Lenovo ThinkCentre E51 Hardware Maintenance Manual - Page 144

5. Take note of the location of all cable connections on the system board and disconnect all cables. See the system board illustration for your machine type at "Identifying parts on the system board" on page 123. 6. Remove the hard disk drive. See "Replacing the hard disk drive" on page 150. 7. Remove the screws that secure the system board to the chassis. 8. Lift the system board out of the chassis. 9. Remove the memory modules from the failing system board and install them in the same location on the new system board. 10. Disconnect the heat sink and fan assembly cable from the system board. See the system board illustration for your machine type at "Identifying parts on the system board" on page 123. 11. Rotate handle 1 to release the heat sink clamp and then disengage the clamp from the plastic retention bracket. 12. Lift the heat sink and fan assembly off the failing system board. Place the heat sink on its side so that the thermal grease does not come in contact with anything. 138 Hardware Maintenance Manual