Hardware Maintenance Manual

Lenovo N22–20 Touch Chromebook

Hardware Maintenance Manual

Lenovo N22–20 Touch Chromebook

First Edition (May 2016)

© Copyright Lenovo 2016.

Contents

Chapter 1. Safety information. . . . . . 1
General safety. 1
Electrical safety 1
Safety inspection guide 2
Handling devices that are sensitive to electrostatic discharge. 3
Grounding requirements 4
Safety notices (multilingual translations). 4
Chapter 2. General checkout . . . . 19
What to do first 19
Checking the ac power adapter 20
Chapter 3. Idetifying FRUs (CRUs) . 21
All FRUs (CRUs) for Lenovo N22-20 Touch Chromebook 21
Chapter 4. Removing a FRU or CRU . 25
General guidelines 25
Remove the upper case (with keyboard). 25
Remove the battery pack 27
Remove the speakers . 28
Remove the USB board . 28

Remove the WLAN & Bluetooth combo module. 29
Remove the LCD module 31
Remove the system board and the DC-in cable. 31
Disassemble the LCD module. 33
Remove the LCD bezel. 33
Remove the LCD panel 34
Remove the camera assembly or the LCD & camera cable 35
Assemble camera parts 37
Remove the hinges 38
Appendix A. Features, controls, and connectors 41
Appendix B. Lenovo part numbers for replacement FRUs 43
Appendix C. Lenovo part numbers for CRUs and miscellaneous parts. 45
Appendix D. Label locations 49
Trademarks li

Chapter 1. Safety information

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

General safety

Follow these rules to ensure general safety:

• Observe good housekeeping in the area of the machines during and after maintenance.

• When lifting any heavy object:

1. Make sure that you can stand safely without slipping.

2. Distribute the weight of the object equally between your feet.

3. Use a slow lifting force. Never move suddenly or twist when you attempt to lift.

4. Lift by standing or by pushing up with your leg muscles; this action removes the strain from the muscles in your back. Do not attempt to lift any object that weighs more than 16 kg (35 lb) or that you think is too heavy for you.

Do not perform any action that causes hazards to the customer, or that makes the equipment unsafe.

• Before you start the machine, make sure that other service technicians and the customer's personnel are not in a hazardous position.

• Place removed covers and other parts in a safe place, away from all personnel, while you are servicing the machine.

• Keep your tool case away from walk areas so that other people will not trip over it.

Do not wear loose clothing that can be trapped in the moving parts of a machine. Make sure that your sleeves are fastened or rolled up above your elbows. If your hair is long, fasten it.

• Insert the ends of your necktie or scarf inside clothing or fasten it with a non-conductive clip, about 8 centimeters (3 inches) from the end.

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

Attention: Metal objects are good electrical conductors.

• Wear safety glasses when you are hammering, drilling, soldering, cutting wire, attaching springs, using solvents, or working in any other conditions that might be hazardous to your eyes.

• After service, reinstall all safety shields, guards, labels, and ground wires. Replace any safety device that is worn or defective.

• Reinstall all covers correctly before returning the machine to the customer.

• Fan louvers on the machine help to prevent overheating of internal components. Do not obstruct fan louvers or cover them with labels or stickers.

Electrical safety

Observe the following rules when working on electrical equipment.

Important: Use only approved tools and test equipment. Some hand tools have handles covered with a soft material that does not insulate you when working with live electrical currents. Many customers have, near their equipment, rubber floor mats that contain small conductive fibers to decrease electrostatic discharges. Do not use this type of mat to protect yourself from electrical shock.

• Find the room emergency power-off (EPO) switch, disconnecting switch, or electrical outlet. If an electrical accident occurs, you can then operate the switch or unplug the power cord quickly.

Do not work alone under hazardous conditions or near equipment that has hazardous voltages.

Disconnect all power before:

– Performing a mechanical inspection

– Working near power supplies

• Removing or installing main units

• Before you start to work on the machine, unplug the power cord. If you cannot unplug it, ask the customer to power-off the wall box that supplies power to the machine, and to lock the wall box in the off position.

• If you need to work on a machine that has exposed electrical circuits, observe the following precautions:

• Ensure that another person, familiar with the power-off controls, is near you.

Attention: Another person must be there to switch off the power, if necessary.

• Use only one hand when working with powered-on electrical equipment; keep the other hand in your pocket or behind your back.

Attention: An electrical shock can occur only when there is a complete circuit. By observing the above rule, you may prevent a current from passing through your body.

– When using testers, set the controls correctly and use the approved probe leads and accessories for that tester.

• Stand on suitable rubber mats (obtained locally, if necessary) to insulate you from grounds such as metal floor strips and machine frames.

Observe the special safety precautions when you work with very high voltages; Instructions for these precautions are in the safety sections of maintenance information. Use extreme care when measuring high voltages.

• Regularly inspect and maintain your electrical hand tools for safe operational condition.

• Do not use worn or broken tools and testers.

• Never assume that power has been disconnected from a circuit. First, check that it has been powered