Safety First-For You And Your Computer; Removing And Replacing The Computer Cover; Troubleshooting A Wet Computer - Dell Precision 420 User Manual

Safety First—For You and Your Computer
The procedures in this section require that you remove the cover and work inside your computer. While working inside your computer, do not
attempt to service the computer except as explained in this guide and elsewhere in Dell™ documentation. Always follow the instructions closely.
Working inside your computer is safe—if you observe the following precautions.
CAUTION FOR YOUR PERSONAL SAFETY AND PROTECTION OF THE EQUIPMENT
Before you start to work on the computer, perform the following steps in the sequence indicated:
1. Turn off the computer and all peripherals.
2. Touch an unpainted metal surface on the computer chassis, such as the metal around the card-slot openings at the back of your computer,
before touching anything inside your computer.
3. Disconnect the computer and peripherals from their electrical outlets. Doing so reduces the potential for personal injury or shock. Also
disconnect any telephone or telecommunication lines from the computer.
NOTE: Before disconnecting a peripheral from the system or removing a component from the system board, verify that the standby
power light-emitting diode (LED) on the system board has turned off. For the location of this LED, see
Board Options."
While you work, periodically touch an unpainted metal surface on the computer chassis to dissipate any static electricity that might
harm internal components.
In addition, Dell recommends that you periodically review the safety instructions in your System Information Guide.

Removing and Replacing the Computer Cover

If your computer has a desktop chassis, see
Chassis)."
If your computer has a mini tower chassis, see
Tower Chassis)."

Troubleshooting a Wet Computer

NOTE: Dell Precision WorkStation 420 systems are equipped with
problems. Make note of any LED codes you observe before contacting Dell for technical assistance.
Liquids can damage your computer. While you are not likely to submerge your computer, spills, splashes, and excessive humidity can also cause
damage. If an external device (such as a printer or an external drive) gets wet, contact the manufacturer for instructions. If your computer gets wet,
perform the following steps:
1. Turn off the system, including any attached peripherals, and disconnect all the AC power cables from their electrical outlets. Also, disconnect
any telephone or telecommunication lines from the computer.
CAUTION: Before you remove the computer cover, see
2. Remove the cover from your
3. Let the computer dry for at least 24 hours. Make sure that it is thoroughly dry before you proceed.
4. If you have a mini tower chassis, remove the accelerated graphics port (AGP) card brace according to the instructions in
Replacing the AGP Card
5. Remove all expansion cards
6. Replace the computer cover on your
on.
If the system has power, proceed to step 7. If the system does not have power, see
assistance.
7. Turn off the system, disconnect it from the electrical outlet, remove the computer cover, touch an unpainted metal surface to discharge any
static electricity, and reinstall all expansion cards that you removed in step 5.
8. If you have a mini tower chassis, replace the AGP card brace.
"Removing the Computer Cover (Desktop
"Removing the Computer Cover (Mini Tower
desktop chassis or from your
Brace."
installed in the computer except a drive controller card and video expansion card.
desktop chassis or on your
Chassis)" and
Chassis)" and
diagnostic LEDs to help provide information about possible
"Safety First—For You and Your
mini tower chassis.
mini tower chassis, reconnect the system to an electrical outlet, and turn it
"Getting
Figure 1 in "Installing System
"Replacing the Computer Cover (Desktop
"Replacing the Computer Cover (Mini
Computer."
"Removing and
Help" for instructions on obtaining technical