Check Of Indoor Electronic Control P.c. Board - Mitsubishi Electric MSZ-A18YV Service Manual

The unit doesn't operate with the remote controller. Also, the OPERATION INDICATOR lamp doesn't light up by press-
ing the EMERGENCY OPERATION switch.

Check of indoor electronic control P.C. board

C
Check the both "parts side" and "pattern
side" of indoor electronic control P.C.
board visually.
Turn OFF the power supply.
Remove indoor fan motor connector CN211 and
vane motor connector CN151 from the indoor electronic
control P.C. board and turn ON the power supply.
Does the unit operate with the remote controller?
Does the OPERATION INDICATOR lamp light up
by pressing the EMERGENCY OPERATION switch?
Yes
Turn OFF the
power supply.
No
Replace the vane Turn OFF the
motor.
power supply.
Yes
Is winding
resistance of
vane motor 0 "?
No
Is winding
resistance of
No
fan motor 0 "?
Yes
Replace the fan
motor.
Indoor electronic
control P.C. board
Replace the fuse.
Yes
Is fuse(F11) blown?
No
No
Is varistor(NR11) burnt?
Yes
Replace the varistor.
16
Varistor (NR11)
Fuse (F11)
Replace the indoor
electronic control
P.C. board.