Mitsubishi Electric MXZ-2C30VA Service Manual page 103

MXZ-6C120/6C122VA
Disconnect CN931 and measure the
resistance of the outdoor fan motor.
Is the resistance of outdoor fan motor
normal? (Refer to right table)
Yes
Does the outdoor fan motor rotate smoothly?
Yes
Turn on the power supply to start operation
and measure the voltage of connector CN931.
Is the voltage of connector CN931
normal? (Refer to right table.)
Yes
Turn OFF the power supply and connect
the connector CN931.
Turn ON the power supply and measure
the voltage of connector CN931 while
rotating the motor by the hand.
Does the voltage between pin 7 and pin 4
of connector CN931 repeat 0V and 5V?
Yes
Start operation.
Does the fan motor operate for about
5 seconds?
Yes
Replace the control P.C. board or outdoor
control P.C. board.
OBH584E
No
Replace the outdoor fan motor.
No
Replace the outdoor fan motor.
CN931 Voltage
pin 1 - pin 4 325 V DC
pin 5 - pin 4 15V DC
pin 6 - pin 4 1 - 5V DC
* To measure the voltage, connect the negative (-)
end of the tester to pin 4.
* Voltage between pin 4 and 6 should be measured
within 1 minute after the operation starts.
No
Replace the control P.C. board or outdoor
control P.C. board.
No
Replace the outdoor fan motor.
No
Replace the outdoor fan motor.
103
MXZ-6C120
CN931
Control P.C.
board
Measuring points
pin 1 - pin 4
pin 5 - pin 4
pin 6 - pin 4
pin 7 - pin 4
* To measure the resistance, connect
the negative (-) end of the tester to pin 4.
MXZ-6C122
Outdoor control
P.C. board
Resistance
60 kΩ
160 kΩ