7.4. Trouble related to Digital Programmer Circuit
SYMPTOM STEP CHECK RESULT CAUSE/CORRECTIONS
No display when oven is first plugged
in
1 Fuse pattern of D.P.C. Normal →Step2
Open Replace D.P.C. or Fuse
Pattern
2 IC10 pin4 voltage Abnormal 0V IC26
Normal=12V →Step3
3 IC10 pin5 voltage Abnormal IC10
Normal=5V IC1, CX320, Display
No key input 1 Touch switch continuity Abnormal Touch switch
Normal IC1
No beep sound 1 IC1 pin 5 voltage Abnormal IC1
Normal=5V BZ210, Q210
Power relay A(RY2) does not turn on
even though the program had been set
and the start pad is tapped
1 IC1 pin 78 voltage while operation Abnormal IC1
Normal=5V RY2, Q222
No microwave oscillation at any power 1 IC1 pin 77 voltages while operation at high
power
Abnormal IC1
Normal=5V →Step2
2 Collector of Q223 Abnormal Q223 and/or Q225, Q226,
Q227
Normal 0.7V RY1
Dark or unclear display 1 Replace display and check operation Normal Display
Abnormal IC1
Missing or lighting of unnecessary
segment
1 Replace IC1 and check operation Normal IC1
Abnormal Display
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
1 Unplug CN702 (2 pin) connector and
measure voltage between terminals
Abnormal=0V 1. Latch Switch
2. D.P.C. /Power Relay
Normal=220-240V →Step2
2 Unplug CN701 (3 pin) connector and
measure pin1 voltage of D.P.C. CN3
Abnormal=0V D.P.C.
Approx. AC 3V Magnetron
29
NN-DF383B
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