Mitsubishi Electric MSZ-FD25VA Service Manual page 30

The unit does not operate with the remote controller.
Also, POWER lamp does not light up by pressing EMERGENCY OPERATION switch.
Check of indoor P.C. board and indoor fan motor
C
Turn OFF the power supply.
Remove indoor fan motor connector CN211, vane motor
connector CN151 and the i-see Sensor motor connector
CN110 from the indoor electronic control P.C. board and
turn ON the power supply.
Does the unit operate with the remote controller?
Does POWER lamp light up by pressing EMERGENCY
OPERATION switch?
No
Turn OFF the power supply.
Check both "parts side" and "pattern
side" of the indoor electronic control P.C.
board visually.
Measure the resistance of the i-see Sensor
motor coil.
Refer to 10-5.
Yes
Measure the resistance between CN211 3
and 4 of the indoor fan motor connector.
Measure the resistance of the horizontal vane
motor coil and the vertical vane motor coil.
Refer to 10-5.
Replace the varistor(NR11) and fuse(F11).
Are the varistor(NR11) burnt
and the fuse(F11) blown?
Be sure to check both the fuse
and the varistor in any case.
Is the fuse(F11) blown only?
Measure the resistance between
1(+) and 3(-) of the indoor fan
motor connector.
w1,w2
Is the resistance 1 M"
or more?
Replace the fuse (F11).
Measure the resistance of cement
resistor(R111) on the indoor electronic
control P.C. board.
Yes
No
No
Yes
w1. The fan motor connector's 1 lead wire is red, whereas 3 is black.
w2. Connect "+" of the tester to fan motor connector's 1 lead
wire, and "-" to 3 lead wire, otherwise the resistance cannot be
measured properly.
No
Replace the fuse (F11) and the indoor fan motor.
Yes
Is the resistance
approx. 4 "?
Yes
Replace the indoor electronic control P.C. board.
30
Short/open circuit:
Replace the i-see Sensor motor
and the indoor electronic control P.C.
board.
Short/open circuit:
Replace the indoor fan motor.
Short/open circuit:
Replace the horizontal vane motor, the
vertical vane motor and the indoor
electronic control P.C. board.
No
Replace the indoor electronic control P.C. board
and the indoor fan motor.