HP Carrier-Grade rx2800 i2 Server DC User's & Service Manual page 121

15. Remove the power supply backplane ("Removing and replacing the power supply backplane"
(page 102)).
16. Remove the rear retaining screw.
17. Loosen the two system board thumbscrews.
18. Remove the system board from the chassis by pushing it toward the front and then lifting it.
Removing and replacing the system board 121