Panasonic NN-S262SF APH Service Manual page 38

SYMPTOM
5. Timer starts count down but
no microwave oscillation.
(No heat while oven lamp
and fan motor turn on)
6. Oven can program but timer
does not start countdown.
7. Microwave output is low.
Oven takes longer time to
cook food.
8. Fan motor turns on and
turntable rotates when door
is opened.
9. Oven does not operate and
return to plugged in mode
as soon as start pad is
pressed.
10. Loud buzzing noise can be
heard.
11. Turntable motor does not
rotate.
12. Oven stops operation during
cooking.
13. Oven returns to plugged in
mode after 18 seconds
elapses on the Auto sensor
cooking mode.
CAUSE
1. Off-alignment of latch switches
Open or loose connection of high
2. 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.
3. Defective high voltage component
H.V. Inverter Power Supply (u)
Magnetron
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)
1. Open or loose wiring of secondary
latch switch
2. Off-alignment of secondary latch
switch
3. Defective secondary latch switch
1. Decrease in power source voltage
2. Open or loose wiring of magnetron
filament circuit.(Intermittent
oscillation)
3. Aging change of magnetron
1. Shorted primary latch switch
1. Defective DPC
1. Loose fan and fan motor
1. Open or loose wiring of turntable
motor
2. Defective turntable motor
1. Open or loose wiring of primary and
secondary latch switch
2. Operation of thermal cutout
1. Open or loose wiring of sensor
terminal from DPC
2. Open steam sensor
3. Defective DPC
36
CORRECTIONS
Adjust door and latch switches
Check high voltage component
according to component test
procedure and replace if it is
defective.
Refer to DPC troubleshooting
Adjust door and latch switches
Consult electrician
Check tighten screws on
escutcheon base bracket, D.P.C
board.
Adjust door and latch switches