Obh621 - Mitsubishi Electric MS-GF20VA-E1 Service Manual

10-5. TROUBLE CRITERION OF MAIN PARTS
Part name
Room temperature
thermistor (RT11)
Indoor coil thermistor
(RT12)
Indoor fan motor (MF)
INNER FUSE
145 °C CUT OFF
Horizontal vane motor
(MV)
10-6. TROUBLESHOOTING FLOW
A Check of indoor fan motor
Reconnect the lead wires.
Disconnect 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
Indoor terminal
P.C.board
Fuse (F11)

OBH621

Measure the resistance with a tester.
Refer to 10-7. "Test point diagram and voltage", "1. Indoor electronic control
P.C. board", for the chart of thermistor.
Measure the resistance with a tester.
(Part temperature 10 ~ 30 °C)
Color of the lead wire
WHT-BLK
BLK-RED
Measure the resistance between the terminals with a tester.
(Temperature: 10 - 30°C)
Color of the lead wire
RED-BLK
Turn OFF the power supply.
Check connector CN211 visually.
No
Are lead wires connected?
Yes ( 0 or
Replace the indoor fan motor.
Indoor power P.C.board
Varistor
(NR11)
Check method and criterion
Normal
334 Ω ~ 362 Ω
370 Ω ~ 402 Ω
Normal
223 Ω ~ 268 Ω
Yes
Are soldered points of the
connector correctly soldered to
the indoor power P.C. board?
Pay enough attention to the high voltage on the
fan motor connector.
Turn ON the power supply. Stop it if the unit operates.
Insert screwdriver into air outlet to rotate indoor fan
(open circuit)?
motor slowly for 1 revolution or over, and measure the
No
voltage No.2(+) and No.1(-) on CN121.
(others)
)
No
CN121
CN211
20
No
Yes
Does the voltage repeat 0 VDC and 5 VDC?
Yes
Replace the indoor power/terminal P.C. board
and the indoor control P.C. board.
Figure
MAIN
AUX.
FUSE
BLK RED WHT
BLK
ROTOR
BLK
RED
BLK BLK
Resolder it.