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Working Inside Your Computer: Dell™ OptiPlex™ GX1 and GX1p Mini Tower Managed PC Systems

	Overview		Inside Your Computer
	Before You Begin		Removing and Replacing the Expansion-Card Cage
	Removing the Computer Cover		Rotating the Power Supply Away From the System Board
	Replacing the Computer Cover

Overview

Your Dell computer system supports a variety of internal options that expand system capabilities. This chapter prepares you to install options inside the computer. It describes how to remove and replace the computer cover and expansion-card cage, as well as rotate the power supply away from the system board. It also familiarizes you with the internal components you may handle if you install Dell hardware options.

Before You Begin

To make working inside your computer easier, make sure you have adequate lighting and a clean work space. If you temporarily disconnect cables or remove expansion cards, note the position of the connectors and slots 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 in detail elsewhere in this guide.

Safety First — For You and Your Computer

Working inside your computer is safe—if you observe the following precautions.

CAUTION FOR YOUR PERSONAL SAFETY AND PROTECTION OF YOUR EQUIPMENT

Before starting to work on your computer, perform the following steps in the sequence indicated:

1. Touch an unpainted metal surface on the computer chassis, such as the power supply, before touching anything inside your computer.

   While you work, periodically touch an unpainted metal surface on the computer chassis to dissipate any static electricity that might harm internal components. Also avoid touching components or contacts on a card and avoid touching pins on a chip.

2. Turn off your computer and all peripherals.
   
   
3. Disconnect your computer and peripherals from their AC power sources. Also, disconnect any telephone or telecommunication lines from the computer. Doing so reduces the potential for personal injury or shock.
   
   
4. If you are disconnecting a peripheral from the computer or are removing a component from the system board, wait 5 seconds after turning off the computer before disconnecting the peripheral or removing the component to avoid possible damage to the system board.

In addition, Dell recommends that you periodically review the safety instructions in your System Information Guide.

Unpacking Your Hardware Option

When you remove an option from its shipping carton, you may find it wrapped in antistatic packing material designed to protect it from electrostatic damage. Do not remove the packing material until you are ready to install the option.

Removing the Computer Cover

Use the following procedure to remove the computer cover:

1. Turn off your computer and peripherals, and observe the Caution for Your Personal Safety and Protection of Your Equipment described in "Safety First — For You and Your Computer."
   
   
2. If you have installed a padlock through the padlock ring on the back panel (see Figure 1), remove the padlock.

   Figure 1. Padlock Installed

3. Remove the cover.

   Face the back of the computer and slide the upper half of the padlock ring to the left to unlock the cover release mechanism.

   Face the left side cover and press the left-cover release button that is located at the bottom-left corner of the front panel (see Figure 2).

   Lift the bottom of the cover, allowing it to pivot up toward you.

   Disengage the tabs that secure the cover to the top of the chassis, and lift the cover away.

   Figure 2. Removing the Computer Cover

Replacing the Computer Cover

Use the following procedure to replace the 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. Make sure cables are not routed over the drive cage. They will prevent the cover from closing properly.
   
   
2. Check to see that no tools or extra parts (including screws) are left inside the computer's chassis.
   
   
3. Replace the cover.

   Face the left side of the computer and hold the cover at a slight angle as shown in Figure 3. While aligning the top of the cover with the top of the chassis, insert the hooks on the cover into the recessed slots on the computer chassis.

   Pivot the cover down toward the bottom of the chassis and into position. With both hands, press against the bottom edge of the cover to make sure that the securing hooks at the bottom of the cover click into place.

   Slide the two halves of the padlock ring together to lock the cover release mechanism.

NOTE: The computer should be placed fully on a flat surface. It is difficult to align the cover if the front to the computer is hanging over the edge of table.

Figure 3. Replacing the Computer Cover

4. If you are using a padlock to secure your system, reinstall the padlock.

Inside Your Computer

Figure 4 shows a side view of your computer to help orient you when installing hardware options. Unless otherwise specified, locations or directions relative to the computer are as shown.

Figure 4. Computer Orientation View

Figure 5 shows your computer with its cover removed. Refer to this illustration to locate interior features and components discussed in this guide.

When you look inside your computer, note the DC power cables coming from the power supply. These cables supply power to the system board; to internal diskette drives, hard-disk drives, and tape drives; and to certain expansion cards that connect to external peripherals.

The flat ribbon cable in Figure 5 is typical of the interface cables for internal drives. An interface cable connects a drive to a connector on the system board or on an expansion card.

The system board—the large printed circuit board mounted vertically inside the chassis—holds the computer's control circuitry and other electronic components. Some hardware options are installed directly onto the system board. The riser board at the bottom of the chassis contains the expansion-card connectors.

During an installation procedure, you may be required to change a jumper setting on the system board and/or a jumper setting on an expansion card or on a drive. Jumpers provide a convenient and reversible way of reconfiguring the circuitry on a printed circuit board. For more information, see "Jumpers."

Figure 5. Inside the Chassis

Jumpers

Jumpers are small blocks on a circuit board with two or more pins emerging from them. Plastic plugs containing a wire fit down over the pins. The wire connects the pins and creates a circuit.

To change a jumper setting, pull the plug off its pin(s) and carefully fit it down onto the pin(s) indicated.

A jumper is referred to as open or unjumpered when the plug is pushed down over only one pin or if there is no plug at all. When the plug is pushed down over two pins, the jumper is referred to as jumpered. In some documents, the jumper setting may be shown in text as two numbers, such as 1-2. The number 1 is printed on the circuit board so that you can identify each pin number based on the location of pin 1.

Figure 6 shows the location and default settings of the jumper blocks on your system board. See Table 1 for the designations, default settings, and functions of your system's jumpers.

Figure 6. System Board Jumpers

Table 1. System-Board Jumper Settings

Jumper	Setting	Description
PSWD		Password features are enabled.
		Password features are disabled.
BIOS		Reserved (do not change).
BUS66M		Reserved (do not change).
266MHZ*		Reserved (do not change).
300MHZ*		Reserved (do not change).
333MHZ*		Reserved (do not change).
350MHZ*		Reserved (do not change).
400MHZ*		Reserved (do not change).
450MHZ*		Reserved (do not change).
500MHZ*		Reserved (do not change).

jumpered

unjumpered

System Board and Riser Board Labels

Table 2 lists the labels for connectors and sockets on your system board and riser board, and it gives a brief description of their functions.

Table 2. System Board and Riser Board Connectors and Sockets

Removing and Replacing the Expansion-Card Cage

Your Dell computer has a removable expansion-card cage, which greatly simplifies many installation procedures by allowing you to remove the riser board and all installed expansion cards in a single step.

Removing the Expansion-Card Cage

Use the following procedure to remove the expansion-card cage:

CAUTION: Before you remove the computer cover, see "Safety First — For You and Your Computer."

1. Remove the computer cover as instructed in "Removing the Computer Cover."
   
   
2. Check any cables connected to expansion cards through the back-panel openings. Disconnect any cables that will not reach to where the cage must be placed upon removal from the chassis.
   
   
3. Locate the securing lever (see Figure 7). Rotate the lever toward the back of the computer until it stops.
   

   Figure 7. Removing the Expansion-Card Cage

4. Slide the expansion-card cage out of the chassis.
   
   
5. Lift the expansion-card cage up and away from the chassis.

Replacing the Expansion-Card Cage

Use the following procedure to replace the expansion-card cage:

1. With the securing lever in its extended position, align the tabs on the left and right sides of the expansion-card cage with the slots on the back and bottom of the chassis (see Figure 7). Slide the expansion-card cage into place.
   
   
2. Rotate the securing lever inward until it is flush with the side of the chassis. Make sure that the riser board is fully seated in the RISER connector on the system board.
   
   
3. Reconnect any cables you removed in step 2 of "Removing the Expansion-Card Cage."
   
   
4. Replace the computer cover, and reconnect your computer and peripherals to their electrical outlets and turn them on.
   
   

   NOTE: If Enabled, the Chassis Intrusion option will cause the following message to be displayed at the next system start-up: ALERT! Cover was previously removed.

Rotating the Power Supply Away From the System Board

To access some components on the system board, you may have to rotate the system power supply out of the way. Use the following procedure to rotate the power supply:

CAUTION: Before you remove the computer cover, see "Safety First — For You and Your Computer."

1. Remove the computer cover as instructed in "Removing the Computer Cover."
   
   
2. Disconnect the AC power cable from the AC power receptacle on the back of the power supply (see Figure 8).

   Figure 8. Rotating the Power Supply

3. Free the power supply from the securing tab labeled "RELEASE —>, " and rotate it upward until it locks in its extended position.

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