Panasonic Inverter NN-CT776SBPQ Service Manual page 19

H97, H98 appears in
the display window.
Check magnetron
filament continuity
OK
Check Inverter input AC
voltages at CN702
Unplug CN702 and test for
AC 240V
240VAC across the lead wire
connector.
Check Inverter control
signal at CN701
Pin 1 and 2
Unplug CN702 and test for
Approx AC 3V
3 VAC acorss the lead wire
connector.
12.5 Troubleshooting inverter by microwave oven input current
This is an alternative way to test the inverter circuit by monitoring the input current to the microwave oven.
The microwave oven shuts down between 15 and 33 seconds
If the microwave oven shuts down after a short period of time while operating in micropower mode, conduct the
following test.
The microwave oven must be set in self test mode to activate the self diagnostic failure code system.
Stop/Cancel
When the micorwave oven is set in test mode, place a water load (1Ltr) in the oven, set micropower to high and
time to 1 minute, press start.
A short time after the start pad is pressed, H97, H98 appears in the display window and the magnetron does not
oscillate.
Open
Magnetron*
DPC board/Power relay
0V
Loose relay wiring
Latch switch
0V
DPC board
H.V. Inverter
NOTE:
Delay/
S tand
DANGER
HIGH
VOLTAGE
*Check the continuity of the magnetron
filament. Check the fialment is not shorted to the
magnetron case..
DO NOT
NOTE:
power supply.
THE PRESET VOLUME
board. It is very dangerous to repair or adjust this
preset without correct test equipment.
Do not attempt to repair the inverter circuit board,
replace the inverter circuit board with a new unit.
Start
21
REPAIR
try to the inverter
DO NOT ADJUST
on the inverter circuit
Micro Power