Battery Backup; Figure 2-1. Front View Of Chassis With Bezel And Fan Panel Removed - HP 1000 A990 Installation And Service Manual

Positive
Battery
Terminal
B. B. ON
Terminal
Battery B. B. OFF
Negative
Battery
Terminal
Backup Terminal
Assembly
Figure 2-1. Front View of Chassis with Bezel and Fan Panel Removed
Battery Backup
The HP 12157B Battery Backup will sustain memory for 15 to 90 minutes, depending on the
system configuration, state of charge, and temperature. Additional memory hold-up time can be
achieved by connecting an external battery.
If Battery Backup is installed, set the Battery Enable switch on the back panel of the computer to
ENABLE. The switch is shown in Figure 2-3. This switch should be set to the DISABLE
position if the power is turned off and if memory backup is not required. The switch should also
be set to DISABLE if cards are to be connected or disconnected from the backplane.
Refer to the Battery Backup Installation section later in this chapter for instructions on installing
battery backup. Note that if batteries are not installed, the strapping connector from the terminal
on the lower board of the power supply must be connected to B.B. OFF. (See Figure 2-1.) If
batteries are installed, the strapping connector must be connected to B.B. ON.
2-2 Installation