IBM ThinkPad X20 Owner's manual

IBM Mobile Systems
ThinkPad - X20 Series computer
Hardware Maintenance Manual
June 2000

IBM Mobile Systems
ThinkPad - X20 Series computer
Hardware Maintenance Manual
June 2000
IBM

i

note
Before using this information and the product it sup-
ports, be sure to read the general information under
“Notices” on page 79
First Edition (June 2000)
The following paragraph does not apply to the United
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inconsistent with local law:
INTERNATIONAL BUSINESS MACHINES CORPO-
RATION PROVIDES THIS PUBLICATION “AS IS”
WITHOUT ANY WARRANTY OF ANY KIND, EITHER
EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED
TO, THE LIMITED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR
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fore, this statement may not apply to you.
This publication could include technical inaccuracies or
typographical errors. Changes are periodically made to the
information herein; these changes will be incorporated in
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ments or changes to the products or the programs
described in this publication at any time.
It is possible that this publication may contain references
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grams), programming, or services that are not announced
in your country. Such references or information must not
be construed to mean that IBM intends to announce such
IBM products, programming, or services in your country.
Requests for technical information about IBM products
should be made to your IBM authorized dealer or your IBM
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 Copyright International Business Machines Corpo-
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duplication, or disclosure is subject to restrictions set forth
in GSA ADP Schedule Contract with IBM Corp.

Contents
Introduction . . . . . . . . . . . . . . . . . . . 1
Important service information ........... 1
FRU replacement strategy ........... 1
Hard disk drive replacement strategy: ...... 2
How to use error messages .......... 2
How to read POST error messages ....... 2
Safety notices: multilingual translations ....... 3
Safety information . . . . . . . . . . . . . . . . . 10
General safety . . . . . . . . . . . . . . . . . 10
Electrical safety . . . . . . . . . . . . . . . . 11
Safety inspection guide ............ 12
Handling electrostatic discharge-sensitive devices 13
Grounding requirements . . . . . . . . . . . . 14
Laser compliance statement ............ 15
General descriptions . . . . . . . . . . . . . . . 17
Read this first ................... 17
Related service information ............ 19
Service Web site ............... 19
Passwords . . . . . . . . . . . . . . . . . . 19
Power management . . . . . . . . . . . . . . 21
Checkout guide . . . . . . . . . . . . . . . . . . 24
Testing the computer ............. 24
Detecting system information with PC-Doctor . . 26
Power system checkout ............ 26
ThinkPad X20 . . . . . . . . . . . . . . . . . . 31
Product overview . . . . . . . . . . . . . . . . . 32
Specifications . . . . . . . . . . . . . . . . . 32
Status indicators . . . . . . . . . . . . . . . . 32
Fn key combinations .............. 35
Symptom-to-FRU index . . . . . . . . . . . . . . 36
Numeric error codes .............. 36
Error messages . . . . . . . . . . . . . . . . 38
Beep symptoms . . . . . . . . . . . . . . . . 38
LCD-related symptoms . . . . . . . . . . . . . 39
Intermittent problems . . . . . . . . . . . . . . 40
Undetermined problems . . . . . . . . . . . . 40
FRU replacement notices ............. 42
Screw notices . . . . . . . . . . . . . . . . . 42
Retaining serial numbers ............ 43
Removing and replacing a FRU .......... 45
1010 Battery pack ............... 46
1020 DIMM . . . . . . . . . . . . . . . . . . 47
1030 Backup battery .............. 48
1040 Hard disk drive .............. 49
1050 Keyboard . . . . . . . . . . . . . . . . 50
1060 Mini PCI adapter ............. 52
1070 Fan assembly .............. 53
1080 LCD assembly .............. 54
Contents iii

1090 Case Keyboard deck ........... 56
1100 Speaker . . . . . . . . . . . . . . . . . 57
1110 PC Card slot assembly .......... 58
1120 RJ11, RJ45 ............... 59
1130 System board .............. 60
1140 LCD USB cover ............. 61
1150 Front bezel ............... 61
1160 LCD panel ................ 62
Locations . . . . . . . . . . . . . . . . . . . . . 66
Front view . . . . . . . . . . . . . . . . . . . 66
Rear view . . . . . . . . . . . . . . . . . . . 67
Bottom view . . . . . . . . . . . . . . . . . . 68
Parts List . . . . . . . . . . . . . . . . . . . . . 69
X20 series model matrix ............ 69
LCDFRU . . . . . . . . . . . . . . . . . . . 69
System . . . . . . . . . . . . . . . . . . . . 72
Keyboard . . . . . . . . . . . . . . . . . . . 73
Base Cover FRU ............... 74
Miscellaneous parts . . . . . . . . . . . . . . 74
Options FRU list ................ 75
Common parts list ............... 76
Notices . . . . . . . . . . . . . . . . . . . . . 79
Trademarks . . . . . . . . . . . . . . . . . . . 79
iv ThinkPad X20

Introduction
Important service information
Important
Diskette fixes are customer-installable. The diskette
fixes are posted on the IBM support site
(http://www.pc.ibm.com/support/)
Advise customers to contact the PC Company
HelpCenter at 800-772-2227 if they need assistance in
obtaining or installing any diskette fixes.
Customers in Canada should call IBM HelpPC at
800-565-3344 for assistance or download information.
FRU replacement strategy
Before replacing parts
Ensure that all diskette fixes are installed before
replacing any FRUs listed in this manual.
Use the following strategy to prevent unnecessary FRU
replacement and service expense:
If you are instructed to replace a FRU, but the
replacement does not correct the problem,
reinstall the original FRU before you continue.
Some computers have both a processor board and a
system board. If you are instructed to replace either
the processor board or the system board, and the first
board that you replace does not correct the problem,
reinstall the original board, and then replace the other
(processor or system) board.
If an adapter or device consists of more than one
FRU, any of the FRUs may be the cause of the error.
Before replacing the adapter or device, remove the
FRUs, one by one, to see if the symptoms change.
Replace only the FRU that changed the symptoms.
Attention
A customized setup configuration (other than default
settings) may exist on the computer you are servicing.
Running Automatic Configuration may alter those set-
tings. Note the current configuration settings (using the
View Configuration option); then, when service has
been completed, verify that the settings are in place.
Introduction 1

Hard disk drive replacement strategy:
Always try to run a low-level format before replacing a hard
disk drive.
Attention
The drive startup sequence in the computer you are
servicing might have been changed. Be extremely
careful during write operations such as copying,
saving, or formatting. If you select an incorrect drive,
data or programs can be overwritten.
How to use error messages
Use the error codes displayed on the screen to diagnose
failures. If more than one error code is displayed, begin the
diagnosis with the first error code. Whatever causes the
first error code may also cause false error codes. If no
error code is displayed, see if the error symptom is listed
in the Symptom-to-FRU Index for the computer you are
servicing.
How to read POST error messages
POST error messages are displayed on the screen as
three, four, five, or eight digits. The error messages that
can be displayed as shorter POST messages are high-
lighted in this index. Some digits have one meaning for
SCSI errors and a different meaning for non-SCSI errors.
The following example shows which digits display the
shorter POST error messages and also defines the SCSI
information in each digit of an eight-digit error message.
Shorter POST Messages
Reserved
Device Code
00000000
ID (SCSI)
Logical Unit Number (SCSI)
Slot Number (SCSI)
Size (SCSI)
Each SCSI device is assigned a unique SCSI ID. Duplicate
SCSI ID settings can generate a false error message. Use
the SCSI ID to determine whether an error message is
coming from an internal or an external device.
2ThinkPad X20

Safety notices: multilingual translations
In this manual, safety notices appear in English with a
page number reference to the appropriate multi-lingual,
translated safety notice found in this section.
The following safety notices are provided in English,
French, German, Italian, and Spanish languages.
Safety Notice 1
Before the computer is powered-on after FRU replace-
ment, make sure all screws, springs, or other small
parts are in place and are not left loose inside the
computer. Verify this by shaking the computer and lis-
tening for rattling sounds. Metallic parts or metal flakes
can cause electrical shorts.
Avant de remettre l'ordinateur sous tension après
remplacement d'une unité en clientèle, vérifiez que
tous les ressorts, vis et autres pièces sont bien en
place et bien fixées. Pour ce faire, secouez l'unité et
assurez-vous qu'aucun bruit suspect ne se produit.
Des pièces métalliques ou des copeaux de métal
pourraient causer un court-circuit.
Bevor nach einem FRU-Austausch der Computer
wieder angeschlossen wird, muβ sichergestellt
werden, daβ keine Schrauben, Federn oder andere
Kleinteile fehlen oder im Gehäuse vergessen wurden.
Der Computer muβ geschüttelt und auf
Klappergeräusche geprüft werden. Metallteile oder
-splitter können Kurzschlüsse erzeugen.
Prima di accendere l'elaboratore dopo che é stata
effettuata la sostituzione di una FRU, accertarsi che
tutte le viti, le molle e tutte le altri parti di piccole
dimensioni siano nella corretta posizione e non siano
sparse all'interno dell'elaboratore. Verificare ciò
scuotendo l'elaboratore e prestando attenzione ad
eventuali rumori; eventuali parti o pezzetti metallici
possono provocare cortocircuiti pericolosi.
Antes de encender el sistema despues de sustituir
una FRU, compruebe que todos los tornillos, muelles
y demás piezas pequeñas se encuentran en su sitio y
no se encuentran sueltas dentro del sistema.
Compruébelo agitando el sistema y escuchando los
posibles ruidos que provocarían. Las piezas metálicas
pueden causar cortocircuitos eléctricos.
Introduction 3

Safety Notice 2
Some standby batteries contain a small amount of
nickel and cadmium. Do not disassemble it, recharge
it, throw it into fire or water, or short-circuit it. Dispose
of the battery as required by local ordinances or regu-
lations. Use only the battery in the appropriate parts
listing. Use of an incorrect battery can result in ignition
or explosion of the battery.
Certaines batteries de secours contiennent du nickel
et du cadmium. Ne les démontez pas, ne les
rechargez pas, ne les exposez ni au feu ni à l'eau. Ne
les mettez pas en court-circuit. Pour les mettre au
rebut, conformez-vous à la réglementation en vigueur.
Lorsque vous remplacez la pile de sauvegarde ou
celle de l'horloge temps réel, veillez à n'utiliser que les
modèles cités dans la liste de pièces détachées
adéquate. Une batterie ou une pile inappropriée risque
de prendre feu ou d'exploser.
Die Bereitschaftsbatterie, die sich unter dem
Diskettenlaufwerk befindet, kann geringe Mengen
Nickel und Cadmium enthalten. Sie darf nur durch die
Verkaufsstelle oder den IBM Kundendienst
ausgetauscht werden. Sie darf nicht zerlegt,
wiederaufgeladen, kurzgeschlossen, oder Feuer oder
Wasser ausgesetzt werden. Die Batterie kann schwere
Verbrennungen oder Verätzungen verursachen. Bei
der Entsorgung die örtlichen Bestimmungen für
Sondermüll beachten. Beim Ersetzen der
Bereitschafts- oder Systembatterie nur Batterien des
Typs verwenden, der in der Ersatzteilliste aufgeführt
ist. Der Einsatz falscher Batterien kann zu Entzündung
oder Explosion führen.
Alcune batterie di riserva contengono una piccola
quantità di nichel e cadmio. Non smontarle, ricaricarle,
gettarle nel fuoco o nell'acqua né cortocircuitarle.
Smaltirle secondo la normativa in vigore (DPR 915/82,
successive disposizioni e disposizioni locali). Quando
si sostituisce la batteria dell'RTC (real time clock) o la
batteria di supporto, utilizzare soltanto i tipi inseriti
nell'appropriato Catalogo parti. L'impiego di una
batteria non adatta potrebbe determinare l'incendio o
l'esplosione della batteria stessa.
Algunas baterías de reserva contienen una pequeña
cantidad de níquel y cadmio. No las desmonte, ni
recargue, ni las eche al fuego o al agua ni las
cortocircuite. Deséchelas tal como dispone la
normativa local. Utilice sólo baterías que se
encuentren en la lista de piezas. La utilización de una
batería no apropiada puede provocar la ignición o
explosión de la misma.
4ThinkPad X20

Safety Notice 3
The battery pack contains small amounts of nickel. Do
not disassemble it, throw it into fire or water, or short-
circuit it. Dispose of the battery pack as required by
local ordinances or regulations. Use only the battery in
the appropriate parts listing when replacing the battery
pack. Use of an incorrect battery can result in ignition
or explosion of the battery.
La batterie contient du nickel. Ne la démontez pas, ne
l'exposez ni au feu ni à l'eau. Ne la mettez pas en
court-circuit. Pour la mettre au rebut, conformez-vous
à la réglementation en vigueur. Lorsque vous
remplacez la batterie, veillez à n'utiliser que les
modèles cités dans la liste de pièces détachées
adéquate. En effet, une batterie inappropriée risque de
prendre feu ou d'exploser.
Akkus enthalten geringe Mengen von Nickel. Sie
dürfen nicht zerlegt, wiederaufgeladen,
kurzgeschlossen, oder Feuer oder Wasser ausgesetzt
werden. Bei der Entsorgung die örtlichen
Bestimmungen für Sondermüll beachten. Beim
Ersetzen der Batterie nur Batterien des Typs
verwenden, der in der Ersatzteilliste aufgeführt ist. Der
Einsatz falscher Batterien kann zu Entzündung oder
Explosion führen.
La batteria contiene piccole quantità di nichel. Non
smontarla, gettarla nel fuoco o nell'acqua né
cortocircuitarla. Smaltirla secondo la normativa in
vigore (DPR 915/82, successive disposizioni e
disposizioni locali). Quando si sostituisce la batteria,
utilizzare soltanto i tipi inseriti nell'appropriato
Catalogo parti. L'impiego di una batteria non adatta
potrebbe determinare l'incendio o l'esplosione della
batteria stessa.
Las baterías contienen pequeñas cantidades de
níquel. No las desmonte, ni recargue, ni las eche al
fuego o al agua ni las cortocircuite. Deséchelas tal
como dispone la normativa local. Utilice sólo baterías
que se encuentren en la lista de piezas al sustituir la
batería. La utilización de una batería no apropiada
puede provocar la ignición o explosión de la misma.
Introduction 5

Safety Notice 4
The lithium battery can cause a fire, explosion, or
severe burn. Do not recharge it, remove its polarized
connector, disassemble it, heat it above 100°C
(212°F), incinerate it, or expose its cell contents to
water. Dispose of the battery as required by local
ordinances or regulations. Use only the battery in the
appropriate parts listing. Use of an incorrect battery
can result in ignition or explosion of the battery.
La pile de sauvegarde contient du lithium. Elle
présente des risques d'incendie, d'explosion ou de
brûlures graves. Ne la rechargez pas, ne retirez pas
son connecteur polarisé et ne la démontez pas. Ne
l'exposez pas à une temperature supérieure à 100°C,
ne la faites pas brûler et n'en exposez pas le contenu
à l'eau. Mettez la pile au rebut conformément à la
réglementation en vigueur. Une pile inappropriée
risque de prendre feu ou d'exploser.
Die Systembatterie ist eine Lithiumbatterie. Sie kann
sich entzünden, explodieren oder schwere
Verbrennungen hervorrufen. Batterien dieses Typs
dürfen nicht aufgeladen, zerlegt, über 100 C erhitzt
oder verbrannt werden. Auch darf ihr Inhalt nicht mit
Wasser in Verbindung gebracht oder der zur richtigen
Polung angebrachte Verbindungsstecker entfernt
werden. Bei der Entsorgung die örtlichen
Bestimmungen für Sondermüll beachten. Beim
Ersetzen der Batterie nur Batterien des Typs
verwenden, der in der Ersatzteilliste aufgeführt ist. Der
Einsatz falscher Batterien kann zu Entzündung oder
Explosion führen.
La batteria di supporto e una batteria al litio e puo
incendiarsi, esplodere o procurare gravi ustioni.
Evitare di ricaricarla, smontarne il connettore
polarizzato, smontarla, riscaldarla ad una temperatura
superiore ai 100 gradi centigradi, incendiarla o gettarla
in acqua. Smaltirla secondo la normativa in vigore
(DPR 915/82, successive disposizioni e disposizioni
locali). L'impiego di una batteria non adatta potrebbe
determinare l'incendio o l'esplosione della batteria
stessa.
La bateria de repuesto es una bateria de litio y puede
provocar incendios, explosiones o quemaduras
graves. No la recargue, ni quite el conector
polarizado, ni la desmonte, ni caliente por encima de
los 100°C (212°F), ni la incinere ni exponga el
contenido de sus celdas al agua. Deséchela tal como
dispone la normativa local.
6ThinkPad X20

Safety Notice 5
If the LCD breaks and the fluid from inside the LCD
gets into your eyes or on your hands, immediately
wash the affected areas with water for at least 15
minutes. Seek medical care if any symptoms from the
fluid are present after washing.
Si le panneau d'affichage à cristaux liquides se brise
et que vous recevez dans les yeux ou sur les mains
une partie du fluide, rincez-les abondamment pendant
au moins quinze minutes. Consultez un médecin si
des symptômes persistent après le lavage.
Die Leuchtstoffröhre im LCD-Bildschirm enthält
Quecksilber. Bei der Entsorgung die örtlichen
Bestimmungen für Sondermüll beachten. Der
LCD-Bildschirm besteht aus Glas und kann
zerbrechen, wenn er unsachgemäβ behandelt wird
oder der Computer auf den Boden fällt. Wenn der
Bildschirm beschädigt ist und die darin befindliche
Flüssigkeit in Kontakt mit Haut und Augen gerät,
sollten die betroffenen Stellen mindestens 15 Minuten
mit Wasser abgespült und bei Beschwerden
anschlieβend ein Arzt aufgesucht werden.
Nel caso che caso l'LCD si dovesse rompere ed il
liquido in esso contenuto entrasse in contatto con gli
occhi o le mani, lavare immediatamente le parti
interessate con acqua corrente per almeno 15 minuti;
poi consultare un medico se i sintomi dovessero
permanere.
Si la LCD se rompe y el fluido de su interior entra en
contacto con sus ojos o sus manos, lave
inmediatamente las áreas afectadas con agua durante
15 minutos como mínimo. Obtenga atención medica si
se presenta algún síntoma del fluido despues de
lavarse.
Introduction 7

Safety Notice 6
To avoid shock, do not remove the plastic cover that
surrounds the lower portion of the inverter card.
Afin d'éviter tout risque de choc électrique, ne retirez
pas le cache en plastique protégeant la partie
inférieure de la carte d'alimentation.
Aus Sicherheitsgründen die Kunststoffabdeckung, die
den unteren Teil der Spannungswandlerplatine umgibt,
nicht entfernen.
Per evitare scosse elettriche, non rimuovere la
copertura in plastica che avvolge la parte inferiore
della scheda invertitore.
Para evitar descargas, no quite la cubierta de plástico
que rodea la parte baja de la tarjeta invertida.
Safety Notice 7
Though main batteries have low voltage, a shorted or
grounded battery can produce enough current to burn
combustible materials or personnel.
Bien que le voltage des batteries principales soit peu
élevé, le court-circuit ou la mise à la masse d'une
batterie peut produire suffisamment de courant pour
brûler des matériaux combustibles ou causer des
brûlures corporelles graves.
Obwohl Hauptbatterien eine niedrige Spannung
haben, können sie doch bei Kurzschluβ oder Erdung
genug Strom abgeben, um brennbare Materialien zu
entzünden oder Verletzungen bei Personen
hervorzurufen.
Sebbene le batterie di alimentazione siano a basso
voltaggio, una batteria in corto circuito o a massa può
fornire corrente sufficiente da bruciare materiali
combustibili o provocare ustioni ai tecnici di
manutenzione.
Aunque las baterías principales tienen un voltaje bajo,
una batería cortocircuitada o con contacto a tierra
puede producir la corriente suficiente como para
quemar material combustible o provocar quemaduras
en el personal.
8ThinkPad X20

Safety Notice 8
Before removing any FRU, power-off the computer,
unplug all power cords from electrical outlets, remove
the battery pack, then disconnect any interconnecting
cables.
Avant de retirer une unité remplaçable en clientèle,
mettez le système hors tension, débranchez tous les
cordons d'alimentation des socles de prise de courant,
retirez la batterie et déconnectez tous les cordons
d'interface.
Die Stromzufuhr muβ abgeschaltet, alle Stromkabel
aus der Steckdose gezogen, der Akku entfernt und
alle Verbindungskabel abgenommen sein, bevor eine
FRU entfernt wird.
Prima di rimuovere qualsiasi FRU, spegnere il
sistema, scollegare dalle prese elettriche tutti i cavi di
alimentazione, rimuovere la batteria e poi scollegare i
cavi di interconnessione.
Antes de quitar una FRU, apague el sistema,
desenchufe todos los cables de las tomas de corriente
eléctrica, quite la batería y, a continuación,
desconecte cualquier cable de conexión entre
dispositivos.
Introduction 9

Safety information
The following section contains the safety information that
you need to be familiar with before servicing an IBM
mobile computer.
General safety
Follow these rules to ensure general safety:
Observe good housekeeping in the area of the
machines during and after maintenance.
When lifting any heavy object:
1. Ensure you can stand safely without slipping.
2. Distribute the weight of the object equally
between your feet.
3. Use a slow lifting force. Never move suddenly or
twist when you attempt to lift.
4. Lift by standing or by pushing up with your leg
muscles; this action removes the strain from the
muscles in your back.
Do not attempt to lift any
objects that weigh more than 16 kg (35 lb) or
objects that you think are too heavy for you.
Do not perform any action that causes hazards, or
that makes the equipment unsafe.
Before you start the machine, ensure that other
service representatives and the customer's personnel
are not in a hazardous position.
Place removed covers and other parts in a safe
place, away from all personnel, while you are ser-
vicing the machine.
Keep your toolcase away from walk areas so that
other people will not trip over it.
Do not wear loose clothing that can be trapped in the
moving parts of a machine. Ensure that your sleeves
are fastened or rolled up above your elbows. If your
hair is long, fasten it.
Insert the ends of your necktie or scarf inside clothing
or fasten it with a nonconductive clip, approximately 8
centimeters (3 inches) from the end.
Do not wear jewelry, chains, metal-frame eyeglasses,
or metal fasteners for your clothing.
Attention: Metal objects are good electrical conduc-
tors.
Wear safety glasses when you are hammering,
drilling, soldering, cutting wire, attaching springs,
using solvents, or working in any other conditions that
might be hazardous to your eyes.
After service, reinstall all safety shields, guards,
labels, and ground wires. Replace any safety device
that is worn or defective.
10 ThinkPad X20

Reinstall all covers correctly before returning the
machine to the customer.
Electrical safety
Observe the following rules when working on electrical
equipment.
Important
Use only approved tools and test equipment. Some
hand tools have handles covered with a soft material
that does not insulate you when working with live elec-
trical currents.
Many customers have, near their equipment, rubber
floor mats that contain small conductive fibers to
decrease electrostatic discharges. Do not use this type
of mat to protect yourself from electrical shock.
Find the room emergency power-off (EPO) switch,
disconnecting switch, or electrical outlet. If an elec-
trical accident occurs, you can then operate the
switch or unplug the power cord quickly.
Do not work alone under hazardous conditions or
near equipment that has hazardous voltages.
Disconnect all power before:
– Performing a mechanical inspection
– Working near power supplies
– Removing or installing main units
Before you start to work on the machine, unplug the
power cord. If you cannot unplug it, ask the customer
to power-off the wall box that supplies power to the
machine and to lock the wall box in the off position.
If you need to work on a machine that has
exposed
electrical circuits, observe the following precautions:
– Ensure that another person, familiar with the
power-off controls, is near you.
Attention: Another person must be there to
switch off the power, if necessary.
– Use only one hand when working with
powered-on electrical equipment; keep the other
hand in your pocket or behind your back.
Attention: An electrical shock can occur only
when there is a complete circuit. By observing
the above rule, you may prevent a current from
passing through your body.
– When using testers, set the controls correctly
and use the approved probe leads and accesso-
ries for that tester.
Introduction 11

– Stand on suitable rubber mats (obtained locally,
if necessary) to insulate you from grounds such
as metal floor strips and machine frames.
Observe the special safety precautions when you
work with very high voltages; these instructions are in
the safety sections of maintenance information. Use
extreme care when measuring high voltages.
Regularly inspect and maintain your electrical hand
tools for safe operational condition.
Do not use worn or broken tools and testers.
Never assume that power has been disconnected
from a circuit. First, check that it has been powered
off.
Always look carefully for possible hazards in your
work area. Examples of these hazards are moist
floors, nongrounded power extension cables, power
surges, and missing safety grounds.
Do not touch live electrical circuits with the reflective
surface of a plastic dental mirror. The surface is
conductive; such touching can cause personal injury
and machine damage.
Do not service the following parts with the power on
when they are removed from their normal operating
places in a machine:
– Power supply units
– Pumps
– Blowers and fans
– Motor generators
and similar units. (This practice ensures correct
grounding of the units.)
If an electrical accident occurs:
– Use caution; do not become a victim yourself.
– Switch off power.
– Send another person to get medical aid.
Safety inspection guide
The purpose of this inspection guide is to assist you in
identifying potentially unsafe conditions. As each machine
was designed and built, required safety items were
installed to protect users and service personnel from injury.
This guide addresses only those items. You should use
good judgment to identify potential safety hazards due to
attachment of non-IBM features or options not covered by
this inspection guide.
If any unsafe conditions are present, you must determine
how serious the apparent hazard could be and whether
you can continue without first correcting the problem.
12 ThinkPad X20

Consider these conditions and the safety hazards they
present:
Electrical hazards, especially primary power (primary
voltage on the frame can cause serious or fatal elec-
trical shock)
Explosive hazards, such as a damaged CRT face or
a bulging capacitor
Mechanical hazards, such as loose or missing hard-
ware
The guide consists of a series of steps presented in a
checklist. Begin the checks with the power off, and the
power cord disconnected.
Checklist:
1. Check exterior covers for damage (loose, broken, or
sharp edges).
2. Power-off the computer. Disconnect the power cord.
3. Check the power cord for:
a. A third-wire ground connector in good condition.
Use a meter to measure third-wire ground conti-
nuity for 0.1 ohm or less between the external
ground pin and frame ground.
b. The power cord should be the type specified in
the parts list.
c. Insulation must not be frayed or worn.
4. Remove the cover.
5. Check for any obvious non-IBM alterations. Use good
judgment as to the safety of any non-IBM alterations.
6. Check inside the unit for any obvious unsafe condi-
tions, such as metal filings, contamination, water or
other liquids, or signs of fire or smoke damage.
7. Check for worn, frayed, or pinched cables.
8. Check that the power-supply cover fasteners (screws
or rivets) have not been removed or tampered with.
Handling electrostatic
discharge-sensitive devices
Any computer part containing transistors or integrated cir-
cuits (ICs) should be considered sensitive to electrostatic
discharge (ESD). ESD damage can occur when there is a
difference in charge between objects. Protect against ESD
damage by equalizing the charge so that the machine, the
part, the work mat, and the person handling the part are all
at the same charge.
Introduction 13

notes
1. Use product-specific ESD procedures when they
exceed the requirements noted here.
2. Make sure that the ESD protective devices you
use have been certified (ISO 9000) as fully effec-
tive.
When handling ESD-sensitive parts:
Keep the parts in protective packages until they are
inserted into the product. . Avoid contact with other
people.
Wear a grounded wrist strap against your skin to
eliminate static on your body.
Prevent the part from touching your clothing. Most
clothing is insulative and retains a charge even when
you are wearing a wrist strap.
Use the black side of a grounded work mat to provide
a static-free work surface. The mat is especially
useful when handling ESD-sensitive devices.
Select a grounding system, such as those listed
below, to provide protection that meets the specific
service requirement.
note
The use of a grounding system is desirable but
not required to protect against ESD damage.
– Attach the ESD ground clip to any frame ground,
ground braid, or green-wire ground.
– Use an ESD common ground or reference point
when working on a double-insulated or battery-
operated system. You can use coax or
connector-outside shells on these systems.
– Use the round ground-prong of the AC plug on
AC-operated computers.
Grounding requirements
Electrical grounding of the computer is required for oper-
ator safety and correct system function. Proper grounding
of the electrical outlet can be verified by a certified
electrician.
14 ThinkPad X20