Mitsubishi Electric PKA-A12LA1 Service Manual page 23

9-6-2. DC Fan motor (fan motor/indoor controller circuit board)
Check method of DC fan motor (fan motor/indoor controller circuit board)
Notes
· High voltage is applied to the connector (CNMF) for the fan motor. Pay attention to the service.
· Do not pull out the connector (CNMF) for the motor with the power supply on.
(It causes trouble of the indoor controller circuit board and fan motor.)
Self check
Symptom : The indoor fan cannot rotate.
Wiring contact check
Contact of fan motor connector (CNMF)
Is there contact failure?
No
Power supply check (Remove the connector (CNMF))
Measure the voltage in the indoor controller circuit board.
TEST POINT : V (between 1 (+) and 4 (−) of the fan connector): V
DC
TEST POINT : V (between 5 (+) and 4 (−) of the fan connector): V
CC
Is the voltage normal?
Yes
Sensor signal check
Measure the voltage between CNMF
and 15 V DC in the indoor controller circuit board.
Does the voltage repeat
0 V DC and 15 V DC?
Yes
Replace the indoor
controller board.
Check the operation.
Fail
Replace the defective fan motor.
Symptom: The fan motor does not stop when pressing the stop button on the remote controller.
The fan motor starts to rotate when turning on the breaker.
Process: The connector for emergency operation on the indoor controller board is possibly set to ON.
Check the setting of SWE.
Set SWE to OFF if it is set to ON.
TCH117
Yes
Correct the wiring.
No
Replace the indoor
controller board.
Check the operation.
Replace the defective fan motor.
and 0 V DC
No
Replace the defective fan motor.
OK
Complete.
23
294-325 V DC
DC
15 V DC
CC
OK
Complete.
Fail
Yes
Check the operation of fan.
Fail
Replace the indoor
controller board.
OK
Complete.