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NINELOLSIS
FAVA SEEN INE Otsic 3025)
NN-C877WB
NN-C877CB
DIGITAL PROGRAMMER TROUBLESHOOTING GUIDE
SYMPTOM
STEP
CHECK
RESULT
CAUSE/CORRECTION
No display when the oven
1
Fuse patern on the power
Normal
STEP 2
is first plugged in.
Open (see below for)
Short circuit of ZNR, LVT
repair of pattern)
lamp, main IC,s replace DPC
2
Low voltage transformer
Abnormal
OV
Low voltage transformer
secondary
voltage via
Normal
|
Step 3
conector CN100
3
+ 5 volt test rail (emitter of | Abnormal
ZD1,Q1
Q1)
Normal +5V
Step 4
4
ICS pin 14 voltage
Abnormal
IC2
Normal!
1C1,CX1,DISPLAY
Procedure for repairing the fuse pattern is as follows:
1) When
fuse pattern (A) PF1 opens:
a) Replace the DPC
2) When fuse pattern (B) PF2
opens
a) Renove jumper wirefrom PF2 position
b) Insert the jumper wire in PF3 postion
c) If both PF2 and PF3 fuse patterns are open please replace the DPC
NOTE: At the time of repairs , make a visual inspection of the varistors for burning
and also the test the low voltage transformer for layer short circuit. (Check
the primary coil resistance) If any abnormal condition is found replace the
defective component parts.
No Key input
1
Membrane switch continuity | Abnormal
Membrane switch
Normal
C1
Power relay RY2 (lamp and
1
IC9 pin 13 voltage during
|_Abnormal
turntable motor) does not turn
operation
Normal
(5V'
:
|. Step2.
sd
on after program is set and
2
Create short circuit between|
RY2 does not turn on
RY2
start button is pressed
IC9 pin 1 and pin 12
RY2 turns on
Ico
No microwave oscillation
1
IC9 pin 9 during high power | Abnormal
IC1
operation
Normal 5V_
Step 2
2
ICQ pin 4 voltage low level
| Abnormal
Normal
Step 3
3
Create short circuit between|
RY1 switches on
IC3,IC1
IC3 pin 16 and IC3 pin 8
RY1 does not switch on
No grill operation
1
IC9 pin 9 during high power | Abnormal
1C1
operation
Normal 5V
;
Step 2
2
IC9 pin 4 voltage low level
| Abnormal
IC9
Normal
Step 3
Create short circuit between|
RY4 switches on
:
IC3,1C1 *
IC3 pin 15 andIC3 pin8
_|_RY4.does not switch on
No fan motor operation
1
Create short circuit between|
RY5 switches on
IC3 pin12andiC 3pin8
| RY5 does not switch on
RY5
Dark or unclear display
1
Replace display and check
| Normal
|
;
Display
operation
Abnormal
1C1
Unlit segments of display
1
Replace IC and check
Normal
;
1C1
operation
Abnormal
p
No convection operation
1
IC9 pin 9 during high power | Abnormal
. 4
1C1
operation
Normal 5V
|
Step 2
2
ICQ pin 4 voltage low level
| Abnormal
IC9
3
Create short circuit between|
RY7 switches on
.
1C3,IC1
IC3 pin 14 and IC3 pin 8
RY7 does not switch.on
RY7
-25-
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