Panasonic NN-GD566M - Page 66

SYMPTOM
STEP
CHECK RESULT
CAUSE
CORRECTIONS
No display when oven is first
plugged in. Oven is dead.
1 Fuse pattern of DPC Normal STEP 2
Open (NOTE)
Shorted
of
ZNR,L.V.T.,
Oven
Lamp
etc.Replace
2 Low voltage
transformer (LVT)
secondary voltage
Abnormal 0V LVT
Normal
Step
3
IC-1 pin 16 voltage
(Emitter of Q11)
Abnormal ZD11,
Q11
Normal = 5V
Display
NOTE
Procedure of fuse pattern repairing is as follows:
1. When the fuse pattern (PF2) opens.
(1) Remove the jumper wire (PF1).
(2) Insert the removed jumper wire (PF1) to “(PF2)” position and solder it. If both “PF1” and “
PF2”
patterns are open, replace DPC.
2. When the fuse pattern (PF4) opens.
(1) Remove the jumper wire (PF3).
(2) Insert the removed jumper wire (PF3) to “(PF4)” position and solder it. If both “PF3” and “
PF4”
patterns are open, 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.
No key input 1 Membrane switch
continuity
Abnormal
Membrane
Normal IC-1
No beep sound 1 IC-1 pin 29 voltage Abnormal IC-1
Normal BZ,
Q224
Power relay A(RY-2) does not
turn on even though the
program has been set and the
start pad is tapped
1 IC-1 pin 9 voltage
while operation
Abnormal IC-1
Normal = 5V
Step
2 Short circuit between
collector and Emitter
of Q223.
Still does not turn on RY-2
RY-2 turns on Q223
No microwave oscillation at
any power setting
1 IC-1 pin 7 and pin 34
voltages while
operation at high
power
Abnormal IC-1
Normal
Step
7---5V
2 Q220 transistor Abnormal Q220
Normal RY-1
Dark or unclear display 1 Replace display and
check operation
Normal
DISPLAY
Abnormal IC-1
32