Dell Latitude D520 - Manual (Page 40)

15. Turn the computer upside down and remove the four M2 x 3-mm screws labeled "B" that secure the system board to the computer base.
16. Remove the system board assembly:
a. With the back of the computer facing you, grasp the upper-right corner of the system board assembly and lift it slightly; slowly easing the
connectors out of their access holes on the back and side of the computer base.
b. Pull the system board assembly away from you toward the front of the computer to remove the system board assembly.
1 M2.5 x 5-mm screws (2)
1 M2 x 3-mm screws labeled "B" (4)
1 system board assembly