Note：While installing the CDU, make sure that the preset switch to the TMA match with the configuration of the system.
Be careful while removing the soft cables in case the connector breaks; make sure that the connector of each cable be tightly connected to the corresponding socket.
In general, the BOM of the replacing CDU within a cabinet must be the same with of the replaced CDU; once the BOM varies, make sure that the replacing CDU and the RF cables match with the CDU and RF cables being replaced.
The procedure for replacing a CDU board is as follows:
1) Specify the location, operation status, and type of of the CDU in the cabinet.
2) Change cell management status.
3) Change RC management status.
4) Turn off the power that related to the faulty CDU.
The operation is achieved by setting the power switch of the CDU to OFF; the power switch is at the left side of the switch panel at the top of the cabinet.
5) Remove the following screws and cables on the panel of the CDU board .
Power cable
Aviation connector
Data interface line
Alarm and control interface lines of the CDU module
RF cable
The detailed operation steps are as follows:
a. Screw down the power connector of the faulty CDU board.
b. Remove the two screws that tightens the two connectors of the DB15 by using a screwdriver.
c. Remove the RF cable.
d. Check the conditions of the connectors and place them in antistatic boxes for further use.
6) Remove the faulty CDU.
7) Install the new CDU in the slot of the faulty one.
8) Install the cables on the panel of the CDU board.
Note：Make sure that the receiving and transmitting connectors of the RF cables connects to the right socket, otherwise it may burn out the LNA.
9) Turn on the power of the CDU and check whether the CDU operates normally.
10)Check the replaced board.
11) Tighten the screws.
Tighten the two screws on the panel of the CDU board in a clockwise direction and power on the board if it operates normally.
12) Change cell management status.
13) Change RC management status.
14) Testing
Perform the call testing of each carrier to make sure that the installation of the new CDU succeed.