Check Of Indoor Fan Motor; Check Of Remote Controller And Receiver P.c. Board - Mitsubishi Electric MS-18NV Service Manual

Check of indoor fan motor

A
Indoor fan does not operate.
No
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.2.

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.
wCheck if the remote controller is exclusive for this air conditioner.
Switch on the remote controller.
Is LCD display on the remote
controller visible?
Yes
Remove the batteries and then set them
back. 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.
Are lead wires connected?
Is resistance 0 (short circuit) or ° (open circuit)?
Repair the indoor fan motor.
No
Replace the batteries.(See page 18.)
(not clear)
Turn on a radio to AM and press switch on
No
the remote controller.
Is noise heard from radio?
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
Turn ON the power supply.
Measure the voltage between receiver P.C. board connector No.2
pressed.
Is the voltage approx. 4V DC?
Replace the receiver P.C. board.
Yes
Is soldered point normal?
No
(others)
Yes ( 0 or ° )
No
Yes
No
No(5V or 0V DC)
21
No
Yes
Insert screwdriver into air outlet to rotate indoor fan
motor slowly for 1 revolution or over, and measure
voltage No.2(+) and No.3(-) on CN121.
Does voltage repeat 0V DC and 5V DC?
Yes
Replace the indoor electronic control P.C. board.
No
Replace the remote controller.
Yes
Re-install the unit away from lights.
Attach a filter on receiving part.
and No.1when remote controller button is
(+)
Yes
Replace the indoor electronic control P.C.
board.
Resolder it.