Lenovo System x3550 M4 Installation And Service Manual page 99

• Do not touch the thermal grease on the bottom of the heat sink after you remove the plastic
cover. Touching the thermal grease will contaminate it. See "Thermal grease" on page 86
for more information.
Figure 72. Thermal grease
a. Remove the plastic protective cover from the bottom of the heat sink.
b. Position the heat sink over the microprocessor. The heat sink is keyed to assist with proper
alignment.
Figure 73. Heat sink installation
c. Align and place the heat sink on top of the microprocessor in the retention bracket, thermal
material side down.
d. Press firmly on the heat sink.
e. Rotate the heat sink retention module release lever to the closed position and hook it
underneath the lock tab.
Step 11. If you installed the second microprocessor, install the fourth and sixth fans (see "Replacing a
hot-swap fan" on page 244).
If you have other devices to install or remove, do so now. Otherwise, go to "Completing the installation"
on page 89.
.
Chapter 2 Installing optional devices
85