IBM Thinkpad T20 T21 T22 T23 Manual

Power system checkout
To verify a symptom, do the following:
1. Power off the computer.
2. Remove the battery pack.
3. Connect the ac adapter.
4. Check that power is supplied when you power on the
computer.
5. Power off the computer.
6. Disconnect the ac adapter and install the charged
battery pack.
7. Check that the battery pack supplies power when you
power on the computer.
If you suspect a power problem, see the appropriate one
of the following power supply checkouts:
v“Checking the ac adapter”...

Checking operational chargingTo check whether the battery charges properly during
operation, use a discharged battery pack or a battery pack
that has less than 50% of the total power remaining when
installed in the computer.
Perform operational charging. If the battery status indicator
or icon does not turn on, remove the battery pack and let it
return to room temperature. Reinstall the battery pack. If
the charge indicator or icon still does not turn on, replace
the battery pack.
If the charge indicator...

Note:Recharging will take at least 3 hours, even if the
indicator does not turn on.
If the voltage is still less than +11.0 V dc after
recharging, replace the battery.
4. If the voltage is more than +11.0 V dc, measure the
resistance between battery terminals 4 and 5. The
resistance must be 4 to 30 K.
If the resistance is not correct, replace the battery
pack. If the resistance is correct, replace the system
board.
Checking the backup batteryDo the following:
1. Power off the computer, and unplug the ac...

Checkout guide
38ThinkPad T20, T21, T22, T23 (MT 2647/2648) 

ThinkPad T20, T21, T22 and T23
series
Product overview............41
Specifications............43
Status indicators...........45
FRU Tests.............47
Fn key combinations..........48
Symptom-to-FRU index..........49
Numeric error codes..........49
Error messages...........52
Beep symptoms...........53
No-beep symptoms..........53
LCD-related symptoms.........54
Intermittent problems..........55
Undetermined problems.........55
FRU replacement notices.........56
Screw notices............56
Retaining...

1160 Hard-disk bay..........105
1170 Ultrabay 2000 slot........107
For T20 series..........107
For T21 and T22 series........108
For T23 series..........111
1180 System board..........113
For T20, T21, T22 series.......113
For T23 series..........115
1190 Secure chip..........117
1200 Microphone cable.........118
2010 LCD assembly..........121
2020 Front bezel...........122
2030 Inverter card..........123
2040 LCD panel...........125
2050 Antenna assembly........128
2060 Sub card...........131
3010...

Product overview
This section presents the following product-unique
information:
v“Specifications”
v“Status indicators”on page 44
v“FRU Tests”on page 46
v“Fn key combinations”on page 48
Specifications
The following table lists the specifications of the ThinkPad
T20, T21, T22 and T23 series :
Feature Description
ProcessorT20
vMobile Intel
®Pentium®III processor 650 MHz
vMobile Intel®Pentium®III processor 700 MHz
vMobile Intel®Pentium®III processor 750 MHz
T21
vMobile Intel
®Pentium®III processor 750 MHz...

Feature Description
Memory
(optional)T20, T21, T22
v64 MB, 128 MB, or 256 MB DIMM card
(maximum of 512 MB)
T23
v64 MB, 128 MB, 256 MB, or 512 MB DIMM
card (maximum of 1024 MB)
CMOS RAM 242 bytes
DisplayT20
v13.3-inch, 16M colors, XGA (1024×768
resolution) TFT color LCD
v14.1-inch, 16M colors, XGA (1024×768
resolution) TFT color LCD
T21, T22, T23
v13.3-inch, 16M colors, XGA (1024×768
resolution) TFT color LCD
v14.1-inch, 16M colors, XGA (1024×768
resolution) TFT color LCD
v14.1-inch, 16M colors, SXGA+...

Feature Description
Internal
modem56.6 Kbps
AudiovInternal microphone
vInternal speaker
vSoftware control volume
Infrared
transferIrDA 1.1
802.11b (only
for T23 series)Mini PCI Type-IIIa IEEE 802.11b wireless LAN
card
PC Card One Type-III or two Type-II
AC adapter 72-watt type
Bay deviceT20
v1.44 MB (3-mode), 3.5-inch diskette drive
v10-24x CD-ROM drive
v6x DVD-ROM drive
T21, T22, T23
v1.44 MB (3-mode), 3.5-inch diskette drive
v10-24x CD-ROM drive
v8x DVD-ROM drive
vCD-RW drive
vDVD/CD-RW combo...

Status indicators
The system status indicators show the status of the
computer, as follows:
12345
678
Indicator Meaning

1Drive in useGreen:Data is being read from or written
to the hard-disk drive, the diskette
drive, or the drive in the Ultrabay
2000. When this indicator is on, do
not put the computer into standby
mode or turn off the computer.
Note:Do not move the system while the
Green drive in use light is on. Sudden physical
shock could cause drive errors.

2Num lockGreen:The numeric keypad on...