User Guide

Removing and Replacing Parts: Dell Dimension� P75t, P90t, P100t, P133t Midsize

Removing/Replacing Parts: Dell Dimension P75t, P90t, P100t, P133t Midsize

NOTE: To replace parts follow the steps below in reverse.

Removing the Cover

Removing the Cover
1. Turn off the power and unplug the power cable.
2. Unscrew the 5 mounting screws on the back of the computer.
3. Slide the cover toward the back, and lift it away from the system unit.
4. If necessary, remove the screw at the back of the computer and lift out the chassis brace.

Removing/Replacing the Front Bezel and Components

1. Remove the retaining screw from the back of the bezel.
2. Pull upward on the upper 2 tabs on the bezel and then the lower 2 tabs to release them from the chassis.
3. Remove the reset button assembly by forcing the top or bottom retaining tab away from the bottom the assembly while pulling carefully on the cable.
4. Remove the hard-disk drive access indicator and the power indicator by spreading the tabs and pulling the cable away from the bezel.
5. Disconnect the reset cable, hard-disk drive access indicator cable, and the power indicator cable from the system board.
6. Remove the cable from the ferrite EMI suppresser by releasing the catch and opening the ferrite EMI suppresser to remove the cable by pulling it through the hole in the front panel of the chassis.

Removing/Replacing 5.25-Inch Plastic Front-Panel Inserts

1. Remove the cover.
2. Remove the front bezel.
3. Grasp the insert so that the user's thumbs can push against the center of the insert while using the index fingers to pull the outer edges toward the user. While pushing on one side, release the retaining tab on that side and then the other.

Removing/Replacing the Power Switch

1. Remove the cover.
2. Remove the front bezel.
3. Remove the mounting screw from the power switch and then lift the power switch up and away from the back of the front panel.
4. Disconnect the power switch cable from the hook on the floor of the chassis and from the system board.

Removing/Replacing a Drive in an External Bay

1. Remove the cover.
2. Remove the front bezel.
3. Remove the plastic insert, if needed.
4. Remove the power switch, if needed.
5. Disconnect the DC power cable and the interface cable from the back of the drive.
6. Remove the 2 mounting screws from each side of the drive, and slide the drive forward.

NOTE: There are no tabs to support the drive in the center bay. Support the back of the drive while sliding the drive into position.

Removing/Replacing a Hard-Disk Drive Cooling Fan

1. Remove the cover.
2. Disconnect the fan power cable from the auxiliary fan connector (+FAN) located on the system board.
3. Remove any expansion cards that restrict access to the fan bracket, and remove the 2 screws that secure the fan assembly to the hard-disk drive bracket.
4. Lift the fan assembly out of the system unit, and remove the 2 screws that secure the fan to its mounting bracket. Separate the fan from the mounting bracket.

NOTE: When replacing the fan, orient it so that the airflow arrow on the fan points toward the hard-disk drive. If replacing a SCSI hard-disk drive, route the SCSI interface cable so that it does not block the airflow of the fan.

Removing/Replacing a Hard-Disk Drive

1. Remove the cover.
2. Remove the 2 screws that secure the hard-disk drive bracket to the back of the system unit.
3. Remove the hard-disk drive cooling fan, if needed.
4. Lift the hard-disk drive bracket out of the system unit, and then disconnect any cables from the back of the drive.
5. Remove the screws on each side of the hard-disk drive bracket that secures the drives inside the bracket. Slide the drives out of the hard-disk drive bracket.

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.
3. Remove the 3 screws that secure the power supply to the back of the system unit.
4. Lift the system power supply out of the system unit.

Removing/Replacing the Card Guide/Fan Assembly

1. Remove the cover.
2. Remove any full-length ISA cards installed in connector ISA4.
3. Disconnect the fan power cable from the FAN connector located on the system board. 4. Push inward to release the 2 mounting tabs that secure the right side of the card guide/fan assembly to the front panel of the system unit, and then pull the right side of the assembly away from the front panel.
5. Rotate the right side of the card guide/fan assembly toward the back of the system unit far enough to release the 2 mounting tabs on the left side of the assembly from the retaining slots.
6. Lift the card guide/fan assembly out of the system unit.

Removing/Replacing the Microprocessor Cooling Fan

1. Remove the cover.
2. Remove the card guide/fan assembly.
3. Remove 2 screws that secure the cooling fan to the card guide/fan assembly. Note the orientation of the fan in the card guide/fan assembly. Install the replacement fan in the same way to ensure proper airflow over the microprocessor. If the fan has an airflow arrow, the arrow should point toward the microprocessor.

Removing/Replacing the Microprocessor/Heat Sink Assembly

1. Remove the cover.
2. Remove any expansion cards that block access to the microprocessor.
3. Remove the securing clip from the microprocessor/heat sink assembly. Press on the back of the clip with a small screwdriver to release it.
4. Push outward and then upward on the microprocessor-socket release lever to rotate it to its fully vertical position.
5. Lift the microprocessor/heat sink assembly out of its socket.
6. Use the dented corner of the chip to orient the replacement chip in the same direction as the chip that was removed.

Removing/Replacing the Battery

Before removing or replacing the battery, print the system setup program screens to use as a reference later if needed.

1. Remove the cover.
2. Pry the battery out of its socket with a blunt, nonconductive object.

When replacing the battery, insert it with the “+” side facing upward. When finished, the DATE and TIME categories may need to be reset using the system setup program.

Removing/Replacing the System Board

1. Remove the cover.
2. Disconnect any cables attached to the port connectors on the I/O panel.
3. Disconnect any cables attached to the system board.
4. Remove any expansion cards.
5. Remove the 5 screws that secure the system board to the bottom of the system unit.
6. Lift the left edge of the system board up slightly, and then pull the system board to the left until the plastic standoffs in the system board can be lifted out of the slots in the floor of the system unit, and remove the board from the system unit.

Removing/Replacing the Video Memory

1. Remove the cover.
2. Remove the hard-disk drive.
3. Pull the video memory chips straight up, using a chip-removal tool.