IBM Thinkpad X20 X21 X22 X23 X24 Manual

							Memory
1. If two DIMMs are installed, remove one
of them and runDiagnostics-->
Memory Test - Quick.
2. If the problem does not recur, replace
the DIMM, remove the other one, and
run the test again.
3. If the test does not detect the error, run
Diagnostics-->Memory Test - Full.
Fan
1. Turn on the computer and check the air
turbulence at the louver near the power
switch.
2. RunDiagnostics-->Other Devices-->
IBM Fan.
Fn key combinations
The following table shows the function of each combination
of Fn with a function key.
The Fn key works independently from the operating
system.
Key Combination Result
Fn+F1Reserved.
Fn+F2Reserved.
Fn+F3Standby mode.
Fn+F4Suspend mode.
Fn+F5Reserved.
Fn+F6Reserved.
Fn+F7Switch between the LCD, the external
monitor, and both the LCD and external
monitor.
Fn+F8Reserved.
Fn+F9Reserved.
Fn + F12Hibernation mode.
Fn + PgUpThinkLight On/Off.
Fn + HomeThe LCD becomes brighter.
Fn + EndThe LCD becomes less bright.
Chapter 3. ThinkPad X20, X21, X22, X23, X2447 
						

							Symptom-to-FRU index
The symptom-to-FRU index lists symptoms and errors and
their possible causes. The most likely cause is listed first,
in boldface type.
Note:Do the FRU replacement or other actions in the
sequence shown in the column headed″FRU or
action, in Sequence″. If replacing a FRU does not
solve the problem, put the original part back in the
computer. Do not replace a non-defective FRU.
This index can also help you determine, during regular
servicing, what FRUs are likely to need to be replaced
next.
A numeric error is displayed for each error detected in
POST or system operation. In the displays, n can be any
number.
If no numeric code is displayed, check the narrative
descriptions of symptoms. If the symptom is not described
there, go to“Intermittent problems”on page 52.
Note:For an IBM devices not supported by diagnostic
codes in the ThinkPad notebook computers, see the
manual for that device.
Numeric error codes
Symptom or error FRU or action, in sequence
0175
Bad CRC1, stop POST task.
The EEPROM checksum is not
correct.1.System board.
0187
EAIA data access error1.System board.
0190
Critical low battery error.1.Critical low battery error.
Charge the battery pack.
2. Battery pack.
0193
RF antenna has been removed.1.Enter the supervisor
password.
0194The computer has been
carried through a security gate.1.Enter the supervisor
password.
48ThinkPad X20, X21, X22, X23, X24 
						

							0200
Fixed disk failure1.Reseat the hard disk
drive.
2. Load Setup Defaults in IBM
BIOS Setup Utility.
3. Hard disk drive.
4. System board.
021x
Monitor type does not match
CMOS1.Load Setup Defaults in
IBM BIOS Setup Utility.
0220
Shadow RAM failure at offset
nnnn1.System board.
0232
Extended RAM failure at offset
nnnn1.DIMM.
2. System board.
0250
System battery is dead—
replace and run setup1.Replace the backup
battery and run IBM BIOS
Setup Utility to reset the
time and date.
0251
System CMOS checksum
bad—Default configuration used1.Replace the backup
battery and run IBM BIOS
Setup Utility to reset the
time and date..
0252
Password checksum bad.1.Reset the password by
running IBM BIOS Setup
Utility.
0260
System timer error1.Replace the backup
battery and run IBM BIOS
Setup Utility to reset the
time and date.
2. System board.
0270
Real time clock error1.Replace the backup
battery and run IBM BIOS
Setup Utility to reset the
time and date.
2. System board.
0271
Date and time error1.Run IBM BIOS Setup
Utility to reset the time
and date..
0280
Boot incomplete error—Default
configuration used1.Load Setup Defaults in
IBM BIOS Setup Utility.
2. DIMM.
3. System board.
Chapter 3. ThinkPad X20, X21, X22, X23, X2449 
						

							02F4
EISA CMOS not writable.1.Load Setup Defaults in
IBM BIOS Setup
Utility.Replace the backup
battery.
2. System board.
02F5
DIMM test failure1.DIMM.
2. System board.
02F6
Software NMI failure1.DIMM.
2. System board.
02F7
Fail-safe timer NMI failure1.DIMM.
2. System board.
Error messages
Symptom or error FRU or action, in sequence
Device address conflict
1.Load Setup Defaults in
IBM BIOS Setup Utility.
2. Backup battery.
3. System board.
Allocation error for device
1.Load Setup Defaults in
IBM BIOS Setup Utility.
2. Backup battery.
3. System board.
Failing bits: nnnn
1.DIMM.
2. System board.
Invalid system configuration
data1.DIMM.
2. System board.
I/O device IRQ conflict
1.Load Setup Defaults in
IBM BIOS Setup Utility.
2. Backup battery.
3. System board.
Operating system not found
1.Enter IBM BIOS Setup
Utility and see whether
the hard disk drive and
the diskette drive are
properly identified.
2. Diskette drive.
3. Hard disk drive.
4. System board.
50ThinkPad X20, X21, X22, X23, X24 
						

							Hibernation error
1.Restore the system
configuration to what it
was the before the
computer entered
hibernation mode.
2. If memory size has been
changed, re-create the
hibernation file.
Operating system not found
1.Reseat the hard disk
drive.
2. Check the boot sequence
by use of IBM BIOS Setup
Fan error
1.Fan.
Beep symptoms
Symptom or error FRU or action, in sequence
One beep and a blank,
unreadable, or flashing LCD1.Reseat the LCD
connector.
2. LCD assembly.
3. System board.
One long and two short beeps,
and a blank or unreadable LCD1.System board.
2. LCD assembly.
Two short beeps with error
codesPOST error. See“Numeric
error codes”on page 48
Two short beeps with blank
screen1.System board.
Only cursor appears
1.Reinstall operating
system.
No beep symptoms
Symptom or error FRU or action, in sequence
No beep, power-on indicator
on, LCD blank, and no POST1.Make sure that every
connector is connected
tightly and correctly.
2. DIMM.
3. System board.
No beep, power-on indicator
on, and LCD blank during
POST1.Reseat DIMM.
2. System board.
No beep during POST, but
system runs correctly1.Speaker.
Chapter 3. ThinkPad X20, X21, X22, X23, X2451 
						

							The power-on password prompt A power-on password or a
supervisor password is set.
Type the password and press
Enter.
The hard disk password prompt A hard disk password is set.
Type the password and press
Enter.
The DOS-full screen looks
smaller.Start the ThinkPad
Configuration program and set
theScreen expansion
function.
LCD-related symptoms
Important:
The TFT LCD for the notebook computer contains many
thin-film transistors (TFTs). A small number of dots that are
missing, discolored, or always lighted is characteristic of
TFT LCD technology, but excessive pixel problems can
cause viewing concerns. The LCD should be replaced if
the number of missing, discolored, or lighted dots in any
background is:
vSVGA(X20, X21):5 or more bright dots, 5 or more dark
dots, or a total of 9 or more bright and dark dots.
vXGA(X22, X23, X24):8 or more bright dots, 8 or more
dark dots, or a total of 9 or more bright and dark dots.
Symptom or error FRU or action, in sequence
No beep, power-on indicator
on, and a blank LCD during
POST1.System board.
vLCD backlight not working
vLCD too dark
vLCD brightness cannot be
adjusted
vLCD contrast cannot be
adjusted1.Reseat the LCD
connectors.
2. LCD assembly.
3. System board.
vLCD screen unreadable
vCharacters missing pixels
vScreen abnormal
vWrong color displayed1.See important note for
″LCD-related symptoms″.
2. Reseat all LCD connectors.
3. LCD assembly.
vHorizontal or vertical lines
displayed on LCD1.LCD assembly.
Intermittent problems
Intermittent system hang problems can be due to a variety
of causes that have nothing to do with a hardware defect,
52ThinkPad X20, X21, X22, X23, X24 
						

							such as: cosmic radiation, electrostatic discharge, or
software errors. FRU replacement should be considered
only when a recurring problem exists.
When analyzing an intermittent problem, do the following:
1. Run the diagnostic test for the system board in loop
modeat least 10 times.
2. If no error is detected, donotreplace any FRUs.
3. If any error is detected, replace the FRU shown by the
FRU code. Re-run the test to verify that no more errors
exist.
Undetermined problems
If the diagnostic tests did not identify which adapter or
device failed, which installed devices are incorrect, whether
or not a short circuit is suspected, or if the system is
inoperative. Follow these procedures to isolate the failing
FRU (do not isolate FRUs that have no defects).
Verify that all attached devices are supported by the
computer.
Verify that the power supply being used at the time of the
failure is operating correctly. (See“Power system
checkout”on page 35)
1. Power off the computer.
2. Visually check each FRU for damage. Replace any
damaged FRU.
3. Remove or disconnect all of the following devices:
a. Non-IBM devices
b. Devices attached to the port replicator
c. Printer, mouse, and other external devices
d. Battery pack
e. Hard disk drive
f. External diskette drive
g. DIMM
h. CD-ROM and diskette drive in the UltraBase X2
i. PC Cards
4. Power on the computer.
5. Determine whether the problem has changed.
6. If the problem does not recur, reconnect the removed
devices one at a time until you find the failing FRU.
7. If the problem remains, replace the following FRUs one
at a time (do not replace a non-defective FRU):
a. System board
b. LCD assembly
Chapter 3. ThinkPad X20, X21, X22, X23, X24
53 
						

							FRU replacement notices
This section contains notices related to removing and
replacing parts. Read this section carefully before replacing
any FRU.
Screw notices
Loose screws can cause a reliability problem. The IBM
ThinkPad computer addresses this problem with special
nylon-coated screws that have the following characteristics:
vThey maintain tight connections.
vThey do not easily come loose, even with shock or
vibration.
vThey are harder to tighten.
vThey should be used only once.
Do the following when you service this machine:
vKeep the screw kit (P/N 05K4841) in your tool bag.
vAlways use new screws.
vUse a torque screwdriver if you have one.
Tighten screws as follows:
vPlastic to plastic
Turn an additional 90 degrees after the screw head
touches the surface of the plastic part:
90 degrees more
(Cross section)
vLogic card to plastic
54ThinkPad X20, X21, X22, X23, X24 
						

							Turn an additional 180 degrees after the screw head
touches the surface of the logic card:
180 degrees more
(Cross section)
vTorque driver
If you have a torque driver, refer to the″Torque″column
with each step.
vMake sure you use the correct screw. If you have a
torque screwdriver, tighten all screws firmly to the torque
shown in the table.Never use a screw that you
removed. Use a new one. Make sure the screws are
tightened firmly
Retaining serial numbers
This section includes the following descriptions:
v″Restoring the serial number of the system unit″
v″Retaining the UUID″
Restoring the serial number of the system
unit
When the computer was manufactured, the EEPROM on
the system board was loaded with the serial numbers of
the system and all major components. The numbers need
to remain the same throughout the life of the computer.
If you replace the system board, you must restore serial
number of the system unit to its original value.
Before replacing the system board, save the original serial
number by doing the following:
1. Install the ThinkPad Hardware Maintenance Diskette
Version 1.60, and restart the computer.
2. From the main menu, select1. Set System
Identification.
3. Select2. Read S/N data from EEPROM.
The serial number for each device is displayed. Write
down the serial number of the system unit, designated as
follows:
20:System unit serial number
Chapter 3. ThinkPad X20, X21, X22, X23, X24
55 
						

							After you have replaced the system board, restore the
serial number by doing the following:
1. Install the ThinkPad Hardware Maintenance Diskette
Version 1.60 and restart the computer.
2. From the main menu, select1. Set System
Identification.
3. Select1. Add S/N data from EEPROM.
Follow the instructions on the screen.
Note:The serial number of the system unit is written
on the label attached on the bottom of the
computer.
Retaining the UUIDThe Universally Unique Identifier (UUID) is a 128-bit
number uniquely assigned to your computer at production
and stored in the EEPROM of your system board. The
algorithm that generates the unique number is designed to
provide unique IDs until the year A.D. 3400. No two
computers in the world have the same number.
When you replace the system board, you must set the
UUID on the new system board as follows:
1. Install the ThinkPad Hardware Maintenance Diskette
Version 1.60, and restart the computer.
2. Select4. Assign UUIDfrom the main menu. A new
UUID is created and written. If a valid UUID already
exists, it is not overwritten.
56ThinkPad X20, X21, X22, X23, X24