Mitsubishi Electric MXZ-2C20NA2 Service Manual page 126

• Fan motor does not operate or stops operating shortly after starting the operation.
Check of outdoor fan motor
Disconnect CNF1 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 CNF1.
Is the voltage of connector CNF1
normal? (Refer to right table.)
Yes
Turn OFF the power supply and connect
the connector CNF1.
Turn ON the power supply and measure
the voltage of connector CNF1 while
rotating the motor by the hand.
Does the voltage between pin7 and pin4
of connector CNF1 repeat 0V and 5V?
Yes
Start operation.
Does the fan motor operate for about
5 seconds?
Yes
Replace the outdoor control P.C. board.
OBH702N
Replace the outdoor fan motor.
No
Replace the outdoor fan motor.
No
CNF1 Voltage
pin1 - pin4 294/325 V DC
pin5 - pin4 15 V DC
pin6 - pin4 1 - 5 V DC
* To measure the voltage, connect the negative (-)
end of the multimeter to pin4.
* Voltage between pin4 and 6 should be measured
within 1 minute after the operation starts.
Replace the outdoor control P.C. board.
No
Replace the outdoor fan motor.
No
Replace the outdoor fan motor.
No
126
CNF1 Outdoor control
P.C. board
Model name of fan motor*:
SIC-71XX-XXXX-X, SIC-81XX-XXXX-X
Measuring points Resistance
pin1 - pin4
60 kΩ
pin5 - pin4
160 kΩ
pin6 - pin4
pin7 - pin4
Model name of fan motor*:
SIC-82XX-XXXX-X, SIC-88XX-XXXX-X
Measuring points Resistance
1.1 MΩ
pin1 - pin4
40 kΩ
pin5 - pin4
220 kΩ
pin6 - pin4
pin7 - pin4
* To measure the resistance, connect
the negative (-) end of the multimeter
to pin4.
* See the spec name plate indicated in
the diagram for the model name of fan
motor.
* Where "X" in model name of fan motor
represents numbers and letters
Spec name plate
of fan motor