Mitsubishi Electric MSH-GE50VB-E1 Service Manual page 26

10-5. TROUBLESHOOTING FLOW
When OPERATION INDICATOR lamp flashes 3-time. Indoor fan motor does not operate.
A Check of indoor fan motor
No
Are lead wires connected?
Reconnect the lead wires.
Disconnect lead wires from connector CN211 on the indoor electronic control P.C. board.
Measure resistance between lead wires No.1 and No.5 and then No.3 and No.5 (MSC-GE20/25/35VB)/
No.3 and No.4 and then No.1 and No.4 (MS-GE50VB, MSH-GE50VB).
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but does not operate with the remote control-
ler.
Check of remote controller and receiver P.C. board
B
Check if the remote controller is exclusive for this air conditioner.
Press OPERATE/STOP (ON/OFF)
button on the remote controller.
Is LCD display on the remote con-
troller visible?
Yes
Remove the batteries, then set them back
and press the RESET button. Check if the
unit operates with the remote controller.
Does the unit operate with the
remote controller?
Yes
OK
OBH529A
Turn OFF the power supply.
Check connector CN211 visually.
Yes
Is resistance 0 (short circuit) or
Yes ( 0 or
Repair or replace the indoor fan motor.
No
Replace the batteries (Refer to 10-1.4.).
(not clear)
Turn ON a radio to AM and press
No
OPERATE/STOP (ON/OFF) button on the
remote controller.
Is noise heard from radio?
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1 m?
Measure the voltage between receiver P.C. board connector CN302 No.3(-) and No.5(+) (MSC-GE20/
25/35VB)/CN301 No.1(+) and No.3(-) (MS-GE50VB, MSH-GE50VB) when the remote controller button is
pressed (Refer to 10-6.).
Is the voltage approximately 4 V DC?
Replace the power monitor, receiver P.C board or the receiver P.C. board.
Is soldered point of the connector
correctly soldered?
Yes
Turn ON the power supply. Stop it if the unit operate.
Insert screwdriver into air outlet to rotate indoor fan
(open circuit)?
motor slowly for 1 revolution or over, and measure
No
voltage between No.2(+) and No.3(-) on CN121.
)
(others)
No
Replace the indoor electronic control P.C. board.
No
Yes
Yes
No
Yes
No (5 V or 0 V DC)
26
No
Resolder it.
Does voltage repeat 0 V DC and 5 V DC?
Yes
Replace the remote controller.
Reinstall the unit away from lights.
Attach a filter on receiving part.
Replace the indoor electronic control P.C.
board.