A Check Of Indoor Fan Motor - Mitsubishi Electric MSZ-HC25VA Service Manual

10-5. TROUBLE CRITERION OF MAIN PARTS
MSZ-HC25VA MSZ-HC35VA MSZ-HC35VAB
Part name
Room temperature
thermistor (RT11)
Indoor coil thermistor
(RT12, RT13)
Indoor fan motor (MF)
MSZ-HC25
INNER FUSE
BA : 135 ± 3°C CUT OFF
CA : 140 ± 2°C CUT OFF
Indoor fan motor (MF)
MSZ-HC35
Vane motor (MV)
10-6. TROUBLESHOOTING FLOW

A Check of indoor fan motor

MSZ-HC25VA
No
Reconnect the lead wires.
Disconnect the lead wires from connector CN211 on indoor power P.C. board.
Measure the resistance between lead wires No.1 and No.4 and then No.4 and No.7.
Is the resistance 0 (short circuit) or ∞ (open circuit)?
Indoor terminal
P.C.board
Fuse (F11)
Check method and criterion
Measure the resistance with a tester.
Refer to 10-7. "Test point diagram and voltage", "2. Indoor electronic control
P.C. board", the chart of thermistor.
Measure the resistance between the terminals with a tester.
(Part temperature 10 ~ 30°C)
Color of lead wire
WHT - BLK
BLK - RED
Measure the voltage power ON.
Color of lead wire
BRN - YLW
BRN - GRY
Check 10-6. .
Measure the resistance between the terminals with a tester.
(Part temperature 10 ~ 30°C)
Color of the lead wire
RED - BLK
Turn OFF the power supply.
Check connector CN211 visually.
Are lead wires connected?
Yes ( 0 or )
Replace the indoor fan motor.
Indoor power P.C.board
CN121
Varistor
(NR11)
Normal
RC4V18-BA RC4V18-CA
273 ~ 296 Ω 308 ~ 334 Ω
295 ~ 320 Ω 295 ~ 320 Ω
Normal range
4.5 ~ 5.5 V
(When fan revolved one time)
0 V 5 V
(Approx.)
Normal
235 ~ 255 Ω
Are soldered points of the connector
Yes
correctly soldered to indoor power
P.C. board?
Yes
Turn ON the power supply. Rotate indoor fan slowly for 1
revolution or over with a screwdriver etc. from air outlet, and
No measure the voltage No.2(+) and No.1(-) on CN121.
(others)
No
Does the voltage repeat 0 and 5 VDC?
Replace the indoor power P.C. board, the indoor ter-
minal P.C. board and the indoor electronic control P.C.
board.
CN211
22
FUSE
0 V
BLK
BLK
RED
No
Resolder it.
Yes
Figure
MAIN
AUX.
ROTOR
BLK BLK