When Using Your Computer; When Working Inside Your Computer - Dell OptiPlex 3U083 Setup And Quick Reference Manual

When Using Your Computer

As you use your computer, observe the following safe-handling guidelines.
CAUTION: Do not operate your computer with any cover(s) (including computer
covers, bezels, filler brackets, front-panel inserts, and so on) removed.
• Your computer is equipped with one of the following:
– A fixed-voltage power supply — Computers with a fixed-voltage power supply do not
have a voltage selection switch on the back panel and 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 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 correct operating voltage.
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 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.
Setup and Quick Re ference Guide
9