Check Of Remote Controller And Receiver P.c. Board - Mitsubishi MSZ-GA50VA Service Manual

Indoor unit operates by pressing EMERGENCY OPERATION switch, but does not operate with the remote controller.

Check of remote controller and receiver P.C. board

B
wCheck if the remote controller is exclusive for this air conditioner.
Press OPERATE/STOP(ON/OFF) but-
ton on the remote controller.
Is LCD display on the the remote
controller visible?
Yes
Remove the batteries, then set them back
and press RESET button. (Refer to 9-1.4.)
Check if the unit operates with the remote
controller.
Does the unit operate with the
remote controller?
Yes
OK
No
Replace the batteries. (Refer to 9-1.4.)
(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 1m?
Measure the voltage between receiver P.C. board connector CN301 No.2(+) and No.3(-) when the remote
controller button is pressed.
Is the voltage approx. 4V DC?
Replace the receiver P.C. board.
No
Yes
Yes
Yes
No
(5V or 0V DC)
19
Replace the remote controller.
Reinstall the unit away from lights.
Attach a filter on receiving part.
Replace the indoor electronic control P.C.
board.