Lenovo ThinkStation 2551, Hardware Maintenance Manual, Page: 171 / 188

To replace the system board, do the following:
1. Remove all media from the drives and turn off all attached devices and the computer. Then, disconnect
all power cords from electrical outlets and disconnect all cables that are connected to the computer.
2. Open the computer cover. See “Opening the computer cover” on page 122.
3. Remove the front bezel. See “Removing and reinstalling the front bezel” on page 122.
4. Pivot the optical drive bay assembly upward to gain access to the system board. See “Accessing the
system board components and drives” on page 124.
5. Remove all memory modules and PCI cards that are currently installed. See “Installing or replacing a
memory module” on page 125 and “Installing or replacing a PCI card” on page 127.
6. Remove the heat sink and fan assembly from the failing system board. See “Replacing the heat sink and
fan assembly” on page 142.
7. Carefully take note of the location of all cable connections on the system board and disconnect all the
cables. See “Locating parts on the system board” on page 84.
8. Remove the eight screws that secure the system board.
Figure 102. Removing the eight screws that secure the system board
9. Lift the system board out of the chassis.
10. Remove the microprocessor from the failing system board and install it on the new system board. See
“Replacing the microprocessor” on page 150.
11. Install the new system board into the chassis by aligning the eight mounting studs in the chassis with the
corresponding holes in the new system board. Then, install the eight screws to secure the system board.
12. Install the heat sink and fan assembly and connect the heat sink and fan assembly cable to the new
system board. See “Replacing the heat sink and fan assembly” on page 142.
Chapter 11
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Replacing FRUs (for machine types: 3688, 3690, 3691, 3693, and 3695)
165