Mitsubishi Electric MUZ-D-NA Series Service Manual page 26

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
ON the remote controller.
No
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 approximately 4 VDC?
No (5 or 0 VDC)
Replace the receiver P.C. board.
26
Replace the remote controller.
No
• Reinstall the unit away from lights.
• Attach a fi lter on receiving part.
Yes
Replace the remote controller.
Yes