Panasonic NN-V659WB Service Manual page 23

Trouble Related to Digital Programmer Circuit
SYMPTOM
No display when oven is first
plugged in.
Oven is dead.
NOTE
Procedure of fuse pattern repairing is as follows:
1. When the fuse pattern (PF2) opens.
(1) Remove the jumper wire (PF3).
(2) Insert the removed jumper wire (PF3) to "(PF2)" position and solder it. If both "PF2" and "PF3" fuse patterns are open, please replace DPC.
NOTE: * At the time of these repairs, make visual inspection of the varistor for burning damage and examine the transformer with tester for the
presence of layer short-circuit (check primary coil resistance).
If any abnormal condition is detected, replace the defective parts.
SYMPTOM
No key input
No beep sound
Power relay A(RY-2) does not turn on even
though the program has been set and the
start pad is tapped.
No microwave oscillation at any power set-
ting.
Dark or unclear display
Missing or lighting of unnecessary segment
Oven shuts down on Micropower after a
short time (set in test mode) (set high power
1 Min) H97/H98 appears in window and
oven stops operation. Program High power
for 1 minute and conduct following test
quickly, unless H97/H98 appears and oven
NEW H.V.
stops.
How to Check the Semiconductors Using an OHM Meter
Diode
Transistor
NPN Transistor
2SC-----
2SD-----
PNP Transistor
2SA-----
2SB-----
Digital Transistor
PNP Transistor
E C B
STEP CHECK
1 Fuse pattern of DPC
2 IC10 Pin 9
(12V line)
3 IC-1 Pin 16 voltage
(Emitter of Q10)
4 IC-1 pin 10 voltage
(15 pin of IC220)
STEP
1 Push button switch
1 IC-1 pin 8, voltage
1 IC-1 pin 11 voltage while operation
2 Short circuit between pin 6 and pin
16 of IC-2
1 IC-1 pin 7 and 72 voltages while
operation at high power
2 Q220 transistor
1 Replace display and check opera-
tion
1 Replace IC-1 and check operation
1 Unplug CN702(2 pin) connector and
measure voltage between terminals
2 Unplug CN701(3 pin) connector and
measure pin 1 voltage
K
A
(CATHODE)
(ANODE)
A K
C
(COLLECTOR)
B
(BASE)
E
ECB
(EMITTER)
E
B
C
ECB
E
C
B
RESULT
Normal STEP 2
Open (NOTE) Shorted Circuit of ZNR, L.V.T., Oven Lamp etc. Replace DPC
Abnormal 0V IC10
Normal 12V Step 3
Abnormal ZD10, Q10, Ribbon Cable
Normal = 5V Step 4
Abnormal IC-220
Normal IC-1, CX1
CHECK
Abnormal
Normal
Abnormal
Normal
Abnormal
Normal = 5V
Still not turn on
RY-2 turns on
Abnormal
Normal
7---5V, 72---5V
Abnormal
Normal
Normal
Abnormal
Normal
Abnormal
0V
AC line voltage of 240V
0V
Approx. AV 3V
A-K
B-E
B-C
C-E
E-B
C-B
C-E
E-B
C-B
C-E
23
CAUSE/CORRECTIONS
RESULT CAUSE/CORRECTIONS
Push button switch
IC-1
IC-1
IC220, BZ310
IC-1
Step 2
RY-2
IC-220
IC-1
Step 2
Q220
IC220
DISPLAY
IC-1
IC-1
DISPLAY
1. Latch switch
2. DPC/Power relay
Step 2
1. DPC
1. Magnetron
2. Inverter
FORWARD REVERSE
SMALL
FORWARD REVERSE
SMALL
SMALL
FORWARD REVERSE
SMALL
SMALL
FORWARD REVERSE
10kΩ~30kΩ 10kΩ~30kΩ
50kΩ~90kΩ
40kΩ~80kΩ