dell latitude c840 User Manual

							Microprocessor Module: Dell Latitude C840 Service Manual
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Microprocessor Module 
Dellâ„¢ Latitudeâ„¢ 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 Microprocessor Module 
1.  Follow the instructions in Preparing to Work Inside the Computer. 
2.  Remove the 
keyboard. 
3.  Remove the 
hinge cover. 
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							Microprocessor Module: Dell Latitude C840 Service Manual
NOTICE: To ensure maximum cooling for the microprocessor, do not touch the 
heat transfer areas on the microprocessor thermal-cooling assembly. The \
oils in 
your skin reduce the heat transfer capability of the thermal pads. 
4.  Remove the 
microprocessor thermal-cooling assembly. 
NOTICE: When removing the microprocessor module, pull the module straight 
up. Do not bend the pins. 
5.  Remove the microprocessor module. 
NOTICE: To avoid damage to the microprocessor, hold the screwdriver so that 
it is perpendicular to the microprocessor when loosening the cam screw (\
see 

Microprocessor Cam Screw). 
a.  Loosen the cam screw that secures the microprocessor module. The  location of the screw and the rotation direction may vary with the socke\
t 
manufacturer; look for small icons indicating open and locked positions.\
 
Microprocessor Cam Screw (Example) 
NOTICE: Hold the microprocessor down while turning the cam screw to prevent 
intermittent contact between the cam screw and microprocessor. 
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							Microprocessor Module: Dell Latitude C840 Service Manual
 
1 cam screw
2 perpendicular 
screwdriver
3 processor die (do not 
touch)
b.  Use the microprocessor extraction tool to remove the microprocessor module. 
Replacing the Microprocessor Module 
NOTICE: If you received a flash BIOS update floppy disk or CD with the 
replacement microprocessor, you must update the BIOS after replacing the\
 
microprocessor module. 
NOTICE: Proper seating of the microprocessor module does not require force. 
NOTICE: A microprocessor module that is not properly seated can result in an 
intermittent connection and subsequent failures. 
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							Microprocessor Module: Dell Latitude C840 Service Manual
1.  Align the pin-1 triangle on the microprocessor with the pin-1 triangle i\
n the socket, insert the microprocessor into the socket, and move the micropro\
cessor 
around slightly until you feel it settle into the socket. 
When the microprocessor module is correctly seated, all four corners are\
 aligned 
to the same height. If one or more corners of the module are higher than\
 the 
others, the module is not seated correctly.
NOTICE: Hold the microprocessor down while turning the cam screw to prevent 
intermittent contact between the cam screw and microprocessor (see 

Microprocessor Cam Screw). 
2.  Tighten the cam screw. 
NOTICE: Do not over- or undertighten the screw. Tighten the screw until the 
screw indicator points to the closed or locked indicator on the sock\
et. 
3.  Replace the microprocessor thermal-cooling assembly. 
Closing the Microprocessor Retaining Clip 
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							Microprocessor Module: Dell Latitude C840 Service Manual
 
4.  Close the microprocessor retaining clip. 
5.  To latch the clip, insert a flat-blade scribe into the latch mechanism a\
nd pivot  the top of the scribe away from the clip. 
Back to Contents Page
 
 
 
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							Video Graphics Board: Dell Latitude C840 Service Manual
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Video Graphics Board 
Dellâ„¢ Latitudeâ„¢ 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 M2.5 x 8-mm screws (3)
Removing the Video Graphics Board 
1.  Follow the instructions in Preparing to Work Inside the Computer. 
2.  Remove the 
keyboard. 
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							Video Graphics Board: Dell Latitude C840 Service Manual
3.  Remove the hinge cover. 
NOTICE: The video graphics board may have a metallic or cardboard-like EMI 
shield attached to the top. If present, the EMI shield is removed with t\
he board. 
Do not reuse the EMI shield on the replacement video board. Newer versio\
ns of 
the board may not require the shield; if a shield is required, it is alr\
eady 
attached to the replacement board. 
4.  Detach the 
display flex cable from the graphics card. 
5.  Remove the three M2.5 x 8-mm screws that secure the video graphics board\
. 
6.  Separate the video graphics board from the system board connector. 
Replacing the Video Graphics Board 
1.  Align the three screw holes and press down firmly on the word Dell to \
seat the  board in its connector. 
NOTICE: Ensure that the board is correctly and firmly seated before continuing. \
Failure to do so will cause intermittent video failures. 
2.  Replace the three M2.5 x 8-mm screws. 
Back to Contents Page
 
 
 
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							Palm Rest: Dell Latitude C840 Service Manual
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Palm Rest 
Dellâ„¢ Latitudeâ„¢ 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 pull loop
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							Palm Rest: Dell Latitude C840 Service Manual
NOTICE: The reserve battery provides power to the computers time RTC and 
NVRAM when the computer is turned off. Removing the palm rest disconnect\
s 
the reserve battery and causes the computer to lose the date and time 
information as well as all user-specified parameters in NVRAM. If possib\
le, copy 
the information before you disconnect the reserve battery. 
Removing the Palm Rest 
1.  Follow the instructions in Preparing to Work Inside the Computer. 
2.  Remove the 
hard drive and the fixed optical drive. 
3.  Remove the 
keyboard. 
4.  Remove the 
hinge cover. 
5.  Remove the 
display assembly. 
NOTICE: To avoid damaging the palm rest, you must first remove the display 
assembly. 
6.  Turn the computer over. 
7.  Remove the nine M2.5 x 20-mm screws (labeled circle P) that secure t\
he palm  rest to the computer. 
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							Palm Rest: Dell Latitude C840 Service Manual
 
1 M2.5 x 20-mm screws 
(9)
8.  Turn the computer over. 
9.  Use the pull loop to disconnect the palm-rest flex cable from the touch-\
pad  connector on the system board. 
10.  On the left and right sides of the palm rest, use a flat-blade scribe be\
tween the  palm rest and the bottom case of the computer to separate the snaps that\
 
secure the palm rest to the bottom case. 
11.  Lift out the palm rest. 
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