Mitsubishi Electric MSZ-HR25VF-E1 Service Manual page 24

C Check of indoor P.C. board and indoor fan motor
Turn OFF the power supply.
Remove indoor fan motor connector CN211
and vane motor connector CN151 from the
indoor electronic control P.C. board and turn
ON the power supply.
Does the unit operate with the remote
controller?
Does OPERATION INDICATOR lamp light
up by pressing EMERGENCY OPERATION
switch?
No
Turn OFF the power supply.
Check both "parts side" and "pattern
side" of the indoor power P.C. board
visually.
1. Please replace the fuse after removing the
indoor power P.C. board from the electrical
box.
2. The fan motor connector's lead wire is red,
whereas is black.
3. Connect "+" of the tester to fan motor
connector's lead wire, and "-" to
otherwise the resistance cannot be measured
properly.
Measure the resistance of resistor (R111)
on the indoor power P.C. board.
Indoor electronic
control P.C. board
12 VDC
5 VDC
GND
FUSE (F11)
Varistor (NR11)
OBH822
Measure the resistance of indoor fan
motor.
Refer to 10-5.
Measure the resistance of the vane
motor coil.
Yes
Refer to 10-5.
Replace the varistor (NR11)
and fuse (F11). 1
Yes
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?
Yes
Measure the resistance between
CN211 (+) and (-) of indoor fan
motor connector. 2, 3
lead wire,
Is the resistance 1MΩ or more?
Yes
Replace the fuse (F11). 1
Replace the indoor electronic control P.C. board.
No
No
Replace the fuse (F11) and the
No indoor fan motor. 3
Is the resistance of resistor (R111)
approximately 4 Ω ?
Yes
24
Short circuit:
Replace the indoor fan motor.
Short circuit:
Replace the vane motor and the indoor
electronic control P.C. board.
Replace the indoor electronic
control P.C. board and the indoor
No
fan motor.