Lenovo ThinkCentre M90 Hardware Maintenance Manual page 88

5. Remove the hard disk drive from the computer to gain access to the system board. See "Replacing the
primary hard disk drive" on page 85.
6. Carefully take note of the location of all cable connections on the system board and disconnect all
cables. See "Locating parts on the system board" on page 70.
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. See "Replacing a memory module" on page 73.
10. Remove the heat sink and fan assembly from the failing system board. See "Replacing the heat sink and
fan assembly" on page 75.
11. Remove the retention module from the rear of the failing system board and install it in the same position
on the new system board.
12. Remove the microprocessor from the failing system board and install it on the new system board.
See "Replacing the microprocessor" on page 77.
13. Reinstall the heat sink and fan assembly. See "Replacing the heat sink and fan assembly" on page 75.
And connect the heat sink and fan assembly cable to the system board. See "Replacing the heat
sink and fan assembly" on page 75.
14. Install the new system board into the chassis and align the screw holes with those in the chassis. Insert
and tighten the screws that secure the system board.
15. Reinstall the hard disk drive back into position. See "Replacing the primary hard disk drive" on page 85.
16. Reconnect the power and signal cables to the hard disk drive.
17. Reconnect all remaining cables to the system board. See "Locating parts on the system board"
on page 70.
18. Go to "Completing the parts replacement" on page 98.
The failing system board must be returned with a microprocessor socket cover to protect the pins during
shipping and handling.
To install the microprocessor socket cover, do the following:
1. Release the lever securing the microprocessor retainer and open the retainer to access the
microprocessor.
2. Grasp the microprocessor on the sides and lift it straight up and out of the socket. Do not touch the
contacts on the microprocessor socket.
3. Note the orientation of the socket cover. Align the notches
the alignment keys
4. Install one side of the socket cover into the microprocessor socket as shown.
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ThinkCentre Hardware Maintenance Manual
2 of the microprocessor socket.
1 of the microprocessor socket cover with