Panasonic Inverter NN-H275, Service Manual

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SYMPTOM CAUSE CORRECTIONS
5. Timer starts count down but
no microwave oscillation.
(No heat while oven lamp
and fan motor turn on)
1.
2.
Off-alignment of latch switches
Open or loose connection of high
voltage circuit especially magnetron
filament circuit
NOTE:
Large contact resistance will bring
lower magnetron filament voltage
and causing magnetron to lower
output and/or be intermittent. Adjust door and latch switches
3. Defective high voltage component
H.V. Inverter Power Supply (u)
Magnetron
Check high voltage component
according to component test
procedure and replace if it is
defective.
4. Open or loose wiring of power relay
B (RY-1)
5. Defective primary latch switch
6. Defective DPC or power relay B (RY-
1)
Refer to DPC troubleshooting
6. Oven can program but timer
does not start countdown.
1. Open or loose wiring of secondary
latch switch
2. Off-alignment of secondary latch
switch
Adjust door and latch switches
3. Defective secondary latch switch
7. Microwave output is low.
Oven takes longer time to
cook food.
1. Decrease in power source voltage Consult electrician
2. Open or loose wiring of magnetron
filament circuit.(Intermittent
oscillation)
3. Aging change of magnetron
8. Fan motor turns on and
turntable rotates when door
is opened.
1. Shorted primary latch switch
9. Oven does not operate and
return to plugged in mode
as soon as start pad is
pressed.
1. Defective DPC
Check tighten screws on
escutcheon base bracket, D.P.C
board.
10.Loud buzzing noise can be
heard.
1. Loose fan and fan motor
11.Turntable motor does not
rotate.
1. Open or loose wiring of turntable
motor
2. Defective turntable motor
12.Oven stops operation during
cooking.
1. Open or loose wiring of primary and
secondary latch switch
Adjust door and latch switches
2. Operation of thermal cutout
13.Oven returns to plugged in
mode after 18 seconds
elapses on the Auto sensor
cooking mode.
1. Open or loose wiring of sensor
terminal from DPC
2. Open steam sensor
3. Defective DPC
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