About this manual
Chapter 1. Safety information
Chapter 2. Important service information
- Strategy for replacing FRUs
- Strategy for replacing FRUs for CTO, special-bid, and standard models
  - Product definition
  - FRU identification
Chapter 3. General checkout
Chapter 4. Related service information
Chapter 5. Special keys
Chapter 6. Locations
Chapter 7. FRU replacement notices
Chapter 8. Removing or replacing a FRU
Appendix A. Notices
Appendix B. Abbreviation and acronym table

Lenovo P43 User Manual

Displayed below is the user manual for P43 by Lenovo which is a product in the Notebooks category. This manual has pages.

Related Manuals

Lenovo P43s Manual

T490 and P43s

Hardware Maintenance Manual

Note: Before using this information and the product it supports, be sure to read the general information

under Appendix A “Notices” on page 111.

Third Edition (July 2019)

LIMITED AND RESTRICTED RIGHTS NOTICE: If data or software is delivered pursuant a General Services Administration

“GSA” contract, use, reproduction, or disclosure is subject to restrictions set forth in Contract No. GS-35F-05925.

Contents

About this manual . . . . . . . . . . . . iii

Chapter 1. Safety information . . . . . . 1

General safety . . . . . . . . . . . . . . . . 1

Electrical safety . . . . . . . . . . . . . . . . 1

Safety inspection guide . . . . . . . . . . . . . 3

Handling devices that are sensitive to electrostatic

discharge . . . . . . . . . . . . . . . . . . 3

Grounding requirements . . . . . . . . . . . . 4

Safety notices (multilingual translations) . . . . . . 4

Chapter 2. Important service

information . . . . . . . . . . . . . . . 21

Strategy for replacing FRUs . . . . . . . . . . 21

Strategy for replacing a hard disk drive or a

solid-state drive . . . . . . . . . . . . . 21

Important notice for replacing a system

board . . . . . . . . . . . . . . . . . 22

How to use error codes . . . . . . . . . . 22

Strategy for replacing FRUs for CTO, special-bid,

and standard models. . . . . . . . . . . . . 22

Product definition . . . . . . . . . . . . 22

FRU identification . . . . . . . . . . . . 23

Chapter 3. General checkout . . . . . 25

What to do first . . . . . . . . . . . . . . . 25

Checkout guide . . . . . . . . . . . . . . . 26

Diagnosing problems . . . . . . . . . . . 26

Quick test programs . . . . . . . . . . . 26

UEFI diagnostic program . . . . . . . . . 27

Bootable diagnostic programs . . . . . . . 27

Power system checkout . . . . . . . . . . . 28

Checking the ac power adapter . . . . . . . 28

Checking the built-in battery and operational

charging . . . . . . . . . . . . . . . . 29

Checking the coin-cell battery . . . . . . . 29

Chapter 4. Related service

information . . . . . . . . . . . . . . . 31

Recovery overview for the Windows 10 operating

system . . . . . . . . . . . . . . . . . . 31

Resetting your computer . . . . . . . . . . . 31

Using advanced startup options . . . . . . . . 31

Recovering your operating system if Windows 10

fails to start . . . . . . . . . . . . . . . . 32

Creating and using a recovery USB drive . . . . . 32

Passwords. . . . . . . . . . . . . . . . . 33

Power-on password . . . . . . . . . . . 33

Hard disk password . . . . . . . . . . . 33

Supervisor password . . . . . . . . . . . 33

System management password. . . . . . . 34

How to remove the power-on password . . . 34

How to remove the hard disk password. . . . 35

How to remove the system management

password . . . . . . . . . . . . . . . 35

Power management . . . . . . . . . . . . . 36

Sleep mode . . . . . . . . . . . . . . 36

Hibernation mode . . . . . . . . . . . . 36

Symptom-to-FRU index . . . . . . . . . . . 37

Numeric error codes . . . . . . . . . . . 37

Error messages . . . . . . . . . . . . . 39

Beep errors. . . . . . . . . . . . . . . 39

No-beep symptoms . . . . . . . . . . . 41

LCD-related symptoms . . . . . . . . . . 41

Intermittent problems . . . . . . . . . . . 42

Undetermined problems . . . . . . . . . 42

Chapter 5. Special keys . . . . . . . . 45

Chapter 6. Locations . . . . . . . . . 47

Locating computer controls, connectors, and

indicators . . . . . . . . . . . . . . . . . 47

Front . . . . . . . . . . . . . . . . . 47

Base . . . . . . . . . . . . . . . . . 48

Left . . . . . . . . . . . . . . . . . . 49

Right . . . . . . . . . . . . . . . . . 49

Bottom . . . . . . . . . . . . . . . . 50

Rear . . . . . . . . . . . . . . . . . 50

Locating FRUs and CRUs . . . . . . . . . . . 50

Major FRUs and CRUs . . . . . . . . . . 52

LCD FRUs . . . . . . . . . . . . . . . 55

Miscellaneous parts . . . . . . . . . . . 57

Connector and cable guide . . . . . . . . 57

Looking up FRU information . . . . . . . . . . 62

Chapter 7. FRU replacement

notices . . . . . . . . . . . . . . . . . 63

Service tool kit . . . . . . . . . . . . . . . 63

Screw notices . . . . . . . . . . . . . . . 63

Retaining serial numbers . . . . . . . . . . . 64

Restoring the serial number of the system

unit . . . . . . . . . . . . . . . . . . 64

Retaining the UUID. . . . . . . . . . . . 65

Chapter 8. Removing or replacing a

FRU. . . . . . . . . . . . . . . . . . . 67

General guidelines. . . . . . . . . . . . . . 67

Before servicing the computer . . . . . . . . . 68

Disabling the built-in battery . . . . . . . . 68

Removing the nano-SIM card and the nano-

SIM-card tray . . . . . . . . . . . . . . 68

1010 Keyboard . . . . . . . . . . . . . . . 68

1020 Base cover assembly . . . . . . . . . . 71

1030 M.2 solid-state drive . . . . . . . . . . . 73

1040 Memory module . . . . . . . . . . . . 74

1050 Speaker assembly . . . . . . . . . . . 75

1060 Wireless WAN card . . . . . . . . . . . 76

1070 Coin-cell battery . . . . . . . . . . . . 77

1080 Built-in battery . . . . . . . . . . . . . 78

1090 Thermal fan assembly . . . . . . . . . . 79

1100 RJ45 cable, bracket and board . . . . . . 80

1110 USB cable, bracket and board . . . . . . . 82

1120 Fingerprint reader cable, bracket and

board . . . . . . . . . . . . . . . . . . . 83

1130 Smart card reader module and cable . . . . 85

1140 Trackpad and cable . . . . . . . . . . . 86

1150 Hall sensor board with cable . . . . . . . 87

1160 NFC module, cable and antenna . . . . . . 88

1170 RFID reader cable and RFID reader (for T490 20Q9

and 20QH only) . . . . . . . . . . . . . . . 89

1180 Power button board with cable, power

button . . . . . . . . . . . . . . . . . . 90

1190 System board . . . . . . . . . . . . . 91

1210 MIMO wireless-WAN antenna assembly . . . 95

1220 LCD unit . . . . . . . . . . . . . . . 96

1230 Keyboard bezel assembly . . . . . . . . 98

2010 LCD bezel sheet and LCD bezel . . . . . . 99

2020 LCD panel and LCD elastic adhesive tapes . . 99

2030 Camera/microphone module . . . . . . . 103

2040 LCD hinges . . . . . . . . . . . . . . 104

2050 Camera/LED cable . . . . . . . . . . . 105

2060 LCD cable. . . . . . . . . . . . . . . 107

2070 Wireless antenna assembly . . . . . . . . 107

2080 LCD cover assembly. . . . . . . . . . . 109

Appendix A. Notices. . . . . . . . . . 111

Appendix B. Abbreviation and

acronym table . . . . . . . . . . . . . 113

ii T490 and P43s Hardware Maintenance Manual

About this manual

This manual contains service and reference information for the following ThinkPad® product:

ThinkPad T490 Machine types (MT) 20N2, 20N3, 20Q9, 20QH, 20RX and 20RY

ThinkPad P43s Machine types (MT) 20RH and 20RJ

Use this manual along with the advanced diagnostic tests to troubleshoot problems.

Important:

This manual is intended only for trained service technicians who are familiar with ThinkPad products. Use

this manual along with the advanced diagnostic tests to troubleshoot problems effectively.

Before servicing a ThinkPad product, be sure to read all the information under Chapter 1 “Safety

information” on page 1 and Chapter 2 “Important service information” on page 21.

iv T490 and P43s Hardware Maintenance Manual

Chapter 1. Safety information

This chapter presents the following safety information that you need to be familiar with before you service a

ThinkPad notebook computer.

• “General safety” on page 1

• “Electrical safety” on page 1

• “Safety inspection guide” on page 3

• “Handling devices that are sensitive to electrostatic discharge” on page 3

• “Grounding requirements” on page 4

• “Safety notices (multilingual translations)” on page 4

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 that 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 object that weighs more than 16 kg (35 lb) or that you

think is 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 technicians 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 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, about 8

centimeters (3 inches) from the end.

• Do not wear jewelry, chains, metal-frame eyeglasses, or metal fasteners for your clothing, because 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.

• Fan louvers on the machine help to prevent overheating of internal components. Do not obstruct fan

louvers or cover them with labels or stickers.

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 (ESD). 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. That 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.

CAUTION:

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 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. Instructions for these

precautions 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:

– Power supply units

– Pumps

– Blowers and fans

– Motor generators

– Units similar to those listed above

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.

2T490 and P43s Hardware Maintenance Manual

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

technicians from injury. This guide addresses only those items. You should use good judgment to identify

potential safety hazards due to attachment of non-ThinkPad 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

electrical shock)

• Explosive hazards, such as a damaged CRT face or a bulging capacitor

• Mechanical hazards, such as loose or missing hardware

To determine whether there are any potentially unsafe conditions, use the following checklist at the

beginning of every service task. 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. Turn 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 the frame ground.

b. The power cord should be the authorized type specified for your computer. Go to: https://

support.lenovo.com/partslookup.

c. Insulation must not be frayed or worn.

4. Check for cracked or bulging batteries.

5. Remove the cover.

6. Check for any obvious non-ThinkPad alterations. Use good judgment as to the safety of any non-

ThinkPad alterations.

7. 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.

8. Check for worn, frayed, or pinched cables.

9. Check that the power-supply cover fasteners (screws or rivets) have not been removed or tampered

with.

Handling devices that are sensitive to electrostatic discharge

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.

Notes:

1. Use product-specific ESD procedures when they exceed the requirements noted here.

Chapter 1.Safety information 3

2. Ensure that the ESD protective devices you use have been certified (ISO 9000) as fully effective.

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 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 to guard against ESD damage is desirable but not necessary.

– Attach the ESD ground clip to any frame ground, ground braid, or green-wire ground.

– When working on a double-insulated or battery-operated system, use an ESD common ground or

reference point. 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.

Safety notices (multilingual translations)

The safety notices in this section are provided in the following languages:

• English

• Arabic

• Brazilian Portuguese

• French

• German

• Hebrew

• Japanese

• Korean

• Spanish

• Traditional Chinese

DANGER

4T490 and P43s Hardware Maintenance Manual

DANGER

Chapter 1.Safety information 5

DANGER

6T490 and P43s Hardware Maintenance Manual

PERIGO

Chapter 1.Safety information 7

PERIGO

8T490 and P43s Hardware Maintenance Manual

PERIGO

DANGER

Chapter 1.Safety information 9

DANGER

10 T490 and P43s Hardware Maintenance Manual

DANGER

VORSICHT

Chapter 1.Safety information 11

VORSICHT

12 T490 and P43s Hardware Maintenance Manual

Chapter 1.Safety information 13

14 T490 and P43s Hardware Maintenance Manual

Chapter 1.Safety information 15

16 T490 and P43s Hardware Maintenance Manual

Chapter 1.Safety information 17

18 T490 and P43s Hardware Maintenance Manual

Chapter 1.Safety information 19

20 T490 and P43s Hardware Maintenance Manual

Chapter 2. Important service information

This chapter introduces the following important service information that applies to all machine types

supported by this manual:

• “Strategy for replacing FRUs” on page 21

– “Strategy for replacing a hard disk drive or a solid-state drive” on page 21

– “Important notice for replacing a system board” on page 22

– “How to use error codes” on page 22

• “Strategy for replacing FRUs for CTO, special-bid, and standard models” on page 22

– “Product definition” on page 22

– “FRU identification” on page 23

Important:

• Advise customers to contact the Lenovo Customer Support Center if they need any assistance in

obtaining or installing any software fixes, drivers, and UEFI BIOS downloads. Telephone numbers for

Lenovo Support are available at:

https://pcsupport.lenovo.com/supportphonelist

• System disassembly and reassembly videos that show the FRU removal or replacement procedures for

the Lenovo authorized service technicians are available at:

http://www.lenovoservicetraining.com/ion/

Strategy for replacing FRUs

Before replacing parts:

Ensure that all software fixes, drivers, and UEFI BIOS downloads are installed before you replace any FRUs

listed in this manual.

After a system board is replaced, ensure that the latest UEFI BIOS is loaded to the system board before you

complete the service action.

To download and install software fixes, drivers, and UEFI BIOS, go to https://support.lenovo.com and follow

the instructions on the screen.

Use the following strategy to prevent unnecessary expense for replacing and servicing FRUs:

• 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 replacing one of them does not correct the problem,

reinstall that board, and then replace the other one.

• If an adapter or a device consists of more than one FRU, any of the FRUs might 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.

Strategy for replacing a hard disk drive or a solid-state drive

Always try to run a low-level format operation before replacing a hard disk drive or a solid-state drive. This

will cause all customer data on the drive to be lost. Ensure that the customer has a current backup of the

data before you perform this task.

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.

Important notice for replacing a system board

Some components mounted on a system board are very sensitive. Improper handling of a system board can

cause damage to those components, and may cause a system malfunction.

Attention: When handling a system board:

• Do not drop a system board or apply any excessive force to it.

• Avoid rough handling of any kind.

• Avoid bending a system board and hard pushing to prevent cracking at each Ball Grid Array (BGA)

chipset.

How to use error codes

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 might also cause false error

codes. If no error code is displayed, see whether the error symptom is listed in the “Symptom-to-FRU Index”

section.

Strategy for replacing FRUs for CTO, special-bid, and standard models

This topic provides information about the model types and FRU identification.

Product definition

This topic introduces different model types and how to identify each type.

Dynamic Configure To Order (CTO) model

This model provides the ability for a customer to configure a Lenovo solution from a Web site, and have this

configuration sent to fulfillment, where it is built and shipped directly to the customer. The machine label and

eSupport will load these products as the 4-character MT, 4-character model, and 2-character country code.

The model is “CTO1” and the default country code is “WW” (example: 20AACTO1WW).

Special-bid model

This model is a unique configuration that has been negotiated between Lenovo and the customer. A unique

MTM consists of a 4-character MT, a 4-character model, and a numeric 2-character country code is provided

to the customer to place orders (example: 20AA000955). The country code assigned is numeric and does not

designate a specific country or region. The custom model factsheet for the MTM indicates which country the

special-bid MTM is set up for. Special-bid offering is not generally announced.

Standard model

Standard models (fixed configuration) are announced and offered to all customers. The MTM portion of the

machine label consists of a 4-character MT, a 4-character model, and an alphabetic 2-character country

code. The country code assigned is alphabetic and represents a designated country or region (example:

20AA0009UK).

22 T490 and P43s Hardware Maintenance Manual

FRU identification

To identify FRUs for a product, do the following:

1. Go to: https://support.lenovo.com/partslookup

2. Type the Machine Type in the corresponding field to get a general FRU list, or type the Serial Number for

more detailed FRU information.

Chapter 2.Important service information 23

24 T490 and P43s Hardware Maintenance Manual

Chapter 3. General checkout

This chapter presents following information:

• “What to do first” on page 25

• “Checkout guide” on page 26

• “Power system checkout” on page 28

Some descriptions in this chapter might not apply to your particular computer.

Before you go to the checkout guide, be sure to read the following important notes.

Important notes:

• Only certified trained personnel should service the computer.

• Before replacing any FRU, read the entire page on removing and replacing FRUs.

• When you replace FRUs, it is recommended to use new nylon-coated screws.

• Be extremely careful during such write operations as copying, saving, or formatting. Drives in the computer

that you are servicing sequence might have been altered. If you select an incorrect drive, data or programs might be

overwritten.

• Replace a FRU only with another FRU of the correct model. When you replace a FRU, ensure that the model of

the machine and the FRU part number are correct.

• A FRU should not be replaced because of a single, unreproducible failure. Single failures can occur for a variety

of reasons that have nothing to do with a hardware defect, such as cosmic radiation, ESD, or software errors.

Consider replacing a FRU only when a problem recurs. If you suspect that a FRU is defective, clear the error log and

run the test again. If the error does not recur, do not replace the FRU.

• Be careful not to replace a nondefective FRU.

What to do first

When you return a FRU, you must include the following information in the parts exchange form or parts return

form that you attach to it:

1. Name and phone number of service technician

2. Date of service

3. Date on which the machine failed

4. Date of purchase

5. Failure symptoms, error codes appearing on the display, and beep symptoms

6. Procedure index and page number in which the failing FRU was detected

7. Failing FRU name and part number

8. Machine type, model number, and serial number

9. Customer's name and address

Note: During the warranty period, the customer may be responsible for repair costs if the computer damage

was caused by misuse, accident, modification, unsuitable physical or operating environment, or improper

maintenance by the customer. Following is a list of some common items that are not covered under warranty

and some symptoms that might indicate that the system was subject to stress beyond normal use.

Before checking problems with the computer, determine whether the damage is covered under the warranty

by referring to the following list:

The following are not covered under warranty:

• LCD panel cracked from the application of excessive force or from being dropped

• Scratched (cosmetic) parts

• Distortion, deformation, or discoloration of the cosmetic parts

• Plastic parts, latches, pins, or connectors that have been cracked or broken by excessive force

• Damage caused by liquid spilled into the system

• Damage caused by the improper insertion of a PC Card or the installation of an incompatible card

• Diskette drive damage caused by pressure on the diskette drive cover, foreign material in the drive, or the

insertion of a diskette with multiple labels

• Damaged or bent diskette eject button

• Fuses blown by attachment of a nonsupported device

• Forgotten computer password (making the computer unusable)

• Sticky keys caused by spilling a liquid onto the keyboard

• Use of an incorrect ac power adapter on laptop products

The following symptoms might indicate damage caused by nonwarranted activities:

• Missing parts might be a symptom of unauthorized service or modification.

• Check for obvious damage to a hard disk drive. If the spindle of a hard disk drive becomes noisy, the hard

disk drive might have been dropped or subject to excessive force.

Checkout guide

Use the following procedures as a guide in identifying and correcting problems with the ThinkPad notebook

computer.

Note: The diagnostic tests are intended to test only ThinkPad products. The use of non-ThinkPad products,

prototype cards, or modified options can lead to false indications of errors and invalid system responses.

1. Identify the failing symptoms in as much detail as possible.

2. Verify the symptoms. Try to re-create the failure by running the diagnostic test or by repeating the

operation.

Diagnosing problems

Many computer problems can be solved without outside assistance. If you experience a problem with your

computer, the first place to start is the troubleshooting information in your computer documentation. If you

suspect a software problem, see the documentation, including readme files and help information systems,

that come with the operating system or program.

Lenovo Vantage is preinstalled on your computer. It supports the hardware scan function. It combines

diagnostic tests, system information collection, security status, and support information, along with hints and

tips for optimal system performance.

Note: If you are unable to isolate and repair the problem yourself after running the program, save and print

the log files created by the program. You need the log files when you speak to a Lenovo technical support

representative.

The troubleshooting information or the diagnostic programs might tell you that you need additional or

updated device drivers or other software. You can get the latest technical information and download device

drivers and updates from the Lenovo Support Web site at:

https://support.lenovo.com

For additional information, see the help system of the program.

Quick test programs

Run quick test programs to troubleshoot and resolve computer problems, especially when the computer

does not have Lenovo Vantage installed.

26 T490 and P43s Hardware Maintenance Manual

To download and install a quick test program, go to https://www.lenovo.com/diags, and follow the instructions

on the Web site.

To run a test using quick test program, do the following:

1. Go to the C:\SWTOOLS\ldiag directory.

2. Double-click the lsc_lite.exe file.

3. When the User Account Control window opens, click Yes.

4. Select the device class to be tested.

5. Select the devices to be tested.

6. Select the test to be performed.

7. Follow the instructions on the screen to start the test. When a problem is detected, information

messages are displayed. Refer to the messages to troubleshoot the problem.

UEFI diagnostic program

A UEFI diagnostic program is preinstalled on the computer. This program enables you to view system

information and test some hardware devices in your computer, such as memory, storage devices, the LCD,

and system board buses.

To run the UEFI diagnostic program, do the following:

1. Turn on the computer. If the computer cannot be turned on, go to “Power system checkout” on page 28,

and check the power sources. If an error code is displayed, go to “Symptom-to-FRU index” on page 37

for error code descriptions and troubleshooting hints.

2. When the ThinkPad logo is displayed, repeatedly press and release the F10 key. The main screen of the

UEFI diagnostic program is displayed.

3. Follow the instructions on the screen to use the program.

The following table displays the main items of the UEFI diagnostic program. Depending on the model, the

items might differ slightly.

Table 1. Items on the main screen of the UEFI diagnostic program

Tests Tools

• Memory quick test

• Memory extended test

• Memory bit fade test (180 min)

• Quick storage device test

• LCD test

• PCI-e test

• Motherboard buses test

• Exit application

• System information

• Generate configuration file

• Execute from configuration file

• Recover bad sectors tool

Note: The recover bad sectors tool is only available on computers that have hard disk drives installed.

Bootable diagnostic programs

If the computer you are servicing is not installed with the UEFI diagnostic program, you can download a

bootable diagnostic program from the Lenovo Support Web site. The bootable diagnostic program enables

you to view system information and test some hardware devices in your computer, such as memory, storage

devices, the LCD, and system board buses. To use the bootable diagnostic program, you can create a

bootable diagnostic medium using a USB device or disc.

Chapter 3.General checkout 27

To create a bootable diagnostic medium, do the following:

1. Go to https://www.lenovo.com/diags.

2. Click Lenovo Bootable Diagnostics.

3. Follow the instructions on the Web site to create a bootable diagnostic medium on a USB device or disc.

To use the diagnostic medium you have created, do one of the following:

• If you have created the bootable diagnostic medium on a USB device, do the following:

1. Attach the USB device to the computer.

2. Turn on the computer. If the computer cannot be turned on, go to “Power system checkout” on page

28, and check the power sources. If an error code is displayed, go to “Symptom-to-FRU index” on

page 37 for error code descriptions and troubleshooting hints.

3. When the ThinkPad logo is displayed, repeatedly press and release the F12 key. When the Boot Menu

window opens, release the F12 key.

4. Use the arrow keys to select USB HDD and then press Enter. The diagnostic program launches.

5. Follow the instructions on the screen to use the diagnostic program.

• If you have created the bootable diagnostic medium using a disc, do the following:

1. Turn on the computer. If the computer cannot be turned on, go to “Power system checkout” on page

28, and check the power sources. If an error code is displayed, go to “Symptom-to-FRU index” on

page 37 for error code descriptions and troubleshooting hints.

2. Insert the disc into the optical drive.

3. Restart the computer.

4. When the ThinkPad logo is displayed, repeatedly press and release the F12 key. When the Boot Menu

window opens, release the F12 key.

5. Use the arrow keys to select ATAPI CDx (x: 0, 1, ...) and then press Enter. The diagnostic program

launches.

6. Follow the instructions on the screen to use the diagnostic program.

Power system checkout

To verify if a battery or an ac power adapter is functional, do the following:

1. Turn off the computer.

2. Connect the ac power adapter.

3. Turn on the computer. If the computer can be turned on, it means that either the battery or the ac power

adapter is functional.

4. Insert a straightened paper clip into the emergency-reset hole to reset the computer. If the computer is

still powered on, it means that the ac power adapter is functional.

5. Turn off the computer.

6. Disconnect the ac power adapter and turn on the computer. If the computer can be turned on, it means

that the battery is functional.

If you suspect a power problem, see the appropriate one of the following power supply checkouts:

• “Checking the ac power adapter” on page 28

• “Checking the built-in battery and operational charging” on page 29

• “Checking the coin-cell battery” on page 29

Checking the ac power adapter

You are here because the computer fails only when the ac power adapter is used.

• If the power problem occurs only when the docking station or the port replicator is used, replace the

docking station or the port replicator.

28 T490 and P43s Hardware Maintenance Manual

• If the system status indicator does not blink three times when an ac power source is connected, check the

power cord of the ac power adapter for correct continuity and installation.

• If the computer does not charge during operation, go to “Checking the built-in battery and operational

charging” on page 29.

Note: Noise from the ac power adapter does not always indicate a defect.

Checking the USB-C type ac power adapter

To check the USB-C type ac power adapter, do the following:

1. Connect the computer to a power outlet and turn on the computer.

2. Start Lenovo Vantage program, and then click Hardware Settings ➙ Power. The ac power adapter

information is displayed.

Ensure that you use the USB-C type ac power adapter that is shipped with the computer to provide enough

power to the computer. Otherwise, a message will be displayed, prompting you that the computer will not be

charged or will be charged slowly.

Checking the built-in battery and operational charging

This computer supports only batteries specially designed for this specific system and manufactured by

Lenovo or an authorized builder. The system does not support unauthorized batteries or batteries designed

for other systems. If an unauthorized battery or a battery designed for another systems is installed, the

system will not charge.

Attention: Lenovo has no responsibility for the performance or safety of unauthorized batteries, and

provides no warranties for failures or damage arising out of their use.

Move your pointer to the battery-status icon in the Windows notification area to check the battery status. The

battery-status icon displays the percentage of battery power remaining and how long you can use your

computer before you must charge the battery.

To check whether the battery charges properly during operation, do the following:

1. Discharge the battery until the remained battery power is less than 50%.

2. Connect the computer to ac power to charge the battery. If the battery status icon in the Windows

notification area indicates that the battery is not charging, remove the battery and let it return to room

temperature.

3. Reinstall the battery. If the battery is still not charging, replace the battery.

4. Check the battery status icon again. If the same error still exists, replace the system board.

Checking the coin-cell battery

Do the following:

1. Power off the computer, and unplug the ac power adapter from it.

2. Turn the computer upside down.

3. Remove the built-in battery (see “1080 Built-in battery” on page 78).

4. Remove the coin-cell battery (see “1070 Coin-cell battery” on page 77).

5. Measure the voltage of the battery. See the following figure.

Chapter 3.General checkout 29

Wire Voltage (V dc)

Red +2.5 to +3.2

Black Ground

• If the voltage is correct, replace the system board.

• If the voltage is not correct, replace the coin-cell battery.

• If the coin-cell battery discharges quickly after replacement, replace the system board.

30 T490 and P43s Hardware Maintenance Manual

Chapter 4. Related service information

This chapter presents following information:

• “Recovery overview for the Windows 10 operating system” on page 31

• “Passwords” on page 33

• “Power management” on page 36

• “Symptom-to-FRU index” on page 37

Service Web site:

When the latest maintenance diskette and the system program service diskette become available, they will

be posted on:

https://support.lenovo.com

Recovery overview for the Windows 10 operating system

The Windows recovery programs enable you to reset your computer or use advanced startup options.

It is recommended that you create a recovery USB drive as early as possible. Store the recovery USB drive

as a backup or replacement for the Windows recovery programs.

For more information, see “Creating and using a recovery USB drive” on page 32.

Resetting your computer

If your computer does not perform well, you might consider resetting your computer. In the resetting

process, you can choose to keep your files or remove them, and then reinstall the Windows operating

system.

To reset your computer, do the following:

Note: The graphical user interface (GUI) items of the operating system might change without notice.

1. Open the Start menu, and then click Settings ➙ Update & Security ➙ Recovery.

2. In the Reset this PC section, click Get started.

3. Follow the instructions on the screen to reset your computer.

Using advanced startup options

With advanced startup options, you can change the firmware settings of the computer, change the startup

settings of the Windows operating system, start the computer from an external device, or restore the

Windows operating system from a system image.

To use advanced startup options, do the following:

Note: The GUI items of the operating system might change without notice.

1. Open the Start menu, and then click Settings ➙ Update & security ➙ Recovery.

2. In the Advanced startup section, click Restart now ➙ Troubleshoot ➙ Advanced options.

3. Select a startup option you want, and then follow the instructions on the screen.

Recovering your operating system if Windows 10 fails to start

The Windows recovery environment on your computer is capable of operating independently from the

Windows 10 operating system. This enables you to recover or repair the operating system even if the

Windows 10 operating system fails to start.

After two consecutive failed boot attempts, the Windows recovery environment starts automatically. Then

you can choose repair and recovery options by following the instructions on the screen.

Note: Ensure that your computer is connected to ac power during the recovery process.

Creating and using a recovery USB drive

You can create a recovery USB drive as a backup for the Windows recovery programs. With the recovery

USB drive, you can troubleshoot and fix the problems even if the preinstalled Windows recovery programs

are damaged.

Creating a recovery USB drive

The USB drive that you use to create the recovery USB drive must be at least 16 GB of storage. The actual

USB capacity that is required depends on the size of the recovery image.

Attention: The creation process deletes anything stored on the USB drive. To avoid data loss, make a

backup copy of all the data that you want to keep.

To create a recovery USB drive, do the following:

Note: Ensure that your computer is connected to ac power during the following process.

1. Connect a proper USB drive (at least 16 GB of storage).

2. Type recovery in the search box on the taskbar. Then click Create a recovery drive.

3. Click Yes in the User Account Control window to allow the Recovery Media Creator program to start.

4. In the Recovery Drive window, follow the on-screen instructions to create a recovery USB drive.

Using the recovery USB drive

If you cannot start your computer, use the recovery USB drive to recover your computer.

To use a recovery USB drive, do the following:

Note: Ensure that your computer is connected to ac power.

1. Connect the recovery USB drive to the computer.

2. Turn on or restart the computer. Before the Windows operating system starts, repeatedly press the F12

key. The Boot Menu window opens.

3. Select the recovery USB drive as the boot device.

4. Select a preferred keyboard layout.

5. Click Troubleshoot to display the optional recovery solutions.

6. Select a corresponding recovery solution according to your situation. Then follow the instructions on the

screen to complete the process.

32 T490 and P43s Hardware Maintenance Manual

Passwords

As many as four passwords might be needed for a ThinkPad notebook computer: the power-on password,

the hard disk password, the supervisor password, and the system management password.

If any of these passwords has been set, a prompt for it will be displayed on the screen whenever the

computer is turned on. The computer does not start until the password is entered.

Note: If only a supervisor password is set, the password prompt will not be displayed when the operating

system is started.

Power-on password

A power-on password protects the system from being turned on by an unauthorized person. The password

must be entered before the operating system can be started. For instructions on how to remove the power-

on password, see “How to remove the power-on password” on page 34.

Hard disk password

There are two hard disk passwords:

• User hard disk password - for the user

• Master hard disk password - for the system administrator, who can use it to get access to the hard disk

even if the user has changed the user hard disk password.

Note: There are two modes for the hard disk password: User only and Master + User. The Master + User

mode requires two hard disk passwords; the system administrator enters both in the same operation. The

system administrator then provides the user hard disk password to the system user.

Attention: If the user hard disk password has been forgotten, check whether a master hard disk password

has been set. If a master hard disk password has been set, it can be used to access the hard disk drive. If no

master hard disk password is available, neither Lenovo nor Lenovo authorized service technicians provide

any services to reset either the user hard disk password or the master hard disk password, or to recover data

from the hard disk drive. The hard disk drive can be replaced for a scheduled fee.

For instructions on how to remove the hard disk password, see “How to remove the hard disk password” on

page 35.

Supervisor password

The supervisor password protects the system information stored in the ThinkPad Setup program. It provides

the following security features:

• If only a supervisor password is set, a password prompt is displayed when you try to start the ThinkPad

Setup program. Unauthorized users cannot change most of the system configuration options in the

ThinkPad Setup program without the password.

• The system administrator can use the supervisor password to access a computer even if the user of that

computer has set a power-on password. The supervisor password overrides the power-on password.

• The system administrator can set the same supervisor password on many ThinkPad notebook computers

to make administration easier.

Attention: If the supervisor password has been forgotten and cannot be made available to the service

technician, there is no service procedure to reset the password. The system board must be replaced for a

scheduled fee.

Chapter 4.Related service information 33

System management password

The system management password can also protect the system information stored in UEFI BIOS like a

supervisor password, but it has lower authority by default. The system management password can be set

through the UEFI BIOS menu or through Windows Management Instrumentation (WMI) with the Lenovo

client-management interface.

You can enable the system management password to have the same authority as the supervisor password

to control security related features. To customize the authority of the system management password through

the UEFI BIOS menu:

1. Enter the UEFI BIOS menu.

Note: When you are prompted by the icon , enter the correct supervisor password if a supervisor

password has been set, or enter the correct system management password if no supervisor password

has been set. Otherwise, you cannot change the configurations in the following steps.

2. Select Security ➙ Password ➙ System Management Password Access Control.

3. Follow the on-screen instructions.

If you have set both the supervisor password and the system management password, the supervisor

password overrides the system management password. If you have set both the system management

password and the power-on password, the system management password overrides the power-on

password.

How to remove the power-on password

To remove the power-on password, do one of the following:

If no supervisor password has been set, do the following to remove the power-on password:

1. Turn off the computer.

2. Remove the battery. For instructions on how to remove the battery , see “1080 Built-in battery” on page

78.

3. Remove the coin-cell battery. For instructions on how to remove the coin-cell battery, see “1070 Coin-

cell battery” on page 77.

4. Turn on the computer and wait until the POST ends. After the POST ends, the password prompt will not

be displayed. The power-on password has been removed.

5. Reinstall the coin-cell battery and the battery.

If a supervisor password or a system management password has been set and is known to the service

technician, do the following to remove the power-on password:

1. Turn on the computer.

2. When the ThinkPad logo is displayed, immediately press F1.

3. Type the supervisor password or the system management password to enter the ThinkPad Setup

program.

4. Select Security.

5. Select Password.

6. Select Power-On Password.

7. Type the current supervisor password or the system management password in the Enter Current

Password field. Then, leave the Enter New Password field blank, and press Enter twice.

8. In the Changes have been saved window, press Enter.

9. Press F10 to save changes and exit the ThinkPad Setup program.

34 T490 and P43s Hardware Maintenance Manual

How to remove the hard disk password

Attention: If User only mode is selected and the user hard disk password has been forgotten and cannot be

made available to the service technician, neither Lenovo nor Lenovo authorized service technicians provide

any services to reset the user hard disk password, or to recover data from the hard disk drive. The hard disk

drive can be replaced for a scheduled fee. To put the system back to operational status, the only Lenovo and

Lenovo-authorized service solution would be to replace the hard disk drive or solid-state drive with a

scheduled fee.

To remove a user hard disk password that has been forgotten, when the supervisor password and the

master hard disk password are known, do the following:

1. Turn on the computer.

2. When the ThinkPad logo is displayed, immediately press F1 to enter the ThinkPad Setup program.

3. Select Security.

4. Select Password.

5. Select Hard-disk x password where x is the letter of the hard disk drive. A pop-up window opens.

6. Select Master HDP, where HDP stands for hard disk password.

7. Type the current master hard disk password in the Enter Current Password field. Then, leave the Enter

New Password field blank, and press Enter twice.

8. Press F10 to save changes and exit the ThinkPad Setup program. The user hard disk password and the

master hard disk password have been removed.

How to remove the system management password

To remove a system management password, do the following:

If no supervisor password has been set, do the following to remove the system management password:

1. Turn off the computer and disconnect ac power.

2. Disable the built-in battery. See “Disabling the built-in battery” on page 68.

3. Remove the base cover assembly. See “1020 Base cover assembly” on page 71.

4. Remove the built-in battery. See “1080 Built-in battery” on page 78.

5. Remove the coin-cell battery. See “1070 Coin-cell battery” on page 77.

6. Reinstall the coin-cell battery.

7. Reinstall the built-in battery.

8. Reinstall the base cover assembly.

9. Reconnect ac power.

10. Turn on the computer and wait until the POST ends. After the POST ends, the password prompt does

not appear. The system management password has been removed.

If a supervisor password has been set and is known to the service technician, do the following to remove the

system management password:

1. Turn on the computer.

2. When the ThinkPad logo is displayed, immediately press F1.

3. Type the supervisor password to enter the ThinkPad Setup program.

4. Select Security.

5. Select Password.

6. Select System Management Password.

7. Type the current supervisor password in the Enter Current Password field. Then leave the Enter New

Password field blank, and press Enter twice.

Chapter 4.Related service information 35

8. In the Changes have been saved window, press Enter.

9. Press F10 to save changes and exit the ThinkPad Setup program. The system management password

has been removed.

Power management

To reduce power consumption, the computer has two power management modes: sleep and hibernation.

Sleep mode

When the computer enters sleep mode, the following events occur:

• The LCD is powered off.

• The hard disk drive or solid-state drive is powered off.

• The microprocessor stops.

To put your computer into sleep mode, open the Start menu, click Power, and then click Sleep.

In certain circumstances, the computer goes into sleep mode automatically:

• After a period of inactivity specified in power plan settings

• When the battery power is low

To cause the computer to return from sleep mode and resume operation, do one of the following:

• Press any key.

• Open the LCD cover.

• Turn on the power button.

Also, in either of the following events, the computer automatically returns from sleep mode and resumes

operation:

• The ring indicator (RI) is signaled by a serial device or a PC Card device.

• The time set on the resume timer elapses.

Note: The computer does not accept any input immediately after it enters sleep mode. Wait a few

seconds before taking any action to reenter operation mode.

Hibernation mode

In hibernation mode, the following occurs:

• The system status, RAM, VRAM, and setup data are stored on the hard disk drive or solid-state drive.

• The system is powered off.

Note: If the computer enters the hibernation mode while it is connected to the dock, do not disconnect it

before resuming normal operation. If you do disconnect it and then try to resume normal operation, you will

get an error message, and you will have to restart the system.

If you have defined one of the following actions as the event that causes the system to go into hibernation

mode, perform that action.

• Closing the lid.

• Pressing the power button.

Also, the computer goes into hibernation mode automatically after a period of inactivity specified in power

plan settings.

36 T490 and P43s Hardware Maintenance Manual

When the power is turned on, the computer returns from hibernation mode and resumes operation. The

hibernation file in the boot record on the hard disk drive or solid-state drive is read, and system status is

restored from the hard disk drive or solid-state drive.

Symptom-to-FRU index

This section contains following information:

• “Numeric error codes” on page 37

• “Error messages” on page 39

• “Beep errors” on page 39

• “No-beep symptoms” on page 41

• “LCD-related symptoms” on page 41

• “Intermittent problems” on page 42

• “Undetermined problems” on page 42

The symptom-to-FRU index in this section lists symptoms and errors and their possible causes. The most

likely cause is listed first, in boldface type.

Note: Do the FRU replacement or other actions in the sequence shown in the column headed “FRU or

action, in sequence.” If replacing a FRU does not solve the problem, put the original part back in the

computer. Do not replace a nondefective FRU.

This index can also help you determine, during regular servicing, what FRUs are likely to need to be replaced

next.

A numeric error is displayed for each error detected in POST or system operation. In the displays, n can be

any number.

If no numeric code is displayed, check the narrative descriptions of symptoms. If the symptom is not

described there, go to “Intermittent problems” on page 42.

Note: For a device not supported by diagnostic codes in the ThinkPad notebooks, see the manual for that

device.

Numeric error codes

Table 2. Numeric error codes

Symptom or error (beeps, if any) FRU or action, in sequence

0177

Bad SVP data, stop POST task—The checksum of the

supervisor password in the EEPROM is not correct.

Replace the system board.

0183

Bad CRC of Security Settings in EFI Variable. Enter the

ThinkPad Setup program. – The checksum of the Security

settings in the EFI Variable is not correct.

1. Run the ThinkPad Setup program. The settings

will be corrected automatically. Then save the

current settings by pressing F10.

2. Replace the system board.

0187

EAIA data access error - The access to EEPROM is failed.

Replace the system board.

0188

Invalid RFID Serialization Information Area.

Replace the system board.

0189

Invalid RFID configuration information area - The

EEPROM checksum is not correct.

Replace the system board.

Chapter 4.Related service information 37

Table 2. Numeric error codes (continued)

Symptom or error (beeps, if any) FRU or action, in sequence

0190

Critical low-battery error

1. Charge the battery.

2. Replace the battery.

0191

System Security - Invalid Remote Change requested.

1. Run the ThinkPad Setup program, and then save

current setting by pressing F10.

2. Replace the system board.

0199

System Security - Security password retry count

exceeded.

1. Run the ThinkPad Setup program. The retry count

will be reset. Then save the current settings by

pressing F10.

2. Replace the system board.

0251

System CMOS checksum bad - Default configuration

used.

1. Charge the coin-cell battery for more than 8 hours

by connecting the ac power adapter.

2. Replace the coin-cell battery and run the ThinkPad

Setup program to reset the time and date.

0271

Real-Time Clock Error. Check Date and Time settings.

1. Run ThinkPad Setup to reset the time and date

2. Replace the coin-cell battery and run the ThinkPad

Setup program to reset the time and date.

1802

Unauthorized network card is plugged in - Turn off and

remove the network card.

1. Remove the network card.

2. Replace the system board.

1820

More than one external fingerprint reader is attached.

Power off and remove all but the reader that you set up

within your main operating system.

Remove all but the reader that you set up for the

authentication

2000

ThinkVantage Active Protection sensor diagnostics failed.

Have the computer serviced.

2100

Detection error on Main HDD (HDD0) 1. Reseat the M.2 solid-state drive.

2. Replace the M.2 solid-state drive.

3. Replace the system board.

2101

Detection error on Main HDD (HDD0) 1. Reseat the M.2 solid-state drive.

2. Replace the M.2 solid-state drive.

3. Replace the system board.

2110

Read error on M.2 Main Slot (HDD0) 1. Reseat the M.2 solid-state drive.

2. Replace the M.2 solid-state drive.

3. Replace the system board.

2111

Read error on M.2 Main Slot (HDD0) 1. Reseat the M.2 solid-state drive.

2. Replace the M.2 solid-state drive.

3. Replace the system board.

2200

Machine Type and Serial Number are invalid.

Replace the system board.

2201

Machine UUID is invalid

Replace the system board.

2202

Brand Name is invalid.

Have the computer serviced.

38 T490 and P43s Hardware Maintenance Manual

Table 2. Numeric error codes (continued)

Symptom or error (beeps, if any) FRU or action, in sequence

2203

System configuration is invalid.

Have the computer serviced.

2204

System configuration data is invalid.

Have the computer serviced.

Error messages

Table 3. Error messages

Symptom or error (beeps, if any) FRU or action, in sequence

Fan error.

(two short beeps)

1. Replace the fan.

2. Apply thermal grease.

3. Replace the system board.

Thermal sensing error. Replace the system board.

The battery installed is not supported by this system and

will not charge.

Please replace the battery with the correct Lenovo battery

for this system.

Press the ESC key to continue.

Replace the battery.

This system does not support batteries that are not

genuine Lenovo-made or authorized. The system will

continue to boot, but may not charge unauthorized

batteries.

Attention: Lenovo has no responsibility for the

performance or safety of unauthorized batteries, and

provides no warranties for failures or damage arising out

of their use.

Replace the battery.

Beep errors

Lenovo SmartBeep technology enables you to decode beep errors with your smartphone when a black

screen occurs with beeps from your computer. To decode the beep error with Lenovo SmartBeep

technology, do the following:

1. Go to https://support.lenovo.com/smartbeep or scan the following QR Code.

2. Download the proper diagnostic app and install it on your smartphone.

3. Run the diagnostic app and place the smartphone near the computer.

4. Press the Fn key on your computer to emit the beep again. The diagnostic app decodes the beep error

and shows possible solutions on the smartphone.

Chapter 4.Related service information 39

The following section describes some beep errors and the corresponding solutions.

Note: Do not attempt to service a product yourself unless instructed to do so by the Customer Support

Center or product documentation. Only use a Lenovo-authorized service provider to repair your product.

Error codes Solutions

0001: Reset error (platform reset not de-asserted) 1. Remove the ac power adapter and the removable

battery if your computer has one. Then, reset the

computer by doing one of the following:

• For models with the emergency-reset hole,

insert a straightened paper clip into the

emergency-reset hole. Wait for one minute.

Then, reconnect all power resources and restart

the computer.

• For models without the emergency-reset hole,

press and hold the power button for about

seven seconds. Then, reconnect to all power

resources and restart the computer.

2. Replace the system board (service provider only).

0002: Internal bus error Replace the system board (service provider only).

0281: General embedded controller error Replace the system board (service provider only).

0282: Memory module error 1. Reinstall or replace the memory module.

2. Replace the system board (service provider only).

0283: PCI resource error 1. Remove PCIe devices (the M.2 card, PCIe card,

and so on) (service provider only).

2. Replace the system board (service provider only).

0284: TCG-compliant functionality-related error (might be

the BIOS code validation failure) Replace the system board (service provider only).

0285: TCG-compliant functionality-related error (might be

the TPM initialization failure) Replace the system board (service provider only).

0286: Integrated graphics error Replace the system board (service provider only).

0287: Discrete graphics error 1. Reinstall or replace the discrete graphics card

(service provider only).

2. Replace the system board (service provider only).

0288: Computer display error 1. Reconnect the display cable on both the system

board side and the computer display side (service

provider only).

2. Replace the system board (service provider only).

40 T490 and P43s Hardware Maintenance Manual

No-beep symptoms

Table 4. No-beep symptoms

Symptom or error FRU or action, in sequence

No beep, power-on indicator on, LCD blank, and no

POST.

1. Run LCD Self Test.

2. Ensure that every connector is connected tightly and

correctly.

3. Reseat memory module.

4. Replace the system board.

No beep, power-on indicator on, and LCD blank during

POST. 1. Run LCD Self Test.

2. Reseat memory module.

3. Replace the system board.

The power-on password prompt appears. A power-on password or a supervisor password is set.

Type the password and press Enter.

The hard-disk password prompt appears. A hard-disk password is set. Type the password and

press Enter.

LCD-related symptoms

Important: The TFT LCD for the notebook computer contains many thin-film transistors (TFTs). The

presence of a small number of dots that are missing, discolored, or always lighted is characteristic of TFT

LCD technology, but excessive pixel problems can cause viewing concerns.

If the LCD you are servicing has two or less visible defective pixels, it should not be considered faulty.

However, if the LCD has three or more visible defective pixels, it will be deemed as defective by Lenovo and

it should be replaced.

Notes:

• This policy applies to all ThinkPad Notebooks purchased on 1 January, 2008 or later.

• Lenovo will not provide warranty replacement if the LCD is within specifications because we cannot

guarantee that any replacement LCD will have zero pixel defects.

• One pixel consists of R, G, B sub-pixels.

LCD Self Test

When you turn on the computer and the LCD goes black, run LCD Self Test to help you determine whether

the LCD functions normally.

To run LCD Self Test:

1. Ensure that the computer is connected to ac power. Then, press the power button for about seven

seconds to turn off the computer.

2. Press Fn, left Ctrl, and the power button at the same time. If the computer displays five solid colors in

sequence across the entire screen, it indicates that the LCD functions normally.

3. The test lasts for about 20 seconds and then exits automatically. You also can press the power button to

exit the test.

Chapter 4.Related service information 41

Table 5. LCD-related symptoms

Symptom or error FRU or action, in sequence

No beep, power-on indicator on, and a blank LCD during

POST.

1. Run LCD Self Test.

2. Replace the system board.

• LCD backlight not working.

• LCD too dark.

• LCD brightness cannot be adjusted.

• LCD contrast cannot be adjusted.

1. Reseat the LCD connectors.

2. Replace the LCD assembly.

3. Replace the system board.

• LCD screen unreadable.

• Characters missing pixels.

• Screen abnormal.

• Wrong color displayed.

1. See important note for “LCD-related symptoms.”

2. Reseat all LCD connectors.

3. Replace the LCD assembly.

4. Replace the system board.

Horizontal or vertical lines displayed on LCD. Replace the LCD assembly.

Intermittent problems

Intermittent system hang problems can be due to a variety of causes that have nothing to do with a hardware

defect, such as cosmic radiation, ESD, or software errors. FRU replacement should be considered only when

a problem recurs.

When analyzing an intermittent problem, do the following:

1. Run the diagnostic test for the system board in loop mode at least 10 times.

2. If no error is detected, do not replace any FRUs.

3. If any error is detected, replace the FRU shown by the FRU code. Rerun the test to verify that no more

errors exist.

Undetermined problems

If the diagnostic tests did not identify the device that has failed, if wrong devices are installed, or if the

system simply is not operating, follow these procedures to isolate the failing FRU (do not isolate FRUs that

have no defects).

Verify that all attached devices are supported by the computer.

Verify that the power supply being used at the time of the failure is operating correctly. (See “Power system

checkout” on page 28)

1. Turn off the computer.

2. Visually check each FRU for damage. Replace any damaged FRU.

3. Remove or disconnect all of the following devices:

a. Non-ThinkPad devices

b. Devices attached to the dock

c. Printer, mouse, and other external devices

d. Battery

e. Hard disk drive or solid-state drive

f. External diskette drive or optical drive

g. Memory module

4. Turn on the computer.

5. Determine whether the problem has been solved.

6. If the problem does not recur, reconnect the removed devices one at a time until you find the failing FRU.

7. If the problem remains, replace the following FRUs one at a time (do not replace a nondefective FRU):

a. System board

42 T490 and P43s Hardware Maintenance Manual

b. LCD assembly

Chapter 4.Related service information 43

44 T490 and P43s Hardware Maintenance Manual

Chapter 5. Special keys

The following table describes the functions of function keys and key combinations.

Table 6. Special keys

Special key Description

You can configure the Fn key and function keys in the Keyboard Properties window by doing the

following:

1. Go to Control Panel, and then change the view of Control Panel from Category to Large icons

or Small icons.

2. Click Lenovo - Keyboard Manager and the Keyboard Manager window is displayed.

3. Select the options of your preference.

Press Fn+Esc to switch the key function between the standard F1–F12 function and the special

function printed as an icon on each key. You can change the default function in the Keyboard

Properties window.

Mute or unmute the speakers.

If you mute the sound and turn off your computer, the sound will remain muted when you turn on

your computer again. To turn on the sound, press F1, F2, or F3.

Decrease the speaker volume.

Increase the speaker volume.

Mute or unmute the microphones.

Darken the display.

Brighten the display.

Manage external displays.

Enable or disable the built-in wireless networking features.

Open the Settings window.

Enable or disable the built-in Bluetooth feature.

Open a keyboard setting page.

Invoke the function defined by yourself:

1. Open the Start menu and click Lenovo Vantage.

2. Click Hardware Settings and then click Input.

3. Locate the Keyboard: User-defined Key section and follow the on-screen instructions to

complete the setting.

On this setting page, you can also define different functions for the key combinations with F12, such

as Shift+F12, Alt+F12, or Ctrl+F12.

Table 6. Special keys (continued)

Special key Description

Open the Snipping Tool program.

Fn+Spacebar Switch between different keyboard backlight statuses if your computer supports keyboard

backlight.

Fn+4 Put the computer into sleep mode. To wake up the computer, press Fn or the power button.

Fn+B Equal the Break key on a conventional external keyboard.

Fn+K Equal the ScrLK or Scroll Lock key on a conventional external keyboard.

Fn+P Equal the Pause key on a conventional external keyboard.

Fn+S Equal the SysRq key on a conventional external keyboard.

Fn+Left arrow

key

Equal the Home key.

Fn+Right arrow

key

Equal the End key.

46 T490 and P43s Hardware Maintenance Manual

Chapter 6. Locations

Locating computer controls, connectors, and indicators

This topic introduces the locations of the computer controls, connectors, and indicators.

Front

1. Infrared camera* 4. Camera*

2. ThinkShutter* 5. Multi-touch screen*

3. Microphones*

* for selected models

Base

P43s, T490 (20N2, 20N3, 20RX, and 20RY only)

T490 (20Q9 and 20QH only)

1. Power button 5. TrackPoint® pointing device

2. Fingerprint reader* 6. Speakers

3. Trackpad 7. RFID (Radio Frequency Identification) label

4. NFC label*

* for selected models

48 T490 and P43s Hardware Maintenance Manual

Left

1. USB-C™ connector (USB 3.1 Gen 1) 5. HDMI™ connector

2. Thunderbolt™ 3 connector (USB-C) 6. Audio connector

3. Docking-station connector 7. microSD card slot

4. USB 3.1 connector Gen 1

Right

1. Smart-card slot* 3. Ethernet connector

2. Always On USB 3.1 connector Gen 1 4. Security-lock slot

* for selected models

Chapter 6.Locations 49

Bottom

1. Docking-station hook holes 3. Emergency-reset hole

2. Keyboard drainage hole

Rear

1. Nano-SIM-card tray* 2. System status indicator

* for selected models

Locating FRUs and CRUs

This topic introduces the following service parts:

• “Major FRUs and CRUs” on page 52

• “LCD FRUs” on page 55

• “Miscellaneous parts” on page 57

• “Connector and cable guide” on page 57

50 T490 and P43s Hardware Maintenance Manual

Notes:

• Each FRU is available for all types or models, unless otherwise specified.

• CRU statement for customers:

You can resolve some problems with your product with a replacement part you can install yourself, called a

“Customer Replaceable Unit” or “CRU.” Some CRUs are designated as self-service CRUs and others are

designated as optional-service CRUs. Installation of self-service CRUs is your responsibility. For optional-service

CRUs, you can either install the CRU yourself or you can request that a Service Provider install the CRU according to

the warranty service for your product. If you intend on installing the CRU, Lenovo will ship the CRU to you. CRU

information and replacement instructions are shipped with your product and are available from Lenovo at any time

upon request. You can find a list of CRUs for your product in this Hardware Maintenance Manual. An electronic

version of this manual can be found at https://support.lenovo.com. Click Documentation and then follow the on-

screen instructions to find the manual for your product. You might be required to return the defective CRU. When

return is required: (1) return instructions, a prepaid shipping label, and a container will be included with the

replacement CRU; and (2) you might be charged for the replacement CRU if Lenovo does not receive the defective

CRU within thirty (30) days of your receipt of the replacement CRU. See your Lenovo Limited Warranty

documentation for full details.

ThinkPad computers contain the following types of CRUs and FRUs:

– Self-service CRUs: Refer to parts that can be installed or replaced easily by customer themselves or by trained

service technicians at an additional cost.

– Optional-service CRUs: Refer to parts that can be installed or replaced by customers with a greater skill level.

Trained service technicians can also provide service to install or replace the parts under the type of warranty

designated for the customer’s machine.

– FRUs: Refer to parts that must be installed or replaced only by trained service technicians. If customers choose

to replace the FRUs by themselves, the product warranty might be affected.

Chapter 6.Locations 51

Major FRUs and CRUs

Note: Depending on the computer model, your computer might look different from the illustration above.

Table 7. Major FRUs and CRUs

No. FRU description Self-service CRU Optional-service CRU

1LCD unit No No

2Speaker assembly No Yes

3Power button board with cable No No

4Power button No No

52 T490 and P43s Hardware Maintenance Manual

Table 7. Major FRUs and CRUs (continued)

No. FRU description Self-service CRU Optional-service CRU

5Keyboard bezel assembly No No

6RJ45 board No No

7RJ45 cable No No

8USB cable No No

9MIMO antenna assembly* No No

10 USB board No Yes

11 Smart card reader cable* No No

12 Dummy smart card reader* No No

13 Smart card reader* No No

14 RFID reader* No No

15 RFID reader cable* No No

16 Wireless WAN card* Yes No

17 M.2 2280 solid-state drive* Yes No

18 M.2 2242 solid-state drive* Yes No

19 Base cover assembly Yes No

20 Nano-SIM-card tray* Yes No

21 Coin-cell battery Yes No

22 Built-in battery No No

23 System board No No

24 Hall sensor board with cable No No

25 Memory module Yes No

26 Thermal fan assembly No No

27 NFC antenna* No No

28 NFC module* No No

29 NFC cable* No No

30 Fingerprint reader bracket* (for T490 20Q9 and

20QH only)

No No

31 Fingerprint reader module* (for T490 20Q9 and

20QH only)

No No

32 Fingerprint reader cable* (for T490 20Q9 and

20QH only)

No No

33 Fingerprint reader module* (for selected models of

P43s, T490 20N2, 20N3, 20RX and 20RY only)

No No

34 Fingerprint reader cable* (for selected models of

P43s, T490 20N2, 20N3, 20RX and 20RY only)

No No

35 Trackpad No No

36 Trackpad cable No No

Chapter 6.Locations 53

Table 7. Major FRUs and CRUs (continued)

No. FRU description Self-service CRU Optional-service CRU

37 Keyboard No Yes

aLenovo factory recovery USB key* Yes No

bMiscellaneous parts kits (see “Miscellaneous

parts” on page 57)

No No

cPower cord Yes No

dac power adapter Yes No

* for selected models

Note: The Lenovo factory recovery USB key is used to restore the Microsoft Windows operating system. It

might not come with the computer, and a user might order it from https://pcsupport.lenovo.com/

lenovorecovery, though additional shipping and handling fees might apply.

54 T490 and P43s Hardware Maintenance Manual

LCD FRUs

Table 8. LCD FRUs

No. FRU description Self-service CRU Optional-service CRU

1LCD bezel sheet No No

2LCD bezel No No

3LCD panel No No

4LCD hinges No No

5Microphones board* No No

6Conventional camera/mic combo board* No No

Chapter 6.Locations 55

Table 8. LCD FRUs (continued)

No. FRU description Self-service CRU Optional-service CRU

7Infrared camera/mic combo board* No No

8Mic rubbers No No

9Aluminum foil No No

10 LCD elastic adhesive tapes No No

11 LCD cover assembly No No

12 Wireless LAN/WAN antenna assembly* No No

13 Conventional camera/LED cable* No No

14 LED cable* No No

15 Infrared camera/LED cable* No No

16 LCD cable No No

* for selected models

56 T490 and P43s Hardware Maintenance Manual

Miscellaneous parts

Table 9. Miscellaneous part

FRU descriptions Self-service

CRU

Optional-service

CRU

Screw kit:

• Screw M2.5 x L2.5, silver (8)

• Screw M2 x L3, black (2)

• Screw M2 x L3, silver (2)

• Screw M2 x L2.2 + 2.3, black (6)

• Screw M2.5 x L4, black (8)

• Screw M2 x L2.5, black (18)

• Screw M2 x L2, black (10)

• Screw M2 x L4, black (18)

• Spec

No No

Mechanical miscellaneous kit:

• USB board bracket

• RJ45 bracket

• I/O bracket

• M.2 solid-state drive bracket

• Mylar for memory module

• Mylar for wireless-WAN card

• Thermal pad for M.2 2242 solid-state drive

• Thermal pad for M.2 2280 solid-state drive

• Fingerprint reader bracket

• Spec

No No

Label kit:

• GEO label

• Spec

No No

Connector and cable guide

This topic provides information to help Lenovo authorized service technicians identify connectors and cables

for replacement purpose. To view each FRU and the exploded illustration of the computer, see “Major FRUs

and CRUs” on page 52 and “LCD FRUs” on page 55.

Note: Depending on your computer model, some connectors or cables might not be available.

Chapter 6.Locations 57

System board connectors and cables (for P43s, T490 20N2, 20N3, 20RX and 20RY only)

Table 10. System board connector and cable guide

Item Connector (location) Internal cable required Cable connection

1Camera/LED connector (internal) Camera/LED cable Connect one end of the cable to

the camera/mic combo board and

the other end to this connector.

2Power button board connector

(internal)

Power button board cable The power button board comes

with the cable. Connect the cable

to this connector.

3RJ45 board connector (internal) RJ45 cable Connect one end of the RJ45

cable to the RJ45 board and the

other end to this connector.

4Speaker assembly connector

(internal)

Speaker assembly cable The speaker assembly comes with

cable. Connect the cable to this

connector.

5LCD connector (internal) LCD cable Connect one end of the LCD cable

to the LCD panel and the other end

to this connector.

6USB-C connector (external) No Connect USB-C compatible

devices or a USB-C power adapter

to this connector.

58 T490 and P43s Hardware Maintenance Manual

Table 10. System board connector and cable guide (continued)

Item Connector (location) Internal cable required Cable connection

7Wireless-WAN card slot (internal) No Insert the wireless-WAN card into

this slot.

8Thunderbolt 3 connector (USB-C)

(external)

No Connect a USB-C compatible

device or a Thunderbolt 3

compatible device to this

connector.

9Docking-station connector

(external)

No Connect a supported docking

station to your computer through

this connector.

10 M.2 solid-state drive connector

(internal)

No Insert the M.2 solid-state drive into

this slot.

11 USB 3.1 connector Gen 1

(external)

No Connect USB-compatible devices

to this connector.

12 HDMI connector (external) No Connect a compatible digital audio

device or video monitor to this

connector.

13 Audio connector (external) No Connect headphones or a headset

with 3.5-mm (0.14-inch) 4-pole

plug to this connector.

14 Coin-cell battery connector

(internal)

Coin-cell battery cable The coin-cell battery comes with

the cable. Connect the cable to

this connector.

15 NFC connector (internal) NFC cable Connect one end of the cable to

the NFC module and the other end

to this connector.

16 Hall sensor board connector

(internal)

Hall sensor board cable The hall sensor board comes with

the cable. Connect the cable to

this connector.

17 Built-in battery connector (internal) Built-in battery cable The built-in battery comes with

cable. Connect the cable to this

connector.

18 Trackpad connector (internal) Trackpad cable Connect one end of the cable to

the trackpad and the other end to

this connector.

19 Fingerprint reader card connector

(internal)

Fingerprint reader cable Connect one end of the cable to

the fingerprint reader card and the

other end to this connector.

20 Memory module slot (internal) No Insert the memory module into this

slot.

21 Smart card reader connector

(internal)

Smart card reader cable Connect one end of the cable to

the smart card reader and the

other end to this connector.

22 USB board connector (internal) USB board cable Connect one end of the cable to

the USB board and the other end

to this connector.

23 Thermal fan connector (internal) Thermal fan assembly cable The thermal fan assembly comes

with cable. Connect the cable to

this connector.

Chapter 6.Locations 59

Table 10. System board connector and cable guide (continued)

Item Connector (location) Internal cable required Cable connection

Keyboard connectors (internal) Keyboard assembly cables The keyboard assembly comes

with the cables. Connect the

cables to these connectors.

26 Nano-SIM-card slot (external) No Install a nano-SIM card into the

nano-SIM card tray. Then, insert

the tray with the card into this slot.

System board connectors and cables (for T490 20Q9 and 20QH only)

Table 11. System board connector and cable guide

Item Connector (location) Internal cable required Cable connection

1Camera/LED connector (internal) Camera/LED cable Connect one end of the cable to

the camera/mic combo board and

the other end to this connector.

2Power button board connector

(internal)

Power button board cable The power button board comes

with the cable. Connect the cable

to this connector.

3RJ45 board connector (internal) RJ45 cable Connect one end of the RJ45

cable to the RJ45 board and the

other end to this connector.

60 T490 and P43s Hardware Maintenance Manual

Table 11. System board connector and cable guide (continued)

Item Connector (location) Internal cable required Cable connection

4Speaker assembly connector

(internal)

Speaker assembly cable The speaker assembly comes with

cable. Connect the cable to this

connector.

5LCD connector (internal) LCD cable Connect one end of the LCD cable

to the LCD panel and the other end

to this connector.

6USB-C connector (external) No Connect USB-C compatible

devices or a USB-C power adapter

to this connector.

7Wireless-WAN card slot (internal) No Insert the wireless-WAN card into

this slot.

8Thunderbolt 3 connector (USB-C)

(external)

No Connect a USB-C compatible

device or a Thunderbolt 3

compatible device to this

connector.

9Docking-station connector

(external)

No Connect a supported docking

station to your computer through

this connector.

10 M.2 solid-state drive connector

(internal)

No Insert the M.2 solid-state drive into

this slot.

11 USB 3.1 connector Gen 1

(external)

No Connect USB-compatible devices

to this connector.

12 HDMI connector (external) No Connect a compatible digital audio

device or video monitor to this

connector.

13 Audio connector (external) No Connect headphones or a headset

with 3.5-mm (0.14-inch) 4-pole

plug to this connector.

14 Coin-cell battery connector

(internal)

Coin-cell battery cable The coin-cell battery comes with

the cable. Connect the cable to

this connector.

15 RFID reader cable connector

(internal)

RFID reader cable Connect one end of the cable to

the system board, one end to

connector 21 , and the other end

to this connector.

16 Hall sensor board connector

(internal)

Hall sensor board cable The hall sensor board comes with

the cable. Connect the cable to

this connector.

17 Built-in battery connector (internal) Built-in battery cable The built-in battery comes with

cable. Connect the cable to this

connector.

18 Trackpad connector (internal) Trackpad cable Connect one end of the cable to

the trackpad and the other end to

this connector.

19 Fingerprint reader card connector

(internal)

Fingerprint reader cable Connect one end of the cable to

the fingerprint reader card and the

other end to this connector.

Chapter 6.Locations 61

Table 11. System board connector and cable guide (continued)

Item Connector (location) Internal cable required Cable connection

20 Memory module slot (internal) No Insert the memory module into this

slot.

21 RFID reader cable connector

(internal)

RFID reader cable Connect one end of the cable to

the system board, one end to

connector 15 , and the other end

to this connector.

22 USB board connector (internal) USB board cable Connect one end of the cable to

the USB board and the other end

to this connector.

23 Thermal fan connector (internal) Thermal fan assembly cable The thermal fan assembly comes

with cable. Connect the cable to

this connector.

Keyboard connectors (internal) Keyboard assembly cables The keyboard assembly comes

with the cables. Connect the

cables to these connectors.

26 Nano-SIM-card slot (external) No Install a nano-SIM card into the

nano-SIM card tray. Then, insert

the tray with the card into this slot.

Looking up FRU information

For detailed FRU information, including part numbers, descriptions, and substitution part numbers, go to:

https://support.lenovo.com/partslookup.

62 T490 and P43s Hardware Maintenance Manual

Chapter 7. FRU replacement notices

This chapter presents notices related to removing and replacing parts. Read this chapter carefully before

replacing any FRU.

CRU statement for customers:

You can resolve some problems with your product with a replacement part you can install yourself, called a

“Customer Replaceable Unit” or “CRU.” Some CRUs are designated as self-service CRUs and others are

designated as optional-service CRUs. Installation of self-service CRUs is your responsibility. For optional-

service CRUs, you can either install the CRU yourself or you can request that a Service Provider install the

CRU according to the warranty service for your product. If you intend on installing the CRU, Lenovo will ship

the CRU to you. CRU information and replacement instructions are shipped with your product and are

available from Lenovo at any time upon request. You can find a list of CRUs for your product in this Hardware

Maintenance Manual. An electronic version of this manual can be found at https://support.lenovo.com. Click

Documentation and then follow the on-screen instructions to find the manual for your product. You might be

required to return the defective CRU. When return is required: (1) return instructions, a prepaid shipping label,

and a container will be included with the replacement CRU; and (2) you might be charged for the

replacement CRU if Lenovo does not receive the defective CRU within thirty (30) days of your receipt of the

replacement CRU. See your Lenovo Limited Warranty documentation for full details.

Service tool kit

Ensure that the following service tool kit is prepared before you service a ThinkPad notebook computer.

No. Tool name Tool type

1 Phillips-head screwdriver Common tool

2 Torx-head screwdriver Common tool

3Conductive tweezers Common tool

4 Hexagonal socket Common tool

5Silicone grease Consumable tool

6 Polyamide tape Consumable tool

7 Mylar tape Consumable tool

8 Eraser Consumable tool

9 Electrical tape Consumable tool

10 Double-sided tape Consumable tool

11 Conductive tape Consumable tool

Note: The silicone grease can be applied to the surfaces of the microprocessor and heatsink to eliminate air

gaps. The hexagonal socket is used to pick up the antenna connectors.

Screw notices

Loose screws can cause a reliability problem. In the ThinkPad notebook computer, this problem is

addressed with special nylon-coated screws that have the following characteristics:

• They maintain tight connections.

• They do not easily come loose, even with shock or vibration.

• They are harder to tighten.

Do the following when you service the computer:

• Keep the screw kit in your tool bag. For the part number of the screw kit, go to:

https://support.lenovo.com/partslookup

• It is recommended to use new screws.

• It is recommended to use each screw only once.

Tighten screws as follows:

• Plastic to plastic

Turn an additional angle of 90 degrees after the screw head touches the surface of the plastic part.

• Logic card to plastic

Turn an additional angle of 180 degrees after the screw head touches the surface of the logic card.

Notes:

• Ensure that you use the correct screw. It is recommended to use new screws for replacements. If you

have a torque screwdriver, tighten all screws firmly to the torque specified in the screw information table

for each step.

• Ensure torque screwdrivers are calibrated correctly following country specifications.

Retaining serial numbers

This topic provides instructions on the following:

• “Restoring the serial number of the system unit” on page 64

• “Retaining the UUID” on page 65

Restoring the serial number of the system unit

When the computer was manufactured, the EEPROM on the system board was loaded with the serial

numbers of the system and all major components. These numbers need to remain the same throughout the

life of the computer.

If you replace the system board, you must restore the serial number of the system unit to its original value.

64 T490 and P43s Hardware Maintenance Manual

The serial number of the system unit is written on the label attached to the bottom of the computer.

If you can not find the serial number of the system unit on the bottom of the computer, try the following

method to get the number:

Note: Before you perform the operation, ensure that the UEFI/Legacy setting within the Startup menu in the

ThinkPad Setup program is set to UEFI Only.

1. Connect a USB memory key to the computer.

2. Go to https://www.lenovo.com/maintenanceutilities and follow the instructions on the screen to create a

Maintenance key.

Note: Only an authorized Lenovo service technician can access the above Web site.

3. Restart the computer.

4. When the logo is displayed, press Esc. The ThinkPad Config Information Update Utility interface is

displayed.

5. Type 1 under Enter the action desired, then press Enter. The ThinkPad Serial Number Update Utility for

Asset ID screen is displayed.

6. Type 2 under Enter the action desired, then press Enter. The serial number of each device in your

computer is displayed; the serial number of the system unit is listed as follow:

20- Serial number

7. Record the serial number of the system unit.

After you replace the system board, do the following to restore the serial number of the system unit:

1. Connect the Maintenance key to the computer.

2. When the logo is displayed, press Esc. The ThinkPad Config Information Update Utility interface is

displayed.

3. Type 1 under Enter the action desired, then press Enter. The ThinkPad Serial Number Update Utility for

Asset ID screen is displayed.

4. Type 1 under Enter the action desired, then press Enter. Then follow the instructions on the screen to

restore the serial number of the system unit.

Retaining the UUID

The Universally Unique Identifier (UUID) is a 128-bit number uniquely assigned to your computer at

production and stored in the EEPROM of your system board.

The algorithm that generates the number is designed to provide unique IDs until the year A.D. 3400. No two

computers in the world have the same number.

When you replace the system board, perform the following steps to create a new UUID for the system board

if the system board does not have a UUID:

Note: Before you perform the operation, ensure that the UEFI/Legacy setting within the Startup menu in the

ThinkPad Setup program is set to UEFI Only.

1. Connect a USB memory key to the computer.

2. Go to https://www.lenovo.com/maintenanceutilities and follow the instructions on the screen to create a

Maintenance key.

Note: Only an authorized Lenovo service technician can access the above Web site.

3. Restart the computer.

4. When the logo screen is displayed, press Esc. The ThinkPad Config Information Update Utility interface

is displayed.

Chapter 7.FRU replacement notices 65

5. Type 2 under Enter the action desired, then press Enter. The Auto UUID generation utility interface is

displayed.

6. Type y under Change UUID. OK? [Y/N], then press Enter. A new UUID is created and written. If a valid

UUID already exists, it is not overwritten.

66 T490 and P43s Hardware Maintenance Manual

Chapter 8. Removing or replacing a FRU

This chapter provides instructions on how to remove or replace a FRU.