Service Considerations; Cautions, Warnings, And Safety Precautions; Electrostatic Discharge Information - HP xw4300 Service And Technical Reference Manual

4.1

Service Considerations

The following sections discuss service considerations that should be reviewed and practiced before removing and
replacing any system components.
WARNING! When lifting or moving the workstation, do not use the front bezel as a handle or lifting point. Lifting the
workstation from the front bezel or lifting it incorrectly can cause the unit to fall and harm the user and damage the
workstation. To properly and safely lift the workstation, lift it from the bottom of the unit.
Section 4.1.1 "Cautions, Warnings, and Safety Precautions"
•
• Section 4.1.2 "Electrostatic Discharge Information"
• Section 4.1.3 "Tools and Software Requirements"
• Section 4.1.4 "Special Handling of Components"

4.1.1 Cautions, Warnings, and Safety Precautions

For your safety, you must review the
workstation. Also, review the Safety and Regulatory Guide that came with your workstation for more information.
WARNING! Avoid Burn Injuries. Some parts inside the computer will be hot. Turn off and unplug the system, then wait
approximately three to five minutes for them to cool down before opening the system access panels or touching internal
components.

4.1.2 Electrostatic Discharge Information

A sudden discharge of static electricity from your finger or other conductor can destroy static-sensitive devices or
microcircuitry. Often the spark is neither felt nor heard, but damage occurs. An electronic device exposed to electrostatic
discharge (ESD) might not appear to be affected at all and can work perfectly throughout a normal cycle. The device
can function normally for a while, but it has been degraded in the internal layers, reducing its life expectancy.
Networks built into many integrated circuits provide some protection, but in many cases, the discharge contains enough
power to alter device parameters or melt silicon junctions.
Generating Static
The following table shows that:
• Different activities generate different amounts of static electricity.
• Static electricity increases as humidity decreases.
Table 4-6 Static Electricity
Event
Walking across carpet
Walking across vinyl floor
Motions of bench worker
Removing bubble pack from PCB
Packing PCBs in foam-lined box
NOTE: 700V can degrade a product.
Preventing Electrostatic Damage to Equipment
Many electronic components are sensitive to ESD. Circuitry design and structure determine the degree of sensitivity. The
following packaging and grounding precautions are necessary to prevent damage to electric components and
accessories.
• Transport products in static-safe containers, such as tubes, bags, or boxes to avoid hand contact.
• Protect all electrostatic parts and assemblies with conductive or approved containers or packaging.
• Keep electrostatic sensitive parts in their containers until they arrive at static-free stations.
• Place items on a grounded surface before removing them from their container.
• When handling or touching a sensitive component or assembly, ground yourself by touching the chassis.
• Avoid contact with pins, leads, or circuitry.
50 Removal and Replacement Procedures
"Important Safety Warnings" on page 8
Relative Humidity
55%
7,500V
3,000V
400V
7,000V
5,000V
before accessing the components of the
40% 10%
15,000V 35,000V
5,000V 12,000V
800V 6,000V
20,000V 26,500V
11,000V 21,000V