Mitsubishi Electric Mr.Slim MUZ-A09NA Service Manual page 52

I Check of outdoor fan motor
MUZ-A09/12/15/17 MUY-A15/17
Is the resistance
between each terminal
of outdoor fan motor
normal?
(Refer to 10-4.)
No
Replace the outdoor fan
motor.
MUZ-A24 MUY-A24 MUZ-GA24 MUY-GA24
Check the connection between the
connector CN931 and CN932.
Is the resistance between each ter-
minal of outdoor fan motor normal?
(Refer to 10-4.)
No
(Fixed to either 5 or 0 VDC)
Replace the outdoor fan motor.
Disconnect CN932
from the inverter
Yes
P.C. board.
Yes
No
No
Turn ON the power
supply.
(Fixed to either 5 or 0 VDC)
Disconnect CN932 from outdoor electronic control P.C. board,
and turn on the power supply.
Rotate the outdoor fan motor manually and measure the voltage
of CN931.
Between 1(+) and 5(-)
Between 2(+) and 5(-)
Between 3(+) and 5(-)
Does the voltage between each terminal become 5 and 0
VDC repeatedly?
Does the outdoor fan motor rotate smoothly?
Replace the outdoor electronic control P.C. board.
52
Rotate the outdoor fan
slowly by hand, and measure
the voltage of CN931
(Measurement of feedback
output).
Between 1(+) and 5(-)
Between 2(+) and 5(-)
Between 3(+) and 5(-)
Does the voltage between
each terminal repeat 5
No
and 0 VDC by turns?
Yes
Does the outdoor fan
No rotate smoothly?
Yes
Check the inverter P.C.
board. (Refer to 10-5. )
Yes
Yes