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Your Dell computer system supports a variety of internal options
that expand system capabilities. This chapter tells you how to remove the computer cover
and familiarizes you with the internal components you may handle if you install Dell
hardware options. For instructions on installing internal components such as expansion
cards, system board options, and tape and CD-ROM drives, refer to the Installation and
Troubleshooting Guide.
To make working inside your computer easier, make sure you have
adequate lighting and a clean work space. If you should have to disconnect cables or
remove expansion cards temporarily, note the location and orientation of each component so
that you can reassemble the system correctly.
You will use the information in this section every time you install
a hardware option inside your computer. Read this section carefully, because the
information is not repeated elsewhere in this guide.
The procedures in this guide require that you remove the covers and
work inside the computer. While working inside the computer, do not attempt to service the
computer except as explained in this guide and elsewhere in Dell documentation. Always
follow the instructions closely.
Working inside the computer is safe--if you observe the following
precautions.
WARNING FOR YOUR PERSONAL SAFETY AND PROTECTION OF THE EQUIPMENT
Before starting to work on the computer, perform
the following steps in the sequence listed:
1. Turn off the computer and all peripherals.
2. Disconnect the computer, peripherals, and power supplies
from their power sources. Also disconnect any telephone or telecommunication lines from
the computer. Doing so reduces the potential for personal injury or shock.
3. Touch an unpainted metal surface on the computer
chassis, such as the power supply, before touching anything inside the computer.
4. While you work, periodically touch an unpainted metal surface on
the computer chassis to dissipate any static electricity that might harm internal
components.
In addition, Dell recommends that you periodically review the safety
instructions at the front of this guide.
To troubleshoot problems inside the computer, you need to remove one
or both of the computer covers.
When following the procedures in this guide, assume that the
locations or directions relative to the computer are as shown in Figure 1.
Figure 1. Computer Orientation
Use the following procedure to remove
the computer covers:
1. Observe the precautions in
"Safety First--For You and the Computer" found earlier in this chapter. Also
observe the safety instructions at the front of this guide.
2. Turn the keylock on the front bezel
of the computer to the unlocked position.
3. Grasp the bezel on either side of
the external drive bays and pull it slightly away from the chassis to release the two
detents on the back of the bezel.
4. Pivot the bezel downwards (see Figure 2) until it is at right angles to the computer chassis.
5. Grasp the bezel along the edge
adjacent to the computer chassis, and unsnap the bezel to remove it from the chassis.
Figure 2.
Opening the Front Bezel
6. Loosen the three thumbscrews along
the front edge of one of the side covers (see Figure 3).
7. Slide one cover a half-inch (about a
centimeter) or so toward the front of the computer, grasping the top of the cover at both
ends. Rotate the top edge of the cover away from the chassis, and lift it away from the
chassis.
8. Repeat steps 6 and 7 to remove the
remaining side cover, if necessary.
Figure 3. Removing the Computer Covers
Use the following procedure to replace a
computer cover:
1. Check all cable connections,
especially those that might have come loose during your work. Fold cables out of the way
so that they do not catch on the computer cover.
 |
CAUTION: Make sure that
there are no cables or cable connectors lying on the top diskette drive in the upper drive
cage. Foreign objects on top of the drive can interfere with drive operation and
permanently damage the drive.
|
2. Check that no tools or extra parts
(including screws) are left inside the computer.
3. Fit the cover over the side rail at
the bottom of the chassis, and slide it closed.
4. Secure the cover with the three
thumbscrews.
5. Make sure the keylock is in the
unlocked position.
6. Snap the tabs at the inside bottom
of the computer bezel into the metal catches on the chassis, and pivot the bezel upward
into the closed position.
7. Set the keylock to the locked
position.
In Figure 4 the
right computer cover is removed to provide interior views from the right sides. This
illustration also identifies features on the front of the computer. Refer to these
illustrations to locate interior features and components discussed later in this guide.
When you look inside the computer, note
the direct current (DC) power cables leading from the power supply. These cables supply
power to the system board, small computer system interface (SCSI) backplane board,
externally accessible drives, and any expansion cards that connect to external
peripherals.
The wide, flat ribbon cable is the
interface cable for internal
drives. For non-SCSI drives, an interface cable connects each drive to an interface
connector on the system board or on an expansion card. For SCSI devices, two interface
cables connect externally accessible SCSI devices and the SCSI backplane board to a SCSI
host adapter either on the system board or on an expansion card.
The
system board--the large, vertical, printed circuit board at the left side of the
chassis--holds the computer's control circuitry and other electronic components (see Figure 5). Some hardware options are installed directly on the system
board. The external drive bays provide space for up to three half-height 5.25"
drives, typically CD-ROM drives or tape drives. The diskette drive bay holds a 3.5"
diskette drive. The internal drive bays provide space for up to six SCSI hard-disk drives.
These hard-disk drives are connected to a SCSI host adapter on the system board or on an
expansion card, via the SCSI backplane board.
During an installation or
troubleshooting procedure, you may be required to change a jumper or switch setting on the
system board, an expansion card, or a drive. Figure 6 shows the
location of the system board jumpers. For more information about the system board jumpers,
see "Jumpers and Switches," in the Installation and Troubleshooting Guide
Figure 4. Inside
the Chassis--Back/Right Side View
Figure 5. System
Board Features
Figure 6. System
Board Jumpers
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