Note: Position the new heat sink and fan assembly so that the heat sink and fan assembly cable istoward 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 systemboard. See “Locating parts on the system board” on page 12.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 66.Replacing the microprocessorAttention: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 ThinkCentreSafety and Warranty Guide, go to:http://www.lenovo.com/supportThis section provides instructions on how to replace the microprocessor.CAUTION:The heat sink and microprocessor might be very hot. Turn off the computer and wait three to fiveminutes to let the computer cool before removing the computer cover.To replace the microprocessor, do the following:1. Remove all media from the drives and turn off all attached devices and the computer. Then, disconnectall power cords from electrical outlets and disconnect all cables that are connected to the computer.2. Remove the computer cover. See “Removing the computer cover” on page 32.3. Lay the computer on its side for easier access to the system board.4. Locate the system board and disconnect all cables connected to the system board. See “Locatingparts on the system board” on page 12.5. Remove the heat sink and fan assembly. See “Replacing the heat sink and fan assembly” on page 48.Note: Place the heat sink and fan assembly on its side so that the thermal grease on the bottom of itdoes not get in contact with anything.50 ThinkCentre User Guide
