Mitsubishi Electric MSZ-FD25VA Service Manual page 30

C Check of indoor electronic control P.C. board and indoor fan motor
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 cement
resistor (R111) on the indoor elec-
tronic control P.C. board.
Measure the resistance of the i-see
Sensor motor coil.
(Refer to 10-5.)
Measure the resistance between
CN211 and of the indoor fan motor
Yes
connector.
Measure the resistance of the horizon-
tal vane motor coil and the vertical vane
motor coil.
(Refer to 10-5.)
Replace the varistor (NR11)
and fuse (F11).
Yes
Is 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?
Yes
Measure the resistance between
(+) and (-) of the indoor fan motor
connector. 1, 2
Is the resistance 1 MΩ
or more?
Yes
Replace the fuse (F11).
Is the resistance approx.
4 Ω?
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
No
1. The fan motor connector's
black.
2. Connect "+" of the tester to fan motor connector's
wire, and "-" to lead wire, otherwise the resistance can-
not be measured properly.
Replace the fuse (F11) and the
indoor fan motor.
No
Replace the indoor electronic control P.C.
board and the indoor fan motor.
No
Yes
lead wire is red, whereas is
lead