Panasonic CS-Z25UD3EAW Service Manual page 110

18.4.16 H97 (Outdoor Fan Motor – DC Motor Mechanism Locked)
Malfunction Decision Conditions

The rotation speed detected by the Hall IC during fan motor operation is used to determine abnormal fan motor.
Malfunction Caused

Operation stops due to short circuit inside the fan motor winding.

Operation stops due to breaking of wire inside the fan motor.

Operation stops due to breaking of fan motor lead wires.

Operation stops due to Hall IC malfunction.

Operation error due to faulty outdoor unit PCB.
Troubleshooting
When abnormality indication starts again
Turn off power supply and rotate fan by
hand.
Does fan rotate smoothly?
YES
Turn power supply on and operate fan.
Does it rotate?
YES
Stop the fan motor
Check the rotation feedback output from
fan motor's CN-MTR1 output.
Rotate the fan motor manually (by hand)
while measure the voltage at PCB's
CN-MRT1
- Between 1(+) and 5(-)
- Between 2(+) and 5(-)
- Between 3(+) and 5(-)
For safety reason and to prevent
Caution component breakdown, always switch
off the power before remove and
connect the component.
NO
Replace fan motor.
NO
110
FAN MOTOR
MS
Turn off power supply and
disconnect fan motor CN-MRT2
connector.
Check resistance of the motor.
Measure at fan motor connector
CN-MRT1 (1-2, 1-3, 2-3).
Is the resistance normal?
YES
Use an inverter check to check on
the power transistor on board.
Connect it to PCB's CN-MRT2 port.
Turn power ON and run the unit.
Do all 6 LED light turn ON and turn
OFF periodically?
Does the voltage at each terminal
becomes 5 and 0Vdc repeatedly?
CN-MTR2
10
(WHT)
1
W
3
U
5
V
14
16
IC19
CN-MTR1
R105
1
R111
2
1k
R120
3 1k
4 1k
5V
5
C177
C175
+
0.01μ
C173 0.01μ
50V 50V
G5 G5 G5
PCB BOARD
U
V
W
NO
Replace fan motor.
NO
Replace outdoor PCB.
YES
Replace fan motor.
NO
Replace fan motor.
YES
Replace outdoor PCB.
C176
0.01μ
50V
G5