Mitsubishi Electric Mr.Slim MSY-D30NA, Service Manual, Page: 69 / 214

35
Turn OFF the power supply.
Is there rated voltage in the
power supply?
Yes
No
Turn ON the power supply.
Check the power supply.
Is there rated voltage between
outdoor terminal block S1 and
S2?
No
Check the wiring.
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION INDICA-
TOR lamp light up? <Con
fi rmation of the
power to the indoor unit>
Yes
No
Is serial signal error indicated 6 minutes later?
Yes
No
Is there any miswiring, poor
contact, or wire disconnec-
tion of the indoor/outdoor
connecting wire?
Is fuse (F65 or F66) broken?
Yes
Correct them.
No
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not miswiring.
Short-circuit outdoor terminal block S2
and S3. 1
B
1. Miswiring may damage indoor electronic control P.C.
board during the operation.
Be sure to con fi rm the wiring is correct before the opera-
tion starts.
3. Be sure to check this within 3 minutes after turning ON.
After 3 minutes, LED blinks 6 times. Even when the
inverter P.C. board or the outdoor electronic control P.C.
board is normal, LED blinks 6 times after 3 minutes.
Turn ON the power supply.
Does the LED on the inverter P.C. board or
the outdoor electronic control P.C. board
repeat "3.6-second-OFF and 0.8-second-
ON quick blinking"? 3
Yes
No
(Lighted
or not
lighted)
Replace the inverter P.C. board or
the outdoor electronic control P.C. board.
2
2. Be careful of the residual voltage
of smoothing capacitor.
Turn OFF the power supply.
Remove the short-circuit between
outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there amplitude of 10 to 20 VDC
between outdoor terminal block S2 and
S3? <Con
fi rmation of serial signal>
Yes
No
Is there any error of the in-
door/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
Yes
Replace the indoor/
outdoor connecting
wire.
Turn OFF inverter-controlled lighting
equipment.
Turn OFF the power supply and then
turn ON again.
Press EMERGENCY OPERATION
switch. •
•
•
A
Is serial signal
error indicated 6
minutes later?
B
Yes
Reinstall
either the unit
or the light
away from
each other.
Attach a
fi lter
on remote
control
receiving
section of the
indoor unit.
•
•
No
Is there rated voltage between
indoor terminal block S1 and S2?
<Con
fi rmation of power voltage>
No
No
Is there any error of the in-
door/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
Yes
Replace the indoor/
outdoor connecting
wire.
No
Replace the indoor electronic control P.C. board.
Yes
Be sure to release the failure-mode recall function
after checking.
Yes
H How to check miswiring and serial signal error
Outdoor electronic control P.C. board
Blinking Lighted
(Parts side)
LED2 LED1