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# Before You Begin

Dell™ Latitude™ C840 Service Manual

Preparing to Work Inside the Computer

Recommended Tools

Computer Orientation

Screw Identification

## Preparing to Work Inside the Computer

| CAUTION: Only a certified service technician should perform repairs on your computer. Damage due to servicing that is not authorized by Dell is not covered by your warrantly. Read and follow all safety instructions in "Safety and EMC Instructions: Portable Computers" in your System Information Guide.

| NOTICE: To avoid damaging the computer, perform the following steps before you begin working inside the computer.

1. Ensure that the work surface is flat and clean to prevent scratching the computer cover.
2. Save any work in progress and exit all open programs.
3. Turn off the computer and all attached devices.

| NOTE: Before turning off the computer, ensure that the computer is not in a power-management mode.

1. Ensure that the computer is undocked.
2. Disconnect the computer from the electrical outlet.
3. To avoid possible damage to the system board, wait 10 to 20 seconds and then disconnect any attached devices.
4. Disconnect all other external cables from the computer.
5. Remove any installed PC Cards or plastic blanks from the PC Card slot.
6. Close the display and turn the computer upside down on a flat work surface.
7. Remove the battery from the battery bay.

| NOTICE: To avoid component damage, always remove any installed batteries before you service the computer.

1. Remove any device installed in the module bay.
2. To dissipate static electricity while you work, periodically touch an unpainted metal surface on the computer chassis.
3. Handle components and cards by their edges, and avoid touching pins and contacts.

## Recommended Tools

The procedures in this document require the following tools:

- #1 magnetized Phillips screwdriver
- Small flat-blade screwdriver
- Microprocessor extractor
- Nonmarring plastic scribe
- Flash BIOS update floppy disk or CD (provided when needed to upgrade the BIOS)

## Computer Orientation

## Screw Identification

When you are removing and replacing components, photocopy the placemat as a tool to lay out and keep track of the component screws. The placemat provides the number of screws and the sizes.

Screw Identification

| NOTICE: When reinstalling a screw, you must use a screw of the correct diameter and length. Ensure that the screw is properly aligned with its corresponding hole, and avoid overtightening.

Hard-Drive Door Security: M3 x 5 mm (1 each) | Keyboard to Bottom Case: M2.5 x 20 mm (4 each; one in memory door and one in Mini PCI door) | Display to Bottom Case: M2.5 x 6 mm (3 each; 2 at back of computer; 1 at display flex-cable strain relief)
Display Bezel: Rubber screw covers (4 each) Plastic screw covers (2 each) M2.5 x 4 mm (6 each) | Display Panel to Display Mounting Bracket: M2 x 3 mm (6 each) Flex-Cable Mounting Bracket to Top Cover: M2.5 x 4 mm (1 each) | Video Graphics Board: M2.5 x 8 (3 each)
Palm Rest to Bottom Case: M2.5 x 20 mm (9 each) Palm Rest Bracket: M2.5 x 4 mm (4 each)

System Board:

M2.5 x 4 mm captive washer
(3 each)

M2.5 x 20 mm (1 each)

LED Board:

M2 x 4 mm (2 each)

Fan: M2 x 4 mm (3 each) | Memory Module/Modem Cover: M2.5 x 20 mm (1 each) | Modem Daughter Card: M2 x 3 mm (1 each)
Mini PCI Card: M2.5 x 20 mm (1 each) |  |

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