Lenovo ThinkCentre A55 8705 Hardware Replacement Manual page 21

15. Lower the microprocessor straight down into the microprocessor socket.
16. Lower the microprocessor retainer 2 and then lower the lever 1 to secure
the retainer. Make sure the lever is securely locked into position.
Note: There will be a black plastic cover on the microprocessor retainer to
protect the socket on the new system board. When you lock the
microprocessor in position, remove the black plastic cover. Place the black
plastic cover on the microprocessor retainer of the failing system board.
17. Place the heat sink into position and lower the lever to secure the heat sink.
18. To install the new system board into the chassis, tilt the front end of the
system board between the diskette drive and the fan assembly, and position it
so that the slots in the new system board are aligned with the pins on the
chassis.
Chapter 2. Replacing hardware
13