IBM ThinkPad X20 Owner's manual

ThinkPad X20, X21, X22, X23
Hardware Maintenance Manual
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note
Before using this information and the product it
supports, be sure to read the general information
under Chapter 4, “Notices” on page 131
First Edition (February 2001)
The following paragraph does not apply to the United
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PROVIDES THIS PUBLICATION “AS IS” WITHOUT ANY
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© Copyright International Business Machines
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Government Users — Documentation related to restricted
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IBM Corp.

Contents
Chapter 1. Introduction ..........1
Importantserviceinformation.........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
Safetyinformation............12
General safety ............12
Electricalsafety...........13
Safety inspection guide .........14
Handling electrostatic discharge-sensitive devices 15
Grounding requirements .........16
Laser compliance statement.........17
Laser radiation.............18
Chapter 2. General descriptions .......21
Read this first .............21
Relatedserviceinformation.........24
ServiceWebsite...........24
Product recovery program ........24
Using Recovery CD ..........25
Creating a Recovery Repair diskette .....26
Passwords .............26
Power management ..........28
Checkout guide ............32
Testing the computer ..........32
Detecting system information with PC-Doctor. . . 35
Power system checkout .........35
Chapter 3. ThinkPad X20, X21, X22, X23 ....39
Product overview ............41
Specifications ............41
Statusindicators...........43
Fn key combinations ..........46
Symptom-to-FRU index ..........47
Numeric error codes ..........47
Error messages ...........49
Beep symptoms ...........50
LCD-related symptoms .........51
Intermittentproblems..........51
Undetermined problems .........52
FRU replacement notices .........53
Screwnotices............53
Retaining serial numbers.........54
Removing and replacing a FRU........56
1010 Battery pack...........57
1020 DIMM ............58
1030 Backup battery ..........59
1040 Hard disk drive ..........60
iii

1050 Keyboard ...........62
1060 KBD Control Panel Assemble .....66
1070 Mini PCI adapter .........68
1080 CDC adapter ..........69
1090 BDC adapter ..........70
1100 Fan assembly ..........71
1110 Wirelesslan assembly for X22 .....72
1120 LCD assembly ..........74
1130 Case Keyboard deck ........78
1140 Speaker ............81
1150 PC Card slot assembly .......83
1160IRDAPort...........84
1170 RJ11, RJ45 ...........86
1180 System board ..........88
1190 LCD USB cover..........90
1200 Front bezel ...........90
1210 LCD panel ...........92
Locations ..............97
Front view for X20, X21 .........97
FrontviewforX22 ..........97
FrontviewforX23 ..........98
Rear view for X20, X21 .........100
Rear view for X22, X23 .........100
Bottomview............102
PartsList..............103
X20 series model matrix ........103
X21 series model matrix ........103
X22 series model matrix ........104
X23 series model matrix ........104
LCDFRU.............106
System .............111
Keyboard .............117
Base Cover FRU...........118
Recovery CDs for X21 Series .......120
Recovery CDs for X22 Series .......121
Recovery CDs for X23 Series .......123
Miscellaneous parts ..........125
OptionsFRUlist...........126
Common parts list (X20, X21, X22, X23)....127
Chapter 4. Notices ...........131
Trademarks .............131
iv ThinkPad X20, X21, X22, X23

Chapter 1. Introduction
Important service information
Important
BIOS and device driver fixes are
customer-installable. The BIOS and device drivers
are posted on the IBM support site
http://www.ibm.com/pc/support/
Advise customers to contact the IBM
®
HelpCenter
®
at 800-772-2227 if they need assistance in obtaining
or installing any diskette fixes.
FRU replacement strategy
Before replacing parts
Ensure that all BIOS and device driver fixes are
installed before replacing any FRUs listed in this
manual.
Use the following strategy to prevent unnecessary FRU
replacement and service expense:
vIf you are instructed to replace a FRU, but the
replacement does not correct the problem, reinstall
the original FRU before you continue.
vSome 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.
vIf 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 settings. Note the current configuration
settings (using the View Configuration option); then,
when service has been completed, verify that the
settings are in place.
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
highlighted 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, X21, X22, X23

Safety notices: multilingual translations
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
replacement, 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 listening for rattling sounds. Metallic parts or
metal flakes can cause electrical shorts.
Avant de remettre l’ordinateur sous tension après
remplacement d’une unitéen clientèle, vérifiez que
tous les ressorts, vis et autres pièces sont bien en
place et bien fixées. Pour ce faire, secouez l’unitéet
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, muβsichergestellt
werden, daβkeine Schrauben, Federn oder andere
Kleinteile fehlen oder im Gehäuse vergessen
wurden. Der Computer muβgeschüttelt und auf
Klappergeräusche geprüft werden. Metallteile oder
-splitter können Kurzschlüsse erzeugen.
Prima di accendere l’elaboratore dopo che éstata
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
ciòscuotendo 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.
Chapter 1. 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 regulations. 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 àl’eau.
Ne les mettez pas en court-circuit. Pour les mettre
au rebut, conformez-vous àla réglementation en
vigueur. Lorsque vous remplacez la pile de
sauvegarde ou celle de l’horloge temps réel, veillez
àn’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
quantitàdi 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.
4ThinkPad X20, X21, X22, X23

Safety Notice 2
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 utilizaciónde
una batería no apropiada puede provocar la ignición
o explosión de la misma.
Chapter 1. Introduction 5

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 àl’eau. Ne la mettez pas
en court-circuit. Pour la mettre au rebut,
conformez-vous àla 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 quantitàdi 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 bateríano
apropiada puede provocar la ignición o explosiónde
la misma.
6ThinkPad X20, X21, X22, X23

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 polariséet ne la démontez pas. Ne
l’exposez pas àune temperature supérieure à
100°C, ne la faites pas brûleretn’en exposez pas
le contenu àl’eau. Mettez la pile au rebut
conformément àla 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
ol’esplosione della batteria stessa.
Chapter 1. Introduction 7

Safety Notice 4
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.
8ThinkPad X20, X21, X22, X23

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 àcristaux 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 aprèsle
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 unsachgemäβbehandelt 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 algúnsíntoma del fluido
despues de lavarse.
Chapter 1. Introduction 9

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 àla 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 Kurzschluβoder 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
puòfornire 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.
10 ThinkPad X20, X21, X22, X23

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 unitéremplaçable 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 muβabgeschaltet, 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.
Chapter 1. Introduction 11

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:
vObserve good housekeeping in the area of the
machines during and after maintenance.
vWhen 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.
vDo not perform any action that causes hazards, or that
makes the equipment unsafe.
vBefore you start the machine, ensure that other service
representatives and the customer’s personnel are not in
a hazardous position.
vPlace removed covers and other parts in a safe place,
away from all personnel, while you are servicing the
machine.
vKeep your toolcase away from walk areas so that other
people will not trip over it.
vDo 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.
vInsert the ends of your necktie or scarf inside clothing or
fasten it with a non-conductive clip, approximately 8
centimeters (3 inches) from the end.
vDo not wear jewelry, chains, metal-frame eyeglasses, or
metal fasteners for your clothing.
Attention: Metal objects are good electrical
conductors.
vWear 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.
12 ThinkPad X20, X21, X22, X23

vAfter service, reinstall all safety shields, guards, labels,
and ground wires. Replace any safety device that is
worn or defective.
vReinstall 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 electrical 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.
vFind the room emergency power-off (EPO) switch,
disconnecting switch, or electrical outlet. If an electrical
accident occurs, you can then operate the switch or
unplug the power cord quickly.
vDo not work alone under hazardous conditions or near
equipment that has hazardous voltages.
vDisconnect all power before:
–Performing a mechanical inspection
–Working near power supplies
–Removing or installing main units
vBefore 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.
vIf 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.
Chapter 1. Introduction 13

–When using testers, set the controls correctly and
use the approved probe leads and accessories for
that tester.
–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.
vRegularly inspect and maintain your electrical hand tools
for safe operational condition.
vDo not use worn or broken tools and testers.
vNever assume that power has been disconnected from
a circuit. First, check that it has been powered off.
vAlways look carefully for possible hazards in your work
area. Examples of these hazards are moist floors,
non-grounded power extension cables, power surges,
and missing safety grounds.
vDo 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.
vDo 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.)
vIf 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.
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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.
Consider these conditions and the safety hazards they
present:
vElectrical hazards, especially primary power (primary
voltage on the frame can cause serious or fatal
electrical shock)
vExplosive hazards, such as a damaged CRT face or a
bulging capacitor
vMechanical hazards, such as loose or missing hardware
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
continuity 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
conditions, 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
circuits (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.
Chapter 1. Introduction 15

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
effective.
When handling ESD-sensitive parts:
vKeep the parts in protective packages until they are
inserted into the product. Avoid contact with other
people.
vWear a grounded wrist strap against your skin to
eliminate static on your body.
vPrevent the part from touching your clothing. Most
clothing is insulative and retains a charge even when
you are wearing a wrist strap.
vUse 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.
vSelect 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
operator safety and correct system function. Proper
grounding of the electrical outlet can be verified by a
certified electrician.
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