Check Of Remote Controller And Receiver P.c. Board; Check Of Indoor Electronic Control P.c. Board - Mitsubishi Electric MCF-GA35VB Service Manual

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

Check of remote controller and receiver P.C. board

B
w Check if the remote controller is exclusive for this air conditioner.
Switch on the remote controller
Is LCD display on remote controller
visible?
Remove batteries and then set them back and press
the RESET button. Check if the unit operates with
remote controller.
Does the unit operate with remote controller?
OK
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 No.2(+)and No.1 when remote controller button is pressed.
Is the voltage approx. 4V DC?
Replace the receiver.
The unit doesn't operate with the remote controller.
Also, the OPERATION INDICATOR lamp doesn't light up by pressing the EMERGENCY OPERATION switch.

Check of indoor electronic control P.C. board

C
Check both "parts side"and "pattern
side" of indoor electronic control P.C.
board visually.
No
(not clear)
Yes
No
Yes
Turn on a radio to AM and press
switch on remote controller.
No
Yes
Yes
No
No
Yes
No
(5V DC or 0V DC)
Replace the fuse.
Is fuse(F11)blown?
Be sure to check both fuse
and varistor in any case.
Is varistor(NR11)burnt?
Replace the varistor.
Replace the batteries.(Refer to 9-1.)
Replace the remote controller.
Reinstall the unit away from lights.
Attach a filter on receiving part.
Replace the indoor
electronic control P.C. board.
Yes
No
No
Yes
13
Trouble of the indoor electronic
control P.C. board.