Mitsubishi Electric MS-30SV-A1 Service Manual page 30

Check of indoor fan motor
A
Indoor fan does not operate.
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.4 and then No.1 and No.3.
Check of remote controller and receiver P.C. board
B
Indoor unit operates by pressing the EMERGENCY OPERATION switch, but does not operate with the remote controller.
W Check if the remote controller is exclusive for this air conditioner.
Switch on the remote controller.
Is LCD display on the remote con-
troller visible?
Yes
Remove 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
Turn OFF the power supply.
Check connector CN211 visually.
Yes
Is soldering point of the connector correctly soldered?
Is resistance 0 (short circuit) or ∞ (open circuit)?
Yes ( 0 or ∞ )
Repair the indoor fan motor.
No
Replace the batteries.(Refer to page 26.)
(not clear)
No
Turn on a radio to AM and press switch on
the remote controller.
Is noise heard from radio?
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
Measure the voltage between receiver P.C. board connector CN301 No.2
button is pressed.
Is the voltage approx. 4V DC?
Replace the receiver P.C. board.
Yes
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure
No voltage No.2(+) and No.3(-) on CN121.
(others)
No
Replace the indoor electronic control P.C. board.
No
Yes
Yes
No
Yes
No(5V or 0V DC)
30
No
Resolder it.
Does voltage repeat 0V DC and 5V DC?
Yes
Replace the remote controller.
• Re-install the unit away from lights.
• Attach a filter on receiving part.
(-)
(+)
and No.3 when the remote controller
Replace the indoor electronic control
P.C. board.