Huawei DCDU-03B DC power distribution unit

Procedure

1. Put on an ESD wrist strap or a pair of ESD gloves.
    NOTICE:

   Take proper ESD protection measures, for example, put on an ESD wrist strap or a pair of ESD gloves, to prevent electrostatic damage to the boards, modules, or other electronic components.
2. Modify the management state. To modify the management state, you need to block the cells whose RFUs and BBU are powered by the DCDU to be replaced. For details, see Replacing a BBU3900 or BBU3910 Case and Replacing an RFU.
3. Optional: Before replacing a DCDU-03B or DCDU-11B, record the status of circuit breakers SW0 to SW9 on the DCDU, and set all the circuit breakers to OFF. If a DCDU-12B is to be replaced, skip this step.
4. Disconnect the DCDU from power supply provided by the power equipment listed in Table 1.
5. Record the installation positions (DC output ports) of all connectors on the DCDU, and remove the connectors.
    NOTE:

   To remove an EPC4/EPC5 connector, do as follows: Drag the puller on the connector to unlock the latch of the connector. Then pull the connector out from the port.
6. Use a Phillips screwdriver to remove the protective cover for the DC input wiring terminal block from the DCDU, as shown in the following figure.
   Figure 2 Removing the protective cover for the DC input wiring terminal block from a DCDU
   
7. Record the connections of the DC input power cables, and disconnect the power cables.
8. Use a Phillips screwdriver to remove the four screws from both sides of the DCDU, and pull the DCDU out of the cabinet along the guide rails gently, as shown in the following figure.
   Figure 3 Removing a DCDU
   
9. Gently push the new DCDU into the installation position along the guide rails, and tighten the four M6 screws on both sides of the DCDU to 2 N·m (17.7 lbf.in.).
10. Remove the protective cover for the DC input wiring terminal block from the new DCDU, reconnect the removed power cables to the new DCDU according to the record, and reinstall the protective cover.
11. Reinstall the removed cable connectors to the new DCDU according to the record.
12. Turn on the switch on the power equipment for the DCDU to power on the DCDU.
13. Turn on the circuit breakers on the DCDU that have been set to OFF in 3 according to the recorded status of the circuit breakers.
14. Check the indicators according to the following table to check whether the DCDU is working properly.

    Table 2 Maintenance checklist

    Item	Normal Status
    Indicators on the RRU panel	RUN indicator: blinking (on for 0.125s and off for 0.125s, or on for 1s and off for 1s) ALM indicator: steady off
    Indicators on the BBU	The RUN indicator on a UPEU is steady on. The STATE indicator on a FAN is blinking green (on for 1s and off for 1s). The normal status of the indicators on other boards in a BBU is as follows: RUN indicator: blinking green (on for 1s and off for 1s) ALM indicator: steady off ACT indicator: steady on

15. Take off the ESD wrist strap or ESD gloves, and pack up all tools.