Electrostatic Discharge - Esd Protection; Before Working Inside Your Computer - Dell P28S Owner's Manual

E E SD protection summary
It is recommended that all field service technicians use the traditional wired ESD grounding wrist strap and protective anti-static mat at all
times when servicing Dell products. In addition, it is critical that technicians keep sensitive parts separate from all insulator parts while
performing service and that they use anti-static bags for transporting sensitive components.
Electrostatic discharge — ESD protection
ESD is a major concern when you handle electronic components, especially sensitive components such as expansion cards, processors,
memory DIMMs, and system boards. Very slight charges can damage circuits in ways that may not be obvious, such as intermittent
problems or a shortened product life span. As the industry pushes for lower power requirements and increased density, ESD protection is an
increasing concern.
Due to the increased density of semiconductors used in recent Dell products, the sensitivity to static damage is now higher than in previous
Dell products. For this reason, some previously approved methods of handling parts are no longer applicable.
Two recognized types of ESD damage are catastrophic and intermittent failures.
• Catastrophic – Catastrophic failures represent approximately 20 percent of ESD-related failures. The damage causes an immediate and
complete loss of device functionality. An example of catastrophic failure is a memory DIMM that has received a static shock and
immediately generates a "No POST/No Video" symptom with a beep code emitted for missing or nonfunctional memory.
• Intermittent – Intermittent failures represent approximately 80 percent of ESD-related failures. The high rate of intermittent failures
means that most of the time when damage occurs, it is not immediately recognizable. The DIMM receives a static shock, but the
tracing is merely weakened and does not immediately produce outward symptoms related to the damage. The weakened trace may
take weeks or months to melt, and in the meantime may cause degradation of memory integrity, intermittent memory errors, etc.
The more difficult type of damage to recognize and troubleshoot is the intermittent (also called latent or "walking wounded") failure.
Perform the following steps to prevent ESD damage:
• Use a wired ESD wrist strap that is properly grounded. The use of wireless anti-static straps is no longer allowed; they do not provide
adequate protection. Touching the chassis before handling parts does not ensure adequate ESD protection on parts with increased
sensitivity to ESD damage.
• Handle all static-sensitive components in a static-safe area. If possible, use anti-static floor pads and workbench pads.
• When unpacking a static-sensitive component from its shipping carton, do not remove the component from the anti-static packing
material until you are ready to install the component. Before unwrapping the anti-static packaging, ensure that you discharge static
electricity from your body.
• Before transporting a static-sensitive component, place it in an anti-static container or packaging.

Before working inside your computer

1 Ensure that your work surface is flat and clean to prevent the computer cover from being scratched.
2 Turn off your computer.
3 If the computer is connected to a docking device (docked), undock it.
4 Disconnect all network cables from the computer (if available).
CAUTION: If your computer has an RJ45 port, disconnect the network cable by first unplugging the cable from your
computer.
5 Disconnect your computer and all attached devices from their electrical outlets.
6 Open the display.
7 Press and hold the power button for few seconds, to ground the system board.
CAUTION: To guard against electrical shock unplug your computer from the electrical outlet before performing Step # 8.
CAUTION: To avoid electrostatic discharge, ground yourself by using a wrist grounding strap or by periodically touching an
unpainted metal surface at the same time as touching a connector on the back of the computer.
Working on your computer 5