8.4. Trouble related to Digital Programmer Circuit
8.4.1. NN-SD691S, SD671S
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
Low voltage transforment (L.V.T.)
secondary voltage
Abnormal 0V
L.V.T.
Normal
→
Step3
3
IC1 pin 13 voltage
Abnormal
Q10, ZD10
Normal=5V
IC1, Display
No key input
1
Touch switch continuity
Abnormal
Touch switch
Normal
IC1
No beep sound
1
IC1 pin 1 voltage
Abnormal
IC1
Normal=5V
BZ210, Q210
Power relay RY2 does not turn on
even though the program had been
set and the Start pad is tapped
1
IC1 pin 28 voltage while operation
Abnormal
IC1
Normal=5V
→
Step2
2
Collector of Q229 voltage
Abnormal
Q229
Normal 0.7V
RY2
No microwave oscillation at any
power
1
IC1 pin 27 voltages while operation at high
power
Abnormal
IC1
Normal=5V
→
Step2
2
Collector of Q220 voltage
Abnormal
Q220 and/or Q221, Q222, Q225
Normal 0.7V
→
Step3
3
Short circuit between collector of Q220
and emitter of Q225
Still not turn on
RY1
RY1 turns on
Q220 and/or Q221, Q222, Q225
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=120V
→
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
25
NN-SD691S / NN-ST681S / NN-SD671S / NN-ST671S / NN-ST661S / NN-ST661B / NN-ST661W / NN-ST651B / NN-ST651W
Summary of Contents for Inverter NN-ST651W
Page 2: ...2 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...
Page 3: ...3 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...
Page 38: ...38 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...
Page 40: ...40 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...