IBM ThinkPad 240X Owner's manual

S19K-5649-00
IBM Mobile Systems
ThinkPad 240X (2609)
Hardware Maintenance
Manual
May 2000

Before using this information and the product it supports,
be sure to read the general information under “Read This
First” on page 19.
Fourth Edition (May 2000)
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About This Manual
This manual contains service and reference information for
IBM ThinkPad 570Z (2644) and ThinkPad Ultrabase pro-
ducts. Use this manual along with the advanced diag-
nostic tests to troubleshoot problems effectively.
The manual is divided into sections as follows:
The Introduction section provides general information,
guidelines, and safety information required to service
computers.
The product-specific section includes service, refer-
ence, and product-specific parts information.
Important
This manual is intended for trained servicers who are
familiar with ThinkPad products. Use this manual
along with the advanced diagnostic tests to trouble-
shoot problems effectively.
Before servicing an IBM ThinkPad product, be sure to
review the safety information under “Safety Notices
(Multi-lingual Translations)” on page 4 and “Safety
Information” on page 11.
iii

iv ThinkPad 240X

Contents
Introduction . . . . . . . . . . . . . . . . . . . 1
Important Service Information ........... 1
How to Use Error Messages .......... 2
How to Read POST Error Messages ...... 2
Drive and Diskette Compatibility Matrix ....... 3
Safety Notices (Multi-lingual Translations) ..... 4
Safety Information . . . . . . . . . . . . . . . . 11
General Safety . . . . . . . . . . . . . . . . 11
Electrical Safety . . . . . . . . . . . . . . . . 12
Safety Inspection Guide ............ 13
Handling Electrostatic Discharge-Sensitive Devices 15
Grounding Requirements . . . . . . . . . . . . 15
Laser compliance statement ............ 16
General Description . . . . . . . . . . . . . . . 19
Read This First .................. 19
What to Do First ................ 20
How to Disable the Password ......... 21
Product Overview . . . . . . . . . . . . . . . . . 22
Fn Key Combinations ............. 22
Status Indicators . . . . . . . . . . . . . . . . 23
Checkout Guide . . . . . . . . . . . . . . . . . 25
Audio Checkout . . . . . . . . . . . . . . . . 25
Fan ASM Checkout .............. 26
Keyboard and Auxiliary Input Device Checkout . 26
Memory Checkout . . . . . . . . . . . . . . . 26
Modem Board Checkout ............ 27
Power System Checkout ............ 27
TrackPoint Checkout . . . . . . . . . . . . . . 29
I/O Ports Checkout .............. 30
Power Management Features ......... 30
Symptom-to-FRU Index . . . . . . . . . . . . . . 33
Numeric Error Codes .............. 33
Error Messages . . . . . . . . . . . . . . . . 35
No Beep Symptoms .............. 35
LCD-Related Symptoms . . . . . . . . . . . . 36
Keyboard-Related Symptoms . . . . . . . . . . 36
Indicator-Related Symptoms . . . . . . . . . . 36
Power-Related Symptoms . . . . . . . . . . . 37
PC Card (PCMCIA)-Related Symptoms ..... 37
Speaker-Related Symptoms . . . . . . . . . . 37
Power Management-Related Symptoms ..... 37
Peripheral-Device-Related Symptom . . . . . . 38
Intermittent Problems . . . . . . . . . . . . . 38
Undetermined Problems . . . . . . . . . . . . 39
CE Utility Program Diskette ............ 40
Writing the VPD Data ............. 40
Flash UUID . . . . . . . . . . . . . . . . . . 40
Running the Diagnostics .............. 40
FRU Removals and Replacements ......... 41
Contents v

FRU Service Procedures ............ 41
1010 Battery ASM ............... 43
1020 Hard Disk Drive ............. 44
1030 Keyboard . . . . . . . . . . . . . . . . 45
1040 Modem Card ............... 46
1050 DIMM Card ............... 47
1060 LCD Unit ASM .............. 48
1070 Upper Cover ASM ............ 49
1080 Speaker ASM .............. 51
1085 Select Button ASM ............ 52
1090 Cable ASM and Cable ASM LED-R .... 53
1100 Fan ASM ................ 54
1110 Modem Cable ASM ............ 56
1120 Water Channel ASM ........... 57
1130 System Board .............. 58
1135 Rear Bracket ............... 60
1140 PCMCIA Slots .............. 61
1150 LCD Bezel ASM ............. 62
1160 LCD Inverter ASM ............ 63
1170 LCD Panel ASM (LCD Type A and B) . . . 64
1180 LCD FPC ASM (LCD Type A) ....... 66
1185 LCD FPC ASM (LCD Type B) ....... 67
1190 Hinge ASM ............... 68
Computer Parts Listing .............. 69
LCD Unit Parts Listing (LCD Type A) ........ 74
LCD Unit Parts Listing (LCD Type B) ........ 75
Service Tools . . . . . . . . . . . . . . . . . . . 75
Notices . . . . . . . . . . . . . . . . . . . . . . 77
Trademarks . . . . . . . . . . . . . . . . . . . 77
vi ThinkPad 240X

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.
FRU Replacement Strategy
Before Replacing Parts
Ensure that all diskette fixes are installed prior to
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 and that
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 replaced does not correct the problem,
reinstall the original board, then replace the other
(processor or system) board.
If an adapter or device consists of more than one
FRU, an error code may be caused by any of the
FRUs. Before replacing the adapter or device,
remove the FRUs, one by one, to see if the symp-
toms 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) and verify that the set-
tings are in place when service is complete.
Hard Disk Drive Replacement Strategy:
Always try to run a low-level format before replacing a hard
disk drive.
Introduction 1

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. Data or programs can be over-
written if you select an incorrect drive.
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. The cause of the
first error code can result in false error codes being dis-
played. 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 will represent different
information for SCSI errors versus non-SCSI errors.
The following example shows which digits display the
shorter POST error messages and also defines the SCSI
information in an eight-digit error message.
Shorter POST Messages
┌────┬────┬────┬────┐
│ │ │ │ │
┌────┬────┬────┬────┬────┬────┬────┬────┐
│ ð│ ð│ ð│ ð│ ð│ ð│ ð│ ð│
└────┴────┴────┴────┴────┴────┴────┴────┘
│ │ │ │ │ │ │ │
Reserved ││││││Size (SCSI)
└────┴────┘ │ │ Slot Number (SCSI)
Device Code │ Logical Unit Number (SCSI)
ID (SCSI)
All SCSI devices are set to a different SCSI ID.
Duplicate SCSI ID settings can generate a false error
message. Use the SCSI ID to determine whether the error
message is coming from an internal or an external device.
2ThinkPad 240X

Drive and Diskette Compatibility Matrix
The following table provides identification information for
3.5-inch drives.
Diskette
Drive Identifying Mark
3.5-Inch - 1.44MB 1.44 on the eject button
3.5-Inch - 2.88MB 2.88 on the eject button
The following table provides compatibility information for
3.5-inch diskettes and 3.5-inch diskette drives.
The following table provides identification information for
5.25-inch diskette drives.
Diskette
Capacity 1.44MB Drive 2.88MB Drive
1.0MB Read/Write Read/Write
2.0MB Read/Write Read/Write
4.0MB Not Compatible Read/Write
Diskette
Drive Identifying Mark
5.25-Inch - 360KB (External) Asterisk on bezel
5.25-Inch - 1.2MB (Internal) 1.2 on the eject button
The following table provides compatibility information for
5.25-inch diskettes and 5.25-inch diskette drives.
Note: A 360KB diskette written to or formatted on a
1.2MB drive can be read reliably only on a 1.2MB
drive.
Diskette
Capacity 360KB Drive 1.2MB Drive
360KB Read/Write Read/Write
1.2MB Not Compatible Read/Write
Introduction 3

Safety Notices (Multi-lingual
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, muß sichergestellt
werden, daß keine Schrauben, Federn oder andere
Kleinteile fehlen oder im Gehäuse vergessen wurden.
Der Computer muß 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.
4ThinkPad 240X

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.
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 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.
6ThinkPad 240X

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.
Introduction 7

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 unsachgemäß 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
anschließend 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.
8ThinkPad 240X

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 Kurzschluß 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.
Introduction 9

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 muß 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.
10 ThinkPad 240X

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 to the
customer, 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 tool case 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.
Reinstall all covers correctly before returning the
machine to the customer.
Introduction 11

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: There must be a complete circuit to
cause electrical shock. 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.
– 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.
12 ThinkPad 240X

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 your-
self.
– Switch off power.
– Send another person to get medical aid.
Safety Inspection Guide
The intent of this inspection guide is to assist you in identi-
fying potentially unsafe conditions on these products.
Each machine, as it was designed and built, had required
safety items installed to protect users and service per-
sonnel from injury. This guide addresses only those items.
However, good judgment should be used to identify poten-
tial 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.
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
bulging capacitor
Mechanical hazards, such as loose or missing hard-
ware
Introduction 13

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 appropriate type
as specified in the parts listings.
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 alter-
ations.
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.
14 ThinkPad 240X