14
A
A
Check of indoor fan motor
Is soldered point of the
connector correctly soldered?
Is resistance 0 (short circuit) or
∞
(open circuit)?
Yes ( 0 or
∞
)
Yes
No
Yes
No
Turn OFF the power supply.
Check connector CN211 visually.
Disconnect lead wires from connector CN211 on indoor electronic control P.C. board.
Measure resistance between lead wires No.1 and No.5 and then No.3 and No.5.
When OPERATION INDICATOR lamp flashes 3-time.
Indoor fan motor doesn’t operate.
Turn ON the power supply. Stop it if the unit operates.
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure volt-
age No.2(+) and No.3(-) on CN121.
No
(others)
Replace the indoor electronic control P.C. board.
Does voltage repeat 0V DC and 5V DC?
Yes
No
Are lead wires connected?
Reconnect the lead wires.
Resolder it.
Repair or replace the indoor fan motor.
Measure the resistance between the terminals with a tester.
(Coil wiring temperature10°C ~ 30°C)
Room
temperature
thermistor (RT11)
9-4. Trouble criterion of main parts
Part name
Indoor coil
thermistor (RT12)
Indoor fan
motor (MF)
INNER FUSE
136
i
3°C
CUT OFF
Motor part
Sensor part
Check method and criterion
Measure the resistance with a tester.
(Part temperature 10°C ~ 30°C)
Measure the voltage Power ON.
Figure
8k
Ω
~ 20k
Ω
Normal
Abnormal
Open or
short-circuit
271 ~ 295
Ω
WHT-BLK
BLK-RED
BRN-YLW
YLW-GRY
Normal
4.5 ~ 5.5V
Abnormal
Remain 0V or 5V
(When fan revolved one time)
0V
➔
5V
➔
0V
(Approx.)
MSC-GA20/GA25VB
180 ~ 196
Ω
RED
BLK
YLW
FUSE
GRY
BRN
WHT
MSC-GA20VB -
MSC-GA25VB -
MSC-GA35VB -
E1
E1
E1
Normal
Abnormal
Open or
short-circuit
MSC-GA20/GA25/GA35VB
MSC-GA20/GA25/GA35VB
Vane motor
(MV)
Measure the resistance between the terminals with a tester.
(Part temperature10°C ~ 30°C)
Normal
Abnormal
Open or
short-circuit
240 ~ 260
Ω
RED
YLW
BRN
ORN
GRN
ROTOR
MSC-GA20/GA25/GA35VB
Color of
lead wire
215 ~ 233
Ω
MSC-GA35VB
305 ~ 331
Ω
Color of
lead wire
9-5. Troubleshooting flow
OB385-1.qxp 05.1.25 14:50 Page 14
