Trouble Related To Digital Programmer Circuit - Panasonic NN-DF383B Service Manual

7.4.

Trouble related to Digital Programmer Circuit

SYMPTOM
No display when oven is first plugged
in
No key input
No beep sound
Power relay A(RY2) does not turn on
even though the program had been set
and the start pad is tapped
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.
2 IC10 pin4 voltage
3 IC10 pin5 voltage
1 Touch switch continuity
1 IC1 pin 5 voltage
1 IC1 pin 78 voltage while operation
1 IC1 pin 77 voltages while operation at high
power
2 Collector of Q223
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 of D.P.C. CN3
29
RESULT CAUSE/CORRECTIONS
→Step2
Normal
Open Replace D.P.C. or Fuse
Pattern
Abnormal 0V IC26
→Step3
Normal=12V
Abnormal IC10
Normal=5V IC1, CX320, Display
Abnormal Touch switch
Normal IC1
Abnormal IC1
Normal=5V BZ210, Q210
Abnormal IC1
Normal=5V RY2, Q222
Abnormal IC1
→Step2
Normal=5V
Abnormal Q223 and/or Q225, Q226,
Q227
Normal 0.7V RY1
Normal Display
Abnormal IC1
Normal IC1
Abnormal Display
Abnormal=0V 1. Latch Switch
2. D.P.C. /Power Relay
Normal=220-240V →Step2
Abnormal=0V D.P.C.
Approx. AC 3V Magnetron
NN-DF383B