Mitsubishi Electric EHST20C-VM6HB Service Manual page 44

Check method of DC fan motor (fan motor/outdoor controller circuit board)
Notes
1
· High voltage is applied to the connecter (CNF1, 2) for the fan motor. Pay attention to the service.
· Do not pull out the connector (CNF1, 2) for the motor with the power supply on.
(It causes trouble of the outdoor controller circuit
Self check
2
Symptom : The outdoor fan cannot rotate.
Fuse check
Check the fuse (F5) on outdoor
controller board.
Did the fuse blow?
No
Wiring contact check
Contact of fan motor connector (CNF1, 2)
Is there contact failure?
No
Power supply check (Remove the connector (CNF1, 2))
Measure the voltage in the outdoor controller circuit
TEST POINT
1 : V
DC
TEST POINT 2 : V
CC
Is the voltage normal?
No
Replace the outdoor
controller board.
Check the operation.
Fail
Replace the fan motor.
11-5. HOW TO CHECK THE COMPONENTS
<HIGH PRESSURE SENSOR>
Vout (V)
4.5
2.5
0.5
OCH533D
Replace the outdoor controller board
Yes
(C.B) and the fan motor (MF1, 2).
Recover wiring.
Yes
(between 1 (+) and 4 (−) of the fan connector):V
(between 5 (+) and 4 (−) of the fan connector):V
Yes
OK
END
2.5 5
PRESSURE
(MPa)
board and fan motor.)
board.
250–330 V DC
DC
15 V DC
CC
Replace the fan motor.
Yes
Check the operation of fan.
Fail
Replace the outdoor controller board.
WHT
BLU
Vout
BLK
63HS
3-1 : 5 V (DC)
2-1 : Output Vout (DC)
44
OK
END
MULTI
CONTROLLER BOARD
5 V DC
3
2
MICRO
PROCESSOR
1
GND