Lenovo x3650 M4 BD 5466 Installation And Service Manual page 252

Figure 182. Heat-sink installation
a. Remove the plastic protective cover from the bottom of the heat sink.
b. Align the screw holes on the heat sink with the holes on the system board.
c. Place the heat sink on the microprocessor with the thermal-grease side down.
d. Press firmly on the captive screws and tighten them with a screwdriver. The follow illustration
shows the sequence in tightening the screws, which is also shown on top of the heat sink.
Begin with the screw labeled as "1", then "2", "3" and finally "4". If possible, each screw
should be rotated two full rotations at a time. Repeat until the screws are tight. Do not
overtighten the screws by using excessive force. If you are using a torque wrench, tighten the
screws to 8.5 Newton-meters (Nm) to 13 Nm (6.3 foot-pounds to 9.6 foot-pounds).
Note: Please use Phillips screw driver No.0 to fasten screws.
Figure 183. Screws sequence
Step 7. If you are replacing microprocessor 1, install the previously removed memory module into DIMM
connector 6. If you are replacing microprocessor 2, install the previously removed memory module
from DIMM connector 12. See "Replacing a memory module" on page 178 for instructions.
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Lenovo System x3650 M4 BDInstallation and Service Guide