Lenovo ThinkCentre M75n User Manual

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ThinkCentre M75n User Guide

Read this first

Before using this documentation and the product it supports, ensure that you read and understand the following:

• Appendix A “Important safety information” on page 77

• Safety and Warranty Guide

• Setup Guide

First Edition (April 2020)

LIMITED AND RESTRICTED RIGHTS NOTICE: If data or software is delivered pursuant to a General Services Administration “GSA” contract, use, reproduction, or disclosure is subject to restrictions set forth in Contract No. GS35F-05925.

Contents

About this documentation . . . . . . . . iii

Chapter 1. Meet your computer. . . . . 1

Top . . . . . . . . . . . . . . . . . . . . 1

Front . . . . . . . . . . . . . . . . . . . . 2

Rear . . . . . . . . . . . . . . . . . . . . 3

Bottom . . . . . . . . . . . . . . . . . . . 4

System board . . . . . . . . . . . . . . . . 5

Features and specifications . . . . . . . . . . . 7

Statement on USB transfer rate . . . . . . . . 8

Chapter 2. Get started with your

computer . . . . . . . . . . . . . . . . . 9

Get started with Windows 10 . . . . . . . . . . 9

Windows account . . . . . . . . . . . . . 9

Windows user interface . . . . . . . . . . 10

Connect to networks. . . . . . . . . . . . . 11

Connect to the wired Ethernet . . . . . . . 11

Connect to Wi-Fi networks (for selected

models) . . . . . . . . . . . . . . . . 11

Use Lenovo Vantage . . . . . . . . . . . . . 11

Use multimedia . . . . . . . . . . . . . . . 12

Use audio . . . . . . . . . . . . . . . 12

Connect to an external display . . . . . . . 12

Use the I/O box (for selected fanless models) . . . 13

Chapter 3. Explore your computer . . 17

Manage power . . . . . . . . . . . . . . . 17

Set power button behaviors . . . . . . . . 17

Set the power plan . . . . . . . . . . . . 17

Transfer data . . . . . . . . . . . . . . . . 17

Connect to a Bluetooth-enabled device (for

selected models) . . . . . . . . . . . . 17

Purchase accessories . . . . . . . . . . . . 18

Chapter 4. Secure your computer

and information . . . . . . . . . . . . 19

Lock the computer . . . . . . . . . . . . . 19

Use passwords . . . . . . . . . . . . . 20

Use software security solutions. . . . . . . . . 21

Use firewalls . . . . . . . . . . . . . . 21

Use antivirus programs . . . . . . . . . . 22

Use computrace Agent software embedded in

firmware (for selected models) . . . . . . . 22

Use BIOS security solutions . . . . . . . . . . 22

Erase all storage drive data . . . . . . . . 22

Use the cover presence switch . . . . . . . 22

Use Smart USB Protection. . . . . . . . . 23

Chapter 5. UEFI BIOS . . . . . . . . . 25

What is UEFI BIOS. . . . . . . . . . . . . . 25

Enter the BIOS menu. . . . . . . . . . . . . 25

Navigate in the BIOS interface . . . . . . . . . 25

Change the display language of UEFI BIOS . . . . 25

Change the display mode of UEFI BIOS . . . . . 26

Set the system date and time . . . . . . . . . 26

Change the startup sequence . . . . . . . . . 26

Enable or disable the configuration change

detection feature . . . . . . . . . . . . . . 27

Enable or disable the automatic power-on

feature . . . . . . . . . . . . . . . . . . 27

Enable or disable the smart power-on feature (for

selected models) . . . . . . . . . . . . . . 27

Enable or disable the ErP LPS compliance mode

(for selected models). . . . . . . . . . . . . 27

Change the ITS performance mode (for selected

models) . . . . . . . . . . . . . . . . . . 28

Change BIOS settings before installing a new

operating system . . . . . . . . . . . . . . 28

Update UEFI BIOS. . . . . . . . . . . . . . 29

Recover from a BIOS update failure . . . . . . . 29

Clear CMOS . . . . . . . . . . . . . . . . 30

Chapter 6. Troubleshooting,

diagnostics, and recovery . . . . . . . 31

Basic procedure for resolving computer

problems . . . . . . . . . . . . . . . . . 31

Troubleshooting . . . . . . . . . . . . . . 31

Startup problems . . . . . . . . . . . . 32

Audio problems . . . . . . . . . . . . . 33

Network problems . . . . . . . . . . . . 33

Performance problems . . . . . . . . . . 36

Storage drive problems . . . . . . . . . . 37

Serial connector problems. . . . . . . . . 37

USB device problems . . . . . . . . . . 37

Software problems. . . . . . . . . . . . 38

Lenovo diagnostic tools . . . . . . . . . . . 38

Recovery . . . . . . . . . . . . . . . . . 38

Restore system files and settings to an earlier

point . . . . . . . . . . . . . . . . . 38

Restore your files from a backup . . . . . . 38

Reset your computer . . . . . . . . . . . 38

Use advanced options . . . . . . . . . . 39

Windows automatic recovery. . . . . . . . 39

Create and use a recovery USB device . . . . 39

Update the device driver . . . . . . . . . 40

M.2 solid-state drives. . . . . . . . . . . 71

Chapter 7. CRU replacement . . . . . 41

What are CRUs . . . . . . . . . . . . . . . 41

Replace a CRU (for fan models) . . . . . . . . 41

Power adapter and power cord . . . . . . . 42

DIN rail bracket kit . . . . . . . . . . . . 43

Power adapter bracket kit . . . . . . . . . 45

VESA mount bracket kit . . . . . . . . . . 49

Rear Wi-Fi antenna. . . . . . . . . . . . 50

Bottom cover . . . . . . . . . . . . . . 51

Wi-Fi card . . . . . . . . . . . . . . . 53

M.2 solid-state drive . . . . . . . . . . . 54

Replace a CRU (for fanless models) . . . . . . . 55

Power adapter and power cord . . . . . . . 55

Heat sink cover . . . . . . . . . . . . . 57

DIN rail bracket kit . . . . . . . . . . . . 58

Power adapter bracket kit . . . . . . . . . 60

VESA mount bracket kit . . . . . . . . . . 63

I/O box . . . . . . . . . . . . . . . . 65

Rear Wi-Fi antenna. . . . . . . . . . . . 67

Bottom cover . . . . . . . . . . . . . . 68

Wi-Fi card . . . . . . . . . . . . . . . 69

Chapter 8. Help and support . . . . . 73

Self-help resources . . . . . . . . . . . . . 73

Call Lenovo . . . . . . . . . . . . . . . . 74

Before you contact Lenovo . . . . . . . . 74

Lenovo Customer Support Center . . . . . . 74

Purchase additional services. . . . . . . . . . 75

Appendix A. Important safety

information . . . . . . . . . . . . . . . 77

Appendix B. Accessibility and

ergonomic information . . . . . . . . 91

Appendix C. Supplemental information about the Ubuntu operating

system . . . . . . . . . . . . . . . . . 95

Appendix D. Compliance and TCO

Certified information. . . . . . . . . . 97

Appendix E. Notices and

trademarks . . . . . . . . . . . . . . . 109

ii ThinkCentre M75n User Guide

About this documentation

• Illustrations in this documentation might look different from your product.

• Depending on the model, some optional accessories, features, and software programs might not be available on your computer.

• Depending on the version of operating systems and programs, some user interface instructions might not be applicable to your computer.

• Documentation content is subject to change without notice. Lenovo makes constant improvements on the documentation of your computer, including this User Guide. To get the latest documentation, go to:

https://pcsupport.lenovo.com

• Microsoft® makes periodic feature changes to the Windows® operating system through Windows Update. As a result, some information in this documentation might become outdated. Refer to Microsoft resources for the latest information.

iv ThinkCentre M75n User Guide

Chapter 1. Meet your computer

Top

Fan models

Fanless models

1. ThinkCentre® LED

This indicator is on when the computer is on.

Front

Fan models

Fanless models

Press to turn on the computer.

1. Power button

2. Serial connectors (2)

3. USB-C

4. USB 2.0 connector

5. USB 3.2 connector Gen 2

6. Headset connector

™

(3.2 Gen 2) connector

To turn off the computer, open the Start menu, click Shut down.

The indicator in the power button shows the system status of your computer.

• On: The computer is on.

• Off: The computer is off or in hibernation mode.

• Blinking: The computer is in sleep mode.

• Breathing: The computer is in modern standby mode.

Used to connect an external modem, a serial printer, or other devices that use a serial connector.

• The output voltage and current are 5 V and 0.9 A.

• Transfer data at USB 3.2 speed, up to 10 Gbps.

• Connect to USB-C accessories to help expand your computer functionality. To purchase USB-C accessories, go to

Connect USB-compatible devices, such as a USB keyboard, USB mouse, USB storage device, or USB printer.

Connect a headset or headphones to your computer.

https://www.lenovo.com/accessories.

Power, and then select

2 ThinkCentre M75n User Guide

Rear

Fan models

Fanless models

1. Power adapter connector Connect the power adapter to your computer for power supply.

2. DisplayPort

out connector

3. USB 3.2 connector Gen 2

4. USB-C

™

(3.2 Gen 2) connector

5. USB 2.0 connector

6. Ethernet connector

7. Security-lock slot

8. Wi-Fi

antenna slot*

Send audio and video signals from the computer to another audio or video device, such as a high-performance monitor.

Connect USB-compatible devices, such as a USB keyboard, USB mouse, USB storage device, or USB printer.

• The output voltage and current are 5 V and 0.9 A.

• Transfer data at USB 3.2 speed, up to 10 Gbps.

• Connect to an external display:

– USB-C to VGA: 1900 x 1200 pixels, 60 Hz – USB-C to DP: 3840 x 2160 pixels, 60 Hz

• Connect to USB-C accessories to help expand your computer functionality. To

purchase USB-C accessories, go to

https://www.lenovo.com/accessories.

Connect USB-compatible devices, such as a USB keyboard, USB mouse, USB storage device, or USB printer. This connector supports the smart power-on feature. For more information, see “Enable or disable the smart power-on feature (for selected models)” on page 27.

Connect to a local area network (LAN). When the green indicator is on, the computer is connected to a LAN. When the yellow indicator blinks, data is being transmitted.

Lock your computer to a desk, table, or other fixtures through a Kensington-style cable lock.

Used to install the rear Wi-Fi antenna cable connector that is available only on some models. The rear Wi-Fi antenna is installed on the rear Wi-Fi antenna cable connector.

* for selected models

Chapter 1. Meet your computer 3

Bottom

Fan models

Fanless models

1. VESA® threaded holes

4 ThinkCentre M75n User Guide

Connect the matched DIN rail bracket, power adapter bracket, or VESA mount bracket with the matched screws (M3 x 4 mm x 3 pcs) when you install the computer on a wall.

System board

Fan models

1 Microprocessor fan connector

3 Clear CMOS (Complementary Metal Oxide

Semiconductor) / Recovery jumper

5 M.2 solid-state drive slot 1

7 Wi-Fi card slot

2 Coin-cell battery connector

4 Internal speaker connector

6 M.2 solid-state drive slot 2 (M.2 SATA solid-state drive

compatible)

8 Cover presence switch connector (intrusion switch

connector)

Chapter 1. Meet your computer 5

Fanless models

1 Coin-cell battery connector 2 Clear CMOS (Complementary Metal Oxide

Semiconductor) / Recovery jumper

3 4G/5G LTE slot

5 M.2 solid-state drive slot 2 (for M.2 SATA solid-state

4 M.2 solid-state drive slot 1

6 Internal speaker connector

drive only)

7 Wi-Fi card slot

8 Cover presence switch connector (intrusion switch

connector)

6 ThinkCentre M75n User Guide

Features and specifications

Fan models:

• Width: 179 mm (7.05 inches)

• Height: 22 mm (0.87 inches)

• Depth: 88 mm (3.46 inches)

Dimensions

Weight (without the package)

Hardware configuration

Fanless models:

• Width: 179 mm (7.05 inches)

• Height: 34.5 mm (1.36 inches)

• Depth: 88 mm (3.46 inches)

Maximum configuration as shipped:

• Fan models: 0.51 kg (1.11 lb)

• Fanless models: 0.72 kg (1.59 lb)

1. Right-click the Start button to open the Start context menu.

2. Click Device Manager. Type the administrator password or provide confirmation if prompted.

Electrical input

Power supply 65-watt automatic voltage-sensing power adapter

Microprocessor

Memory

Storage device

Video features

Audio features

Expansion

• Input voltage: From 100 V ac to 240 V ac

• Input frequency: 50/60 Hz

To view the microprocessor information of your computer, right-click the Start button and then click System.

Double data rate 4 (DDR4) synchronous dynamic random-access memory module (SDRAM), soldered on the system board

Your computer supports up to two M.2 solid-state drives.

To know the storage drive capacity:

1. Right-click the Start button to open the Start context menu.

2. Click Disk Management.

Note: The storage drive capacity indicated by the system is less than the nominal capacity.

DisplayPort out connector

The integrated audio card supports the following:

• Headset connector

• Internal speaker*

• I/O box*

• M.2 solid-state drive slots (2)

• M.2 Wi-Fi slot

Network features

• Bluetooth*

• Ethernet LAN

• Wireless LAN*

Chapter 1. Meet your computer 7

* for selected models

Statement on USB transfer rate

Depending on many factors such as the processing capability of the host and peripheral devices, file attributes, and other factors related to system configuration and operating environments, the actual transfer rate using the various USB connectors on this device will vary and will be slower than the data rate listed below for each corresponding device.

USB device Data rate (Gbit/s)

3.2 Gen 1 / 3.1 Gen 1

3.2 Gen 2 / 3.1 Gen 2

3.2 Gen 2 × 2

8 ThinkCentre M75n User Guide

Chapter 2. Get started with your computer

Get started with Windows 10

Learn the basics of Windows 10 and start working with it right away. For more information about Windows 10, see the Windows help information.

Windows account

A user account is required to use the Windows operating system. It can either be a Windows user account or a Microsoft account.

Windows user account

When you start Windows for the first time, you are prompted to create a Windows user account. This first account you created is of the “Administrator” type. With an Administrator account, you can create additional user accounts or change account types by doing the following:

1. Open the Start menu and select Settings ➙ Accounts ➙ Family & other users.

2. Follow the on-screen instructions.

Microsoft account

You can also log in to the Windows operating system with a Microsoft account.

To create a Microsoft account, go to the Microsoft sign-up page at screen instructions.

With a Microsoft account, you can:

• Enjoy one-time signing in if you are using other Microsoft services, such as OneDrive, Skype, and Outlook. com.

• Sync personalized settings across other Windows-based devices.

https://signup.live.com and follow the on-

Windows user interface

1. Account

2. Documents

3. Pictures

4. Settings

5. Power

6. Start button

7. Windows Search

8. Task View

9. Windows notification area

10. Battery status icon

11. Network icon

12. Action center

Change account settings, lock the computer, or sign out from the current account.

Open the Documents folder, a default folder to save your received files.

Open the Pictures folder, a default folder to save your received pictures.

Launch Settings.

Shut down, restart, or put the computer into sleep mode.

Open the Start menu.

Type what you are looking for in the search box and get search results from your computer and the Web.

Display all opened apps and switch among them.

Display notifications and status of some features.

Display power status and change battery or power settings. When your computer is not connected to ac power, the icon changes to

Connect to an available wireless network and display the network status. When connected to a wired network, the icon changes to

Display the latest notifications from apps and provide quick access to some features.

Open the Start menu

• Click the Start button.

• Press the Windows logo key on the keyboard.

Open the Start context menu Right-click the Start button.

ThinkCentre M75n User Guide

Access Control Panel

• Open the Start menu and click Windows System ➙ Control Panel.

• Use Windows Search.

Launch an app

• Open the Start menu and select the app you want to launch.

• Use Windows Search.

Connect to networks

Your computer helps you connect to the world through a wired or wireless network.

Connect to the wired Ethernet

Connect your computer to a local network through the Ethernet connector on your computer with an Ethernet cable.

Connect to Wi-Fi networks (for selected models)

If your computer includes a wireless LAN module, you can connect your computer to Wi-Fi® networks. The wireless LAN module on your computer may support different standards. For some countries or regions, use of 802.11ax may be disabled according to local regulations.

1. Click the network icon in the Windows notification area. A list of available wireless networks is displayed.

2. Select a network available for connection. Provide required information, if needed.

Use Lenovo Vantage

The preinstalled Lenovo Vantage is a customized one-stop solution to help you maintain your computer with automated updates and fixes, configure hardware settings, and get personalized support.

Access Lenovo Vantage

Open the Start menu and click Lenovo Vantage. You also can type Lenovo Vantage in the search box.

To download the latest version of Lenovo Vantage, go to Microsoft Store and search by the app name.

Key features

Lenovo Vantage enables you to:

• Know the device status easily and customize device settings.

• Download and install UEFI BIOS, firmware and driver updates to keep your computer up-to-date.

• Monitor your computer health, and secure your computer against outside threats.

• Look up warranty status (online).

• Access User Guide and helpful articles.

Notes:

Chapter 2. Get started with your computer 11

• The available features vary depending on the computer model.

• Lenovo Vantage makes periodic updates of the features to keep improving your experience with your computer. The description of features might be different from that on your actual user interface.

Use multimedia

Use your computer for business or entertainment with the devices (such as a camera, a monitor, or speakers).

Use audio

To enhance the audio experience, connect speakers, headphones, or a headset to the audio connector.

Adjust the volume

1. Click the volume icon in the Windows notification area on the taskbar.

2. Follow the on-screen instructions to adjust the volume. Click the speaker icon to mute the audio.

Change the sound settings

1. Go to Control Panel and view by category.

2. Click Hardware and Sound ➙ Sound.

3. Change the settings as you prefer.

Connect to an external display

Connect to a wired display

Connect your computer to a projector or a monitor through the video output connector on your computer to give presentations or expand your workspace.

If your computer cannot detect the external display, right-click an empty area of the desktop, and then click

Display settings ➙ Detect.

Connect to a wireless display

To use a wireless display, ensure that both your computer and the external display support the Miracast feature.

• Open the Start menu, and then click Settings ➙ Devices ➙ Bluetooth & other devices ➙ Add Bluetooth or other device. In the Add a device window, click Wireless display or dock. Then, follow the instructions on the screen.

• Click the action center icon display and follow the on-screen instructions.

Set the display mode

Right-click a blank area on the desktop and select Display settings. Then, select a display mode of your preference from the Multiple displays menu.

in the Windows notification area and click Connect. Select the wireless

• Duplicate these displays: Display the same video output on both your computer screen and an external display.

• Extend these displays: Extend the video output from your computer display to an external display. You can drag and move items between the two displays.

• Show only on 1: Display the video output only on your computer screen.

ThinkCentre M75n User Guide

• Show only on 2: Display the video output only on an external display.

If you show programs using DirectDraw or Direct3D

in full-screen mode, only the main display shows the

video output.

Change display settings

1. Right-click a blank area on the desktop and select Display settings.

2. Select the display that you want to configure.

3. Change display settings of your preference.

You can change the settings for both the computer display and the external display. For example, you can define which one is the main display and which one is the secondary display. You also can change the resolution and orientation.

Note: If you set a higher resolution for the computer display than the external display, only part of the screen can be displayed on the external display.

Use the I/O box (for selected fanless models)

If your computer has an I/O box, you can use it to supply power to your computer and expand your computer functionality.

https://support.lenovo.com/solutions/iobox

Front

1. Serial connectors (2)

2. Ethernet connectors (2) (PoE)

• Connect an external modem, a serial printer, or other devices that use a serial connector.

• Support RS-232, RS-422, and RS-485 standards. The default standard is RS-

232. You can configure the connectors with the IoT IOBOX DT1 IO CONTROLLER application.

• Connect to a local area network (LAN). When the green indicator is on, the computer is connected to a LAN. When the yellow indicator blinks, data is being transmitted.

• Support Power over Ethernet (PoE) technology. Supply power to external device connected to this connector over an Ethernet cable, such as a VoIP phone, an IP camera, or other devices that also support PoE technology.

Note: To use the PoE function, the dc power input needs to be higher than 135 W.

Rear

The items

a , b , c , d shown below come with the I/O box.

Chapter 2. Get started with your computer 13

Connect to dc power for power supply through the DC-in connector

b .

Note: You can use the DC-in cable

1. DC-in power connector

environment where no dc power is available. Connect one end of the DC-in cable

a to a 135W ac power adapter or greater. and connect the other end to the DC-in

power connector on the I/O box. You can purchase the ac power adapter separately from Lenovo.

• Connect to the computer through the USB-C adapter

• Transfer data at USB 3.1 speed, up to 5 Gbps.

2. USB-C connector (USB 3.1 Gen 1)

• Supply power to the computer.

Note: When the computer is not connected to ac power and the I/O box is connected to dc power, the I/O box supplies power to the computer through the USB-C connector. In this case, the output voltage and current are 20 V and 3 A.

3. Digital input and Digital output (DI/DO) connectors

Connect to proximity sensors or other devices that use DI/DO connectors through the DI/DO adapters

d .

Digital Input and Digital Output Pin definition mapping table

a when you are testing the I/O box in an

c .

D-OUT pin number D-OUT pin definition D-IN pin number D-IN pin definition

COM

GND

Digital Output-1

Digital Output-2

Digital Output-3

Digital Output-4

COM

GND

3 Digital Input-1

4 Digital Input-2

Digital Input-3

6 Digital Input-4

14 ThinkCentre M75n User Guide

Digital Input and Digital Output

Digital Input

Digital Output

• Channels: 4

• Input type: NPN, PNP

• Dry contact:

– Logic 0: Open – Logic 1: Close to GND

• Wet contact:

– Logic 0: 0 V to 0.8 V – Logic 1: 5 V to 30 V

• Input resistance: 9.8 kΩ

• Isolation voltage: 1.5 kV (DC)

• Overvoltage protection: 70 V (DC)

• Channels: 4

• Output type: NPN

• Output voltage range: 5 V to 30 V

• Normal output current: 200 mA

• Isolation voltage: 1.5 kV (DC)

Chapter 2. Get started with your computer 15

16 ThinkCentre M75n User Guide

Chapter 3. Explore your computer

Manage power

Use the information in this section to achieve the best balance between performance and power efficiency.

Set power button behaviors

You can define what the power button does according to your preference. For example, by pressing the power button, you can turn off the computer or put the computer to sleep or hibernation mode.

To change what the power button does:

1. Go to Control Panel and view by large icons or small icons.

2. Click Power Options ➙ Choose what the power buttons do.

3. Change the settings as you prefer.

Set the power plan

For ENERGY STAR® compliant computers, the following power plan takes effect when your computers have been idle for a specified duration. The default power plan varies depending on your computer models. To know the machine type of your computer model, see “Before you contact Lenovo” on page 74.

Table 1. Default power plan when plugged into ac power (for machine types: 11BS, 11BT, 11BU, 11BV, 11GW, 11GX, 11GV, 11GY, 11C0, 11GB, 11HU, 11HV, 11HW, 11HX, 11HY, 11J0, 11J1, and 11J2)

• Turn off the display: After 10 minutes

• Put the computer to sleep: After 10 minutes

Table 2. Default power plan when plugged into ac power (for machine types: 11G4, 11G5, 11G6, 11G7, 11G8, 11G9, 11BW, and 11BX)

• Turn off the display: After 10 minutes

• Put the computer to sleep: After 25 minutes

To awaken the computer from Sleep mode, press any key on your keyboard.

To reset the power plan to achieve the best balance between performance and power saving:

1. Go to Control Panel and view by large icons or small icons.

2. Click Power Options, and then choose or customize a power plan of your preference.

Transfer data

Quickly share your files using the built-in Bluetooth technology among devices with the same features. You also can install a disc or media card to transfer data.

Connect to a Bluetooth-enabled device (for selected models)

You can connect all types of Bluetooth-enabled devices to your computer, such as a keyboard, a mouse, a smartphone, or speakers. To ensure that the connection is successful, place the devices 10 meters (33 feet), at most, from the computer.

1. Turn on Bluetooth on the computer. a. Open the Start menu, and then click Settings ➙ Devices ➙ Bluetooth & other devices. b. Turn on the Bluetooth switch.

2. Click Add Bluetooth or other device ➙ Bluetooth.

3. Select a Bluetooth device, and then follow the on-screen instructions.

Your Bluetooth device and computer will automatically connect the next time if the two devices are in range of each other with Bluetooth turned on. You can use Bluetooth for data transfer or remote control and communication.

Purchase accessories

Lenovo has a number of hardware accessories and upgrades to help expand the capabilities of your computer. Options include memory modules, storage devices, network cards, power adapters, keyboards, mice, and more.

To shop at Lenovo, go to

There are some tutorial videos that introduce how to use your computer with some accessories, such as ThinkCentre Nano TIO Cube, ThinkCentre Nano IoT IOBOX， and ThinkCentre Tiny/Nano Monitor Clamp II.

https://support.lenovo.com/solutions/nanofeaturevideo

https://www.lenovo.com/accessories.

18 ThinkCentre M75n User Guide

Chapter 4. Secure your computer and information

Lock the computer

Note: You are responsible for evaluating, selecting, and implementing the locking device and security

feature. Lenovo makes no comments, judgments, or warranties about the function, quality, or performance of the locking device and security feature. You can purchase computer locks from Lenovo.

Kensington-style cable lock (fan models)

Lock your computer to a desk, table, or other fixtures through a Kensington-style cable lock.

Kensington-style cable lock (fanless models)

Lock your computer to a desk, table, or other fixtures through a Kensington-style cable lock.

Log in to your computer securely

This section provides secure ways to log in to your computer with a password or your face.

Use passwords

Password types

You can set the following passwords in UEFI (Unified Extensible Firmware Interface) BIOS (Basic Input/ Output System) to prevent unauthorized access to your computer. However, you are not prompted to enter any UEFI BIOS password when your computer resumes from sleep mode.

• 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 be used until the valid password is entered.

• Supervisor password Setting a supervisor password deters unauthorized users from changing configuration settings. If you are

responsible for maintaining the configuration settings of several computers, you might want to set a supervisor password.

When a supervisor password is set, you are prompted to enter a valid password each time you try to enter the BIOS menu.

If both the power-on password and supervisor password are set, you can enter either password. However, you must use your supervisor password to change any configuration settings.

• Hard disk password Setting a hard disk password prevents unauthorized access to the data on the storage drive. When a hard

disk password is set, you are prompted to enter a valid password each time you try to access the storage drive.

ThinkCentre M75n User Guide

Note: After you set a hard disk password, your data on the storage drive is protected even if the storage drive is removed from one computer and installed in another.

• System management password (for selected models) 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. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Security ➙ 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.

Set, change, and remove a password

Before you start, print these instructions.

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Security.

3. Depending on the password type, select Set Supervisor Password, Set Power-On Password, Set System Management Password, or Hard Disk Password and press Enter.

4. Follow the on-screen instructions to set, change, or remove a password.

5. Press F10 or Fn+F10 to save the changes and exit.

You should record your passwords and store them in a safe place. If you forget the passwords, see “Clear CMOS” on page 30 to remove them by yourself. You can also contact a Lenovo-authorized service provider to have the passwords removed.

Notes:

• If the supervisor password is forgotten, it might not be removed by clearing CMOS depending on your BIOS settings.

• If the hard disk password is forgotten, Lenovo cannot remove the password or recover data from the storage drive.

Use software security solutions

This section provides software solutions to secure your computer and information.

Use firewalls

A firewall can be hardware, software, or a combination of both depending on the level of security required. Firewalls work on a set of rules to determine which inbound and outbound connections are authorized. If the computer is preinstalled with a firewall program, it helps protect against computer Internet security threats, unauthorized access, intrusions, and Internet attacks. It also protects your privacy. For more information about how to use the firewall program, refer to the help system of your firewall program.

To use firewalls:

1. Go to Control Panel and view by large icons or small icons.

2. Click Windows Defender Firewall, and then follow the on-screen instructions.

Chapter 4. Secure your computer and information 21

Use antivirus programs

The computer is preinstalled with an antivirus program to help you guard against, detect, and eliminate viruses.

Lenovo provides a full version of antivirus software on the computer with a free 30-day subscription. After 30 days, you must renew the license to continue receiving the antivirus software updates.

Note: Virus definition files must be kept up-to-date to guard against new viruses.

For more information about how to use your antivirus software, refer to the help system of your antivirus software.

Use computrace Agent software embedded in firmware (for selected models)

The Computrace Agent software is an IT asset management and computer theft recovery solution. The software detects if changes have been made on the computer, such as hardware, software, or the computer call-in location. You might have to purchase a subscription to activate the Computrace Agent software.

Use BIOS security solutions

This section provides BIOS solutions to secure your computer and information.

Erase all storage drive data

It is recommended that you erase all storage drive data before recycling a storage drive or the computer.

To erase all storage drive data:

1. Set a hard disk password for the storage drive you will recycle. See “Use passwords” on page 20.

2. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

3. Select Security ➙ Hard Disk Password ➙ Security Erase HDD Data and press Enter.

4. Select the storage drive you will recycle and press Enter.

5. A message is displayed, prompting you to confirm the operation. Select Yes and press Enter. The erasing process begins.

Note: During the erasing process, the power button and the keyboard are disabled.

6. After the erasing process is completed, a message is displayed, prompting you to reset the system. Select Continue.

Note: Depending on the storage drive capacity, the erasing process will take half an hour to three hours.

7. After the resetting process is completed, one of the following will happen:

• If the data on the system storage drive is erased, you will be prompted that no operating system is

available.

• If the data on the non-system storage drive is erased, the computer restarts automatically.

Use the cover presence switch

The cover presence switch prevents the computer from logging in to the operating system when the computer cover is not properly installed or closed.

To enable the cover presence switch connector on the system board:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

ThinkCentre M75n User Guide

2. Select Security ➙ Cover Tamper Detected and press Enter.

3. Select Enabled and press Enter.

4. Press F10 or Fn+F10 to save the changes and exit.

When the cover presence switch connector on the system board is enabled, if the cover presence switch detects that the computer cover is not correctly installed or closed, an error message will be displayed when you turn on the computer. To bypass the error message and log in to the operating system:

1. Properly install or close the computer cover.

2. Enter the BIOS menu, save and then exit.

Use Smart USB Protection

The Smart USB Protection function is a security function that helps prevent data from being copied from the computer to USB storage devices connected to the computer. You can set the Smart USB Protection function to one of the following modes:

• Disabled (default setting): You can use the USB storage devices without limitation.

• Read Only: You cannot copy data from the computer to the USB storage devices. However, you can access or modify data on the USB storage devices.

• No Access: You cannot access the USB storage devices from the computer.

To configure the Smart USB Protection function:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Security ➙ Smart USB Protection and press Enter.

3. Select the desired setting and press Enter.

4. Press F10 or Fn+F10 to save the changes and exit.

Chapter 4. Secure your computer and information 23

24 ThinkCentre M75n User Guide

Chapter 5. UEFI BIOS

This chapter provides information about configuring and updating UEFI BIOS, and clearing CMOS.

What is UEFI BIOS

Note: The operating system settings might override any similar settings in UEFI BIOS.

UEFI BIOS is the first program that the computer runs when the computer is turned on. UEFI BIOS initializes the hardware components and loads the operating system and other programs. Your computer comes with a setup program with which you can change UEFI BIOS settings.

Enter the BIOS menu

Restart the computer. When the logo screen is displayed, press F1 or Fn+F1 to enter the BIOS menu.

Note: If you have set BIOS passwords, enter the correct passwords when prompted. You also can select No or press Esc to skip the password prompt and enter the BIOS menu. However, you cannot change the system configurations that are protected by passwords.

Navigate in the BIOS interface

Attention: The default configurations are already optimized for you in boldface. Improper change of the

configurations might cause unexpected results.

Depending on your keyboard, you can navigate in the BIOS interface by pressing the following keys, or combinations of Fn and the following keys:

F1 or Fn+F1

Esc or Fn+Esc Exit the submenu and return to the parent menu.

↑↓ or Fn+↑↓ Locate an item.

← → or Fn+← → Select a tab.

+/– or Fn++/– Change to a higher or lower value.

Enter Enter the selected tab or submenu.

F9 or Fn+F9 Restore to the default settings.

F10 or Fn+F10 Save your configuration and exit.

Display the General Help screen.

Change the display language of UEFI BIOS

UEFI BIOS supports four display languages: English, French, Russian, and simplified Chinese.

To change the display language of UEFI BIOS:

1. Select Main ➙ Language and press Enter.

2. Set the display language as desired.

Change the display mode of UEFI BIOS

You can use UEFI BIOS in the graphic mode or the text mode according to your needs.

• Text mode: The keys on the keyboard used to perform various tasks are displayed at the bottom of the screen.

Note: The Serial Port Console Redirection item is available only in the text mode.

• Graphic mode (for selected models): In addition to the keyboard, you also can use the mouse to make selections.

To change the display mode of UEFI BIOS:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Main ➙ Setup mode select and press Enter.

3. Set the display mode as desired.

Set the system date and time

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Main ➙ System Time & Date and press Enter.

3. Set the system date and time as desired.

4. Press F10 or Fn+F10 to save the changes and exit.

Change the startup sequence

If the computer does not start up from a device as expected, you can change the startup device sequence permanently or select a temporary startup device.

Change the startup device sequence permanently

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 the 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. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

3. Select Startup, and then follow the on-screen instructions to change the startup sequence.

4. Press F10 or Fn+F10 to save the changes and exit.

Select a temporary startup device Note: Not all discs and storage drives are bootable.

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 the 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.

ThinkCentre M75n User Guide

2. Restart the computer. When the logo screen is displayed, press F12 or Fn+F12.

3. Select the storage device as desired and press Enter.

If you want to change the startup device sequence permanently, select Enter Setup on Startup Device Menu and press Enter to enter the BIOS menu.

Enable or disable the configuration change detection feature

If you enable configuration change detection, when the POST detects configuration changes of some hardware devices (such as storage drives or memory modules), an error message will be displayed when you turn on the computer.

To enable or disable the configuration change detection feature:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Security ➙ Configuration Change Detection and press Enter.

3. Enable or disable the feature as desired.

4. Press F10 or Fn+F10 to save the changes and exit.

To bypass the error message and log in to the operating system, press F2 or Fn+F2. To clear the error message, enter the BIOS menu, save and then exit.

Enable or disable the automatic power-on feature

The Automatic Power On item in UEFI BIOS provides various options for you to make your computer start up automatically.

To enable or disable the automatic power-on feature:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Power ➙ Automatic Power On and press Enter.

3. Select the feature as desired and press Enter.

4. Enable or disable the feature as desired.

5. Press F10 or Fn+F10 to save the changes and exit.

Enable or disable the smart power-on feature (for selected models)

Ensure that the keyboard is connected to a USB connector supporting the smart power-on feature. With the smart power-on feature enabled, you can start up or wake up the computer from the hibernation mode by pressing Alt+P.

To enable or disable the smart power-on feature:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Power ➙ Smart Power On and press Enter.

3. Enable or disable the feature as desired.

4. Press F10 or Fn+F10 to save the changes and exit.

Enable or disable the ErP LPS compliance mode (for selected models)

Lenovo computers meet the eco-design requirements of the ErP Lot 3 regulation. For more information, go to:

https://www.lenovo.com/us/en/compliance/eco-declaration

Chapter 5. UEFI BIOS 27

You can enable the ErP LPS compliance mode to reduce the consumption of electricity when the computer is off or in sleep mode.

To enable or disable the ErP LPS compliance mode:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Power ➙ Enhanced Power Saving Mode and press Enter.

3. Depending on whether you select Enabled or Disabled, do one of the following:

• If you select Enabled, press Enter. Then, select Power ➙ Automatic Power On and press Enter. Check whether the Wake on LAN feature is disabled automatically. If no, disable it.

• If you select Disabled, press Enter. Then, go to the next step.

4. Press F10 or Fn+F10 to save the changes and exit.

When the ErP LPS compliance mode is enabled, you can wake up the computer by doing one of the following:

• Press the power button.

• Enable the Wake Up on Alarm feature to make the computer wake up at a set time.

To meet the off mode requirement of ErP compliance, you need to disable the Fast Startup function.

1. Go to Control Panel and view by large icons or small icons.

2. Click Power Options ➙ Choose what the power buttons do ➙ Change settings that are currently unavailable.

3. Clear the Turn on fast startup (recommended) option from the Shutdown settings list.

Change the ITS performance mode (for selected models)

You can adjust the acoustic and thermal performance of your computer by changing the ITS performance mode. Three choices are available:

• Best Performance (default setting): The computer works at the best system performance with normal acoustic level.

• Best Experience: The computer works at the best experience with balanced noise and better performance.

• Full Speed: All fans in the computer will run at full speed.

To change the ITS performance mode:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. Select Power ➙ Intelligent Cooling and press Enter.

3. Select Performance Mode and press Enter.

4. Set the performance mode as desired.

5. Press F10 or Fn+F10 to save the changes and exit.

Change BIOS settings before installing a new operating system

BIOS settings vary by operating system. Change the BIOS settings before installing a new operating system.

Microsoft constantly makes updates to the Windows 10 operating system. Before installing a particular Windows 10 version, check the compatibility list for the Windows version. For details, go to:

https://support.lenovo.com/us/en/solutions/windows-support

28 ThinkCentre M75n User Guide

To change the BIOS settings:

1. Restart the computer. When the logo screen is displayed, press F1 or Fn+F1.

2. From the main interface, select Security ➙ Secure Boot and press Enter.

3. Depending on the operating system to be installed, do one of the following:

• To install the Windows 10 (64-bit) and most of Linux operating system, select Enabled for Secure Boot.

• To install an operating system that does not support secure boot, select Disabled for Secure Boot.

4. Press F10 or Fn+F10 to save the changes and exit.

Update UEFI BIOS

When you install a new program, device driver, or hardware component, you might need to update UEFI BIOS. You can update the BIOS from your operating system or a flash update disc (supported only on selected models).

Download and install the latest UEFI BIOS update package by one of the following methods:

• From Lenovo Vantage: Open Lenovo Vantage to check the available update packages. If the latest UEFI BIOS update package is

available, follow the on-screen instructions to download and install the package.

• From the Lenovo Support Web site:

1. Go to

2. Download the flash BIOS update driver for the operating system version or the ISO image version

3. Print the installation instructions and follow the instructions to update the BIOS.

https://pcsupport.lenovo.com.

(used to create a flash update disc). Then, download the installation instructions for the flash BIOS update driver you have downloaded.

Recover from a BIOS update failure

1. Remove all media from the drives and turn off all connected devices.

2. Insert the BIOS update disc into the optical drive, and then turn off the computer.

3. Disconnect all power cords from electrical outlets. Then, remove any parts that impede access to the Clear CMOS /Recovery jumper.

4. Move the jumper from the standard position to the maintenance position.

5. Reconnect the power cords for the computer and the monitor to electrical outlets.

6. Turn on the computer and the monitor. When the computer beeps, the recovery process begins.

7. After the recovery process is completed, the computer will be turned off automatically.

Note: Depending on the computer model, the recovery process will take two to three minutes.

8. Disconnect all power cords from electrical outlets.

9. Move the jumper back to the standard position.

10. Reinstall all the parts that have been removed. Then, reconnect the power cords for the computer and the monitor to electrical outlets.

11. Turn on the computer and the monitor. When the logo screen is displayed, press F1 or Fn+F1.

12. To prevent data loss, ensure that BIOS settings are restored to an earlier point. For BIOS configurations, see Chapter 5 “UEFI BIOS” on page 25.

Chapter 5. UEFI BIOS 29

Clear CMOS

1. Remove all media from the drives and turn off all connected devices and the computer.

2. Disconnect all power cords from electrical outlets. Then, remove any parts that impede access to the Clear CMOS /Recovery jumper.

3. Move the jumper from the standard position to the maintenance position.

4. Reconnect the power cords for the computer and the monitor to electrical outlets.

5. Turn on the computer and the monitor. When the computer beeps, wait for approximately 10 seconds.

6. Turn off the computer by holding the power button for approximately four seconds.

7. Disconnect all power cords from electrical outlets.

8. Move the jumper back to the standard position.

9. Reinstall all the parts that have been removed. Then, reconnect the power cords for the computer and the monitor to electrical outlets.

10. Turn on the computer and the monitor. When the logo screen is displayed, press F1 or Fn+F1.

11. To prevent data loss, ensure that BIOS settings are restored to an earlier point. For BIOS configurations, see Chapter 5 “UEFI BIOS” on page 25.

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Chapter 6. Troubleshooting, diagnostics, and recovery

This chapter provides solutions to resolve computer problems. Use the basic procedure as a starting point for resolving computer problems.

Basic procedure for resolving computer problems

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

1. Check that: a. The cables for all connected devices are connected correctly and securely. b. All components have been reassembled correctly. c. All connected devices that require ac power are connected to properly grounded and working

electrical outlets.

d. All connected devices are enabled in UEFI BIOS.

2. Use an antivirus program (if any) to see if the computer has been infected by a virus. If the program detects a virus, remove the virus.

3. See Chapter 6 “Troubleshooting, diagnostics, and recovery” on page 31 to resolve the problem you are experiencing, run the diagnostic program, and recover your operating system.

4. If the problem persists, contact Lenovo. See Chapter 8 “Help and support” on page 73.

Troubleshooting

Use the troubleshooting information to find solutions to problems that have definite symptoms.

Startup problems

Problem Solution

• Ensure that the power cord is correctly connected to the rear of the computer and to a working electrical outlet.

The computer does not start up when you press the power button.

The operating system does not start up from the correct storage drive or fails to start up

• If the computer has a secondary power switch on the rear of the computer, ensure that it is switched on.

• The power indicator on the front of the computer is on.

• The computer voltage matches the voltage available at the electrical outlet for your country or region.

• Ensure that all storage drive signal cables and power cables are connected correctly.

• Ensure that the storage drive the computer starts up from is listed as the first startup device in UEFI BIOS.

• In rare cases, the storage drive with the operating system might get corrupted or damaged. In such cases, you might need to replace the storage drive.

• If the computer is installed with an Optane memory:

– Ensure that the Optane memory is not removed. – Ensure that the Optane memory is not damaged. Check the

Optane memory using diagnostic tools.

The computer beeps multiple times before the operating system starts up.

Ensure that no keys are stuck.

32 ThinkCentre M75n User Guide

Audio problems

Problem Solution

• If you are using powered external speakers that have an On/Off

control, ensure that:

– The On/Off control is set to the On position. – The speaker power cable is connected to a properly grounded,

• If your external speakers have a volume control, ensure that the

volume is not set too low.

• Click the volume icon in the Windows notification area on the

taskbar. Check the speaker and volume settings. Do not mute the speaker or set the volume at a very low level.

• If your computer has a front audio panel, ensure that the volume is

not set too low.

The audio cannot be heard on the Windows operating system.

• Ensure that your external speakers (and headphones, if used) are

connected to the correct audio connector on the computer. Most speaker cables are color-coded to match the audio connector.

Note: When external-speaker or headphone cables are connected to the audio connector, the internal speaker, if present, is disabled. In most cases, if an audio adapter is installed in one of the expansion slots, the audio function built into the system board is disabled. Therefore, you must use the audio connectors on the audio adapter.

• Ensure that the program you are running is designed for use in the

Microsoft Windows to run in DOS, the program does not use the Windows sound feature. The program must be configured to use SoundBlaster Pro or SoundBlaster emulation.

• Ensure that the audio device drivers are correctly installed.

functional ac electrical outlet.

operating system. If the program is designed

The sound does not come from the headset or headphones.

The sound comes from one of the external speakers.

Select the headset or headphones as the default audio output device in advanced sound settings.

• Ensure that the speaker cable is inserted completely into the

connector on the computer.

• Ensure that the cable that connects the left speaker to the right

speaker is securely connected.

• Ensure that the balance settings are set correctly.

1. Right-click the volume icon in the Windows notification area on the taskbar. Then, click Open Volume Mixer and select the desired speaker.

2. Click the speaker icon on top of the volume control, and then click the Levels tab.

Network problems

Note: The Wi-Fi® and Bluetooth features are optional.

Chapter 6. Troubleshooting, diagnostics, and recovery 33

Problem Solution

• Connect the cable from the Ethernet connector to the RJ45 connector of the hub.

• Enable the Ethernet LAN feature in UEFI BIOS.

• Enable the Ethernet LAN adapter.

1. Go to Control Panel and view by large icons or small icons.

2. Click Network and Sharing Center ➙ Change adapter

The computer cannot connect to an Ethernet LAN.

When a Gigabit Ethernet model computer is used at a speed of 1000 Mbps, the Ethernet LAN connection fails or errors occur.

The Wake On LAN (WOL) feature does not work.

3. Right-click the Ethernet LAN adapter icon and click Enable.

• Update or reinstall the Ethernet LAN driver.

• Install all networking software that is necessary for your network environment. Check with your LAN administrator for the necessary networking software.

• Set the same duplex for the switch port and the adapter. If you configured the adapter for full duplex, ensure that the switch port is also configured for full duplex. Setting a wrong duplex mode might degrade performance, cause data loss, or result in lost connections.

Connect the network cable to the Ethernet connector using Category 5 wiring and a 100 BASE-T hub/switch (not 100 BASE-X).

Enable the Wake On LAN feature in UEFI BIOS.

settings.

The Wi-Fi feature does not work.

• Enable the Wi-Fi feature in UEFI BIOS.

• Enable all Wi-Fi devices.

1. Right-click the Start button to open the Start context menu.

2. Click Device Manager. Type the administrator password or provide confirmation, if prompted.

3. Expand Network adapters to display all network devices.

4. Right-click each Wi-Fi device, and then click Enable device.

• Enable the Wi-Fi feature in Windows Settings.

1. Open the Start menu.

2. Click Settings ➙ Network & Internet ➙ Wi-Fi.

3. Enable the Wi-Fi feature.

• Update or reinstall the Wi-Fi driver.

34 ThinkCentre M75n User Guide

Problem Solution

• Enable the Bluetooth feature in UEFI BIOS.

• Enable all Bluetooth devices.

1. Right-click the Start button to open the Start context menu.

2. Click Device Manager. Type the administrator password or

3. Expand Bluetooth to display all Bluetooth devices. Right-click

The Bluetooth feature does not work.

4. Expand Network adapters to display all network devices.

• Turn on the Bluetooth radio.

1. Open the Start menu.

2. Click Settings ➙ Devices ➙ Bluetooth & other devices.

3. Turn on the Bluetooth switch to enable the Bluetooth feature.

• Update or reinstall the Bluetooth driver.

provide confirmation if prompted.

each Bluetooth device, and then click Enable device.

Right-click each Bluetooth device, and then click Enable device.

Sound does not come from the Bluetooth headset or headphones.

Select the Bluetooth headset or headphones as the default audio output device in advanced sound settings.

Chapter 6. Troubleshooting, diagnostics, and recovery 35

Performance problems

Problem Solution

Note: Depending on the volume of the storage drives and amount of

data stored on the storage drives, the disk-defragmentation process might take up to several hours.

1. Close any open programs and windows.

2. Open the Start menu. Excessive fragmented files exist on the storage drives.

The free storage drive space is insufficient.

3. Click Windows System ➙ File Explorer ➙ This PC.

4. Right-click your C drive and then click Properties.

5. Click the Tools tab.

6. Click Optimize. Select the drive as desired, and then click

7. Follow the on-screen instructions.

• Clean out your Inbox, Sent Items, and Deleted Items folders from your e-mail application.

• Clean up your C drive.

1. Open the Start menu.

2. Click Windows System ➙ File Explorer ➙ This PC.

3. Right-click your C drive and then click Properties.

4. Check the amount of free space, and then click Disk Cleanup.

5. A list of unnecessary file categories is displayed. Select the

• Disable some Windows features or remove some unnecessary programs.

1. Go to Control Panel and view by large icons or small icons.

2. Click Programs and Features.

3. Do one of the following:

Optimize.

category you want to delete, and then click OK.

– To disable some Windows features, click Turn Windows

features on or off. Follow the on-screen instructions.

– To remove some unnecessary programs, select the

program you want to remove, and then click Uninstall/ Change or Uninstall.

The free memory space is insufficient.

36 ThinkCentre M75n User Guide

• Right-click a blank area on the taskbar and open Task Manager. Then, end some tasks you are not performing.

• Install additional memory modules.

Storage drive problems

Problem Solution

• Ensure that the signal cables and power cables for all the storage

drives are connected correctly.

• Ensure that the computer is configured correctly to support the

storage drives. Some or all storage drives are missing from the BIOS menu.

– If the computer is installed with SATA storage drives, ensure

– If the computer is installed with SAS storage drives, ensure that

Serial connector problems

Problem Solution

• Connect the serial cable from the serial connector on the computer to the serial device. If the serial device has its own power cord, connect the power cord to a grounded electrical outlet.

• Turn on the serial device and keep the device online.

The serial connector cannot be accessed.

• Install any programs supplied with the serial device. Refer to the documentation that comes with the serial device for more information.

• If you added one serial-connector adapter, ensure that the adapter is installed correctly.

that the SATA storage drive enablement module (one to five storage drives) is installed.

the SAS storage drive enablement module (one to five storage drives) or the LSI MegaRAID SAS adapter is installed.

USB device problems

Problem Solution

• Connect the USB cable from the USB connector to the USB device. If the USB device has its own power cord, connect the power cord to a grounded electrical outlet.

• Turn on the USB device and keep the device online.

A USB device cannot be accessed.

• Install any device drivers or programs supplied with the USB device. Refer to the documentation that comes with the USB device for more information.

• Disconnect and reconnect the USB connector to reset the USB device.

• Ensure that the Smart USB Protection function is disabled in UEFI BIOS.

Chapter 6. Troubleshooting, diagnostics, and recovery 37

Software problems

Problem Solution

1. Check whether the problem is caused by a program. a. Ensure that the software is compatible with the computer.

Refer to the information supplied with the software for more

information. b. Verify that other software works correctly on the computer. c. Verify that the software you are using works on another

Some programs do not work as expected.

computer.

2. If the problem is caused by a program:

• Refer to the printed documentation that comes with the

program or the help system of the program.

• Update the program.

• Uninstall the program and then reinstall it. To download a

program that is preinstalled on your computer, go to

pcsupport.lenovo.com

Lenovo diagnostic tools

For information about Lenovo diagnostic tools, go to:

https://pcsupport.lenovo.com/lenovodiagnosticsolutions

https://

and follow the on-screen instructions.

Recovery

This section introduces the recovery information of the Windows 10 operating system. Ensure that you read and follow the on-screen recovery instructions. The data on your computer might be deleted during the recovery process. To avoid data loss, make a backup copy of all the data that you want to keep.

Restore system files and settings to an earlier point

1. Go to Control Panel and view by large icons or small icons.

2. Click Recovery ➙ Open System Restore. Then, follow the on-screen instructions.

Restore your files from a backup

Note: If you use the File History tool to restore your files from a backup, ensure that you backed up your

data earlier with the tool.

1. Go to Control Panel and view by large icons or small icons.

2. Click File History ➙ Restore personal files. Then, follow the on-screen instructions.

Reset your computer

In the resetting process, you can choose to keep your files or remove them when you reinstall the operating system.

Note: The items in the graphical user interface (GUI) 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 on-screen instructions to reset your computer.

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Use advanced options

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 preferred option, and then follow the on-screen instructions.

Windows automatic recovery

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

The Windows recovery environment on your computer operates independently from the Windows 10 operating system. It 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 on-screen instructions.

Create and use a recovery USB device

It is recommended that you create a recovery USB drive as early as possible 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. If you did not create a recovery USB drive as a precautionary measure, you can contact Lenovo Customer Support Center and purchase one from Lenovo. For a list of the Lenovo Support phone numbers for your country or region, go to:

https://pcsupport.lenovo.com/supportphonelist

Create a recovery USB drive 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.

1. Ensure that your computer is connected to ac power.

2. Prepare a USB drive with capacity of at least 16 GB. The actual USB capacity required depends on the size of the recovery image.

3. Connect the prepared USB drive to the computer.

4. Type recovery in the search box. Then, click Create a recovery drive.

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

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

Use the recovery USB drive

If your computer cannot be started, go to Chapter 8 “Help and support” on page 73 first to try to solve the problem by yourself. If the problem persists, use the recovery USB drive to recover your computer.

1. Ensure that your computer is connected to ac power.

2. Connect the recovery USB drive to the computer.

3. Turn on or restart the computer. When the logo screen is displayed, press F12. The Boot Menu window opens.

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

5. Click Troubleshoot to display optional recovery solutions.

6. Select a recovery solution as desired. Then, follow the on-screen instructions to complete the process.

Chapter 6. Troubleshooting, diagnostics, and recovery 39

Update the device driver

Attention: Reinstalling device drivers will change the current configuration of the computer.

You should download the latest driver for a component when you notice poor performance from that component or when you added a component. This action might eliminate the driver as the potential cause of a problem. Download and install the latest driver by one of the following methods:

• From Lenovo Vantage: Open Lenovo Vantage to check the available update packages. If the latest UEFI BIOS update package is

available, follow the on-screen instructions to download and install the package.

• From the Lenovo Support Web site: Go to

https://pcsupport.lenovo.com and select the entry for your computer. Then, follow the on-screen

instructions to download and install necessary drivers and software.

• From Windows Update:

Note: The device drivers provided by Windows Update might not be tested by Lenovo. It is recommended that you get device drivers from Lenovo.

1. Open the Start menu.

2. Click Settings ➙ Update & Security ➙ Windows Update.

3. Follow the on-screen instructions.

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Chapter 7. CRU replacement

What are CRUs

Customer Replaceable Units (CRUs) are parts that can be upgraded or replaced by the customer. Lenovo computers contain the following types of CRUs:

• 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.

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 might be required to return the defective part that is replaced by the 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. For full details, see the Lenovo Limited Warranty documentation at:

https://www.lenovo.com/warranty/llw_02

Refer to the following CRU list for your computer.

Self-service CRUs

• Bottom cover

• DIN rail bracket kit*

• I/O box* (for fanless models)

• Keyboard*

• M.2 solid-state drive

• Mouse*

• Power adapter*

• Power adapter bracket kit*

• Power cord*

• Rear Wi-Fi antenna*

• VESA mount bracket kit*

Optional-service CRUs

• Heat sink cover* (for fanless models)

• Wi-Fi card*

* for selected models

Replace a CRU (for fan models)

Follow the replacement procedure to replace a CRU.

Power adapter and power cord

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the power adapter.

4. Remove the power cord.

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5. Install the power cord.

6. Install the power adapter.

7. Reconnect the external cables to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

DIN rail bracket kit

Note: The DIN rail bracket kit is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

Chapter 7. CRU replacement 43

3. Remove the computer with the DIN rail bracket from the rail.

4. Turn over the computer so that the bottom cover is facing up. Then, remove the DIN rail bracket.

5. Install the DIN rail bracket.

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6. If you have not installed the rail, install it to a place where you want to mount the computer.

7. Install the computer with the DIN rail bracket to the rail.

8. Reconnect the external cables to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Power adapter bracket kit

Note: The power adapter bracket kit is available only on some models.

Chapter 7. CRU replacement 45

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the screw that secures the power adapter bracket to the wall mount bracket.

4. Remove the power adapter bracket from the wall mount bracket.

5. Remove the power cord from the power adapter. See “Power adapter and power cord” on page 42.

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6. Remove the power adapter from the power adapter bracket.

7. Turn over the computer so that the bottom cover is facing up.

8. Remove the power adapter bracket from the computer.

9. Install the power adapter bracket to the computer.

10. Turn over the computer so that the bottom cover is facing down.

Chapter 7. CRU replacement 47

11. Install the power adapter into the power adapter bracket.

12. Install the power cord to the power adapter. See “Power adapter and power cord” on page 42.

13. Install the power adapter bracket to the wall mount bracket.

14. Install the screw to secure the power adapter bracket to the wall mount bracket.

15. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

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VESA mount bracket kit

Note: The VESA mount bracket kit is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the screw that secures the VESA mount bracket.

4. Remove the VESA mount bracket from the wall mount bracket.

5. Turn over the computer so that the bottom cover is facing up.

6. Remove the VESA mount bracket from the computer.

Chapter 7. CRU replacement 49

7. Install the VESA mount bracket to the computer.

8. Install the VESA mount bracket to the wall mount bracket.

9. Install the screw to secure the VESA mount bracket to the wall mount bracket.

10. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Rear Wi-Fi antenna

Note: The rear Wi-Fi antenna is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

ThinkCentre M75n User Guide

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the rear Wi-Fi antenna.

4. Install the rear Wi-Fi antenna.

5. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Bottom cover

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Chapter 7. CRU replacement 51

Before you open the bottom cover, turn off the computer and wait several minutes until the computer is cool.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Unlock any locking device that secures the computer cover.

4. Remove the bracket, if any. See “DIN rail bracket kit” on page 43, “Power adapter bracket kit” on page 45, or “VESA mount bracket kit” on page 49.

5. Turn over the computer so that the bottom cover is facing up.

6. Remove the bottom cover.

7. Install the bottom cover.

8. Turn over the computer so that the bottom cover is facing down.

9. Reinstall the bracket you have removed.

10. If a locking device is available, use it to lock the computer.

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11. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Wi-Fi card

Note: The Wi-Fi card and Wi-Fi antenna cables are available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Turn over the computer so that the bottom cover is facing up.

2. Remove the bottom cover. See “Bottom cover” on page 51.

3. Remove the Wi-Fi card.

4. Install the Wi-Fi card.

5. Reinstall the removed parts. Turn over the computer so that the bottom cover is facing down.

6. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Chapter 7. CRU replacement 53

M.2 solid-state drive

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Turn over the computer so that the bottom cover is facing up.

2. Remove the bottom cover. See “Bottom cover” on page 51.

3. Remove an M.2 solid-state drive.

Note: A thermal pad might cover the M.2 solid-state drive. To access the M.2 solid-state drive, peel off the thermal pad first.

4. Install an M.2 solid-state drive. For more information about the corresponding slot for the M.2 solid-state drive, see “System board” on page 5. Cover the M.2 solid-state drive with a thermal pad if you have removed one.

5. Reinstall the removed parts. Turn over the computer so that the bottom cover is facing down.

6. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

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Replace a CRU (for fanless models)

Follow the replacement procedure to replace a CRU.

Power adapter and power cord

Note: The power adapter and power cord are available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Avoid contact with the hot computer. During operation, the computer becomes hot enough to burn the skin. Before you touch the computer, turn off the computer, disconnect power, and wait approximately 30 minutes for the computer to cool.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the power adapter.

Chapter 7. CRU replacement 55

4. Remove the power cord.

5. Install the power cord.

6. Install the power adapter.

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7. Reconnect the external cables to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Heat sink cover

Note: The heat sink cover is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the heat sink cover.

4. Install the heat sink cover.

5. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Chapter 7. CRU replacement 57

DIN rail bracket kit

Note: The DIN rail bracket kit is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the computer with the DIN rail bracket from the rail.

4. Remove the heat sink cover, if any. See “Heat sink cover” on page 57.

5. Turn over the computer so that the bottom cover is facing up. Then, remove the DIN rail bracket.

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6. Install the DIN rail bracket.

7. Reinstall all removed parts.

8. If you have not installed the rail, install it to a place where you want to mount the computer.

Chapter 7. CRU replacement 59

9. Install the computer with the DIN rail bracket to the rail.

10. Reconnect the external cables to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Power adapter bracket kit

Note: The power adapter bracket kit is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the heat sink cover, if any. See “Heat sink cover” on page 57.

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4. Remove the screw that secures the power adapter bracket to the wall mount bracket.

5. Remove the power adapter bracket from the wall mount bracket.

6. Remove the power cord from the power adapter. See “Power adapter and power cord” on page 55.

7. Remove the power adapter from the power adapter bracket.

8. Turn over the computer so that the bottom cover is facing up.

Chapter 7. CRU replacement 61

9. Remove the power adapter bracket from the computer.

10. Install the power adapter bracket to the computer.

11. Turn over the computer so that the bottom cover is facing down.

12. Install the power adapter into the power adapter bracket.

13. Install the power cord to the power adapter. See “Power adapter and power cord” on page 55.

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14. Install the power adapter bracket to the wall mount bracket.

15. Install the screw to secure the power adapter bracket to the wall mount bracket.

16. Reinstall all removed parts, if any.

17. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

VESA mount bracket kit

Note: The VESA mount bracket kit is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

Chapter 7. CRU replacement 63

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Remove the heat sink cover, if any. See “Heat sink cover” on page 57.

4. Remove the screw that secures the VESA mount bracket.

5. Remove the VESA mount bracket from the wall mount bracket.

6. Turn over the computer so that the bottom cover is facing up.

7. Remove the VESA mount bracket from the computer.

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8. Install the VESA mount bracket to the computer.

9. Install the VESA mount bracket to the wall mount bracket.

10. Install the screw to secure the VESA mount bracket to the wall mount bracket.

11. Reinstall all removed parts, if any.

12. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

I/O box

Notes:

• The I/O box is available only on some models.

Chapter 7. CRU replacement 65

• After you install the I/O box to the computer, you can still mount the I/O box and the computer together to the wall by using a matched DIN rail bracket kit or a VESA mount bracket kit. For details, see “DIN rail bracket kit” on page 58 or “VESA mount bracket kit” on page 63.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer and the I/O box.

3. Remove the heat sink cover, if any. See “Heat sink cover” on page 57.

4. Turn over the computer and the I/O box together so that the I/O box is on top.

5. Loosen the two screws that secure the USB-C adapter to the I/O box to remove the USB-C adapter. Remove the three screws that secure the I/O box to the computer. Then, remove the I/O box.

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6. Install a new I/O box. Then, install the USB-C adapter.

7. Turn over the computer and the I/O box together so that the computer is on top.

8. Reinstall all removed parts, if any. Then, reconnect the power cord and all disconnected cables to the computer and the I/O box.

Rear Wi-Fi antenna

Note: The rear Wi-Fi antenna is available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

Chapter 7. CRU replacement 67

3. Remove the rear Wi-Fi antenna.

4. Install the rear Wi-Fi antenna.

5. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Bottom cover

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

68 ThinkCentre M75n User Guide

Replacement procedure

1. Remove any media from the drives and turn off all connected devices and the computer.

2. Disconnect the power cord from the electrical outlet and disconnect all cables from the computer.

3. Unlock any locking device that secures the computer cover.

4. Remove the bracket, if any. See “DIN rail bracket kit” on page 58, “VESA mount bracket kit” on page 63, and “Power adapter bracket kit” on page 60.

5. Turn over the computer so that the bottom cover is facing up.

6. Remove the bottom cover.

7. Install the bottom cover.

8. Turn over the computer so that the bottom cover is facing down.

9. Reinstall all removed parts, if any.

10. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

Wi-Fi card

Note: The Wi-Fi card and Wi-Fi antenna cables are available only on some models.

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Chapter 7. CRU replacement 69

Replacement procedure

1. Turn over the computer so that the bottom cover is facing up.

2. Remove the bottom cover. See “Bottom cover” on page 68.

3. Remove the Wi-Fi card.

Note: Pay attention not to get the backup washer under the Wi-Fi card lost.

4. Install the Wi-Fi card.

5. Reinstall all removed parts. Turn over the computer so that the bottom cover is facing down.

6. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

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M.2 solid-state drives

Prerequisite

Before you start, read Appendix A “Important safety information” on page 77 and print the following instructions.

Replacement procedure

1. Turn over the computer so that the bottom cover is facing up.

2. Remove the bottom cover. See “Bottom cover” on page 68.

3. Remove an M.2 solid-state drive.

Note: A thermal pad might cover the M.2 solid-state drive. To access the M.2 solid-state drive, peel off the thermal pad first.

Chapter 7. CRU replacement 71

5. Reinstall all removed parts. Turn over the computer so that the bottom cover is facing down.

6. Reconnect the external cables and power adapter to the corresponding connectors on the computer, and then reconnect the power cord to the electrical outlet.

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Chapter 8. Help and support

Self-help resources

Use the following self-help resources to learn more about the computer and troubleshoot problems.

Resources How to access?

Use Lenovo Vantage to:

• Configure device settings.

• Download and install UEFI BIOS, drivers and firmware updates.

• Secure you computer from outside threats.

• Check the computer warranty status.

• Access User Guide and helpful articles.

Product documentation:

• Safety and Warranty Guide

• Setup Guide

• This User Guide

• Regulatory Notice

Lenovo Support Web site with the latest support information of the following:

• Drivers and software

• Diagnostic solutions

• Product and service warranty

• Product and parts details

• Knowledge base and frequently asked questions

• Open the Start menu and click Lenovo Vantage.

• Use Windows Search.

Go to

https://pcsupport.lenovo.com. Then, follow the on-

screen instructions to filter out the documentation you want.

https://pcsupport.lenovo.com

• Open the Start menu and click Get Help or Tips.

Windows help information

• Use Windows Search or the Cortana assistant.

• Microsoft support Web site:

https://support.microsoft.com

personal

Call Lenovo

If you have tried to correct the problem yourself and still need help, you can call Lenovo Customer Support Center.

Before you contact Lenovo

Before contacting Lenovo, ensure that your computer is connected to a monitor, a keyboard, and a mouse. Then, prepare the following:

1. Record the problem symptoms and details:

• What is the problem? Is it continuous or intermittent?

• Any error message or error code?

• What operating system are you using? Which version?

• Which software applications were running at the time of the problem?

• Can the problem be reproduced? If so, how?

2. Record the system information:

• Product name

• Machine type and serial number The following illustration shows where to find the machine type and serial number of your computer.

Fan models

Fanless models

Lenovo Customer Support Center

During the warranty period, you can call Lenovo Customer Support Center for help.

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Telephone numbers

For a list of the Lenovo Support phone numbers for your country or region, go to:

https://pcsupport.lenovo.com/supportphonelist

Note: Phone numbers are subject to change without notice. If the number for your country or region is not provided, contact your Lenovo reseller or Lenovo marketing representative.

Services available during the warranty period

• Problem determination - Trained personnel are available to assist you with determining if you have a hardware problem and deciding what action is necessary to fix the problem.

• Lenovo hardware repair - If the problem is determined to be caused by Lenovo hardware under warranty, trained service personnel are available to provide the applicable level of service.

• Engineering change management - Occasionally, there might be changes that are required after a product has been sold. Lenovo or your reseller, if authorized by Lenovo, will make selected Engineering Changes (ECs) that apply to your hardware available.

Services not covered

• Replacement or use of parts not manufactured for or by Lenovo or nonwarranted parts

• Identification of software problem sources

• Configuration of UEFI BIOS as part of an installation or upgrade

• Changes, modifications, or upgrades to device drivers

• Installation and maintenance of network operating systems (NOS)

• Installation and maintenance of programs

For the terms and conditions of the Lenovo Limited Warranty that apply to your Lenovo hardware product, see “Warranty information” in the Safety and Warranty Guide that comes with your computer.

Purchase additional services

During and after the warranty period, you can purchase additional services from Lenovo at:

https://www.lenovo.com/services

Service availability and service name might vary by country or region.

Chapter 8. Help and support 75

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Appendix A. Important safety information

Safety notices

This information can help you safely use your computer. Follow and retain all information included with your computer. The information in this document does not alter the terms of your purchase agreement or the Limited Warranty. For more information, see "Warranty Information" in the Safety and Warranty Guide that comes with your computer.

Customer safety is important. Our products are developed to be safe and effective. However, personal computers are electronic devices. Power cords, power adapters, and other features can create potential safety risks that can result in physical injury or property damage, especially if misused. To reduce these risks, follow the instructions included with your product, observe all warnings on the product and in the operating instructions, and review the information included in this document carefully. By carefully following the information contained in this document and provided with your product, you can help protect yourself from hazards and create a safer computer work environment. If the computer is used in a manner not specified by the manufacturer, the protection provided by the computer may be impaired.

Note: This information includes references to power adapters and batteries. In addition, some products (such as speakers and monitors) ship with external power adapters. If you have such a product, this information applies to your product. In addition, computer products contain a coin-sized internal battery that provides power to the system clock even when the computer is unplugged, so the battery safety information applies to all computer products.

Conditions that require immediate action

Products can become damaged due to misuse or neglect. Some product damage is serious enough that the product should not be used again until it has been inspected and, if necessary, repaired by an authorized servicer.

As with any electronic device, pay close attention to the product when it is turned on.

On very rare occasions, you might notice an odor or see a puff of smoke or sparks vent from your product. You might also hear sounds like popping, cracking, or hissing. These might merely mean that an internal electronic component has failed in a safe and controlled manner. Or, they might indicate a potential safety issue. Do not take risks or attempt to diagnose the situation yourself. Contact the Customer Support Center for further guidance. For a list of Service and Support phone numbers, see the following Web site:

https://pcsupport.lenovo.com/supportphonelist

Frequently inspect your computer and its components for damage, wear, or signs of danger. If you have any question about the condition of a component, do not use the product. Contact the Customer Support Center or the product manufacturer for instructions on how to inspect the product and have it repaired, if necessary.

In the unlikely event that you notice any of the following conditions, or if you have any safety concerns with your product, stop using the product and unplug it from the power source and telecommunication lines until you can speak to the Customer Support Center for further guidance.

• Power cords, plugs, power adapters, extension cords, surge protectors, or power supplies that are cracked, broken, or damaged.

• Signs of overheating, smoke, sparks, or fire.

• Damage to a battery (such as cracks, dents, or creases), discharge from a battery, or a buildup of foreign substances on the battery.

• A cracking, hissing, or popping sound, or strong odor that comes from the product.

• Signs that liquid has been spilled or an object has fallen onto the computer product, the power cord, or power adapter.

• The computer product, power cord, or power adapter has been exposed to water.

• The product has been dropped or damaged in any way.

• The product does not operate normally when you follow the operating instructions.

Note: If you notice these conditions with a product (such as an extension cord) that is not manufactured for or by Lenovo, stop using that product until you can contact the product manufacturer for further instructions, or until you get a suitable replacement.

Service and upgrades

Do not attempt to service a product yourself unless instructed to do so by the Customer Support Center or your documentation. Only use a Service Provider who is approved to repair your particular product.

Note: Some computer parts can be upgraded or replaced by the customer. Upgrades typically are referred to as options. Replacement parts approved for customer installation are referred to as Customer Replaceable Units, or CRUs. Lenovo provides documentation with instructions when it is appropriate for customers to install options or replace CRUs. You must closely follow all instructions when installing or replacing parts. The Off state of a power indicator does not necessarily mean that voltage levels inside a product are zero. Before you remove the covers from a product equipped with a power cord, always ensure that the power is turned off and that the product is unplugged from any power source. If you have any questions or concerns, contact the Customer Support Center.

Although there are no moving parts in the computer after the power cord has been disconnected, the following warnings are required for your safety.

Moving Parts:

Keep fingers and other parts of your body away from hazardous, moving parts. If you suffer an injury, seek medical care immediately.

Hot Surface:

Avoid contact with hot components inside the computer. During operation, some components become hot enough to burn the skin. Before you open the computer cover, turn off the computer, disconnect power, and wait approximately 10 minutes for the components to cool.

After replacing a CRU, reinstall all protective covers, including the computer cover, before connecting power and operating the computer. This action is important to help prevent unexpected electrical shock and help ensure the containment of an unexpected fire that could happen under extremely rare conditions.

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Sharp Edges:

When replacing CRUs, be cautious of sharp edges or corners that might cause injury. If you suffer an injury, seek medical care immediately.

Power cords and power adapters

DANGER

Use only the power cords and power adapters supplied by the product manufacturer.

The power cords shall be safety approved. For Germany, it shall be H03VV-F, 3G, 0.75 mm better. For other countries, the suitable types shall be used accordingly.

Never wrap a power cord around a power adapter or other object. Doing so can stress the cord in ways that can cause the cord to fray, crack, or crimp. This can present a safety hazard.

Always route power cords so that they will not be walked on, tripped over, or pinched by objects.

Protect power cords and power adapters from liquids. For instance, do not leave your power cord or power adapter near sinks, tubs, toilets, or on floors that are cleaned with liquid cleansers. Liquids can cause a short circuit, particularly if the power cord or power adapter has been stressed by misuse. Liquids also can cause gradual corrosion of power cord terminals and/or the connector terminals on a power adapter, which can eventually result in overheating.

Ensure that all power cord connectors are securely and completely plugged into receptacles.

Do not use any power adapter that shows corrosion at the ac input pins or shows signs of overheating (such as deformed plastic) at the ac input pins or anywhere on the power adapter.

Do not use any power cords where the electrical contacts on either end show signs of corrosion or overheating or where the power cord appears to have been damaged in any way.

To prevent possible overheating, do not cover the power adapter with clothing or other objects when the power adapter is plugged into an electrical outlet.

, or

Power cord notice

Note: The power cord and adapter provided with this product are intended to be used with this product

only. Do not use them with any other products.

For your safety, Lenovo provides a power cord with a grounded attachment plug to use with this product. To avoid electrical shock, always use the power cord and plug with a properly grounded outlet.

Power cords provided by Lenovo in the United States and Canada are listed by Underwriter’s Laboratories (UL) and certified by the Canadian Standards Association (CSA).

Appendix A. Important safety information 79

For units intended to be operated at 115 volts: Use a UL-listed and CSA-certified cord set consisting of a minimum 18 AWG, Type SVT or SJT, three-conductor cord, a maximum of 15 feet in length and a parallel blade, grounding-type attachment plug rated 10 amperes, 125 volts.

For units intended to be operated at 230 volts (U.S. use): Use a UL-listed and CSA-certified cord set consisting of a minimum 18 AWG, Type SVT or SJT, three-conductor cord, a maximum of 15 feet in length and a tandem blade, grounding-type attachment plug rated 10 amperes, 250 volts.

For units intended to be operated at 230 volts (outside the U.S.): Use a cord set with a grounding-type attachment plug. The cord set should have the appropriate safety approvals for the country in which the equipment will be installed.

Power cords provided by Lenovo for a specific country or region are usually available only in that country or region.

For units intended to be operated in Germany: The power cords must be safety approved. For Germany, it must be H05VV-F, 3G, 0.75 mm2, or better. For other countries, the suitable types must be used accordingly.

For units intended to be operated in Denmark: Use a cord set with a grounding-type attachment plug. The cord set should have the appropriate safety approvals for the country in which the equipment will be installed.

For units intended to be operated in Norway, Sweden, Finland: Use a cord set with a two-prong attachment plug. The cord set should have the appropriate safety approvals for the country in which the equipment will be installed.

If you intend to use your PC in a country or region that is different from your ordering location, please purchase an additional Lenovo power cord for the country or region where the PC will be used. Refer to the power cord guide provided in our Web site, regions support multiple voltages, so make sure you order the appropriate power cord for the intended voltage.

https://pcsupport.lenovo.com, for details. Some countries and

Extension cords and related devices

Ensure that extension cords, surge protectors, uninterruptible power supplies, and power strips that you use are rated to handle the electrical requirements of the product. Never overload these devices. If power strips are used, the load should not exceed the power strip input rating. Consult an electrician for more information if you have questions about power loads, power requirements, and input ratings.

ThinkCentre M75n User Guide

Plugs and outlets

DANGER

If a receptacle (power outlet) that you intend to use with your computer equipment appears to be damaged or corroded, do not use the outlet until it is replaced by a qualified electrician.

Do not bend or modify the plug. If the plug is damaged, contact the manufacturer to obtain a replacement.

Do not share an electrical outlet with other home or commercial appliances that draw large amounts of electricity; otherwise, unstable voltage might damage your computer, data, or attached devices.

Some products are equipped with a three-pronged plug. This plug fits only into a grounded electrical outlet. This is a safety feature. Do not defeat this safety feature by trying to insert it into a non-grounded outlet. If you cannot insert the plug into the outlet, contact an electrician for an approved outlet adapter or to replace the outlet with one that enables this safety feature. Never overload an electrical outlet. The overall system load should not exceed 80 percent of the branch circuit rating. Consult an electrician for more information if you have questions about power loads and branch circuit ratings.

Be sure that the power outlet you are using is properly wired, easily accessible, and located close to the equipment. Do not fully extend power cords in a way that will stress the cords.

Be sure that the power outlet provides the correct voltage and current for the product you are installing.

Carefully connect and disconnect the equipment from the electrical outlet.

Power supply statement

Never remove the cover on a power supply or any part that has the following label attached.

Hazardous voltage, current, and energy levels are present inside any component that has this label attached. There are no serviceable parts inside these components. If you suspect a problem with one of these parts, contact a service technician.

External devices

CAUTION: Do not connect or disconnect any external device cables other than Universal Serial Bus (USB) and 1394 cables while the computer power is on; otherwise, you might damage your computer. To avoid possible damage to attached devices, wait at least five seconds after the computer is shut down to disconnect external devices.

Appendix A. Important safety information 81

Lithium coin-cell battery notice

DANGER

Danger of explosion if battery is incorrectly replaced.

If the coin-cell battery is not a CRU, do not attempt to replace the coin-cell battery. Replacement of the battery must be done by a Lenovo-authorized repair facility or technician.

The Lenovo-authorized repair facilities or technicians recycle Lenovo batteries according to local laws and regulations.

When replacing the lithium coin-cell battery, use only the same type or equivalent type that is recommended by the manufacturer. The battery contains lithium and can explode if not properly used, handled, or disposed of. Swallowing the lithium coin-cell battery will cause chocking or severe internal burns in just two hours and might even result in death.

Keep batteries away from children. If the lithium coin-cell battery is swallowed or placed inside any part of the body, seek medical care immediately.

Do not:

• Throw or immerse into water

• Heat to more than 100 °C (212°F)

• Repair or disassemble

• Leave in an extremely low air pressure environment

• Leave in an extremely high-temperature environment

• Crush, puncture, cut, or incinerate

Dispose of the battery as required by local ordinances or regulations.

The following statement applies to users in the state of California, U.S.A.

California Perchlorate Information: Products containing manganese dioxide lithium coin-cell batteries may contain perchlorate. Perchlorate Material - special handling may apply, see

perchlorate/

https://www.dtsc.ca.gov/hazardouswaste/

Heat and product ventilation

Computers, power adapters, and many accessories can generate heat when turned on and when batteries are charging. Always follow these basic precautions:

• Do not leave your computer, power adapter, or accessories in contact with your lap or any part of your body for an extended period when the products are functioning or when the battery is charging. Your

ThinkCentre M75n User Guide

computer, power adapter, and many accessories produce some heat during normal operation. Extended contact with the body could cause discomfort or, potentially, a skin burn.

• Do not charge the battery or operate your computer, power adapter, or accessories near flammable materials or in explosive environments.

• Ventilation slots, fans, and heat sinks are provided with the product for safety, comfort, and reliable operation. These features might inadvertently become blocked by placing the product on a bed, sofa, carpet, or other flexible surface. Never block, cover, or disable these features.

Inspect your desktop computer for dust accumulation at least once every three months. Before inspecting your computer, turn off the power and unplug the computer's power cord from the electrical outlet; then remove any dust from vents and perforations in the bezel. If you notice external dust accumulation, then examine and remove dust from the inside of the computer including heat sink inlet fins, power supply vents, and fans. Always turn off and unplug the computer before opening the cover. If possible, avoid operating your computer within two feet of high-traffic areas. If you must operate your computer in or near a high-traffic area, inspect and, if necessary, clean your computer more frequently.

For your safety and to maintain optimum computer performance, always follow these basic precautions with your desktop computer:

• Keep the cover closed whenever the computer is plugged in.

• Regularly inspect the outside of the computer for dust accumulation.

• Remove dust from vents and any perforations in the bezel. More frequent cleanings might be required for computers in dusty or high-traffic areas.

• Do not restrict or block any ventilation openings.

• Do not store or operate your computer inside furniture, as this might increase the risk of overheating.

• Airflow temperatures into the computer should not exceed 50°C (122°F) for selected models (11GW, 11GX, 11GV, 11GY, 11C0, 11GB, 11HU, 11HV, 11HW, 11HX, 11HY, 11J0, 11J1, and 11J2), or 35°C (95°F) for selected models (11BW, 11BX, 11G8, 11G9, 11BS, 11BT, 11BU, 11BV, 11G4, 11G5, 11G6, and 11G7).

• Do not install air filtration devices. They may interfere with proper cooling.

Electrical current safety information

DANGER

Electric current from power, telephone, and communication cables is hazardous.

To avoid a shock hazard:

• Do not use your computer during a lightning storm.

• Do not connect or disconnect any cables or perform installation, maintenance, or reconfiguration of this product during an electrical storm.

• Connect all power cords to a properly wired and grounded electrical outlet.

• Connect properly wired outlets to any equipment that will be attached to this product.

• Whenever possible, use one hand only to connect or disconnect signal cables.

• Never turn on any equipment when there is evidence of fire, water, or structural damage.

• Disconnect the attached power cords, battery, and all the cables before you open the device covers, unless instructed otherwise in the installation and configuration procedures.

• Do not use your computer until all internal parts enclosures are fastened into place. Never use the computer when internal parts and circuits are exposed.

Appendix A. Important safety information 83

DANGER

Connect and disconnect cables as described in the following procedures when installing, moving, or opening covers on this product or attached devices.

To connect:

1. Turn everything OFF.

2. First, attach all cables to devices.

3. Attach signal cables to connectors.

4. Attach power cords to outlets.

5. Turn devices ON.

The power cord must be disconnected from the wall outlet or receptacle before installing all other electrical cables connected to the computer.

The power cord may be reconnected to the wall outlet or receptacle only after all other electrical cables have been connected to the computer.

DANGER

During electrical storms, do not perform any replacement and do not connect the telephone cable to or disconnect it from the telephone outlet on the wall.

To disconnect:

1. Turn everything OFF.

2. First, remove power cords from outlets.

3. Remove signal cables from connectors.

4. Remove all cables from devices.

Liquid crystal display (LCD) notice

DANGER

To avoid shock hazards:

• Do not remove the covers.

• Do not operate this product unless the stand is attached.

• Do not connect or disconnect this product during an electrical storm.

• The power cord plug must be connected to a properly wired and grounded power outlet.

• Any equipment to which this product will be attached must also be connected to properly wired and grounded power outlets.

• To isolate the monitor from the electrical supply, you must remove the plug from the power outlet. The power outlet should be easily accessible.

Handling:

• If your monitor weighs more than 18 kg (39.68 lb), we recommend that it be moved or lifted by two people.

Product disposal (TFT monitors):

• The fluorescent lamp in the liquid crystal display contains mercury; dispose according to local, state, or federal laws.

ThinkCentre M75n User Guide

Battery warnings:

• Risk of explosion if battery is replaced by an incorrect type.

• Dispose of used batteries according to the instructions.

Use earphones, headphones, or a headset

• If your computer has both a headphone connector and an audio line-out connector, always use the headphone connector for earphones, headphones, or a headset. However, the headphone connector does not support the microphone of the headset.

• If your computer has both a headset connector and an audio line-out connector, always use the headset connector for earphones, headphones, or a headset.

Excessive sound pressure from earphones and headphones can cause hearing loss. Adjustment of the equalizer to maximum increases the earphone and headphone output voltage and the sound pressure level. Therefore, to protect your hearing, adjust the equalizer to an appropriate level.

Excessive use of headphones or earphones for a long period of time at high volume can be dangerous if the output of the headphone or earphone connectors do not comply with specifications of EN 50332-2. The headphone output connector of your computer complies with EN 50332-2 Sub clause 7. This specification limits the computer’s maximum wide band true RMS output voltage to 150 mV. To help protect against hearing loss, ensure that the headphones or earphones you use also comply with EN 50332-2 (Clause 7 Limits) or a wide band characteristic voltage of 75 mV. Using headphones that do not comply with EN 503322 can be dangerous due to excessive sound pressure levels.

If your Lenovo computer came with headphones or earphones in the package, as a set, the combination of the headphones or earphones and the computer already complies with the specifications of EN 50332-1. If different headphones or earphones are used, ensure that they comply with EN 50332-1 (Clause 6.5 Limitation Values). Using headphones that do not comply with EN 50332-1 can be dangerous due to excessive sound pressure levels.

Choking hazard notice

CHOKING HAZARD – Product contains small parts.

Keep away from children under three years.

Plastic bag notice

DANGER

Plastic bags can be dangerous. Keep plastic bags away from babies and children to avoid danger of suffocation.

Appendix A. Important safety information 85

Glass parts notice

CAUTION: Some parts of your product may be made of glass. This glass could break if the product is dropped on a hard surface or receives a substantial impact. If glass breaks, do not touch or attempt to remove it. Stop using your product until the glass is replaced by trained service personnel.

Computer placement notices

Inappropriate computer placement might cause harm to children.

• Place the computer on a sturdy piece of low-rise furniture or furniture that has been anchored.

• Do not place the computer at the edge of the furniture.

• Keep the computer cables out of the reach of children.

• Some items, such as toys, might attract children. Keep such items away from the computer.

Supervise children in rooms where the above safety instructions cannot be fully implemented.

Hazardous energy statement

DANGER

Disconnect all power cords from electrical outlets before removing the computer cover or any part that has the above label attached.

DO NOT disassemble components that have the above label attached. There are no serviceable parts inside these components.

Your product is designed for safe use. However, hazardous voltage, current, and energy levels are present inside any component that has this label attached. Disassembling of these components might cause fire or might even result in death. If you suspect a problem with one of these parts, contact a service technician.

CAUTION:

Bright Light, possible skin or eye damage. Disconnect power before servicing.

CAUTION:

Infrared Light, possible skin or eye damage. Disconnect power before servicing.

Eye comfort

The property of the display in combination with following notes result in reduced eye fatigue and increased comfort.

ThinkCentre M75n User Guide

For tips on how to minimize visual fatigue, please go to https://www.lenovo.com/us/en/safecomp/ to visit “Minimizing Visual Fatigue”.

Tip-over hazard prevention notice

The computer may cause harm to children if it is not located in an appropriate place. Follow the tips below to protect children from harm caused by the computer tipping over:

• Place the computers or monitors on sturdy furniture with a low base or furniture that has been anchored. Push the computers or monitors as far from the edge of the furniture as possible..

• Keep remote controls, toys, and other items that might attract children away from the computers or monitors

• Keep the computer or monitor cables out the reach of the children.

• Supervise children in rooms where these safety tips have not been followed.

CAUTION: Some parts of your product may be made of glass. This glass could break if the product is dropped on a hard surface or receives a substantial impact. If glass breaks, do not touch it or attempt to remove it. Stop using your product until the glass is replaced by trained service personnel.

Static electricity prevention

Static electricity, although harmless to you, can seriously damage computer components and options. Improper handling of static-sensitive parts can damage the part. When you unpack an option or CRU, do not open the static-protective package containing the part until the instructions direct you to install it.

When you handle options or CRUs, or perform any work inside the computer, take the following precautions to avoid static-electricity damage:

• Limit your movement. Movement can cause static electricity to build up around you.

• Always handle components carefully. Handle adapters, memory modules, and other circuit boards by the edges. Never touch exposed circuitry.

• Prevent others from touching components.

• When you install a static-sensitive option or CRU, touch the static-protective package containing the part to a metal expansion-slot cover or other unpainted metal surface on the computer for at least two seconds. This reduces static electricity in the package and your body.

• When possible, remove the static-sensitive part from the static-protective packaging and install the part without setting it down. When this is not possible, place the static-protective packaging on a smooth, level surface and place the part on it.

• Do not place the part on the computer cover or other metal surface.

Operating environment

Maximum altitude (without pressurization)

• 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)

Temperature

• Operating:

Appendix A. Important safety information 87

– From 10°C (50°F) to 50°C (122°F) for selected models (11GW, 11GX, 11GV, 11GY, 11C0, 11GB, 11HU,

11HV, 11HW, 11HX, 11HY, 11J0, 11J1, and 11J2)

– From 10°C (50°F) to 35°C (95°F) for selected models (11BW, 11BX, 11G8, 11G9, 11BS, 11BT, 11BU,

11BV, 11G4, 11G5, 11G6, and 11G7)

• 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)

Note: If your computer is stored or transported in temperatures less than 10°C (50°F), allow the computer to rise slowly to an optimal operating temperature before use. This process might take up to two hours. Using the computer in a lower operating temperature might result in irreparable damage to your computer.

Relative humidity

• Operating: 20%-80% (non-condensing)

• Storage: 20%–90% (non-condensing)

Cleaning and maintenance

With appropriate care and maintenance, your computer will serve you reliably. The following topics offer information to help you keep your computer working with best performance.

Basic maintenance tips

Here are some basic points about keeping your computer functioning properly:

• Keep the computer in a clean, dry environment. Ensure that the computer rests on a flat, steady surface.

• Do not cover any of air vents. These air vents provide airflow to keep the computer from overheating.

• Keep electrical appliances such as an electric fan, radio, high-powered speakers, air conditioner, and microwave oven away from your computer because the strong magnetic fields generated by these appliances can damage the monitor and data on the storage drive.

• Keep food and drinks away from all parts of the computer. Food particles and spills might make the keyboard and mouse stick and unusable.

• Do not get the power switches or other controls wet. Moisture can damage these parts and cause an electrical hazard.

• Always disconnect a power cord by grasping the plug instead of the cord.

• Keep the computer software, device drivers, and operating system up-to-date.

• Empty your recycle bin on a regular basis.

• Clean out your Inbox, Sent Items, and Deleted Items folders in your e-mail application on a regular basis.

• Clean up files and free up storage drive space and memory space occasionally to prevent performance problems.

• Keep a log book. Entries might include major software or hardware changes, device-driver updates, intermittent problems and what you did to resolve them, and other issues you might have experienced. The cause of a problem might be change in hardware, change in software, or any other actions that might have taken place. A log book can help you or a Lenovo technician determine the cause of a problem.

• Back up your data on the storage drive regularly. You can restore the storage drive from a backup.

• Create a recovery medium as early as possible. You can use the recovery medium to recover your operating system even if Windows fails to start up.

• Get the most up-to-date operating system update patches, software programs, and device drivers.

ThinkCentre M75n User Guide

Maintenance tips about moving the computer

Before moving the computer, take the following precautions:

1. Back up your data on the storage drive.

2. Remove any media from the drives and turn off all connected devices and the computer. Then, disconnect all power cords from electrical outlets and disconnect all cables that are connected to the computer.

3. If you saved the original shipping cartons and packing materials, use them to pack the units. If you are using different cartons, cushion the units to avoid damage.

When you move the computer to another country or region, you must take local electrical standards into consideration. If the local electrical outlet style is different from the type you are currently using, contact the Lenovo Customer Support Center to purchase either an electrical plug adapter or a new power cord.

Clean your computer

CAUTION: Remove any media from the drives and turn off all connected devices and the computer. Then, disconnect all power cords from electrical outlets and disconnect all cables that are connected to the computer.

It is a good practice to clean your computer periodically to protect the surfaces and ensure trouble-free operation.

Clean the computer surface: Wipe it with a lint-free cloth dampened in mild soap and water. Avoid applying liquids directly to the surface.

Clean the keyboard: Wipe the keys one by one with a lint-free cloth dampened in mild soap and water. If you wipe several keys at a time, the cloth might hook onto an adjacent key and possibly damage it. Avoid spraying cleaner directly onto the keyboard. To remove any crumbs or dust from beneath the keys, you can use a camera blower with a brush or use cool air from a hair dryer.

Clean the computer screen: Scratches, oil, dust, chemicals, and ultraviolet light can affect the performance of your computer screen. Use a dry, soft lint-free cloth to wipe the screen gently. If you see a scratchlike mark on your screen, it might be a stain. Wipe or dust the stain gently with a soft, dry cloth. If the stain remains, moisten a soft, lint-free cloth with water or eyeglass cleaner, but do not apply liquids directly to your computer screen. Ensure that the computer screen is dry before closing it.

Appendix A. Important safety information 89

90 ThinkCentre M75n User Guide

Appendix B. Accessibility and ergonomic information

This chapter provides information about accessibility and ergonomics.

Accessibility information

Lenovo is committed to providing users who have hearing, vision, and mobility limitations with greater access to information and technology. This section provides information about the ways these users can get the most out of their computer experience. You also can get the most up-to-date accessibility information from the following Web site:

https://www.lenovo.com/accessibility

Keyboard shortcuts

The following list contains keyboard shortcuts that can help make your computer easier to use.

Note: Depending on your keyboard, some of the following keyboard shortcuts might not be available.

• Windows logo key + U: Open Ease of Access Center

• Right Shift for eight seconds: Turn on or turn off Filter Keys

• Shift five times: Turn on or turn off Sticky Keys

• Num Lock for five seconds: Turn on or turn off Toggle Keys

• Left Alt+Left Shift+Num Lock: Turn on or turn off Mouse Keys

• Left Alt+Left Shift+PrtScn (or PrtSc): Turn on or turn off High Contrast

For more information, go to keywords: keyboard shortcuts, key combinations, shortcut keys.

Ease of Access Center

Ease of Access Center on the Windows operating system enables you to configure your computers to suit their physical and cognitive needs.

To access Ease of Access Center:

1. Go to Control Panel and view by Category.

2. Click Ease of Access ➙ Ease of Access Center.

3. Choose the appropriate tool by following the on-screen instructions.

Ease of Access Center mainly includes the following tools:

• Magnifier Magnifier is a useful utility that enlarges the entire screen or part of the screen so that you can see the

items better.

• Narrator Narrator is a screen reader that reads what is displayed on the screen aloud and describes events such as

error messages.

• On-Screen Keyboard If you prefer to type or enter data into your computer using a mouse, joystick, or other pointing device

instead of a physical keyboard, you can use On-Screen Keyboard. On-Screen Keyboard displays a visual

https://windows.microsoft.com, and then search using any of the following

keyboard with all the standard keys. You can select keys using the mouse or another pointing device, or you can tap to select the keys if your computer supports multi-touch screen.

• High Contrast High Contrast is a feature that heightens the color contrast of some text and images on your screen. As a

result, those items are more distinct and easier to identify.

• Personalized keyboard Adjust keyboard settings to make your keyboard easier to use. For example, you can use your keyboard

to control the pointer and make the keyboard easier to type certain key combinations.

• Personalized mouse Adjust mouse settings to make your mouse easier to use. For example, you can change the pointer

appearance and make your mouse easier to manage windows.

Speech Recognition

Speech Recognition enables you to control your computer by voice.

You can use verbal instructions to control the keyboard and mouse. With verbal instructions, you can start programs, open menus, click objects on the screen, dictate text into documents, and write and send e-mails.

To use Speech Recognition:

1. Go to Control Panel and view by Category.

2. Click Ease of Access ➙ Speech Recognition.

3. Follow the on-screen instructions.

Screen-reader technologies

Screen-reader technologies are primarily focused on software program interfaces, help systems, and various online documents. For additional information about screen readers, see the following:

• Use PDFs with screen readers:

https://www.adobe.com/accessibility.html?promoid=DJGVE

• Use the JAWS screen reader:

https://www.freedomscientific.com/Products/Blindness/JAWS

• Use the NVDA screen reader:

https://www.nvaccess.org/

Screen resolution

You can make the text and images on your screen easier to read by adjusting the screen resolution of your computer.

To adjust the screen resolution:

1. Right-click an empty area of the desktop and then click Display settings ➙ Display.

2. Follow the on-screen instructions.

Note: Setting a resolution too low might prevent some items from fitting on the screen.

Customizable item size

You can make the items on your screen easier to read by changing the item size.

• To change the item size temporarily, use the Magnifier tool in Ease of Access Center.

• To change the item size permanently:

ThinkCentre M75n User Guide

– Change the size of all the items on your screen.

1. Right-click an empty area of the desktop and then click Display settings ➙ Display.

2. Change the item size by following the on-screen instructions. For some applications, your configuration might not take effect until you sign out and then sign in again.

– Change the size of the items on a Web page.

Press and hold Ctrl, and then press the plus-sign key (+) to enlarge or the minus-sign key (–) to reduce the text size.

– Change the size of the items on the desktop or a window.

Note: This function might not work on some windows. If your mouse has a wheel, press and hold Ctrl, and then scroll the wheel to change the item size.

Industry-standard connectors

Your computer provides industry-standard connectors that enable you to connect assistive devices.

Documentation in accessible formats

Lenovo provides electronic documentation in accessible formats, such as properly tagged PDF files or HyperText Markup Language (HTML) files. Lenovo electronic documentation is developed to ensure that visually impaired users can read the documentation through a screen reader. Each image in the documentation also includes adequate alternative text so that visually impaired users can understand the image when they use a screen reader.

Ergonomic information

Good ergonomic practice is important to get the most from your personal computer and to avoid discomfort. Arrange your workplace and the equipment you use to suit your individual needs and the kind of work that you perform. In addition, use healthy work habits to maximize your performance and comfort when using your computer.

Working in the virtual office might mean adapting to frequent changes in your environment. Adapting to the surrounding light sources, active seating, and the placement of your computer hardware, can help you improve your performance and achieve greater comfort.

This example shows someone in a conventional setting. Even when not in such a setting, you can follow many of these tips. Develop good habits, and they will serve you well.

General posture: Make minor modifications in your working posture to deter the onset of discomfort caused by long periods of working in the same position. Frequent short breaks from your work also help to prevent minor discomfort associated with your working posture.

Appendix B. Accessibility and ergonomic information 93

Display: Position the display to maintain a comfortable viewing distance of 510 mm to 760 mm (20 inches to 30 inches). Avoid glare or reflections on the display from overhead lighting or outside sources of light. Keep the display screen clean and set the brightness to levels that enable you to see the screen clearly. Press the brightness control keys to adjust display brightness.

Head position: Keep your head and neck in a comfortable and neutral (vertical, or upright) position.

Chair: Use a chair that gives you good back support and seat height adjustment. Use chair adjustments to

best suit your comfort posture.

Arm and hand position: If available, use chair arm rests or an area on your working surface to provide weight support for your arms. Keep your forearms, wrists, and hands in a relaxed and neutral (horizontal) position. Type with a soft touch without pounding the keys.

Leg position: Keep your thighs parallel to the floor and your feet flat on the floor or on a footrest.

ThinkCentre M75n User Guide

Lenovo ThinkCentre M75n User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

About this documentation

Chapter 1. Meet your computer

Front

Rear

Bottom

System board

Features and specifications

Statement on USB transfer rate

Chapter 2. Get started with your computer

Get started with Windows 10

Windows account

Windows user interface

Connect to networks

Connect to the wired Ethernet

Connect to Wi-Fi networks (for selected models)

Use Lenovo Vantage

Use multimedia

Use audio

Connect to an external display

Use the I/O box (for selected fanless models)

Chapter 3. Explore your computer

Manage power

Set power button behaviors

Set the power plan

Transfer data

Connect to a Bluetooth-enabled device (for selected models)

Purchase accessories

Chapter 4. Secure your computer and information

Lock the computer

Log in to your computer securely

Use passwords

Use software security solutions

Use firewalls

Use antivirus programs

Use computrace Agent software embedded in firmware (for selected models)

Use BIOS security solutions

Erase all storage drive data

Use the cover presence switch

Use Smart USB Protection

Chapter 5. UEFI BIOS

What is UEFI BIOS

Enter the BIOS menu

Navigate in the BIOS interface

Change the display language of UEFI BIOS

Change the display mode of UEFI BIOS

Set the system date and time

Change the startup sequence

Enable or disable the configuration change detection feature

Enable or disable the automatic power-on feature

Enable or disable the smart power-on feature (for selected models)

Enable or disable the ErP LPS compliance mode (for selected models)

Change the ITS performance mode (for selected models)

Change BIOS settings before installing a new operating system

Update UEFI BIOS

Recover from a BIOS update failure

Clear CMOS

Chapter 6. Troubleshooting, diagnostics, and recovery

Basic procedure for resolving computer problems

Troubleshooting

Startup problems

Audio problems

Network problems

Performance problems

Storage drive problems

Serial connector problems

USB device problems

Software problems

Lenovo diagnostic tools

Recovery

Restore system files and settings to an earlier point

Restore your files from a backup

Reset your computer

Use advanced options

Windows automatic recovery

Create and use a recovery USB device

Update the device driver