Trouble Related To Digital Programmer Circuit - Panasonic NN-GN68KS Service Manual

NN-GN68KS
8.4.

Trouble related to Digital Programmer Circuit

SYMPTOM
No display when oven is first plugged
in
No key input
No beep sound
No microwave oscillation at any power
Dark or unclear display
Missing or lighting of unnecessary
segment
H95/H97/H98 appears in window and
oven stops operation.Program High
power for 1 minute and conduct
following test quickly, unless
H95/H97/H98 appears and oven stops
STEP CHECK
1 Fuse pattern of D.P.C., FUSE1
2 Low voltage transforment (L.V.T.)
secondary voltage
3 IC1 pin 13 voltage/IC10 pin voltage
1 Touch switch continuity
1 IC1 pin 49 voltage
1 IC1 pin 50 voltages while operation at high
power
2 Collector of Q227 voltage
3 Short circuit between collector of Q227
and emitter of Q225
1 Replace display and check operation
1 Replace IC1 and check operation
1 Unplug CN702 (2 pin) connector and
measure voltage between terminals
2 Unplug CN701 (3 pin) connector and
measure pin1 voltage
26
RESULT CAUSE/CORRECTIONS
→Step2
Normal
Open Replace D.P.C. or Fuse Pattern
or FUSE
Abnormal 0V L.V.T. (T10)
→Step3
Normal
Abnormal IC10
Normal=5V IC1, Display
Abnormal Touch switch
Normal IC1
Abnormal IC1
Normal=5V BZ210, Q210
Abnormal IC1
→Step2
Normal=5V
Abnormal Q227 and/or Q225, Q226
→Step3
Normal 0.7V
Still not turn on RL1
RL1 turns on Q227 and/or Q225, Q226
Normal Display
Abnormal IC1
Normal IC1
Abnormal Display
Abnormal=0V 1. Interlock Switch
2. D.P.C. /Power Relay
→Step2
Normal=120V
Abnormal=0V D.P.C.
Approx. AC 3V Magnetron