System Design; Desktop Design Overview - Compaq Deskpro EN Series Maintenance & Service Manual

1.3

System Design

This section presents a design overview and functional descriptions of the key components of the
Compaq Deskpro EN Series of Personal Computers. All replaceable components are identified in
Chapter 3, and removal and replacement instructions are presented in Chapters 5 and 6.
1.3.1

Desktop Design Overview

The desktop models of the Compaq Deskpro EN Series of Personal Computers use a highly
serviceable chassis to house the slide-out system board, expansion board cage, power supply, and
mass storage devices. The expansion board cage houses the expansion boards.
All internal components are accessible when the cover with its integrated front bezel is removed.
The cover assembly is attached to the chassis with quick release cover latches; no tools are
required to remove the cover assembly.
The system board is easily removed from the chassis after the cover is removed and the expansion
board cage is raised by lifting a pair of top-mounted green levers. Once the system unit cover has
been removed and the expansion board cage raised, there is no need to remove any other
component to access the system board. Details of the disassembly procedure are found in
Chapter 5, "Removal and Replacement Procedures."
The tilt drive cage is located on the right side of the chassis, directly in front of the power supply.
Tilting the cage allows full service access to the rear of the drives without the need for any tools.
The drive cage accommodates one side-mounted internal hard drive and provides three bays for
external access drives.
The drive cage allows drive installation without the use of rails. Two screws on each side of the
drive are used as guides, and drive release latches are used to secure the drives into the bays. Extra
guide screws (standard and metric thread) are provided on the front of the chassis, to the left of the
drive cage for use when installing additional drives.
The expansion board cage with the riser board mounts at a right angle to the system board. The
riser board is secured to the expansion board cage with three screws. Expansion boards are
installed at a right angle into the riser board. A single screw secures each expansion board to the
expansion board cage.
The power supply is mounted in the right rear corner of the chassis. Embedded clips located on
the bottom of the power supply engage cutouts in the floor of the chassis. The power supply is
held in place by three screws that are installed through the rear panel of the chassis.
Compaq EN Series of Personal Computers 1-5