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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.
When the microwave 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.
H97, H98 appears in
the display window.
Check magnetron
filament continuity
Check Inverter input AC
voltages at CN702
Check Inverter control
signal at CN701
Pin 1 and 2
Magnetron*
DPC board/Power relay
Loose relay wiring
Latch switch
DPC board
H.V. Inverter
NOTE:
DANGER
HIGH
VOLTAGE
Open
0V
0V
Unplug CN702 and test for
3 VAC acorss the lead wire
connector.
AC 240V
Approx AC 3V
Unplug CN702 and test for
240VAC across the lead wire
connector.
OK
*Check the continuity of the magnetron
filament. Check the fialment is not shorted to the
magnetron case..
NOTE:
try to
the inverter
power supply.
on the inverter circuit
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.
DO NOT
REPAIR
DO NOT ADJUST
THE PRESET VOLUME
Delay/
S tand
Stop/Cancel
Start
Micro Power
