Mitsubishi Electric MSC-A07WV-E1 Service Manual page 113

The unit doesn't operate with the remote controller.
Also, the OPERATION INDICATOR lamp doesn't light up by pressing the EMERGENCY OPERATION switch.
C C Check of indoor electronic control P.C. board
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 Replace the vane
power supply. motor.
Is winding
resistance of
vane motor 0 "?
Be sure to check both resistances.
Is winding
resistance of
fan motor 0 "?
Replace the fan motor.
Compressor and/or outdoor fan motor doesn't operate.
D D Check of outdoor unit
Start
Is the switch SW2-2 on the
indoor electronic control
P.C. board set to MUH type?
Yes
Operate the unit in COOL or HEAT mode by pressing the EMERGENCY OPERATION switch.
3-minute time delay works.
Test run operation operates for 30 minutes.
Compressor
doesn't operate.
Is there 5V DC between J205
the deicer P.C. board?
Yes
Is there 230V AC between 3 on the
compressor contactor (52C) and N
on the outdoor terminal block (TB1)?
Yes
Check the compressor and compressor
capacitor, and rectify the connecting wire.
Outdoor fan motor
doesn't operate.
Is there 5V DC between J205
the deicer P.C. board?
Yes
Check the outdoor fan motor
and rectify the connecting
wire.
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No
Turn OFF the
Replace the fuse.
power supply.
Yes
Is fuse (F11) blown?
No
Be sure to check both fuse
and varistor in any case.
Is varistor (NR11) burnt?
No
Yes
Replace the varistor.
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Change the switch SW-2-2
No
on the indoor electronic control
P.C. board to MUH type.
No Is there 230V AC between 4 on the
+ –J101 on
–
compressor contactor (52C) and
TAB20 on the deicer P.C. board?
Replace the
No
Replace the
deicer P.C.
deicer P.C. board.
board.
Is there 230V AC between 4 on the
No
+
–J101 on –
compressor contactor (52C) and
TAB 20 on the deicer P.C. board?
Replace the
deicer P.C. board.
Yes
No
Replace the indoor
electronic control
P.C. board.
No
Yes
No
Is there 230V AC between L–N
on the outdoor terminal block (TB1)?
Yes
No
Is there 230V AC between L–N on
the outdoor terminal block (TB1)?
Yes
113
Rectify the indoor and
outdoor connecting wire.
No
Yes
Rectify the connecting wire.
Rectify the indoor and
outdoor connecting wire.
No
Yes
Rectify the connecting wire.