Replacing the system board - ThinkCentre M90 (type 3245, 3491), M90p (type 3269)
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 the Lenovo Support Website.
This section provides instructions on how to replace the system board.
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.
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.
Install all memory modules and adapter cards removed from the failing system board on the new system board.
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".