System board removal and installation - ThinkStation D20 (type 4155, 4158, 4218)
The heat sink, microprocessor, and memory module might be very hot. Turn off the computer and wait three to five minutes to let the computer cool before opening the computer cover.
Attention: Do not open your computer or attempt any repair before reading and understanding the "Important safety information" in the ThinkStation Safety and Warranty Guide that came with your computer.
This section provides instructions on how to remove and install the system board.
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 following the sequence shown in the figure above.
Install the memory modules in the same location on the new system board.