Panasonic NN-CT577SEPG Service Manual page 21

Power relay (RY2 ) does not
operate
No microwave oscillation
Dark or unclear display
Missing segments in display
Microwave oven shuts down
between 15 - 33 seconds.
Set the microwave oven to test
mode
Set to high power 1 minute.
H97 or H98 appears in the dis-
play and the microwave oven
stops working
Program for 1 minute and per-
form the following test
12.8 Checking the semiconductors using a resistance meter
Diode
Transistor
Digital transistor
1 IC-1 pin 23 during
operation
2 Create a short circuit
between pin 6 and pin
16 of IC-2
1 IC-1 pin 18 and 16
during high power
operation
2 Q221 transistor
1 Replace display
Replace IC-1
1 Unplug CN702 connec-
tor and measure the
voltage between the
terminlas
2 Unplug CN703 connec-
tor and measure the
voltage at Pin 1
A K
A K
C
B
E
C
B
E
E
C
B
E C B
22
Abnormal
Normal 5V
RY2 does not turn on RY2
RY2 turns on
Abnormal
Normal 18 - 5V
16 - 5V
Abnormal
Normal
Abnormal
Normal
Abnormal
Normal
Abnormal
Normal
Forward
A - K Low
Forward
Low
B - E
B - C Low
C - E
Forward
E - B Low
C - B Low
C - E
Forward
E - B 10 -30 k
C - B 50 -90 k
40 -60 k
C - E
IC-220
IC-1
Step 2
Display
IC-1
IC-1
Display
1. Latch switch
2. DPC/Power relay
Step 2
DPC
1. Magnetron
2. Inverter circuit
Reverse
Reverse
Reverse
Reverse
10 -30 k