5. Lay the computer on its side and remove the four screws at the rear of the chassis that secure the
power supply assembly.
Figure 27. Removing the screws for the power supply assembly
6. Slide the power supply assembly to the front of the computer and then lift it out of the chassis.
7. Ensure that the new power supply assembly is the correct replacement.
8. Install the new power supply assembly into the chassis so that the screw holes in the power supply
assembly align with those in the chassis.
9. Install and tighten the four screws to secure the power supply assembly.
Note: Use only screws provided by Lenovo.
10. Reconnect the power supply assembly cables to the system board and each of the drives.
11. Secure the power supply assembly cables with the cable clips and ties in the chassis.
12. To complete the installation or replacement, go to “Completing the parts replacement” on page 113.
Replacing the heat sink and fan assembly
Attention:
Do not open your computer or attempt any repair before reading and understanding the “Important safety information”
in the ThinkCentre User Guide. To obtain a copy of the ThinkCentre User Guide, go to:
http://www.lenovo.com/ThinkCentreUserGuides
This section provides instructions on how to replace the heat sink and fan assembly.
CAUTION:
The heat sink and fan assembly might be very hot. Turn off the computer and wait three to ve
minutes to let the computer cool before removing the computer cover.
To replace the heat sink and fan assembly, do the following:
1. Turn off the computer and disconnect all power cords from electrical outlets.
Chapter 8. Replacing FRUs (Machine Types: 4468, 4473, 4476, 4479, 4495, 4497, 4499, 4504, 4513, 4517, 4524,
7021, 7032, 7034, 7049, 7052, 7053, 7073, 7136, and 7178.) 95