Lenovo ThinkCentre M91p 4524 Hardware Maintenance Manual page 159

4. Remove the hard disk drive. See "Replacing the hard disk drive" on page 134.
5. 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.
6. 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 126.
7. Remove the heat sink and fan assembly from the failing system board. See "Replacing the heat sink and
fan assembly" on page 139.
8. 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 119.
9. Remove the eight screws that secure the system board.
Figure 89. Removing the eight screws that secure the system board
10. Lift the system board out of the chassis.
11. Remove the microprocessor from the failing system board and install it on the new system board. See
"Replacing the microprocessor" on page 147.
12. 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.
13. 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 139.
14. Install all memory modules and PCI cards removed from the failing system board on the new system
board. See "Installing or replacing a memory module" on page 125 and "Installing or replacing a PCI
card" on page 126.
15. Reconnect all remaining cables to the system board. See "Locating parts on the system board" on
page 119.
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Chapter 9 Replacing FRUs (Machine Types: 4466, 4471, 4474, 4477, 4480, 4485, 4496, 4498, 4503, 4512, 4514,
4518, 4554, 7005, 7023, 7033, 7035, 7072, 7079, and 7177.)
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