Toshiba MML-AP0124H2UL Service Manual page 84

Procedure 2: replacing P.C. board
1
Replace the faulty P.C. board with a service P.C. board.
Be sure to replicate the old jumper setting (removal), and connector short-circuit setting (e.g. CN030) on
the service P.C. board. (See the diagram at below.)
2
It is necessary to establish a one-to-one correspondence between the indoor unit being
serviced and the remote control.
Turn on the indoor unit using one of the methods described below according to the system configuration.
(1)Single (stand-alone) operation
Turn on the indoor unit and proceed to Procedure 3.
(2) Group operation
A) If it is possible to selectively turn on the indoor unit being serviced
Turn on the indoor unit being serviced and proceed to Procedure 3.
B) If it is not possible to selectively turn on the indoor unit being serviced (Case 1)
a) Temporarily disconnect the group control wiring from terminals A and B of the indoor unit being
serviced.
b) Connect the remote control wiring to the terminals, turn on the indoor unit, and proceed to
Procedure 3.
* If this method cannot be used, proceed to the alternative method described below (Case 2).
C) If it is not possible to selectively turn on the indoor unit being serviced (Case 2)
a) Remove the CN041 connectors of all other indoor units in the same group.
b) Turn on the indoor unit and proceed to Procedure 3.
Case 1
Case 2
Remove CN041
connectors of all
other indoor units
in same group.
* Be sure to restore the temporarily removed group control wiring and CN041 connectors to their initial states
after Procedure 3 has been completed.
(MCC-1403)
If a short-circuiting plug had been used on the replaced
P.C. board, reuse it on the service P.C. board.
Indoor unit Indoor unit
P.C. board
A B A B
Group control wiring
Indoor unit Indoor unit
P.C. board
CN
041
A B A B
Group control wiring
CN041
CN030
Indoor unit (one being serviced)
P.C. board
Service P.C. board
A B
Remote control
Indoor unit (one being serviced)
P.C. board
Service P.C. board
A B
Remote control
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Remove group control wiring from terminals
A and B of indoor unit being serviced, and
connect remote control wiring.