Replacement Battery - Compaq Deskpro 4000N Maintenance & Service Manual

5.14 Replacement Battery

The real-time clock battery that came with the computer is nonreplaceable and is permanently
installed on the system board.
WARNING: The system board contains a clock/CMOS lithium battery. The lithium battery may explode if
!
mistreated. The battery is soldered into place and may not be removed. Do not abuse or disassemble. Use
only replacement batteries supplied by Compaq Computer Corporation.
It is important to make a set of backup diagnostic diskettes before you install a new battery.
To install the external real-time battery, complete the following steps:
1. Prepare the computer for disassembly (Section 5.4).
2. Remove the system unit cover (Section 5.7).
3. Raise the drive cage to its upright position.
4. Connect the new battery to pins 9 and 12 on the P14 battery header connector. When this battery
is connected, the internal battery is automatically disconnected.
The battery connector is keyed for proper installation.
Compaq Deskpro 4000S and 4000N Personal Computers 5-23