Grounding guidelines
Electrostatic discharge damage
Electronic components are sensitive to electrostatic discharge (ESD). Circuitry design and structure determine
the degree of sensitivity. Networks built into many integrated circuits provide some protection, but in many
cases, ESD contains enough power to alter device parameters or melt silicon junctions.
A discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or
microcircuitry. Even if the spark is neither felt nor heard, damage may have occurred.
An electronic device exposed to ESD may not be affected at all and can work perfectly throughout a normal
cycle. Or the device may function normally for a while, then degrade in the internal layers, reducing its life
expectancy.
CAUTION:
To prevent damage to the computer when you are removing or installing internal components,
observe these precautions:
Keep components in their electrostatic-safe containers until you are ready to install them.
Before touching an electronic component, discharge static electricity by using the guidelines described in this
section.
Avoid touching pins, leads, and circuitry. Handle electronic components as little as possible.
If you remove a component, place it in an electrostatic-safe container.
The following table shows how humidity affects the electrostatic voltage levels generated by different
activities.
CAUTION:
A product can be degraded by as little as 700 V.
Typical electrostatic voltage levels
Relative humidity
Event
10%
40%
55%
Walking across carpet
35,000 V
15,000 V
7,500 V
Walking across vinyl floor
12,000 V
5,000 V
3,000 V
Motions of bench worker
6,000 V
800 V
400 V
Removing DIPS from plastic tube
2,000 V
700 V
400 V
Removing DIPS from vinyl tray
11,500 V
4,000 V
2,000 V
Removing DIPS from plastic foam
14,500 V
5,000 V
3,500 V
Removing bubble pack from PCB
26,500 V
20,000 V
7,000 V
Packing PCBs in foam-lined box
21,000 V
11,000 V
5,000 V
30
Chapter 4 Removal and replacement procedures preliminary requirements
Содержание EliteBook 1040 G4
Страница 4: ...iv Safety warning notice ...
Страница 8: ...viii ...
Страница 29: ...Item Component Spare part number 1 Display panel see Display assembly on page 48 Computer major components 21 ...
Страница 35: ...Component Spare part number For use in India 914726 001 Screw kit L02258 001 Miscellaneous parts 27 ...
Страница 45: ...Reverse this procedure to install the front speakers Component replacement procedures 37 ...
Страница 57: ...Reverse this procedure to install the display assembly Component replacement procedures 49 ...
