Dell PowerEdge 2850 - Manual (Page 9)

8. If applicable, remove the RAC card.
9. Remove the memory modules.
10. Remove the memory module cover. See Figure 1 -6 .
11. If applicable, remove the RAID key.
12. Remove the front fans.
13. Remove the heatsink(s) and microprocessor(s).
14. Raise the drive-cage retraction bar and swing it toward the front of the chassis to disengage the SCSI backplane from the system board.
15. Remove the front-fan tray:
a. Press and hold the front-fan tray release button. See Figure 1 -6 .
b. Slide the front-fan tray to the right until it stops.
c. Lift the front-fan tray from its three securing posts.
Figure 1-6. Front-Fan Tray and Memory Module Cover Removal
16. Remove the system board:
a. Pull the system-board tray riser release pin. See Figure 1 -7 .
b. While pulling the release pin, slide the system-board tray toward the front of the chassis.
c. Lift up the system-board tray and remove it from the chassis.
Figure 1-7. System Board Removal
NOTE: While removing the memory modules, record the memory module socket locations to ensure proper installation.