Dell Inspiron L400 Service Guide

							www.dell.com
Dell™ Latitude™ L400 
SERVICE MANUAL 
						

							Notes, Notices, and Cautions
Throughout this guide, blocks of text may be accompanied by an icon and printed in bold type or 
in italic type. These blocks are notes, notices, and cautions, and they are used as follows:
NOTE: A NOTE indicates important information that helps you make better use of your computer 
system.
NOTICE: A NOTICE indicates either potential damage to hardware or loss of data 
and tells you how to avoid the problem.
CAUTION: A CAUTION indicates a potentially hazardous situation which, if not 
avoided, may result in minor or moderate injury.
____________________
Information in this document is subject to change without notice.
© 2001 Dell Computer Corporation. All rights reserved.
Reproduction in any manner whatsoever without the written permission of Dell Computer Corporation is 
strictly forbidden.
Trademarks used in this text: Dell, the DELL logo, and Latitude are trademarks of Dell Computer Corporation. 
Other trademarks and trade names may be used in this document to refer to either the entities claiming the 
marks and names or their products. Dell Computer Corporation disclaims any proprietary interest in trademarks 
and trade names other than its own.
February 2001     P/N 67CUJ Rev. A00 
						

							v
Contents
Recommended Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Preparing to Work Inside Your Computer  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Screw Identification and Tightening  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
ZIF Connectors  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Removing Field-Replaceable Parts and Assemblies  . . . . . . . . . . . . . . . . . . . . 6
Hard-Disk Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Keyboard Bezel  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Display Assembly  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Display Assembly Bezel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Display Assembly Latch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
LCD Panel    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Display Assembly Hinges  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Keyboard Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Memory Module  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Palmrest Assembly  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Touch Pad Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Bottom Assembly  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Reserve Battery   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Main Battery  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Modem  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Speaker  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
System Board Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Main Battery Release Latch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
APR Docking Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Index
Figures
Figure 1. Computer Orientation  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 2. Main Battery Assembly Removal . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Figure 3. Screw Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Figure 4. Disconnecting an Interface Cable  . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 5. Exploded View—Computer  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
						

							vi
Figure 6. Hard-Disk Drive Assembly Removal  . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 7. Keyboard Bezel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 8. Display Assembly Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 9. Display Assembly Bezel Removal  . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 10. Display Assembly Latch Removal  . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 11. LCD Panel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 12. Keyboard Assembly Removal  . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 13. Memory Module Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 14. Removing the Palmrest Assembly Bottom Screws. . . . . . . . . . . 19
Figure 15. Removing the Palmrest Assembly Top Screws. . . . . . . . . . . . . . 20
Figure 16. Touch Pad Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 17. Bottom Assembly    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 18. Reserve Battery Removal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 19. Modem Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 20. Fan Removal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 21. Speaker Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 22. System Board Assembly Removal. . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 23. Hard-Disk Drive EMI Clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure 24. Main Battery Release Latch Removal  . . . . . . . . . . . . . . . . . . . . . 32
TablesTable 1. Screw Placement Mat With Component Screw Counts 
and Sizes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 
						

							support.dell.comDell Latitude L400 Service Manual  1
Dell™ Latitude™ L400 Service 
Manual
This manual provides instructions for removing and replacing field-replaceable 
components, assemblies, and subassemblies in your Dell Latitude computer. 
Unless other wise noted, each procedure in this manual assumes the following 
conditions:
•The computer and any attached peripherals are turned off, and the 
peripherals are disconnected from the I/O panel on the back and right side 
of the computer.
•A part can be replaced by performing the removal procedure in reverse 
order unless other wise noted.
When the display assembly is open nearly 180 degrees, use a book or 
something similar to support it. The angle of the display assembly with   
respect to the bottom case should never exceed 180 degrees. Also, when 
performing the procedures in this manual, the locations or directions relative  
to the computer are as shown in Figure 1 unless otherwise specified.
Figure 1.  Computer Orientation
right side
 left side back of computer
 front of computer 
						

							2 Dell Latitude L400 Service Manual
Recommended Tools
Most of the procedures in this manual require the use of one or more of the 
following tools:
•#0 and #1 magnetized Phillips-head screwdrivers
•Small flat-blade screwdriver
•5-mm socket wrench
•Small plastic scribe
•Needle-nose pliers
Preparing to Work Inside Your Computer
Before you start to work on the computer, perform the following steps:
1. Save any work in progress and close all open application programs.
2. Turn off the computer and any attached peripherals.
NOTE: Make sure that the computer is turned off and not in suspend-to-       
disk mode (S2D). If you cannot shut down the computer using its operating 
system, press the power button for 4 seconds.
3. If the computer is docked in the L400 Advanced Port Replicator (APR), 
undock the computer.
4. Disconnect the computer and any attached peripherals from their electrical 
outlets to reduce the potential for personal injury or shock. Also disconnect 
any telephone or telecommunications lines from the computer.
5. Remove the power cable.
6. Disconnect all other external cables from the computer.
7. Remove any installed PC Cards.
NOTICE: Make sure that the work surface is clean to prevent scratch-
ing the computer cover.
NOTICE: To avoid damaging the system board, you must remove the 
main battery before you service the computer.
8. Turn the computer over and remove the main battery assembly from the 
battery bay.
Slide the battery bay latch toward the right side of the computer to push 
the back side of the battery up and out of the battery bay (see Figure 2). 
						

							support.dell.com Dell Latitude L400 Service Manual 3
Figure 2.  Main Battery Assembly Removal
9. Ground yourself by touching the unpainted metal surface of an I/O 
connector on the back of the computer. 
NOTICE: While you work, periodically touch the I/O panel to           
dissipate any static electricity that might harm components.   
Screw Identification and Tightening
The illustrations in the following removal procedures provide lengths of the 
correct screws for each procedure. Figure 3 shows examples. Match the actual 
screw to the illustration to check for correct length.
Figure 3.  Screw Identification
NOTICE: When reinstalling a screw, you must use a screw of the     
correct length. Otherwise, you could damage the hardware. Make 
sure that the screw is properly aligned with its corresponding hole, 
and avoid overtightening. 
batterybatter y latch 
						

							4 Dell Latitude L400 Service Manual
When you are removing and replacing components, photocopy the Table 1 
placement mat as a tool to lay out and keep track of the component screws.
Table 1. Screw Placement Mat With Component Screw Counts 
and Sizes
Hard-Disk Drive 
Assembly:
M3 x 3 mm
(2 each, black)
Display Assembly 
Hinge to Base:
M2 x 4 mm 
(2 each, black)
M2 x 4.5 mm 
(2 each, silver)
Display Assembly 
Bezel:
M2 x 3.5 mm (6 each)
Rubber Screw Covers 
(6 each)
LCD Panel and 
Inverter:
M2 x 3.5 mm (5 each)
Display Assembly 
Hinges:
M2.6 x 4 mm (4 each)
Keyboard 
Assembly:
M2 x 4 mm (4 each)
Palmrest Assembly:
M2.6 x 1.6 mm (6 each 
[battery bay])
M2 x 4 mm
(4 each, black)
M2 x 6 mm
(3 each, silver) 
Touch Pad:
M2 x 3.5 mm (3 each) 
Modem Retainer 
Bracket:
M2 x 9.5 mm (2 each)
VGA and Parallel 
Port:
5 mm socket (4 each)
IDE Connector:
IDE connector screws 
(2 each)
Fan:
M2 x 8 mm
(2 each, silver,
with 2 rubber washers 
each)
Speaker:
M2 x 5 mm
(2 each, silver,
with rubber washer)Audio I/O Cover:
M2 x 4 mm (2 each)
System Board 
Assembly:
M2 x 3.5 mm (6 each) 
						

							support.dell.com Dell Latitude L400 Service Manual 5
ZIF Connectors
Some of the computer’s interface connectors are zero insertion force (ZIF) 
connectors. These connectors are not removable, but they must be released 
to disconnect a cable from them (see Figure 4).
Figure 4.  Disconnecting an Interface Cable
NOTICE: The ZIF connectors are fragile. To avoid damage, do not 
apply too much pressure to the movable part of the connector.
To disconnect an interface cable from a ZIF connector, perform the following 
steps:
1. Insert a small flat-blade screwdriver under the movable part of the 
connector.
2. Pull gently upward on the movable part of the connector until it releases 
the interface cable.
3. Grasp the interface cable and pull it out of the connector.
To reconnect an interface cable to a ZIF connector, perform the following 
steps:
1. Use a small flat-blade screwdriver to open the movable part of the ZIF 
connector.
2. Orient the end of the interface cable with the ZIF connector, and insert the 
end of the cable into the connector.
3. While holding the cable in place, close the ZIF connector.
To ensure a firm connection, make sure the ZIF connector is completely 
closed.
movable part of 
connector 
(do not remove) 
						

							6 Dell Latitude L400 Service Manual
Removing Field-Replaceable Parts 
and Assemblies     
Figure 5.  Exploded View—Computer
display 
assembly
keyboard
palmrest 
assembly
system board assembly
hard-disk drive
main batter ybottom case assembly
right hinge cover
left hinge cover
audio EMI 
shield
audio I/O port cover
keyboard bezel
speaker
fan
APR docking 
doors
modem