Lenovo 3557 Personal Computer User Manual


 
Note: Carefully remove the four screws from the system board to avoid any possible damage to the
system board. The four screws cannot be removed from the heat sink.
Figure 16. Removing the heat sink
5. Carefully lift the heat sink off the system board.
Notes:
a. You might have to gently twist the heat sink to free it from the microprocessor.
b. Do not touch the thermal grease while handling the heat sink.
6. Position the new heat sink on the system board so that the four screws are aligned with the holes
on the system board.
7. Alternate tightening each screw a small and equal amount until the heat sink is secured to the system
board. Do not over-tighten the screws.
What to do next:
To work with another piece of hardware, go to the appropriate section.
To complete the installation or replacement, go to “Completing the parts replacement” on page 25
.
Replacing the internal speaker
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 internal speaker.
To replace the internal speaker, do the following:
1. Remove all media from the drives and turn off all attached devices and the computer. Then, disconnect
all power cords from electrical outlets and disconnect all cables that are connected to the computer.
2. Open the computer cover. See “Opening the computer cover” on page 12.
Chapter 2. Installing or replacing hardware 19