IBM Thinkpad T20 T21 T22 T23 Manual

Indicator Meaning

4Scroll lockGreen:Scroll Lock mode is enabled. Arrow
keys can be used as screen-scroll
function keys, but not to move the
cursor. To enable or disable Scroll
Lock mode, press Fn + ScrLk key.
Not all application programs
support this function.

5Power onGreen:This indicator stays lighted
whenever the computer is on. If
the power-on indicator is on and
the standby indicator is off, the
system is ready to use. If both the
power-on indicator and the standby
indicator are on, you can use...

FRU Tests
The following table shows the test for each FRU.
FRU Applicable test
System board 1.Diagnostics --> CPU/Coprocessor
2.Diagnostics --> Systemboard
PowerDiagnostics --> Other Devices --> IBM AC
Adapter, IBM Battery 1 (IBM Battery 2)
LCD unit 1.Diagnostics --> Video Adapter
2.Interactive Tests --> Video
Modem 1. Make sure the modem is set up correctly.
2. Replace the modem jack and the modem
card in turn, and run the following test in
Diagnostics --> Communication:
a. Lucent Modem (M2) Loopback
b....

FRU Applicable test
Diskette drive 1.Diagnostics --> Diskette Drives
2.Interactive Tests --> Diskette
CD-ROM, DVD,
CD-RW or
CD-RW/DVD
combo drive1.Diagnostics --> Other Devices -->
CD-ROM/DVD
2.Interactive Tests --> CD-ROM/DVD Test
Memory 1. If two DIMMs are installed, remove one of
them and runDiagnostics --> Memory
Test - Quick.
2. If the problem does not recur, return the
DIMM to its place, remove the other one,
and run the test again.
3. If the test does not detect the error, run
Diagnostics -->...

Fn key combinations
The following table shows the function of each combination
of Fn with a function key.
Key
combinationDescription
Fn+F1 Reserved.
Fn+F2 Reserved.
Fn+F3 Turn off the LCD display, leaving the screen
blank. To turn the LCD display on again, press
any key or the TrackPoint stick.
Note:To use Fn+F3 for screen blank in
Windows 2000 and Windows XP, you must have
IBM PM device driver installed on your
computer.
Fn+F4 Turn standby mode on. To return to normal
operation, press the Fn key...

Symptom-to-FRU index
The symptom-to-FRU index in this section 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 nondefective FRU.
This index can also help you determine, during regular
servicing, what FRUs are likely to need...

Symptom or error FRU or action, in sequence
0193
RF antenna has been removedEnter the supervisor
password.
0194
The computer has been carried
through a security gateEnter the supervisor
password.
0195
Security hardware tamper
detected1.Enter IBM BIOS Setup
Utility by entering
supervisor password, and
select“Password”-->
“IBM Security Chip”-->
“Clear IBM Security Chip”
to clear this error.
2. Security chip.
3. System board.
0196
Security hardware removed1.Enter IBM BIOS Setup
Utility by entering...

Symptom or error FRU or action, in sequence
0232
Extended RAM
error—Extended RAM fails at
offset nnnn.1.DIMM.
2. System board.
0250
System battery error—System
battery is dead.Replace the backup battery
and run IBM BIOS Setup
Utility to reset the time and
date.
0251
System CMOS checksum
bad—Default configuration
used.Replace the backup battery
and run IBM BIOS Setup
Utility to reset the time and
date.
0252
Password checksum bad—The
password is cleared.Reset the password by
running IBM BIOS Setup...

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
data.1.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...

Beep symptoms
Symptom or error FRU or action, in sequence
One beep and a blank,
unreadable, or flashing LCD.1.Reseat the LCD
connector.
2. LCD assembly.
3. External CRT.
4. System board.
One long and two short beeps,
and a blank or unreadable
LCD.1.System board.
2. LCD assembly.
3. DIMM.
Two short beeps with error
codes.POST error. See“Numeric
error codes”on page 49.
Two short beeps and a blank
screen.1.System board.
2. DIMM.
Two or more beeps, or a
continuous beep. Operating
system starts...

LCD-related symptoms
ImportantThe 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:
vXGA:8 or more bright dots, 8 or more dark dots,
or a total of 9 or more bright and dark dots.
vSXGA+:11 or more bright dots,...