Dell GX240 - OptiPlex Pentium 4 1.8GHz 512MB 40GB CD Win2K, Service Manual

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Before You Begin 11
3
Disconnect the computer and devices from their AC power sources.
Also, disconnect any telephone or telecommunication lines from the
computer. Doing so reduces the potential for personal injury or shock.
If you are disconnecting a device from the computer or are removing a
component from the system board, wait 15 to 30 seconds after
disconnecting the computer from AC power before disconnecting the
device or removing the component to avoid possible damage to the
system board.
Verify that the auxiliary power light on the system board is not on. If it
is on, you may need to wait 15 to 30 seconds for it to go out (see
" System Board Components " for the location of this light).
4
Wear a wrist grounding strap, and clip it to an unpainted metal
surface, such as the padlock ring on the back of the computer. If a wrist
grounding strap is not available, touch an unpainted metal surface on
the computer, such as the power supply, to discharge static charge from
your body before touching anything inside the computer. While you
work, periodically touch an unpainted metal surface on the computer
to dissipate static electricity that might harm internal components.
In addition, take note of the following safety guideline when appropriate:
• Handle components and cards with care. Do not touch the
components or contacts on a card. Hold a card by it edges or by its
metal mounting bracket. Hold a component such as a microprocessor
by its edges, not by its pins.