Compaq Prolinea Family Maintenance & Serice Manual page 136

Reverse the above procedure to install a backplane board.
IMPORTANT: If installing a Revision A backplane board, slide the board
toward the front of the baseman before tightening the mounting
screws. This will ensure proper alignment with the system
board.
Chapter 5.22 System Board Guide
This procedure applies to the 486-based system board only. The system
board guide for is attached to the floor of the base pan with adhesive.
The guide is shipped with a protective strip over the adhesive. The system
board, fax/modem card, and option cards must be removed prior to replacing
the system board card guide.
To remove the system board guide, complete the following steps.
1. Complete the steps in Section 5.3 to prepare the computer for
disassembly.
2. Complete the steps in Unit Cover Removal and Replacement in Section 5.4
to gain access to the option cards, system board, and LEDs.