Lenovo M5800 Desktop - Manual (Page 87)

Note: Position the new heat sink and fan assembly so that the heat sink and fan assembly cable is
toward the microprocessor fan connector on the system board.
9. Follow the following sequence to install the four screws to secure the new heat sink and fan assembly.
Do not over-tighten the screws.
a. Partially tighten screw 1 , then fully tighten screw 2 , and then fully tighten screw 1 .
b. Partially tighten screw 3 , then fully tighten screw 4 , and then fully tighten screw 3 .
10. Connect the heat sink and fan assembly cable to the microprocessor fan connector on the system
board. See “Locating parts on the system board” on page 65.
11. To complete the installation or replacement, go to “Completing the parts replacement” on page 102.
Replacing the power supply assembly
Attention:
Do not open your computer or attempt any repair before reading and understanding Chapter 1 “Safety information”
on page 1.
This section provides instructions on how to replace the power supply assembly.
Although there are no moving parts in your computer after the power cord has been disconnected, the
following warnings are required for your safety and proper Underwriters Laboratories (UL) certification.
CAUTION:
Hazardous moving parts. Keep fingers and other body parts away.
CAUTION:
Never remove the cover on a power supply or any part that has the following label attached.
Hazardous voltage, current, and energy levels are present inside any component that has this label
attached. There are no serviceable parts inside these components. If you suspect a problem with
one of these parts, contact a service technician.
To replace the power supply assembly, do the following:
1. Turn off the computer and disconnect all power cords from electrical outlets.
2. Remove the computer cover. See “Removing the computer cover” on page 69.
3. Disconnect the power supply assembly cables from all drives and from the 24-pin power connector and
4-pin power connector on the system board. See “Locating parts on the system board” on page 65.
Chapter 8 . Replacing FRUs 81