19
Troubleshooting of Inverter Circuit (U) and Magnetron
Oven shuts down after approximately 15 or 33 seconds.
If the microwave oven shuts down after a short time in micropower mode, conduct the following test.
The microwave oven must be set in test mode to activate the self diagnostic failure code system.
SELF TEST MODE
When oven is set in test mode place water load in oven, set micropower to high and time to 1 minute, press start.
H97, H98 appears in display window a short time after start key is pressed and there is no microwave oscillation.
9
Loud buzzing noise can be heard.
1.
Loose fan and fan motor
10 Turntable motor does not rotate.
1.
Open or loose wiring of turntable motor
2.
Defective turntable motor
11 Oven
stops
operation
during
cooking.
1.
Open or loose wiring of primary and
secondary latch switch
2.
Operation of thermal cutout (Magnetron)
Adjust door and latch switches.
SYMPTOMS
CAUSE
CORRECTIONS
NEW H.V.
CLO CK
D ELAY/
STA N D
STA R T
H IG H POW ER
D ISPLAY
4L1B PQ
H97, H98 appears in the
Check magnetron filament
OK
Check Inverter input AC
AC 240V
Check Inverter control signal
Approx AC 3V
refer to component
unplug CN702 and measure
unplug CN701 and measure
Open
0V
0V
DANGER
Magnetron*
DPC board/Power Relay
Loose relay wiring
Latch switch
DPC board
H.V. Inverter (U)
NOTE:
DO NOT try to REPAIR this Inverter Power Supply(U)
*Check magnetron filament for open or short to casing before
display window
continuity
voltages at CN702
at CN701, pin 1 and 2
test procedures
at lead wire harness side.
at lead wire harness side.
HIGH
VOLTAGE
and also DO NOT RE-ADJUST PRESET VOLUME
on the board. It is very dangerous to repair or adjust
without sufficient test equipment because this circuit
handles very high voltage and very large current. Off
alignment of inverter board operation is dangerous.
Operating a misaligned Inverter circuit is dangerous
due to the very high voltage and current that is
produced by this board. Defective boards must be
replaced with a new one.
proceeding to determine a good magnetron.
NOTE:
Summary of Contents for NN-T259WB
Page 7: ...7 3 SCHEMATIC DIAGRAM...
Page 28: ...28 15 DIGITAL PROGRAMMER CIRCUIT...
Page 29: ...29...
Page 31: ...31 NOTES...
