Microwave displays H0 or HO and does not heat; fan may run briefly then stop.
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.
Possible Causes
How to Fix / Troubleshooting
Critical safety warning: High-voltage components can be lethal. Do not attempt to test or replace the magnetron, transformer, or capacitor unless you are trained.
User-level checks:
- Confirm that you are not running the microwave empty; always test with a cup of water.
- Unplug the unit for 10 minutes to reset any protection circuits, then test again.
Visual inspection (unplugged):
- Remove the outer cabinet and visually inspect the magnetron and high-voltage wiring for burn marks, melted insulation, or arcing.
- If you see obvious damage to the magnetron or smell strong burnt odors from the high-voltage area, the magnetron or related components are likely shorted.
Recommendation: Due to the risk, have a qualified technician diagnose and replace the defective high-voltage component.