To determine whether there are any potentially unsafe conditions, use the following checklist at the beginning
of every service task. Begin the checks with the power off, and the power cord disconnected.
Checklist:
1. Check exterior covers for damage (loose, broken, or sharp edges).
2. Power off the computer. Disconnect the power cord.
3. Check the power cord for:
a. A third-wire ground connector in good condition. Use a meter to measure third-wire ground
continuity for 0.1 ohm or less between the external ground pin and the frame ground.
b. The power cord should be the authorized type specified for your computer. Go to:
http://www.lenovo.com/serviceparts-lookup
c. Insulation must not be frayed or worn.
4. Check for cracked or bulging batteries.
5. Remove the cover.
6. Check for any obvious non-Lenovo alterations. Use good judgment as to the safety of any non-Lenovo
alterations.
7. Check inside the unit for any obvious unsafe conditions, such as metal filings, contamination, water or
other liquids, or signs of fire or smoke damage.
8. Check for worn, frayed, or pinched cables.
9. Check that the power-supply cover fasteners (screws or rivets) have not been removed or tampered with.
Handling devices that are sensitive to electrostatic discharge
Any computer part containing transistors or integrated circuits (ICs) should be considered sensitive to
electrostatic discharge (ESD). ESD damage can occur when there is a difference in charge between objects.
Protect against ESD damage by equalizing the charge so that the machine, the part, the work mat, and the
person handling the part are all at the same charge.
Notes:
1. Use product-specific ESD procedures when they exceed the requirements noted here.
2. Make sure that the ESD protective devices you use have been certified (ISO 9000) as fully effective.
When handling ESD-sensitive parts:
• Keep the parts in protective packages until they are inserted into the product.
• Avoid contact with other people.
• Wear a grounded wrist strap against your skin to eliminate static on your body.
• Prevent the part from touching your clothing. Most clothing is insulative and retains a charge even
when you are wearing a wrist strap.
• Use a grounded work mat to provide a static-free work surface. The mat is especially useful when
handling ESD-sensitive devices.
• Select a grounding system, such as those listed below, to provide protection that meets the specific
service requirement.
Note:
The use of a grounding system to guard against ESD damage is desirable but not necessary.
– Attach the ESD ground clip to any frame ground, ground braid, or green-wire ground.
– When working on a double-insulated or battery-operated system, use an ESD common ground or
reference point. You can use coax or connector-outside shells on these systems.
– Use the round ground prong of the ac plug on ac-operated computers.
Chapter 1
.
Safety information
3
Summary of Contents for N22-20
Page 1: ...Hardware Maintenance Manual Lenovo N22 20 Chromebook ...
Page 2: ......
Page 3: ...Hardware Maintenance Manual Lenovo N22 20 Chromebook ...
Page 4: ...First Edition February 2016 Copyright Lenovo 2016 ...
Page 6: ...iv Hardware Maintenance Manual ...
Page 11: ...DANGER DANGER DANGER DANGER Chapter 1 Safety information 5 ...
Page 12: ...6 Hardware Maintenance Manual ...
Page 13: ...PERIGO PERIGO PERIGO PERIGO Chapter 1 Safety information 7 ...
Page 14: ...PERIGO PERIGO PERIGO PERIGO DANGER DANGER 8 Hardware Maintenance Manual ...
Page 15: ...DANGER DANGER DANGER DANGER DANGER Chapter 1 Safety information 9 ...
Page 16: ...DANGER VORSICHT VORSICHT VORSICHT VORSICHT 10 Hardware Maintenance Manual ...
Page 17: ...VORSICHT VORSICHT VORSICHT VORSICHT Chapter 1 Safety information 11 ...
Page 18: ...12 Hardware Maintenance Manual ...
Page 19: ...Chapter 1 Safety information 13 ...
Page 20: ...14 Hardware Maintenance Manual ...
Page 21: ...Chapter 1 Safety information 15 ...
Page 22: ...16 Hardware Maintenance Manual ...
Page 23: ...Chapter 1 Safety information 17 ...
Page 24: ...18 Hardware Maintenance Manual ...
Page 46: ...40 Hardware Maintenance Manual ...
Page 48: ...42 Hardware Maintenance Manual ...
Page 54: ...48 Hardware Maintenance Manual ...
Page 56: ...50 Hardware Maintenance Manual ...
Page 58: ......
Page 59: ......
Page 60: ......
