Mitsubishi Electric Mr.Slim MSY-D30NA, Service Manual

Page: 108 / 214

30
C Check of indoor P.C. board and indoor fan motor
Turn OFF the power supply.
Remove indoor fan motor connector CN211
from indoor power P.C. board 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?
Yes
No
Measure the resistance of indoor fan
motor.
(Refer to 9-5.)
Short circuit:
Replace the indoor fan motor.
Turn OFF the power supply.
Check both “parts side” and “pat-
tern side” of the indoor terminal P.C.
board visually.
Replace the varistor (NR11)
and fuse (F11). 3
Are the varistor (NR11)
burnt and the fuse (F11)
blown?
No
No
Yes
Yes
Be sure to check both the fuse
and the varistor in any case.
Is the fuse (F11) blown
only?
Measure the resistance between
CN211 (+) and (-) of indoor fan
motor connector. 1, 2
Yes
Is the resistance 1M Ω or more?
Replace the fuse (F11) and the
indoor fan motor. 3
No
Replace the fuse (F11). 3
Measure the resistance of resistor
(R111) on the indoor power P.C.
board.
No
Is the resistance of
resistor (R111) approxi-
mately 4 Ω ?
No
Replace the indoor
power P.C. board, the
indoor terminal P.C.
board and the indoor fan
motor.
Replace the indoor electronic control P.C. board.
Measure the resistance of the vane
motor coil.
(Refer to 9-5.)
Short circuit:
Replace the vane motor and the indoor
electronic control P.C. board.
1. The fan motor connector's lead wire is red,
whereas is black.
2. Connect "+" of the tester to fan motor connector's
lead wire, and “-” to lead wire, otherwise the
resistance cannot be measured properly.
3. Please replace the fuse after removing the indoor
terminal P.C. board from the electrical box.
Is there approximately 5 VDC between
5 V (+) and JPG (GND) (-) of the
indoor electronic control P.C. board?
Is there approximately 9 to 13 VDC
between 12 V (+) and JPG (GND) (-)
of the indoor electronic control P.C.
board?
Are connector CN10A on the
indoor electronic control P.C.
board or lead wires discon-
nected?
Yes
Replace the indoor fan motor.
Yes
Connect the connector or repair
disconnection.
Yes
No
Indoor electronic control
P.C. board
JPG (GND)
CN10A
12 VDC
5 VDC
Indoor terminal
P.C. board
Indoor power P.C. board
Fuse
(F11)
Varistor
(NR11)
CN211
R111
MSZ-GE06/09/12/15/18NA
MSY-GE09/12/15/18NA
OBH548D