Dell XPS 15 (L502X, Early 2011) - Manual (Page 101)

System Board 101
15 Carefully ease the connectors on the system board out of the slots on the
top cover, and lift the system board off the top cover.
Replacing the System Board
1 Follow the instructions in "Before You Begin" on page 9.
2 Align the connectors on the system board with the slots on the top cover
and place the system board on the top cover.
3 Replace the six screws that secure the system board to the top cover.
4 Connect the AC-adapter cable to the connector on the system board.
1 AC-adapter connector 2 screws (6)
3 system board
2
3
1