Check Of Remote Controller And Receiver P.c. Board; Check Of Indoor Electronic Control P.c. Board - Mitsubishi Electric MCFZ-A12WV 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?
Yes
Remove the batteries, then set them back and
press the RESET button. (Refer to 10.) Check
if the unit operates with the remote controller.
Does the unit operate with remote
controller?
Yes
OK
The unit does not 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
Replace the batteries.(Refer to page 10.)
(not clear)
No
Turn on a radio to AM and press switch
on remote controller.
Is noise heard from radio?
Yes
Are there any fluorescent lights of
inverter or rapid-start type within
the range of 1m?
No
Measure the voltage between receiver P.C.board connector CN101 No.2(+) and No.1 (-)
when remote controller button is pressed.
Is the voltage approx. 4V DC ?
No(5V or 0V DC)
Replace the receiver P.C. board.
Replace the fuse.
Is fuse (F11) blown?
Is varistor (NR11) burnt?
Replace the varistor.
14
No
Yes
Yes
Yes
No
Replace the indoor
No
electronic control
P.C. board.
Yes
Replace the remote controller.
Reinstall the unit away from lights.
Attach a filter on receiving section of
the indoor unit.
Replace the indoor electronic control
P.C. board.