Mitsubishi Electric MXZ-3C30NA Service Manual page 81

• 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.
OBH702E
No
Replace the outdoor fan motor.
No
Replace the outdoor fan motor.
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 tester to pin4.
* Voltage between pin4 and 6 should be measured
within 1 minute after the operation starts.
No
Replace the outdoor control P.C. board.
No
Replace the outdoor fan motor.
No
Replace the outdoor fan motor.
81
CNF1 Outdoor control
P.C. board
Measuring points Resistance
pin1 - pin4
pin5 - pin4
pin6 - pin4
pin7 - pin4
* To measure the resistance, connect
the negative (-) end of the tester to pin4.