Removing/Replacing Parts

Removing the Cover
Removing/Replacing the Expansion-Card Cage
Installing/Removing an Expansion Card
Installing Cache Memory
Installing/Removing SIMMs
Upgrading the Microprocessor
Replacing the System Battery
Removing/Replacing a Drive in a Drive Bay
Installing/Removing a Hard-Disk Drive
Verifying Drive Operation
Removing/Replacing the Power Supply
Removing/Replacing the System Board

Removing the Cover

Removing the Cover

1. Turn off the power and unplug the power cable.
2. If there is a keylock on the back panel, insert the key and turn the lock to the horizontal (unlocked) position.
3. Unscrew the 3 cover-mounting screws on the back of the computer.
4. Slide the cover forward until it disengages from the teeth along the sides of the chassis base. Lift the cover straight up and away from the chassis.

Removing/Replacing the Expansion-Card Cage

Removing the Expansion-Card Cage

1. Remove the cover.
2. Remove the chassis support bracket.
   Remove the screw if the bracket is screwed to the top of the cage. Press the plastic tab toward the left side of the computer to release the bracket, while pulling up the card-cage end of the bracket. Then unhook the drive-cage end of the bracket.
   
   Chassis Support Bracket
   
   
3. Remove the drive/bracket assembly from the chassis.
   Disconnect the DC power cable and IDE cable from any drives that are installed. Remove the screw securing the bottom drive bracket to the drive cage.
   Press on the plastic tab (on the wall of the card cage) while pivoting the front of the bracket up, disengage the tabs at the back, and lift the drive/bracket assembly out.
   
   Bottom Drive Bracket
   
   
4. Remove the screw securing the expansion-card cage to the chassis.
   
   Expansion-Card Cage
   
   
5. Lift the expansion-card cage up and away from the chassis.
   Grasp the cage at the point indicated in the picture above, and pull up firmly until the cage disengages from the chassis.

Replacing the Expansion-Card Cage

1. Fit the cage back into its plastic guides on the chassis; make sure the riser board is fully seated in its connector.
2. Replace the screw that secures the cage to the chassis.
3. Replace the chassis support bracket.
   Hook the drive-cage end of the bracket into place, and then press the card-cage end of the bracket into the channel in the top of the card cage. Replace the screw (if there is one.)
4. Replace the drive/bracket assembly
   Insert the 2 tabs on the back of the bottom drive bracket into the 2 slots on the back of the chassis. Lower the drive bracket to its normal position, and secure it to the drive cage with its screw.
5. Connect the IDE cable to the 40-pin interface connector on the back of the hard-disk drive for each drive.
   
   Hard-Disk Drive Cables
   
   
6. Plug a DC power cable into the power input connector on the back of the drive(s).

Installing/Removing an Expansion Card

Installing an ISA Expansion Card

1. Prepare the card for installation.
2. Remove the cover.
3. Unscrew and remove the metal filler bracket that covers the card-slot opening.
4. Insert the card into the card guide slot on the inside of the expansion-card cage, and slide the card into the chassis.
5. Insert the card-edge connector firmly into the expansion connector on the riser board.
   Gently rock the card into the connector while fitting the metal card-mounting bracket into the card-slot opening on the back panel of the chassis.
   
   Installing an ISA Card
   
   
6. Secure the bracket with its screw.
7. Connect any cables that should be attached to the card.
8. Replace the computer cover, reconnect to power, and turn on.

Installing the VESA Riser Card

1. Remove the cover.
2. Remove the expansion-card cage. See Removing/Replacing the Expansion-Card Cage.
3. Position the card as shown in the following picture. Place the VESA riser card, connectors facing up, into position on the wall of the expansion-card cage. Align the 2 sets of screw holes and insert and tighten the 2 screws that came with the card.
   
   Installing the VESA Riser Card
   
   
4. A VL-Bus expansion card can now be installed on the VESA riser card.
5. Replace the expansion-card cage. See Removing/Replacing the Expansion-Card Cage.
6. Replace the computer cover, reconnect to power, and turn on.
7. Enter System Setup, and verify that the system recognizes the presence of the VESA riser card.

Installing a VL-Bus Expansion Card

1. Prepare the card for installation.
2. Remove the cover.
3. Temporarily remove any installed ISA expansion cards that block access to the VESA riser card. See Installing/Removing an Expansion Card.
4. Unscrew and remove the metal filler bracket that covers the expansion card-slot opening.
5. Install the VL-Bus expansion card.
   Insert the end of the card into the card guide slot on the inside of the expansion-card cage, and slide the card into the chassis.
   Insert the card-edge connector firmly into the VL1 and ISA2 connectors or the VL2 and ISA3 connectors. Gently rock the card into the connectors while the metal card-mounting bracket is going into the back panel of the chassis.
   
   Installing a VL-Bus Card
   
   
6. When the card is firmly seated in its connectors and the card-mounting bracket is flush with the brackets on either side of it, secure the bracket with its screw.
7. Connect any cables that should be attached to the card.
8. Replace any ISA cards.
9. Replace the cover, reconnect to power, and turn on.

Removing an Expansion Card

1. Remove the cover, and disconnect any cables from the card.
2. Unscrew the card-mounting bracket.
3. Grasp the card by the outside corners, and ease it out of its connector.
4. Install a metal filler bracket over the slot opening if the card is being removed permanently.

Installing Cache Memory

1. Remove the cover.
2. Remove expansion-card cage. See Removing/Replacing the Expansion-Card Cage.
3. Locate the 7 cache-memory upgrade sockets on the system board.
   
   Cache Upgrade Sockets
   
   
4. Unpack and identify the cache-directory chip.
   It has 28 pins and a -15 at the end of its part number.
   
5. Install the cache-directory chip in the cache-directory upgrade socket, labeled "U2."
   First orient the chip to match the notch at one end of the chip with the corresponding notch in the U2 cache-directory upgrade socket. Next, align the pins of the chip with the holes in the socket. Check to be sure the chip is oriented correctly, and then carefully press the chip into place.
   
   Cache Upgrade Chip
   
   
6. Unpack and install the 2 cache-buffer chips in the cache-buffer upgrade sockets (labeled "U57" and "U55").
7. Install the 4 cache-memory chips in the sockets (labeled "U52," "U59," "U60," and "U68").
8. Replace the expansion-card cage in the chassis. See Removing/Replacing the Expansion-Card Cage.
9. Replace the cover, reconnect to power, and turn on.
10. Enter System Setup, and verify that EXTERNAL CACHE displays 128 KB.
11. Exit System Setup and reboot.

Installing/Removing SIMMs

NOTE: There is no SIMM-slot priority. If there is only 1 SIMM, it can be installed in either SIMM_A or SIMM_B. If there are 2 SIMMs with different memory capacities, each one can be installed in either SIMM_A or SIMM_B.

Installing a SIMM

1. Locate the cutout area on one corner of the SIMM.
2. Hold the SIMM at a 45-angle and with the cutout facing the back of the chassis. Align the SIMM's edge connector with the slot in the center of the SIMM socket.
   
   Installing a SIMM
   
   
3. Press the SIMM's edge connector firmly into the SIMM socket.
4. Pivot the SIMM up and to the right until it clicks into place.

Removing a SIMM

1. Carefully spread the inner metal tabs of the socket apart just far enough for the SIMM to disengage from the socket (it should pop to the left slightly).
2. Lift the SIMM away from the socket.
   
   Removing a SIMM

Upgrading the Microprocessor

NOTE: This system does not support non-SL Enhanced versions of the Intel486 family of microprocessors. Before upgrading, make sure that the replacement is identified as "SL Enhanced."

Items included in upgrade kit:

• New microprocessor chip
• Heat sink and graphite pad
  NOTE: If the microprocessor is an IntelDX4 chip, it will be permanently attached to a small voltage-regulator card.
• A chip-removal tool for removing the installed microprocessor chip
• New system label (reflecting the new model number)
• Flash BIOS Update diskette and document containing instructions for upgrading the system's BIOS

NOTE: Dell recommends that only technically knowledgeable persons perform this procedure.

To Upgrade the Microprocessor:

1. Remove the cover.
2. Remove the expansion-card cage. See Removing/Replacing the Expansion-Card Cage.
3. Locate the microprocessor socket and the SPEED jumper on the system board.
4. All microprocessors except 33-MHz have an attached heat sink, which must be removed before removing the microprocessor.
   A metal clip beneath the heat sink secures the microprocessor to the heat sink. Insert an extremely small screwdriver under one end of the clip and twist it to snap off the clip. Remove the heat sink and the thin graphite pad that lies below it.
5. Remove the microprocessor chip from the socket.
   Insert the tool's metal tooth between the chip and the socket (not under the socket). Press on the end of the tool to pry the chip slightly out of the socket. Repeat this process on each accessible side of the chip, prying the chip a little more out of the socket each time, until the chip can be lifted away.
   
   Removing the Microprocessor Chip
   
   
6. Unpack the new microprocessor chip.
   CAUTION: Be careful not to bend any of the pins when removing the chip. This can permanently damage the chip.
7. Align the pin-1 corner of the microprocessor chip with the pin-1 corner of the socket.
   
   For IntelSX2 and IntelDX2 microprocessors, on the back of the microprocessor, find the small gold finger that extends from one corner of the large central square portion of the chip. The gold finger points toward pin 1.
   
   Pin-1 (DX2, SX)
   
   For IntelDX4 microprocessors, turn the chip/card assembly over. On the underside of the card, the pin-1 corner is identified by 3 missing pins that give one corner a "cut off" appearance.
   The pin-1 corner of the socket is designated by a small triangle printed on the system board.
   
   Pin-1 (DX4)
   
   
8. Install the chip in the socket.
   Align the pins on the chip with the holes in the socket.
   For IntelDX2 and IntelSX2 microprocessors, center the chip in the socket. The socket has 4 rows of holes on each side; the microprocessor has only 3 rows of pins. Set the chip lightly in the socket, so that a row of holes shows around all 4 sides of the chip.
   For IntelDX4 microprocessors, set the chip/card assembly into the socket by first aligning the row of pins and holes closest to the left side of the system board. A row of empty holes should remain at the opposite side of the socket (the side that faces the cache-memory upgrade sockets). Press the chip down evenly into the socket to seat the pins in the socket
   
   Installing the Microprocessor Chip
   
   
9. Install the new heat sink.
   Place the graphite pad on top of the microprocessor chip. Place the heat sink on top of the microprocessor chip. Fit the 2 ribs on the underside of the heat sink around the chip, and align the notches in the heat sink with the other 2 sides of the chip.
   Hook one end of the securing clip through one of the notches, and press the other end down until it snaps into place.
   
   Installing the Heat Sink
   
   
10. If necessary, change the microprocessor speed jumper setting.
    The SPEED jumper should be set for the rated speed of the microprocessor. For dual chips, it should be set for the microprocessor's external speed. For 50/25 MHz install a jumper plug on the SPEED jumper; for 100/33 MHz, remove the jumper plug. See Jumper Locations.
    
11. If the upgrade has created a new model number, replace the plastic model number label on the front of the computer.
    From inside the cover, pry up the tab at the middle of the label to pop it out. Place the new label into position on the outside of the cover and snap into place.
    
12. Replace the expansion-card cage, the cover, reconnect to power and turn on.
13. Enter System Setup and confirm that MICROPROCESSOR correctly identifies the installed microprocessor.
14. Run the embedded diagnostics to verify the new microprocessor is operating correctly.

Replacing the System Battery

1. Make a copy of the system configuration information in System Setup.
2. Remove the cover and the internal drive bracket assembly from the chassis.
   The battery is mounted on the system board under the bottom hard-disk drive bracket, between the IDE interface connector and the POWER connector.
   Disconnect any internal drives and their cables. Remove the screw securing the bottom drive bracket to the drive cage.
   A plastic tab on the wall of the expansion-card cage helps secure the bottom drive bracket. Pressing on the tab while pivoting the front of the bracket up, disengage the tabs at the back of the bottom drive bracket and lift it out of the computer.
3. Remove the old battery.
   Pry the battery out of its socket with a blunt, nonconductive object such as a plastic screwdriver.
   
   Lithium Battery and Socket
   
   
4. Install the new battery.
   Orient the battery with the side labeled "+" facing up. Insert the battery into the socket and snap it into place.
5. Replace the internal hard-disk drive bracket assembly.
   Insert the 2 tabs on the back of the bottom drive bracket into the 2 slots on the back of the chassis.
   Lower the drive bracket assembly to its normal position, and secure the bottom drive bracket to the drive cage with its screw.
6. For each installed hard-disk drive, connect the IDE cable to the 40-pin interface connector on the back of the hard-disk drive and plug a DC power cable into the power input connector on the back of the drive.
7. Replace the computer cover, reconnect to power, and turn on.
8. Enter System Setup, and confirm that the battery is operating properly.
   Type in the correct TIME and DATE.
9. Turn off system and unplug it for 10 minutes.
10. Turn on the computer and enter System Setup. If TIME and DATE are still incorrect, get technical assistance.

Removing/Replacing a Drive in a Drive Bay

1. Prepare the drive for installation.
   Attach drive rails if needed.
2. Remove the cover.
3. Remove any front-panel or metal inserts if installing a new drive. If replacing a drive, disconnect the old drive from its cables.
4. Slide the drive into the drive bay until it snaps securely into place.
5. Connect the cables to the drive.
6. Replace the computer cover, reconnect to power, and turn on.
7. Update the appropriate category in System Setup.
8. Test each drive by running the appropriate Test Group in the diskette-based diagnostics.

Installing/Removing a Hard-Disk Drive

Removing/Replacing a Hard-Disk Drive in the Lower Drive Bracket

1. Make backup of files if a hard-disk drive containing data is being removed.
2. Remove the cover.
3. Disconnect the IDE cable and DC power cable from the back of the drive.
4. Remove the drive bracket from the chassis.
   Remove the screw securing the drive assembly to the drive cage.
   Press in on the plastic tab on the expansion-card cage to release the drive bracket. Lift the drive assembly up, and slide it forward to release it from the chassis.
5. Turn the drive assembly upside down, and remove the 4 screws securing the drive to the drive bracket.
   
   Bottom Drive Bracket
   
   
6. To replace (or reinstall) a hard-disk drive, follow steps 1 through 6 in reverse.
   When replacing the drive in the drive bracket, route the power cables around the outside of the drive bracket, not under the drive bracket.
7. See Verifying Drive Operation.

Removing/Replacing a Hard-Disk Drive in the Upper Drive Bracket

1. Make backup of files if a hard-disk drive containing data is being removed.
2. Remove the cover.
3. Disconnect the IDE cable and DC power cable from the back of the drive.
4. Detach the upper drive bracket from the lower drive bracket.
   Unscrew the 4 screws that secure the upper drive bracket to the lower drive bracket.
   
   Upper Drive Bracket
   
   
5. Turn the drive assembly upside down, and remove the 4 screws securing the drive to the drive bracket.
6. To replace (or reinstall) a 2-drive assembly, follow steps 1 through 5 in reverse.
   When replacing the drive in the drive bracket, route the power cables around the outside of the drive bracket, not under the drive bracket.

Verifying Drive Operation

Verifying Diskette Drive Operation

1. Turn on the computer, and wait till the boot routine is complete.
2. Start System Setup, and verify that DISKETTE DRIVE A and DISKETTE DRIVE B are set correctly.
3. If the settings are incorrect, make the corrections and reboot.
4. Insert a diagnostics diskette into the boot drive, and run the Diskette Drive(s) Test Group to verify that each diskette drive operates correctly.

Verifying Hard-Disk Drive Operation

1. Start System Setup, and verify that the hard-disk drive categories are configured correctly.
2. If the settings are inaccurate, make the corrections and reboot.
3. For a replacement drive, partition and logically format the drive. Restore the files to the drive.
4. Insert a diagnostics diskette into the boot drive, and run the Diskette Drive(s) Test Group to verify that each hard-disk drive operates correctly.

Removing/Replacing the Power Supply

1. Remove the cover.
2. Disconnect the DC power cables from the system board, from any drives, and from any expansion cards.
   
   DC Power Cables
   
   
3. Remove the 4 screws that secure the power supply to the chassis.
   
   Power Supply Screws
   
   
4. Slide the power supply toward the front of the computer, and lift it up and out of the chassis.
5. To replace (or reinstall) the power supply, follow steps 1 through 4 in reverse.

Removing/Replacing the System Board

1. Remove the cover.
2. Disconnect any peripheral device cables attached to the port connectors on the I/O panel.
3. Remove the chassis support bracket.
4. Remove the hard-disk drive bracket(s). See Installing/Removing a Hard-Disk Drive.
5. Remove the expansion-card cage. See Removing/Replacing the Expansion-Card Cage.
6. Disconnect any of the following cables that are connected to the system board:
   • Diskette/tape drive interface cable
   • IDE cable
   • Hard-disk drive access indicator cable
   • DC power cables
   • Control panel cable
   • Battery cable
   • Speaker cable
7. Remove the system board from the computer.
   
   Removing the System Board
   
   
8. To replace (or reinstall) the system board, follow steps 1 through 8 in reverse.
   Align the system board with the connecting guides, and slide the board toward the back of the computer until the board snaps into its plastic catch. Reconnect all internal cables.
   Check all cable connections inside the computer to ensure they have not loosened. Fold cables out of the way.
9. Enter System Setup, and verify that the system configuration information is correct.
10. Insert the diagnostics diskette into drive A, and run the System Set Test Group to verify that the new system board is operating properly.