Dell Precision 690 Guide De Référence Rapide page 26

6 Locate the three hinge tabs on the edge of the computer.
7 Grip the sides of the computer cover and pivot the cover up, using the hinges as leverage points.
8 Release the cover from the hinge tabs and set it aside in a secure location.
NOTICE:
The computer cooling system cannot function properly while the computer cover is not installed.
Do not attempt to boot the computer before reinstalling the computer cover.
26
Quick Reference Guide
1 cover latch release
2 computer cover
3 cover hinges
2
3
1