Lenovo ThinkCentre M90p, Maintenance Manual, Page: 88 / 112

15. Reinstall the hard disk drive. See “Replacing the hard disk drive” on page 84.
16. Reconnect the heat sink and fan assembly cable to the microprocessor fan connector on the system
board.
17. Go to “Completing the parts replacement” on page 93.
Replacing the system board
Attention
Do not open your computer or attempt any repair before reading and understanding the “Important safety information”
in the
ThinkCentre Safety and Warranty Guide that came with your computer. To obtain a copy of the ThinkCentre
Safety and Warranty Guide , go to:http://www.lenovo.com/support
This section provides instructions on how to replace the system board.
CAUTION:
The heat sink and microprocessor might be very hot. Turn off the computer and wait
three to five minutes to let the computer cool before opening the computer cover.
To replace the system board:
1. Open the computer cover. See “Opening the computer cover” on page 68.
2. Pivot the drive bay assembly upward to gain access to the system board.
3. Remove the hard disk drive. See “Replacing the hard disk drive” on page 84.
4. Remove all memory modules and PCI cards that are currently installed. See “Replacing a memory
module” on page 73 and “Replacing a PCI card” on page 74.
5. 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 70.
6. Remove the heat sink and fan assembly from the failing system board. See “Replacing the heat sink”
on page 78.
7. Carefully slide the system board so that it can be released from the four mounting studs that secure
the system board in place.
8. Lift the system board out of the chassis.
9. Remove the microprocessor from the failing system board and install it on the new system board.
See “Replacing the microprocessor” on page 79.
10. Install the new system board into the chassis by aligning the four mounting studs in the chassis with
the corresponding holes on the new system board, and then carefully slide the new system board in to
the chassis until it is secured in place by the four mounting studs.
11. Install all memory modules and adapter cards removed from the failing system board on the new
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” on page 78.
13. Reinstall the hard disk drive. See “Replacing the hard disk drive” on page 84.
14. Reconnect all remaining cables to the system board. See “Locating parts on the system board”
on page 70.
15. Go to “Completing the parts replacement” on page 93.
The failing system board must be returned with a microprocessor socket cover to protect the pins during
shipping and handling.
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ThinkCentre Hardware Maintenance Manual