Chapter 5: Subsystem Maintenance
Subsystem Maintenance 5-9
BBU failure can result from the following:
1. A BBU (Battery Backup Unit) has lost its ability to hold electrical charge.
This may be the case after the battery cells have been recharged for many
times regardless of how long the module has been used. Therefore, a stable
power source is important for system operation.
2. The charger circuitry mounted underneath the controller top cover has
failed.
There are other conditions that might trigger the BBU fault events and light the
BBU fault LED:
1. The temperature sensor embedded with the subsystem’s charger circuit
reports a temperature reading exceeding 45 degree Celsius. The charger
circuits will enter a low-power and self-protection state.
2. A BBU module has been charged for over seven (7) hours. A timer is
embedded with the charger. When this occurs, the charger will
enter a timer fault state. The fault condition usually occurs with a
brand new BBU or with a totally discharged BBU. Charging will
resume automatically if you remove and re-install the BBU module.
To replace a BBU module, please follow these steps:
S tep 1. Remove the BBU module from the subsystem by
loosening its retention screw, and then gently removing the
module from the chassis.
Figure 5-5: Removing the BBU Module
Step 2. Re-install the new BBU. To do this, insert the BBU into the
module slot, and fasten the retention screw to secure the
BBU.