IBM ThinkPad 310 Owner's manual

Thank you for purchasing this Factory Service
Manual CD/DVD from servicemanuals4u.com.
Please check out our eBay auctions for more great
deals on Factory Service Manuals:
servicemanuals4u

S05L-1935-00
IBM Mobile Systems
ThinkPad 310, 310D, 310E, 310ED
Hardware Maintenance Manual
February 1998

S05L-1935-00
IBM Mobile Systems
ThinkPad 310, 310D, 310E, 310ED
Hardware Maintenance Manual
February 1998
IBM

Note
Before using this information and the product it
supports, be sure to read the general information
under “Notices” at the back of this manual.
First Edition (February 1998)
The following paragraph does not apply to the United
Kingdom or any country where such provisions are
inconsistent with local law: INTERNATIONAL
BUSINESS MACHINES CORPORATION PROVIDES THIS
PUBLICATION “AS IS” WITHOUT WARRANTY OF ANY
KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT
NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. Some states do not allow disclaimer of
express or implied warranties in certain transactions,
therefore, 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 new editions of the publication. IBM may make
improvements and/or changes in the product(s) and/or the
program(s) described in this publication at any time.
This publication was developed for products and services
offered in the United States of America. IBM may not offer
the products, services, or features discussed in this
document in other countries, and the information is subject
to change without notice. Consult your local IBM
representative for information on the products, services,
and features available in your area.
Requests for technical information about IBM products
should be made to your IBM reseller or IBM marketing
representative.
 Copyright International Business Machines
Corporation 1998. All rights reserved.
Note to U.S. Government users–Documentation related to
Restricted rights–Use, duplication, or disclosure is subject
to restrictions set forth in GSA ADP Schedule Contract
with IBM Corp.
ii IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

About This Manual
This manual contains service and reference information for
IBM ThinkPad 310, 310D, 310E or 310ED (2600) products.
Use this manual along with the advanced diagnostic 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,
reference, 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
troubleshoot problems effectively.
Before servicing an IBM mobile product, be sure to
review the safety information under “Safety Notices
(Multi-lingual Translations)” on page ix and “Safety
Information” on page xvi.
iii

Related Publications
The following mobile product publications are available
through IBM or your IBM Authorized Dealer.
Related Diskettes
The following diskettes are available through IBM or your
IBM Authorized Dealer.
Publication Part, Form Number
Mobile Systems HMM
Volume 1: Laptop,
Notebook, Portable, and
ThinkPad Computers
(Models L40, CL57, N45,
N51, P70/P75, ThinkPad
300, 350, 500, 510, 710T,
Expansion Unit, Dock I,
Dock II)
30H2356, S82G-1501-01
Mobile Systems HMM
Volume 2: ThinkPad
Computers
(Model 340, 355, 360, 370,
700, 701, 720, 750, 755)
30H2357, S82G-1502-03
Mobile Systems HMM
Volume 3: ThinkPad
Computers
(Model 365, 380, 385, 560,
760, SelectaDock
84H8099, S82G-1503-05
Mobile Systems HMM
Volume 4: ThinkPad
Computers
(Model 365, 380, 385, 560,
760, 765, 770, SelectaDock
05L1271, S05L-1270-01
Diskette Part, Form Number
ThinkPad 310 Diagnostics
Diskette 05L1936, S05L-1936
ThinkPad 310 Maintenance
Diskette 05L1770, S05L-1770
iv IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

Contents
Introduction . . . . . . . . . . . . . . . . . . . vii
How to Use Error Messages .......... viii
How to Read POST Error Messages ...... viii
Safety Notices (Multi-lingual Translations) ..... ix
Safety Information . . . . . . . . . . . . . . . . xvi
General Safety . . . . . . . . . . . . . . . . xvi
Electrical Safety . . . . . . . . . . . . . . . xvii
Safety Inspection Guide ........... xviii
Handling Electrostatic Discharge-Sensitive Devices xx
Grounding Requirements . . . . . . . . . . . . xx
Laser Compliance Statement ........... xxi
ThinkPad 310, 310D, 310E, 310ED (2600) .... 1
Read This First .................. 1
Note for Warranty: ................ 2
Checkout Guide . . . . . . . . . . . . . . . . . 3
BIOS Utility . . . . . . . . . . . . . . . . . . . . 11
Power Management Features ........... 12
Symptom-to-FRU Index . . . . . . . . . . . . . . 14
Related Service Procedures ............ 24
Utility Program Diskette .............. 29
Product Overview . . . . . . . . . . . . . . . . . 32
FRU Removals and Replacements ......... 33
Locations . . . . . . . . . . . . . . . . . . . . . 65
310 - System Unit Parts Listing .......... 70
310D - System Unit Parts Listing .......... 71
310/310D - System Unit FRU List ......... 72
310/310D LCD Unit Parts Listing .......... 75
310E System Unit Parts Listing .......... 77
310ED System Unit Parts Listing .......... 78
310E/310ED System Unit FRU List ........ 79
310E/310ED LCD Unit Parts Listing ........ 82
310E/310ED LCD Module FRU list ......... 83
310E (2600-Axx/Cxx/Exx/Fxx) System Unit Parts
Listing . . . . . . . . . . . . . . . . . . . . . 84
310ED (2600-Bxx/Dxx) System Unit Parts Listing . . 85
310E/310ED (2600-Axx/Bxx/Cxx/Dxx/Exx/Fxx) System
Unit FRU List .................. 86
310E/310ED LCD Unit Parts Listing ........ 89
310/310E/310D/310ED Miscellaneous and Other Parts 91
 Copyright IBM Corp. 1998 v

vi IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

Introduction
Important
Diskette fixes are customer installable. The diskette
fixes are located on the PC Company Bulletin Board
Service (BBS). The direct phone line for modem
connection is 919-557-0001 or tieline 255-0001.
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 down-load information.
The Canadian BBS phone numbers are:
Montreal 514-938-3022
Toronto 905-316-4255
Vancouver 604-664-6464
Winnipeg 204-934-2735
FRU Replacement Strategy
Ensure that all diskette fixes are installed prior to replacing
any FRUs. And, 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
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) and verify that the
settings are in place when service is complete.
The advanced diagnostic tests are intended to test only
IBM products. Non-IBM products or modified options can
give false errors and invalid responses.
 Copyright IBM Corp. 1998 vii

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. Data or programs can be
overwritten 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
displayed. 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 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.
viii IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

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
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 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.
Introduction ix

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 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.
xIBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

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 xi

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.
xii IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

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.
Introduction xiii

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.
xiv IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

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.
Introduction xv

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
servicing 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
conductors.
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.
xvi IBM Mobile Systems ThinkPad 310 (D/E/ED) HMM

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.
Find 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.
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
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.
Introduction xvii