Dell Precision 5520 Owner's Manual

Before working inside your computer

1. Ensure that your work surface is flat and clean to prevent the computer cover from being scratched.
2. Turn off your computer.
3. Disconnect all network cables from the computer (if available).
   CAUTION If your computer has an RJ45 port, disconnect the network cable by first unplugging the cable from your computer.
4. Disconnect your computer and all attached devices from their electrical outlets.
5. Open the display.
6. Press and hold the power button for few seconds, to ground the system board.
   CAUTION To guard against electrical shock unplug your computer from the electrical outlet before performing Step # 8.

   CAUTION To avoid electrostatic discharge, ground yourself by using a wrist grounding strap or by periodically touching an unpainted metal surface at the same time as touching a connector on the back of the computer.
7. Remove any installed ExpressCards or Smart Cards from the appropriate slots.