run for 1–2 minutes. If the water remains cold and H0 appears, heating has failed.
- 2. Basic checks only: Ensure the door closes properly and that the unit is not in a demo mode (see user manual). If all basic settings are correct, H0 indicates an internal HV fault.
- 3. Do not continue to run: Repeated attempts may stress other components.
- 4. Professional service: A technician will test the magnetron, HV transformer, capacitor, and diode, and replace the failed part with a Russell Hobbs-compatible component.
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Repair Difficulty
Professional Required
5/5
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