Dc Fan Motor; Sensor Signal Check; Wiring Contact Check; Power Supply Check - Mitsubishi Electric Mr.Slim PKA Series Service Manual

9-6-2. DC Fan motor (fan motor/indoor controller circuit board)
Check method of DC fan motor (fan motor/indoor controller circuit board)
1 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.)
2 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.
(between 1 (+) and 4 (−) of the fan connector): V
TEST POINT 1 : V
DC
(between 5 (+) and 4 (−) of the fan connector): V
TEST POINT 2 : V
CC
Is the voltage normal?
Yes

Sensor signal check

Measure the voltage between CNMF 6 and 3 0 V DC
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.
OCH758
Yes
Correct the wiring.
NO
Indoor controller board fuse check
Is the fuse normal?
Replace the indoor
controller board.
Check the operation.
Replace the defective fan motor.
NO
Replace the defective fan motor.
OK
Complete.
310–340 V DC
DC
15 V DC
CC
NO
Yes
Fail
Check the operation.
OK
Complete.
Fail
Yes
Check the operation of fan.
Fail
Replace the indoor
controller board.
26
Replace the fuse.
OK
Complete.
OK
Complete.