Inverter Circuit and Magnetron Troubleshooting
This microwave oven is programmed with a self-diagnostic failure code system
used for troubleshooting.
The error codes H97, H98, and H99 are used to indicate problems related to the
inverter circuit and the magnetron. These codes appear on the display window
after the start key is pressed and there is no microwave oscillation.
Condition
H97, H98, or H99 appears
on the display window.
Open
Magnetron
0V
DPC board
Loose relay
wiring
H.V. Inverter
3V AC
0V
DPC board
Check the inverter control signal at pins
1 and 2 of CN701 (Unplug CN701 and
measure at lead wire harness side.)
Check for inverter AC line input at
CN702. (Unplug CN702 and measure at
lead wire harness side.)
Check for magnetron filament continuity.
(Refer to the “how to diagnose for an
open filament or a shorted magnetron”
procedure listed on page 4.)
OK
120V AC
Note: Do not re-adjust preset volume, or try to repair this inverter power supply.
33
