9.2.4. Trouble related to Digital Programmer Circuit
SYMPTOM STEP CHECK RESULT CAUSE/CORRECTIONS
No display when oven is first plugged
in
1 Printed fuse pattern of D.P.C. Normal STEP 2
Open (NOTE) Shorted circuit of ZNR,
L. V. T., Oven Lamp etc.
Replace D.P.C.
2 Low voltage transformer (L.V.T.)
secondary voltage
Abnormal 0V L.V.T.
Normal → Step 3
3 IC-1 pin 1 voltage (Emitter of Q1) Abnormal ZD1,Q1
Normal = 5V → Step 4
4 IC-1 pin 27 voltage (pin 14 of IC-2) Abnormal IC-2
Normal 5V → IC-1, CX1, DISPLAY
No key input 1 Membrane switch continuity Abnormal Membrane switch
Normal IC-1
No beep sound 1 IC-1 pin 23 voltage Abnormal IC-1
Normal BZ, Q3, Q4, Q8, Q9
Power relay A(RY-3) does not turn on
even though the program has been set
and the start pad is tapped
1 IC-1 pin 12 voltage while operation Abnormal IC-1
Normal=5V → Step 2
2 short circuit between pin 1 and pin 12 of
IC-2
Still not turn on RY-2
RY-2 turns on IC-2
No microwave oscillation at any power
setting
1 IC-1 pin 10 and pin 20 voltages while
operation at high power
Abnormal IC-1
Normal
10---5V, 20---5V IC-1
→ Step 2
2 Q7 transistor Abnormal Q2
Normal IC-2, RY-1
Dark or unclear display 1 Replace display and check operation Normal DISPLAY
Abnormal IC-1
Missing or lighting of unnecessary
segment
1 Replace IC-1 and check operation Normal IC-1
Abnormal DISPLAY
24
NE-1027 / NE-1037
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