Mitsubishi Electric MSC-C07TV Service Manual page 54

Check of indoor electronic control P.C. board
C
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 both "parts side"
and "pattern side" of
indoor electronic control
P.C. board visually.
Check of outdoor unit
D
Compressor and / or outdoor fan motor doesn't operate.
<MU-C07/C09/C12TV>
Start
Check the voltage to terminal block of
outdoor unit. Is there 230V AC to terminal
L N?
block between -
Yes
Turn on the indoor power supply.
Press the EMERGENCY OPERATION switch.
3-minute time delay works.
Test run operation operates for 30 minutes.
Check the voltage to terminal block of
outdoor unit. Is there 12V DC to terminal
1 2?
block between -
Yes
Outdoor unit does not
operate.
Compressor
does not operate.
Outdoor fan motor
does not operate.
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
Check the outdoor power supply, power
supply cord and connection.
Check the voltage to terminal block of
No
indoor unit. Is there 12V DC to terminal block
1
between
Check the indoor electronic
control P.C. board.
Yes
Is the connection of wiring
in outdoor unit correct?
Make the connection of
wiring in outdoor unit
correct.
Is the connection of wiring
from terminal block to
compressor correct ?
Make the connection of
wiring from terminal block
to compressor correct .
Is the connection of wiring
from terminal block to
outdoor fan motor correct ?
Make the connection of
wiring from terminal block
to outdoor fan motor
correct .
No
Turn OFF the
power supply.
Yes
No
Be sure to check both fuse
and varistor in any case.
No
Yes
2?
-
No
Check the contactor(52C),
Yes
outdoor fan motor and
compressor.
No
Does outdoor unit operate?
Yes
Check the compressor.
Refer to page 52.
No
Does outdoor unit operate?
Replace the fuse "F"(2A).
Yes
Is fuse "F"(2A) blown?
No
Does outdoor unit operate?
54
Replace the fuse.
Yes
No
Is fuse(F11) blown?
No
Is varistor(NR11) burnt?
Yes
Replace the varistor.
Yes
Check the continuity of indoor and
outdoor unit connection.
No
Yes
Ok
No
Yes
Ok
Yes
No
Check the outdoor fan motor.
Refer to page 52.
No
Yes
Ok
Replace the indoor
electronic control
P.C. board.