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CAUTION: To disconnect a network cable, first unplug the cable from your computer and then unplug the cable from
the network device.
5. Remove any media card and optical disc from your computer, if applicable.
Safety precautions
The safety precautions chapter details the primary steps to be taken before performing any disassembly instructions.
Observe the following safety precautions before you perform any installation or break or fix procedures involving disassembly or
reassembly:
● Turn off the computer and all attached peripherals.
● Disconnect the computer and all attached peripherals from AC power.
● Disconnect all network cables, telephone, and telecommunications lines from the computer.
● Use an ESD field service kit when working inside any notebook to avoid electrostatic discharge (ESD) damage.
● After removing any computer component, carefully place the removed component on an anti-static mat.
● Wear shoes with non-conductive rubber soles to reduce the chance of getting electrocuted.
Standby power
Dell products with standby power must be unplugged before you open the case. Systems that incorporate standby power are
powered while turned off. The internal power enables the computer to be remotely turned on (Wake-on-LAN) and suspended into a
sleep mode and has other advanced power management features.
Unplugging, pressing, and holding the power button for 15 seconds should discharge residual power in the system board.
Bonding
Bonding is a method for connecting two or more grounding conductors to the same electrical potential. This is done by using a field
service electrostatic discharge (ESD) kit. When connecting a bonding wire, ensure that it is connected to bare metal and never to
a painted or nonmetal surface. The wrist strap should be secure and in full contact with your skin, and ensure that you remove all
jewelry such as watches, bracelets, or rings prior to bonding yourself and the equipment.
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. 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 that is 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 that are 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, and so on.
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.
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