Checking Mis-Wiring/Serial Signal Error (Outdoor Unit Does Not Work) - Mitsubishi Electric MSC-07RV Service Manual

How to check mis-wiring and serial signal error (when outdoor unit does not work)
E
Turn OFF the power supply(indoor/outdoor unit).
•Turn ON the power supply(indoor/outdoorunit).
•Press once EMERGENCY OPERATION switch.
Yes
Make them sure.
1. Turn OFF the power supply
2. Short-circuit between indoor terminal block N and 3.
3. Turn ON the power supply
(indoor unit)
Start
Is the outdoor unit "MUH or MXZ" type?
Yes
3 min. later, what self-check result is
displayed on Operation Indicator
w
lamp on indoor unit? 2
Mis-wiring is indicated.
(0.5-sec. ON, 0.5-sec. OFF)
Is this mis-wiring, poor contact,
or wire disconnection?
No
and disconnect in-out connecting wire on indoor side.
(indoor/outdoor unit)
and press once EMERGENCY OPERATION switch.
Is there 20V DC between both ends of
R132 on indoor electronic control P.C.
board ?
( By tester, the stylus is between 0 ~ 20V. )
Yes
•Turn OFF the power supply(indoor unit).
•Connect ON in-out connecting wire.
Turn ON the power supply(outdoor unit).
Is the outdoor unit "MUH" type?
Yes
Is there 220-240V AC between outdoor
L N
terminal block - ?
Yes
-
Is there 5V DC between J8 -J9
(See page 143.)
Yes
Turn ON the power supply(indoor unit).
During EMERGENCY OPERATION,
is there 10V DC between both ends
of R601? (See page 143.)
(By tester, the stylus is between 5 ~10V)
Yes
Replace the DEICER P.C. board.
w
1 Set the switch(SW2-2) on indoor electronic control P.C. board to
MU type, when the outdoor unit is MU type.
If the setting is MUH type, the unit does not work.
w
2 Short circuit of JPG and JPS on the indoor electronic control
P.C. board enables self -check to be displayed in 3 seconds.
No
Serial signal error is indicated.
(0.5-sec. ON, 2.5-sec. OFF)
No
Replace the indoor electronic
control P.C. board.
Refer to T Check of mis-wiring
No
or mis-piping.(See page 141)
Check the outdoor power supply,
No
power supply cord and
connection.
No
+
?
Replace the DEICER P.C. board.
Make the wiring between CN730
No
on the DEICER P.C. board and
outdoor terminal block correct.
(See page 143.)
135
Set the switch(SW2-2) on the indoor electronic
control P.C. board to MU& MUX type.
w
(See page 121.) 1
Does the unit operate?
No
Follow the chart
on page 123.
Yes
Ok