Lenovo ThinkServer RD550 - Manual (Page 156)

19. Install the new system board into the chassis and press the system board to the rear of the server.
Ensure that:
• The new system board is engaged by the mounting stud on the chassis.
• The rear connectors on the new system board are inserted into the corresponding holes in the
rear panel.
Figure 122. Installing the system board
20. Remove the microprocessors from the old system board and install them on the new system board. See
“Installing or replacing the microprocessor” on page 107.
Note: Do not drop anything onto the microprocessor socket on the old system board while it is exposed.
The socket pins must be kept as clean as possible.
21. Use a cleaning pad to wipe the thermal grease from the heat sinks and the top of the microprocessors.
Dispose of the cleaning pad after all of the thermal grease is removed.
22. Use one of the following methods to apply appropriate amount of thermal grease to the top of the
microprocessors in the shape of a cross or a circle as shown. Using too much or too less thermal grease
can cause a thermal problem due to imperfect contact with the components.
Notes:
• Do not touch the thermal grease.
• Keep the thermal grease off the system board.
Figure 123. Applying the thermal grease to the top of the microprocessor
142 ThinkServer RD550 User Guide and Hardware Maintenance Manual