Lenovo ThinkStation C20x 4269 Hardware Manual page 148

10. Go to "Completing the FRU replacement" on page 158.
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Hardware Maintenance Manual
sink or set the heat sink down to prevent the grease from coming in
contact with any surface or contaminates.
4. Carefully lift the heat sink off of the system board.
5. Remove the plastic cover from the bottom of the new heat sink to expose the
heat sink grease (this cover protects the heat sink grease from contamination).
Notes:
a. Do not remove the plastic covering the grease until you are ready to install
the heat sink on the microprocessor. Do not touch the grease and the heat
sink. Do not put the heat sink anywhere except on the microprocessor
after the plastic covering has been removed and the grease exposed.
b. Some heat sink part numbers will have orientation labels showing "Front
of System." Heat Sinks that do not have orientation labels should be
oriented so the fan cable is toward the board connector labeled "CPU Fan."
6. Place the new heat sink into position.
Important: Do not touch the thermal grease while handling the heat sink.
7. Align the screws on the heat sink with the mounting studs in the chassis.
8. Follow this sequence to install the screws, noting that fully tight is 5 in-lbs +/-
0.5 in-lbs:
a. Partially tighten screw 1 , then fully tighten screw 3 , and fully tighten
screw 1 .
b. Partially tighten screw 2 , then fully tighten screw 4 , and fully tighten
screw 2 .
9. Reconnect the heat sink and fan assembly cable. See "System board connectors
and components" on page 129.