When Working Inside Your Computer; Protecting Against Electrostatic Discharge - Dell OptiPlex SX270 User Manual

A fixed-voltage power supply — Computers with a fixed-voltage power supply do not have a voltage selection switch on the back panel and
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operate at only one voltage (see the regulatory label on the outside of the computer for its operating voltage).
An auto-sensing voltage circuit — Computers with an auto-sensing voltage circuit do not have a voltage selection switch on the back panel and
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automatically detect the correct operating voltage.
A manual voltage selection switch — Computers with a voltage selection switch on the back panel must be manually set to operate at the
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correct operating voltage.
Set the switch to the position that most closely matches the voltage used in your location.
NOTICE: To help avoid damaging a computer with a manual voltage selection switch, set the switch for the voltage that most closely matches the AC
power available in your location. For Japan, the voltage selection switch must be set to the 115-V position even though the AC power available in
Japan is 100 V. Also, ensure that your monitor and attached devices are electrically rated to operate with the AC power available in your location.
Before working inside the computer, unplug the computer to help prevent electric shock or system board damage. Certain system board components
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continue to receive power any time the computer is connected to AC power.

When Working Inside Your Computer

Before you open the computer cover, perform the following steps in the sequence indicated.
CAUTION: Do not attempt to service the computer yourself, except as explained in your online Dell™ documentation or in instructions otherwise
provided to you by Dell. Always follow installation and service instructions closely.
NOTICE: To help avoid possible damage to the system board, wait 5 seconds after turning off the computer before removing a component from the
system board or disconnecting a device from the computer.
1. Perform an orderly computer shutdown using the operating system menu.
2. Turn off your computer and any devices connected to the computer.
3. Ground yourself by touching an unpainted metal surface on the chassis, such as the metal around the card-slot openings at the back of the computer,
before touching anything inside your computer.
While you work, periodically touch an unpainted metal surface on the computer chassis to dissipate any static electricity that might harm internal
components.
4. Disconnect your computer and devices, including the monitor, from their electrical outlets. Also, disconnect any telephone or telecommunication lines
from the computer.
Doing so reduces the potential for personal injury or shock.
In addition, take note of these safety guidelines when appropriate:
When you disconnect a cable, pull on its connector or on its strain-relief loop, not on the cable itself. Some cables have a connector with locking tabs;
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if you are disconnecting this type of cable, press in on the locking tabs before disconnecting the cable. As you pull connectors apart, keep them evenly
aligned to avoid bending any connector pins. Also, before you connect a cable, ensure that both connectors are correctly oriented and aligned.
Handle components and cards with care. Do not touch the components or contacts on a card. Hold a card by its edges or by its metal mounting
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bracket. Hold a component such as a microprocessor chip by its edges, not by its pins.
CAUTION: There is a danger of a new battery exploding if it is incorrectly installed. Replace the battery only with the same or equivalent type
recommended by the manufacturer. Do not dispose of the battery along with household waste. Contact your local waste disposal agency for the
address of the nearest battery deposit site.

Protecting Against Electrostatic Discharge

Static electricity can harm delicate components inside your computer. To prevent static damage, discharge static electricity from your body before you touch
any of your computer's electronic components, such as the microprocessor. You can do so by touching an unpainted metal surface on the computer chassis.
As you continue to work inside the computer, periodically touch an unpainted metal surface to remove any static charge your body may have accumulated.
You can also take the following steps to prevent damage from electrostatic discharge (ESD):
Do not remove components from their antistatic packing material until you are ready to install the component in your computer. Just before
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unwrapping the antistatic packaging, discharge static electricity from your body.
When transporting an electrostatic sensitive component, first place it in an antistatic container or packaging.
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