Lenovo Yoga A940 Owner's manual

Yoga A940
Hardware Maintenance Manual
Machine Types (MT): F0E4 and F0E5

Note: Before using this information and the product it supports, e sure to read and understand Chapter 1
“Read this first: Important safety information” on page 1.
First Edition (December 2018)
© Copyri ht Lenovo 2018.
LIMITED AND RESTRICTED RIGHTS NOTICE: If data or software are delivered pursuant to a General Services
Administration “GSA” contract, use, reproduction, or disclosure is su ject to restrictions set forth in Contract No. GS-
35F-05925

Contents
About this manual . . . . . . . . . . . . iii
Chapter 1. Read this first: Important
safety information . . . . . . . . . . . . 1
General safety . . . . . . . . . . . . . . . . 1
Electrical safety . . . . . . . . . . . . . . . . 1
Safety inspection guide . . . . . . . . . . . . . 3
Handling electrostatic discharge-sensitive
devices . . . . . . . . . . . . . . . . . . . 3
Grounding requirements . . . . . . . . . . . . 4
Safety notices . . . . . . . . . . . . . . . . 4
Chapter 2. Environment and
electrical input . . . . . . . . . . . . . . 7
Chapter 3. General Checkout . . . . . . 9
Chapter 4. Usin the Setup Utility
pro ram . . . . . . . . . . . . . . . . 11
Starting the Setup Utility program . . . . . . . . 11
Ena ling or disa ling a device . . . . . . . . . 11
Ena ling or disa ling the Automatic Power On
features . . . . . . . . . . . . . . . . . . 11
Using BIOS passwords . . . . . . . . . . . . 11
Setup Utility program password types . . . . 12
Password considerations . . . . . . . . . 12
Setting, changing, and deleting a password . . 12
Selecting a startup device . . . . . . . . . . . 12
Changing the startup device sequence
permanently . . . . . . . . . . . . . . 13
Selecting a temporary startup device. . . . . 13
Exiting the Setup Utility program . . . . . . . . 13
Chapter 5. Symptom-to-FRU
Index . . . . . . . . . . . . . . . . . . 15
Hard disk drive oot error . . . . . . . . . . . 15
Power Supply Pro lems . . . . . . . . . . . 15
POST error codes . . . . . . . . . . . . . . 16
Undetermined pro lems . . . . . . . . . . . 16
Chapter 6. Hardware locations . . . . 17
Overview . . . . . . . . . . . . . . . . . 17
Major FRUs and CRUs . . . . . . . . . . . . 20
Parts on the system oards . . . . . . . . . . 23
Chapter 7. Installin or replacin
hardware . . . . . . . . . . . . . . . . 25
Handling static-sensitive devices . . . . . . . . 25
Installing or replacing hardware . . . . . . . . 25
Replacing the computer display panel . . . . 25
Replacing the USB connector . . . . . . . 28
Replacing the function oard shield . . . . . 28
Replacing the Wi-Fi card . . . . . . . . . 29
Replacing the function oard . . . . . . . . 30
Replacing the touch oard shield . . . . . . 31
Replacing the touch oard. . . . . . . . . 32
Replacing the su woofer . . . . . . . . . 33
Replacing the LED light ar . . . . . . . . 34
Replacing the panel cover . . . . . . . . . 34
Replacing the microphone module and the
camera module . . . . . . . . . . . . . 36
Replacing the mainframe . . . . . . . . . 37
Replacing the front ezel . . . . . . . . . 38
Replacing the memory module . . . . . . . 39
Replacing the SSD . . . . . . . . . . . . 40
Replacing the fan . . . . . . . . . . . . 40
Replacing the CMOS attery . . . . . . . . 41
Replacing the speakers . . . . . . . . . . 42
Replacing the housing top metal assem ly . . 43
Replacing the fan duct . . . . . . . . . . 44
Replacing the thermal module . . . . . . . 45
Replacing the CPU. . . . . . . . . . . . 46
Replacing the HDD. . . . . . . . . . . . 47
Replacing the HDD SATA connector . . . . . 48
Replacing the system oard . . . . . . . . 48
Replacing the power utton oard. . . . . . 49
Replacing the HDMI switch oard . . . . . . 50
Replacing the wireless charger cover . . . . 51
Replacing the Bluetooth speaker oard. . . . 51
Replacing the wireless charger LED oard . . 52
Replacing the wireless charger module . . . . 53
Completing the parts replacement. . . . . . 55
Chapter 8. Additional Service
Information. . . . . . . . . . . . . . . 57
Trademarks . . . . . . . . . . . . . . . 1
© Copyright Lenovo 2018 i

ii Yoga A940Hardware Maintenance Manual

About this manual
This manual provides service and reference information for Lenovo® computers listed on the front cover.
Use this manual along with the advanced diagnostic tests to trou leshoot pro lems.
Important: This manual is intended only for trained service technicians who are familiar with Lenovo
computers. Use this manual along with the advanced diagnostic tests to trou leshoot pro lems effectively.
Before servicing a Lenovo computer, e sure to read and understand Chapter 1 “Read this first: Important
safety information” on page 1.
© Copyright Lenovo 2018 iii

iv Yoga A940Hardware Maintenance Manual

Chapter 1. Read this first: Important safety information
This chapter contains the safety information that you must e familiar with.
General safety
Follow these rules to ensure general safety:
• Keep the areas around the computer clear and clean during and after maintenance.
• When lifting any heavy o ject:
1. Ensure you can stand safely without slipping.
2. Distri ute the weight of the o ject equally across oth feet.
3. Lift slowly. Never move suddenly or twist when you attempt to lift.
4. Lift y standing or y pushing up with your leg muscles; this action removes the strain from the
muscles in your ack.
Do not attempt to lift any objects that weigh more than 16 kg (35 lb) or objects that you think are too
heavy for you.
• Do not perform any action that would create a hazard for the customer, or would make the computer
unsafe.
• Before you start the computer, ensure that other service representatives and customer personnel are not
in a position that would create a hazard for them.
• Place removed covers and other parts in a safe place, away from all personnel, while you are servicing the
computer.
• Keep your tool case away from areas that people may walk through to ensure no-one trips over it.
• Do not wear loose clothing that can e trapped in the moving parts of a machine. Ensure that your sleeves
are fastened or rolled up a ove your el ows. If your hair is long, tie or fasten it ack.
• Insert the ends of your necktie or scarf inside clothing or fasten it with a non-conductive clip,
approximately 8 centimeters (3 inches) from the end.
• Do not wear jewelry, chains, metal-frame eyeglasses, or metal fasteners for your clothing.
Remember: Metal o jects 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 e hazardous to your eyes.
• After service, reinstall all safety shields, guards, la els, and ground wires. Replace any safety device that
is worn or defective.
• Reattach all covers correctly efore returning the computer to the customer.
Electrical safety
CAUTION:
Electrical current from power, telephone, and communication cables can be hazardous. To avoid
personal injury or equipment dama e, disconnect any attached power cords, telecommunication
© Copyright Lenovo 2018 1

cables, network cables, and modem cables before you open the computer covers, unless instructed
otherwise in the installation and confi uration procedures.
O serve 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 ru er
floor mats near their equipment that contain small conductive fi ers to decrease electrostatic discharge.
• 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 efore:
– Performing a mechanical inspection
– Working near power supplies
– Removing or installing Field Replacea le Units (FRUs)
• Before you start to work on the computer, unplug the power cord. If you cannot unplug it, ask the
customer to power-off the electrical outlet that supplies power to the machine and to lock the electrical
outlet in the off position.
• If you need to work on a computer that has exposed electrical circuits, o serve the following precautions:
– Ensure that another person, familiar with the power-off controls, is near you.
Remember: Another person must e 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 ehind your ack.
Remember: There must e a complete circuit to cause electrical shock. By o serving the a ove rule,
you may prevent a current from passing through your ody.
– When using a tester, set the controls correctly and use the approved pro e leads and accessories for
that tester.
– Stand on suita le ru er mats (o tained locally, if necessary) to insulate you from grounds such as
metal floor strips and machine frames.
O serve the special safety precautions when you work with very high voltages; these instructions are in
the safety sections of the maintenance information. Use extreme care when measuring high voltages.
• Regularly inspect and maintain your electrical hand tools to ensure they are safe to use.
• Do not use worn or roken tools and testers.
• ever assume that power has een disconnected from a circuit. First, check that it has een powered off.
• Always look carefully for possi le hazards in your work area. Examples of these hazards are wet floors,
non-grounded power extension ca les, conditions that may cause or allow power surges, and missing
safety grounds.
• Do not touch live electrical circuits with the reflective surface of a plastic dental mirror. This surface is
conductive, and touching a live circuit can cause personal injury and damage to the computer.
• Do not service the following parts with the power on when they are removed from their normal operating
positions in a computer:
– Power supply units
– Pumps
– Blowers and fans
– Motor generators
and similar units. (This practice ensures correct grounding of the units.)
2Yoga A940Hardware Maintenance Manual

• If an electrical accident occurs:
– Use caution; do not ecome a victim yourself.
– Switch off power.
– Send another person to get medical aid.
Safety inspection uide
The intent of this inspection guide is to assist you in identifying potential hazards posed y these products.
Each computer, as it was designed and uilt, had required safety items installed to protect users and service
personnel from injury. This guide addresses only those items. However, good judgment should e used to
identify potential safety hazards due to attachment of features or options not covered y this inspection
guide.
If any hazards are present, you must determine how serious the apparent hazard could e and whether you
can continue without first resolving the pro lem.
Consider the following items 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 ulging capacitor
• Mechanical hazards, such as loose or missing hardware
The guide consists of a series of steps presented as a checklist. Begin the checks with the power off, and the
power cord disconnected.
Checklist:
1. Check exterior covers for damage (loose, roken, or sharp edges).
2. Power-off the computer. Disconnect the power cord.
3. Check the power cord for:
a. A third-wire ground connector in good condition. Use a meter to measure third-wire ground
continuity for 0.1 ohm or less etween the external ground pin and frame ground.
. The power cord should e the appropriate type as specified in the parts listings.
c. Insulation must not e frayed or worn.
4. Remove the cover.
5. Check for any o vious alterations. Use good judgment as to the safety of any alterations.
6. Check inside the unit for any o vious hazards, such as metal filings, contamination, water or other
liquids, or signs of fire or smoke damage.
7. Check for worn, frayed, or pinched ca les.
8. Check that the power-supply cover fasteners (screws or rivets) have not een removed or tampered
with.
Handlin electrostatic dischar e-sensitive devices
Any computer part containing transistors or integrated circuits (ICs) should e considered sensitive to
electrostatic discharge (ESD). ESD damage can occur when there is a difference in charge etween o jects.
Protect against ESD damage y equalizing the charge so that the computer, the part, the work mat, and the
person handling the part are all at the same charge.
Notes:
Chapter 1.Read this first: Important safety information 3

1. Use product-specific ESD procedures when they exceed the requirements noted here.
2. Make sure that the ESD protective devices you use have een 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 while handling the part.
• Wear a grounded wrist strap against your skin to eliminate static on your ody.
• Prevent the part from touching your clothing. Most clothing is insulative and retains a charge even when
you are wearing a wrist strap.
• Use the lack side of a grounded work mat to provide a static-free work surface. The mat is especially
useful when handling ESD-sensitive devices.
• Select a grounding system, such as those listed elow, to provide protection that meets the specific
service requirement.
Note: The use of a grounding system is desira le ut not required to protect against ESD damage.
– Attach the ESD ground clip to any frame ground, ground raid, or green-wire ground.
– Use an ESD common ground or reference point when working on a dou le-insulated or attery-
operated system. You can use coax or connector-outside shells on these systems.
– Use the round ground-prong of the AC plug on AC-operated computers.
Groundin requirements
Electrical grounding of the computer is required for operator safety and correct system function. Proper
grounding of the electrical outlet can e verified y a certified electrician.
Safety notices
The CAUTION and DANGER safety notices in this section are provided in the language of English.
DANGER
Electrical current from power, telephone and communication ca les is hazardous.
To avoid a shock hazard:
• Do not connect or disconnect any cables or perform installation, maintenance, or reconfi uration
of this product durin an electrical storm.
• Connect all power cords to a properly wired and rounded electrical outlet.
• Connect any equipment that will be attached to this product to a properly wired outlet.
• When possible, use one hand only to connect or disconnect si nal cables.
• Never turn on any equipment when there is evidence of fire, water, or structural dama e.
• Disconnect the attached power cords, telecommunications cables, network cables, and modem
cables before you open the device covers, unless instructed otherwise in the installation and
confi uration procedures.
4Yoga A940Hardware Maintenance Manual

• Connect and disconnect cables as described in the followin table when installin , movin , or
openin covers on this product or attached devices.
To Connect To Disconnect
1. Turn everything OFF.
2. First, attach all ca les to devices.
3. Attach signal ca les to connectors.
4. Attach power cords to outlet.
5. Turn device ON.
1. Turn everything OFF.
2. First, remove power cords from outlets.
3. Remove signal ca les from connectors.
4. Remove all ca les from devices.
CAUTION:
When replacin the lithium battery, use only Part Number 45C1566 or an equivalent type battery
recommended by the manufacturer. If your system has a module containin a lithium battery, replace
it only with the same module type made by the same manufacturer. The battery contains lithium and
can explode if not properly used, handled, or disposed of.
Do not:
• Throw into or immerse in water
• Heat to more than 100°C (212°F)
• Repair or disassemble
Dispose of the battery as required by local ordinances or re ulations.
CAUTION:
When laser products (such as CD-ROMs, DVD-ROM drives, fiber optic devices, or transmitters) are
installed, note the followin :
• Do not remove the covers. Removin the covers of the laser product could result in exposure to
hazardous laser radiation. There are no serviceable parts inside the device.
• Use of controls or adjustments or performance of procedures other than those specified herein
mi ht result in hazardous radiation exposure.
DANGER
Some laser products contain an embedded Class 3A or Class 3B laser diode. Note the followin :
These diodes emit radiation when open. Do not stare into the beam, do not view directly with optical
instruments, and avoid direct exposure to the beam.
Chapter 1.Read this first: Important safety information 5

≥18 k (37 lbs) ≥32 k (70.5 lbs) ≥55 k (121.2 lbs)
CAUTION:
Use safe practices when liftin .
CAUTION:
The power control button on the device and the power switch on the power supply do not turn off the
electrical current supplied to the device. The device also mi ht have more than one power cord. To
remove all electrical current from the device, ensure that all power cords are disconnected from the
power source.
1
2
CAUTION:
Do not place any object wei hin more than 82 k (180 lbs.) on top of rack-mounted devices.
6Yoga A940Hardware Maintenance Manual

Chapter 2. Environment and electrical input
Environment
• Air temperature:
Operating: From 10°C (50°F) to 35°C (95°F)
Storage in original shipping package: From -40°C (-40°F) to 60°C (140°F)
Storage without package: From -10°C (14°F) to 60°C (140°F)
• Humidity:
Operating: 20%–80% (non-condensing)
Storage: 20%–90% (non-condensing)
• Altitude:
Operating: From -15.2 m (-50 ft) to 3048 m (10 000 ft)
Storage: From -15.2 m (-50 ft) to 10 668 m (35 000 ft)
Electrical input
Input voltage: For PSU400W, 200 – 240 VAC； For PSU 450W/280W, 100 – 240 VAC
Input frequency: 50/60 Hz
© Copyright Lenovo 2018 7

8Yoga A940Hardware Maintenance Manual

Chapter 3. General Checkout
Attention: The drives in the computer you are servicing might have een rearranged or the drive startup
sequence may have een changed. Be extremely careful during write operations such as copying, saving, or
formatting. Data or programs can e overwritten if you select an incorrect drive.
General error messages appear if a pro lem or conflict is found y an application, the operating system, or
oth. For an explanation of these messages, refer to the information supplied with that software package.
Use the following procedure to help determine the cause of the pro lem:
1. Power off the computer and all external devices.
2. Check all ca les and power cords.
3. Set all display controls to the middle position.
4. Power on all external devices.
5. Power on the computer.
• Look for error codes displayed.
• Look for reada le instructions or a main menu on the display.
If you did not receive the correct response, proceed to step 6.
If you did receive the correct response, proceed to step 7.
6. If one of the following happens, follow the instruction given:
• If the computer displays a POST error, go to “POST error codes”.
• If the computer hangs and no error is displayed, proceed to step 7.
7. If the test stops and you cannot continue, replace the last device tested.
© Copyright Lenovo 2018 9

10 Yoga A940Hardware Maintenance Manual

Chapter 4. Usin the Setup Utility pro ram
The Setup Utility program is used to view and change the configuration settings of your computer. This
section provides information a out only the major configuration settings availa le in the program.
Note: The operating system settings might override some similar settings in the Setup Utility program.
Startin the Setup Utility pro ram
To start the Setup Utility program, do the following:
1. Turn on or restart your computer.
2. Before Windows® starts up, repeatedly press and release the F1 key until the Setup Utility program
opens. If a BIOS password has een set, the Setup Utility program will not open until you enter the
correct password. For more information, see “Using BIOS passwords” on page 11.
Note: For some key oards, you might need to press Fn+F1 to open the Setup Utility program.
To view and change the configuration settings, follow the instructions on the right side of the screen. The
keys used to perform various tasks are displayed at the ottom of the screen.
Enablin or disablin a device
This section provides information a out how to ena le or disa le user access to hardware devices (such as
USB connectors or storage drives).
To ena le or disa le a device, do the following:
1. Start the Setup Utility program. See “Starting the Setup Utility program” on page 11.
2. Select Devices.
3. Select the device you want to ena le or disa le and press Enter.
4. Select the desired setting and press Enter.
5. Exit the Setup Utility program. See “Exiting the Setup Utility program” on page 13.
Enablin or disablin the Automatic Power On features
If you ena le the Automatic Power On features, your computer will start up automatically.
To ena le or disa le the Automatic Power On features, do the following:
1. Start the Setup Utility program. See “Starting the Setup Utility program” on page 11.
2. Select Power ➙ Automatic Power On and press Enter.
3. Select the feature you want to ena le or disa le and press Enter.
4. Select the desired setting and press Enter.
5. Exit the Setup Utility program. See “Exiting the Setup Utility program” on page 13.
Usin BIOS passwords
By using the Setup Utility program, you can set passwords to prevent unauthorized access to your computer
and data.
© Copyright Lenovo 2018 11

You do not have to set all passwords to use your computer. However, using passwords improves computer
security.
Setup Utility pro ram password types
The following types of passwords are availa le:
• Power-on password
When a power-on password is set, you are prompted to enter a valid password each time the computer is
turned on. The computer cannot e used until the valid password is entered.
• Administrator password
Setting an administrator password deters unauthorized users from changing configuration settings. If you
are responsi le for maintaining the configuration settings of several computers, you might want to set an
administrator password.
When an administrator password is set, you are prompted to enter a valid password each time you try to
access the Setup Utility program. The Setup Utility program cannot e accessed until a valid password is
entered.
If oth the power-on password and administrator password are set, you can enter either password.
However, you must use your administrator password to change all configuration settings.
Password considerations
A password can e any com ination of up to 64 alpha etic and numeric characters. For security reasons, it
is recommended to use a strong password that cannot e easily compromised.
Note: The Setup Utility program passwords are not case sensitive.
To set a strong password, consider the following guidelines:
• Have at least eight characters in length
• Contain at least one alpha etic character and one numeric character
• Not e your name or your user name
• Not e a common word or a common name
• Be significantly different from your previous passwords
Settin , chan in , and deletin a password
To set, change, or delete a password, do the following:
1. Start the Setup Utility program. See “Starting the Setup Utility program” on page 11.
2. Select Security.
3. Depending on the password type, select Set Power-On Password or Set Administrator Password,
and press Enter.
4. Follow the instructions on the right side of the screen to set, change, or delete a password.
Note: A password can e any com ination of up to 64 alpha etic and numeric characters. For more
information, see “Password considerations” on page 12.
5. Exit the Setup Utility program. See “Exiting the Setup Utility program” on page 13.
Selectin a startup device
If your computer does not start up from a device as expected, you can choose to change the startup device
sequence permanently or select a temporary startup device.
12 Yoga A940Hardware Maintenance Manual

Chan in the startup device sequence permanently
To change the startup device sequence permanently, do the following:
1. Depending on the type of the storage device, do one of the following:
• If the storage device is internal, go to step 2.
• If the storage device is a disc, ensure that your computer is on or turn on the computer. Then, insert
the disc into the optical drive.
• If the storage device is an external device other than a disc, connect the storage device to the
computer.
2. Start the Setup Utility program. See “Starting the Setup Utility program” on page 11.
3. Select Startup.
4. Follow the instructions on the right side of the screen to change the startup device sequence.
5. Exit the Setup Utility program. See “Exiting the Setup Utility program” on page 13.
Selectin a temporary startup device
Note: Not all discs and storage drives are oota le.
To select a temporary startup device, do the following:
1. Depending on the type of the storage device, do one of the following:
• If the storage device is internal, go to step 2.
• If the storage device is a disc, ensure that your computer is on or turn on the computer. Then, insert
the disc into the optical drive.
• If the storage device is an external device other than a disc, connect the storage device to the
computer.
2. Turn on or restart the computer. Before Windows starts up, repeatedly press and release the F12 key
until Startup Device Menu is displayed.
Note: For some key oards, you might need to press Fn+F12 to display Startup Device Menu.
3. Select the desired storage device and press Enter. The computer will start up from the device you select.
If you want to select a permanent startup device, select Enter Setup on Startup Device Menu and press
Enter to start the Setup Utility program. For more information a out how to select a permanent startup
device, see “Changing the startup device sequence permanently” on page 13.
Exitin the Setup Utility pro ram
To exit the Setup Utility program, do one of the following:
• If you want to save the new settings, press the F10 key. Then, select Yes in the window displayed and
press Enter.
Note: For some key oards, you might need to press Fn+F10 to exit the Setup Utility program.
• If you do not want to save the new settings, select Exit ➙ Discard Chan es and Exit and press Enter.
Then, select Yes in the window displayed and press Enter.
Chapter 4.Using the Setup Utility program 13

14 Yoga A940Hardware Maintenance Manual