Mitsubishi Electric Mr. SLIM PKA Series Service Manual page 27

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
1
· High voltage is applied to the connecter (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
Self check
2
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
TEST POINT
1 : V (between 1 (+) and 3 (−) of the fan connector): V
DC
TEST POINT
2 : V (between 4 (+) and 3 (−) 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 fan motor.
TCH069A
board and fan motor.)
Wiring recovery
Yes
board.
No
Indoor controller board fuse check
and 0 V DC
6 3
No
OK
END
27
310–340 V DC
DC
15 V DC
CC
Is the fuse normal?
Yes
Fail
Replace the indoor
controller board.
OK
Check the operation.
Fail
Replace the fan motor.
Replace the fan motor.
Yes
Check the operation of fan.
Fail
Replace the indoor controller board.
No
Replace
the fuse.
OK
Check the operation
END
OK
END
END