Mitsubishi Electric City Multi PMFY-P06NBMU-E Technical & Service Manual page 23

9-2. TROUBLESHOOTING
Check method of indoor fan motor (fan motor / controller board)
1
Notes
· High voltage is applied to the connecter (FAN) for the fan motor. Give attention to the service.
· Do not pull out the connector (FAN) for the motor with the power supply on, doing so may result in damage to the board.
2 Self check
Conditions : The indoor fan does not rotate.
Turn OFF the power supply.
Wiring contact check
Contact of fan motor connector (FAN)
Contact of power supply cable.
Was contact good?
Yes
Fan motor check
Measure the resistance between the fan motor connecter 1(+) and 3(–).
(With the connector pulled out from the
Is the resistance 1M " or more?
Yes
Turn ON the power supply.
Power supply check
Check the voltage of the indoor
Approx. 294~325V DC between the connecter (FAN) 1 (+) and 3 (–)
Is the voltage normal?
Yes
Fan motor position sensor signal check
Rotate the fan motor more than one turn slowly and check the voltage between
the connector (FAN) 6 (+) and 3 (–) with the connector (FAN) connected to the board.
Does the voltage repeat 0V DC and 15V DC ?
Yes
Replace the indoor controller board.
No
Correct wiring connection.
board)
No
Replace the fan motor.
controller board with the connector (FAN) connected to the board.
No
Indoor controller board fuse check
Turn off the power supply and check if there is
any broken wire by using a tester.
Is the fuse normal?
Replace the indoor controller board.
No
23
No
Yes
Replace the fan motor.
Replace the fuse.