Mitsubishi Electric MSZ-D30NA Service Manual page 26

Indoor unit operates by pressing EMERGENCY OPERATION switch, but does not operate with the remote controller.
B Check of remote controller and receiver P.C. board
Check 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, 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
Replace the batteries. (Refer to 9-1.4.)
No
(not clear)
Turn ON a radio to AM and press switch
No ON the remote controller.
Is noise heard from radio?
Yes
Are there any fl uorescent lights of
inverter or rapid-start type within the
range of 3.28 ft.?
No
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. 4VDC?
No (5 or 0 VDC)
Replace the receiver P.C. board.
No
Yes
Yes
26 26
Replace the remote controller.
• Reinstall the unit away from lights.
• Attach a fi lter on receiving part.
Replace the remote controller.