Panasonic Microwave H98 Error Code - Inverter Board / Magnetron Failure

What Caused This Error?

The control system reports H98 when the monitored condition described by the error code is outside the expected operating range. In this case, the most likely trigger is defective inverter power board. Other common contributors include burnt magnetron tube filament and blown high voltage diode or thermal fuse.

Step-by-Step Diagnostic Check

1. Disconnect wall power and safely discharge high voltage capacitor before servicing.
2. Check magnetron filament terminals for short to ground.
3. Disconnect electrical power before opening panels. Test high voltage thermal cutouts for continuity.
4. Disconnect electrical power before opening panels. Replace high-voltage inverter circuit board or magnetron.