dell latitude c840 User Manual
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![Page 56
System Board: Dell Latitude C840 Service Manual
2system board
3 network connector
4 modem connector
5 network cable cover
6 M2.5 x 20-mm screw
The BIOS chip on the system board contains the service tag sequence, whi\
ch is also
visible on a bar code label on the bottom of the computer.
The replacement kit for the system board includes a floppy disk or CD th\
at provides a
utility for transferring the service tag sequence to the replacement sys\
tem board.
NOTICE: If you received a flash BIOS update...](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-55.png "Page 56
System Board: Dell Latitude C840 Service Manual
2system board
3 network connector
4 modem connector
5 network cable cover
6 M2.5 x 20-mm screw
The BIOS chip on the system board contains the service tag sequence, whi\
ch is also
visible on a bar code label on the bottom of the computer.
The replacement kit for the system board includes a floppy disk or CD th\
at provides a
utility for transferring the service tag sequence to the replacement sys\
tem board.
NOTICE: If you received a flash BIOS update...")
![Page 57
System Board: Dell Latitude C840 Service Manual
12. If migrating the microprocessor, remove the microprocessor module.
13. Separate the network cable from the system board: a. First remove the network cable cover: Insert a narrow plastic scribe or \
small screwdriver just barely into the slot that faces the back of the
computer (do not insert the scribe far enough to catch on the wires
inside), press down on the cover lightly to secure it, and pry upward t\
o
release the cover.
1 network cable...](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-56.png "Page 57
System Board: Dell Latitude C840 Service Manual
12. If migrating the microprocessor, remove the microprocessor module.
13. Separate the network cable from the system board: a. First remove the network cable cover: Insert a narrow plastic scribe or \
small screwdriver just barely into the slot that faces the back of the
computer (do not insert the scribe far enough to catch on the wires
inside), press down on the cover lightly to secure it, and pry upward t\
o
release the cover.
1 network cable...")
![Page 58
System Board: Dell Latitude C840 Service Manual
1 outer corner of upper
connector
2 network cable
14. Remove the three M2.5 x 4-mm captive-washer screws from the system board\
.
15. Remove the M2.5 x 20-mm screw from the center of the LED board.
16. Lift the front of the system board and work it out of the back panel.
If necessary to help release the system board, pull outward on the top o\
f the
plastic near the back left corner of the bottom case (see the small arr\
ow at the far
left in the...](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-57.png "Page 58
System Board: Dell Latitude C840 Service Manual
1 outer corner of upper
connector
2 network cable
14. Remove the three M2.5 x 4-mm captive-washer screws from the system board\
.
15. Remove the M2.5 x 20-mm screw from the center of the LED board.
16. Lift the front of the system board and work it out of the back panel.
If necessary to help release the system board, pull outward on the top o\
f the
plastic near the back left corner of the bottom case (see the small arr\
ow at the far
left in the...")
![Page 59
System Board: Dell Latitude C840 Service Manual
Back to Contents Page
file:///F|/Service%20Manuals/Dell/Latitude/c840/sysboard.htm (5 of 5) \
[2/28/2004 8:03:45 AM]](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-58.png "Page 59
System Board: Dell Latitude C840 Service Manual
Back to Contents Page
file:///F|/Service%20Manuals/Dell/Latitude/c840/sysboard.htm (5 of 5) \
[2/28/2004 8:03:45 AM]")
![Page 60
Battery and Module Bay Latches: Dell Latitude C840 Service Manual
Back to Contents Page
Battery and Module Bay Latches
Dell™ Latitude™ C840 Service Manual
NOTICE: Disconnect the computer and attached devices from electrical outlets
and remove any installed batteries.
NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by
periodically touching unpainted metal on the computer.
file:///F|/Service%20Manuals/Dell/Latitude/c840/baylatch.htm (1 of 3) \
[2/28/2004 8:03:46 AM]](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-59.png "Page 60
Battery and Module Bay Latches: Dell Latitude C840 Service Manual
Back to Contents Page
Battery and Module Bay Latches
Dell™ Latitude™ C840 Service Manual
NOTICE: Disconnect the computer and attached devices from electrical outlets
and remove any installed batteries.
NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by
periodically touching unpainted metal on the computer.
file:///F|/Service%20Manuals/Dell/Latitude/c840/baylatch.htm (1 of 3) \
[2/28/2004 8:03:46 AM]")
![Page 62
Battery and Module Bay Latches: Dell Latitude C840 Service Manual
b. Ensure that the slider is inserted so that the side with the two bumps i\
s facing the back of the bottom case, and the surface with the wear ribs l\
ies
against the upper surface of the bottom case.
7. Hold the upper latch assembly in place while you snap the new latch butt\
on in from underneath the bottom case, making certain the snap tabs are fully \
engaged in the slider.
Ensure that the newly installed latch assembly moves...](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-61.png "Page 62
Battery and Module Bay Latches: Dell Latitude C840 Service Manual
b. Ensure that the slider is inserted so that the side with the two bumps i\
s facing the back of the bottom case, and the surface with the wear ribs l\
ies
against the upper surface of the bottom case.
7. Hold the upper latch assembly in place while you snap the new latch butt\
on in from underneath the bottom case, making certain the snap tabs are fully \
engaged in the slider.
Ensure that the newly installed latch assembly moves...")
![Page 64
Battery Charger Board: Dell Latitude C840 Service Manual
4. Remove the display assembly.
5. Remove the
palm rest.
6. Remove the
video graphics board.
7. Lift the battery charger board out of the system board connector.
Replacing the Battery Charger Board
Align the screw holes on the battery charger board with the screw holes \
on the bottom
case, and then press the battery charger board down into its connector.
Back to Contents Page...](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-63.png "Page 64
Battery Charger Board: Dell Latitude C840 Service Manual
4. Remove the display assembly.
5. Remove the
palm rest.
6. Remove the
video graphics board.
7. Lift the battery charger board out of the system board connector.
Replacing the Battery Charger Board
Align the screw holes on the battery charger board with the screw holes \
on the bottom
case, and then press the battery charger board down into its connector.
Back to Contents Page...")
![Page 65
LED Board: Dell Latitude C840 Service Manual
Back to Contents Page
LED Board
Dell™ Latitude™ C840 Service Manual
NOTICE: Disconnect the computer and attached devices from electrical outlets
and remove any installed batteries.
NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by
periodically touching unpainted metal on the computer.
1 M2 x 4-mm screws (2)
file:///F|/Service%20Manuals/Dell/Latitude/c840/led.htm (1 of 2) [2/28\
/2004 8:03:47 AM]](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-64.png "Page 65
LED Board: Dell Latitude C840 Service Manual
Back to Contents Page
LED Board
Dell™ Latitude™ C840 Service Manual
NOTICE: Disconnect the computer and attached devices from electrical outlets
and remove any installed batteries.
NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by
periodically touching unpainted metal on the computer.
1 M2 x 4-mm screws (2)
file:///F|/Service%20Manuals/Dell/Latitude/c840/led.htm (1 of 2) [2/28\
/2004 8:03:47 AM]")
![Page 66
LED Board: Dell Latitude C840 Service Manual
Removing the LED Board
1. Follow the instructions in Preparing to Work Inside the Computer.
2. Remove the
hinge cover.
3. Remove the two M2 x 4-mm screws.
4. Lift the LED board away from its connector.
Replacing the LED Board
1. Align the two screw holes with the two mounting holes on the bottom case\
, and press the board into its connector.
2. Replace the two M2 x 4-mm screws.
Back to Contents Page...](http://img.usermanuals.tech/thumb/19/48086/w64_dell-latitude-c840-service-manual-65.png "Page 66
LED Board: Dell Latitude C840 Service Manual
Removing the LED Board
1. Follow the instructions in Preparing to Work Inside the Computer.
2. Remove the
hinge cover.
3. Remove the two M2 x 4-mm screws.
4. Lift the LED board away from its connector.
Replacing the LED Board
1. Align the two screw holes with the two mounting holes on the bottom case\
, and press the board into its connector.
2. Replace the two M2 x 4-mm screws.
Back to Contents Page...")
Battery and Module Bay Latches: Dell Latitude C840 Service Manual 1 wear ribs (2 on underside) 2 bumps 3 slider 4 spring 5 bottom case 6 latch housing (2) 7 latch buttons (2) 8 location of snap tabs (2) Removing and Replacing the Battery and Module Bay Latches 1. Follow the instructions in Preparing to Work Inside the Computer. 2. Remove the keyboard. 3. Remove the hinge cover. 4. Remove the display assembly. 5. Remove the palm rest. 6. Remove a latch button from the bottom case by squeezing the snap tabs in\ the center of the latch. Tape over or hold down the upper latch assembly (spring and slider) to\ hold the assembly in place. Apply downward pressure to the snap tabs while squeez\ ing them together (tweezers work well) to eject the latch button from the \ underside of the bottom case without loosening the upper latch assembly. If the up\ per latch assembly does come loose: a. Slide the spring onto the slider, and reinstall both pieces in the latch\ housing on the inside of the bottom case. file:///F|/Service%20Manuals/Dell/Latitude/c840/baylatch.htm (2 of 3) \ [2/28/2004 8:03:46 AM]
Battery and Module Bay Latches: Dell Latitude C840 Service Manual b. Ensure that the slider is inserted so that the side with the two bumps i\ s facing the back of the bottom case, and the surface with the wear ribs l\ ies against the upper surface of the bottom case. 7. Hold the upper latch assembly in place while you snap the new latch butt\ on in from underneath the bottom case, making certain the snap tabs are fully \ engaged in the slider. Ensure that the newly installed latch assembly moves smoothly and freely\ when pushed and released. Back to Contents Page file:///F|/Service%20Manuals/Dell/Latitude/c840/baylatch.htm (3 of 3) \ [2/28/2004 8:03:46 AM]
Battery Charger Board: Dell Latitude C840 Service Manual Back to Contents Page Battery Charger Board Dell™ Latitude™ C840 Service Manual NOTICE: Disconnect the computer and attached devices from electrical outlets and remove any installed batteries. NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by periodically touching unpainted metal on the computer. Removing the Battery Charger Board 1. Follow the instructions in Preparing to Work Inside the Computer. 2. Remove the keyboard. 3. Remove the hinge cover. file:///F|/Service%20Manuals/Dell/Latitude/c840/battch.htm (1 of 2) [2\ /28/2004 8:03:46 AM]
Battery Charger Board: Dell Latitude C840 Service Manual 4. Remove the display assembly. 5. Remove the palm rest. 6. Remove the video graphics board. 7. Lift the battery charger board out of the system board connector. Replacing the Battery Charger Board Align the screw holes on the battery charger board with the screw holes \ on the bottom case, and then press the battery charger board down into its connector. Back to Contents Page file:///F|/Service%20Manuals/Dell/Latitude/c840/battch.htm (2 of 2) [2\ /28/2004 8:03:46 AM]
LED Board: Dell Latitude C840 Service Manual Back to Contents Page LED Board Dell™ Latitude™ C840 Service Manual NOTICE: Disconnect the computer and attached devices from electrical outlets and remove any installed batteries. NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by periodically touching unpainted metal on the computer. 1 M2 x 4-mm screws (2) file:///F|/Service%20Manuals/Dell/Latitude/c840/led.htm (1 of 2) [2/28\ /2004 8:03:47 AM]
LED Board: Dell Latitude C840 Service Manual Removing the LED Board 1. Follow the instructions in Preparing to Work Inside the Computer. 2. Remove the hinge cover. 3. Remove the two M2 x 4-mm screws. 4. Lift the LED board away from its connector. Replacing the LED Board 1. Align the two screw holes with the two mounting holes on the bottom case\ , and press the board into its connector. 2. Replace the two M2 x 4-mm screws. Back to Contents Page file:///F|/Service%20Manuals/Dell/Latitude/c840/led.htm (2 of 2) [2/28\ /2004 8:03:47 AM]
Fan: Dell Latitude C840 Service Manual Back to Contents Page Fan Dell™ Latitude™ C840 Service Manual NOTICE: Disconnect the computer and attached devices from electrical outlets and remove any installed batteries. NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by periodically touching unpainted metal on the computer. 1 fan cables 2 M2 x 4-mm screws (3) Removing the Fan 1. Follow the instructions in Preparing to Work Inside the Computer. file:///F|/Service%20Manuals/Dell/Latitude/c840/fan.htm (1 of 2) [2/28\ /2004 8:03:48 AM]
Fan: Dell Latitude C840 Service Manual 2. Remove the system board. 3. Remove the three M2 x 4-mm screws from the fan. 4. Disconnect the two fan cables from the system board. 5. Pull the fan away from the back-panel bracket. NOTICE: When reconnecting the fan cables, connect the shorter cable to the connector closest to the fan. Route both cables so that they will not be\ pinched by the microprocessor thermal-cooling assembly. Back to Contents Page file:///F|/Service%20Manuals/Dell/Latitude/c840/fan.htm (2 of 2) [2/28\ /2004 8:03:48 AM]
RJ-11/RJ-45 Module: Dell Latitude C840 Service Manual Back to Contents Page RJ-11/RJ-45 Module Dell™ Latitude™ C840 Service Manual NOTICE: Disconnect the computer and attached devices from electrical outlets and remove any installed batteries. NOTICE: To avoid ESD, ground yourself by using a wrist grounding strap or by periodically touching unpainted metal on the computer. 1 network cable 2 bottom case 3 RJ-11/RJ-45 module 4 modem cable file:///F|/Service%20Manuals/Dell/Latitude/c840/rj11_45b.htm (1 of 3) \ [2/28/2004 8:03:48 AM]
RJ-11/RJ-45 Module: Dell Latitude C840 Service Manual Removing the RJ-11/RJ-45 Module 1. Follow the instructions in Preparing to Work Inside the Computer. 2. Remove the system board. 3. From outside the bottom case, push in and up on the RJ-11/RJ-45 module w\ hile pulling the side of the bottom case slightly outward. When the module disengages, lift it out. Replacing the RJ-11/RJ-45 Module When replacing the RJ-11/RJ-45 module, hold both cables safely out of th\ e way and snap the housing down into place. Then route the modem cable through the\ vertical slot, through the appropriate posts, and out through the corner of the m\ emory module/modem cutout. file:///F|/Service%20Manuals/Dell/Latitude/c840/rj11_45b.htm (2 of 3) \ [2/28/2004 8:03:48 AM]