Panasonic NN-E251W, Service Manual

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15
SYMPTIOM STEP CHECK RESULT CAUSE/CORRECTIONS
No display when oven is first 1 Low voltage transfrmer (LVT) Abnormal 0V LVT
plugged in secondary voltage Normal
➔
Step 2
2 IC-1 pin 42 voltage Abnormal VL 1
Normal=5V
➔
Step 3
3 IC-1 pin 10 voltage Abnormal ZD1, Q8
(14 pin of IC-2). Normal
➔
IC-1, CR1,Q6,Q7
DISPLAY
9.4 (TROUBLE 4) Trouble related to digital programmer circuit
SYMPTIOM STEP CHECK RESULT CAUSE/CORRECTIONS
No key input. 1 Membrane switch continuity. Abnormal Membrane switch
Normal IC-1
No beep sound. 1 IC-1 pin 34 voltage. Abnormal IC-1
Normal Q12, BZ1
Power relay A(RY-2) does not 1 IC-1 pin 40 voltage while operation. Abnormal IC-1
turn on even though the Normal=5V RY2, Q11, D4
program has been set and the
start pad is tapped.
No microwave oscillation at
1 IC-1 pin 8 voltage while operation Abnormal IC-1
any power setting. at high power. Normal=5V RY1, Q10, D3
Dark or unclear display. 1 Replace display and check operation. Normal DISPLAY
Abnormal IC-1
Missing or lighting of 1 Q1~Q7 check operation. Normal
➔
Step 2
unnecessary segment. Abnormal Q1~Q7
2 Replace IC-1 and check operation. Normal IC-1
Abnormal DISPLAY
A-K
FORWARD
SMALL
REVERSE
∞
B-E
B-C
C-E
FORWARD
SMALL
SMALL
∞
REVERSE
∞
∞
∞
E-B
C-B
C-E
FORWARD
SMALL
SMALL
∞
REVERSE
∞
∞
∞
E-B
C-B
C-E
FORWARD
SMALL
SMALL
∞
REVERSE
∞
∞
∞
E-B
C-B
C-E
FORWARD
10K
Ω
-90K
Ω
SMALL
∞
REVERSE
10K
Ω
-90K
Ω
∞
SMALL
Diode
A K
Transistor
C
B
E
NPN Transistor
TZTA - -- --
ECB
Digital
PNP T
A110
C106
ransistor
E C B
(ANODE)
(CATHODE)
E
C
B
ECB
(EMITTER)
(BASE)
(COLLECTOR)
A
K
TZTC - - --
NPN
E C B
E
B
C
E
C
B
Transistor
Transistor
Digital
PNP Transistor
Transistor
How to check the semiconductors using an ohmmeter