Figure 5-14 Position Of The Uscu; Figure 5-15 Disconnecting Cables - Huawei BBU3900 Hardware Maintenance Manual

5 Replacing Components of the BBU3900
Prerequisite
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Context
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Procedure
Step 1 Wear an ESD wrist strap or a pair of ESD gloves.
Take proper ESD protection measures, for example, wear an ESD wrist strap or a pair of ESD
gloves, to prevent electrostatic damage to the boards, modules, or electronic components.
Step 2 Record all the cable connections on the panel of the board to be replaced.
Step 3 Disconnect the GPS clock signal cable from the USCU, as shown in

Figure 5-15 Disconnecting cables

Step 4 Remove the two M3 screws on the panel, and then remove the USCU, as shown in
5-16.
5-14
The tools and materials, such as an ESD wrist strap or ESD gloves and screwdriver, are
ready.
The quantity and type of board to be replaced are confirmed. For details, see
Board Information.
The authorized personnel are permitted to enter the site. The required keys are available.
Figure 5-14 shows the position of the USCU in the BBU.

Figure 5-14 Position of the USCU

USCU
USCU USCU GPS GPS
RX+ RX- TX+ TX- RX+ RX- TX+ TX- 1S+ 1S- GND PWR 1S+ 1S- GND PWR
TOD0 TOD0 TOD1 TOD1
RGPS RGPS
The board is hot-swappable.
WARNING
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
M-1PPS M-1PPS BITS BITS
RUN RUN
ALM ALM
ACT ACT
BBU3900
Hardware Maintenance Guide
5.1 Querying
Figure 5-15.
Figure
Issue 03 (2010-06-05)