Mitsubishi Electric MS-30SV-A1 Service Manual page 31

Check of indoor electronic control P.C. board
C
Unit does not operate with the remote controller.
OPERATION INDICATOR lamp does not light up either, with the EMERGENCY OPERATION switch ON.
Check both "parts side"
and "pattern side" of indoor
electronic control P.C.
board visually.
Varistor (NR11)
Fuse (F11)
Indoor electronic
control P.C. board
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
Replace the vane motor.
Turn OFF the
power supply.
Is winding resistance
of vane motor 0 "?
Be sure to check both resistance.
Is winding resistance
of fan motor 0 "?
Replace the fan motor .
No
Turn OFF the
power supply.
Yes
No
Be sure to check both fuse
and varistor in any case.
No
Yes
31
Replace the fuse.
Yes
No
Is fuse (F11) blown?
No
Is varistor (NR11) burnt?
Yes
Replace the varistor.
Replace the
indoor electronic
control P.C. board.