H99
Viking
High-Voltage System Overcurrent / Protection Trip
Microwave displays H99 and shuts down or will not start heating.
Advertisements
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.
Advertisements
Possible Causes
Shorted magnetron, Shorted high-voltage diode, Failing inverter board, Shorted high-voltage transformer (if equipped)
How to Fix / Troubleshooting
Critical safety warning: High-voltage diagnostics should only be performed by trained personnel. Do not attempt to test the magnetron, diode, or capacitor yourself.
- Reset and test: Unplug the Viking microwave for 10–15 minutes, then test with a cup of water. If H99 returns, internal HV components are likely shorted.
- Visual inspection: With power off and cabinet removed, look for obvious signs of damage around the magnetron, HV diode, and inverter/transformer—burn marks, melted insulation, or arcing.
- Professional diagnosis: Have a technician test the magnetron, HV diode, and inverter/transformer with appropriate equipment.
- Replace failed components: Common repairs include replacing the Viking magnetron and/or high-voltage diode, and sometimes the inverter board. Ensure all shielding and grounding hardware is reinstalled correctly.
Advertisements
Repair Difficulty
Professional Required
5/5
Advertisements