Compaq Prolinea 4100, Maintenance & Serice Manual

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Chapter 1.7 System Design
This section presents a design overview and functional descriptions of the
key components of the Compaq ProLinea Family of Personal Computers. All
replaceable components are identified in Chapter 3 and removal/replacement
instructions are presented in Chapter 5.
Design Overview
The Compaq ProLinea Family of Personal Computers has a conventional design
that uses a pan-type chassis to house the system board, expansion cards,
power supply, and mass storage devices. The chassis is divided into two
sections by a permanent panel that extends from the front to the rear of
the chassis. This panel provides a mounting surface for the backplane
board and separates the system board section from the section that houses
the power supply and mass storage devices.
All internal components are immediately accessible when the unit cover,
held in place by three thumb screws, is removed. The front bezel is
mounted to the unit cover. Torx T-15 screws are used throughout the system
except for the CD-ROM drive bracket which requires Torx T-10 screws.
The system board is easily removed by sliding it out from the side of the
chassis after the unit cover is removed. The system board bracket,
attached to the system board with three Torx screws, forms the right side
of the chassis when the system board is installed. The system board shares
the common backplane board with the expansion cards. No mounting screws
are used with the system board.
Expansion boards are installed horizontally above the system board,
engaging the backplane board which is attached to the central panel. A
single screw attaches the expansion board to the rear panel of the
chassis.
The power supply is mounted in the right rear corner of the chassis.
Integrated clips on the bottom of the power supply engage cutouts in the
floor of the chassis. The power supply is held in place by four Torx
screws that are installed through the rear panel of the chassis.
The mass storage drive cage is located on the right side of the chassis,
directly in front of the power supply. The drive cage can be tilted up
from the rear to provide access to cable connections. The drive cage can
accommodate one internal hard drive attached to the side of the cage and
provides two or three (model dependent) drive bays for accessible mass
storage devices.
Detailed descriptions of the system components are presented in the
sections that follow.
System Board
The Compaq ProLinea Family of Personal Computers uses four basic system
board configurations.
All of the boards use SIMMs for expanded memory;
four SIMM sockets on 486 models and six SIMM sockets on 586 models. The
486 models have 8 MB RAM soldered down on the system board; one of the 486
models has 4 MB RAM soldered down. The 586 models have either 8 MB or
16 MB SIMMs for RAM.
The configurations are described in the following
sections.