System Board Replacement - Lenovo ThinkSystem ST550 7X09 Maintenance Manual

Step 2. Install the processor-heat-sink module on the system board.
Figure 124. Installing a PHM
a. Align the triangular marks and guide pins on the processor socket with the PHM; then, insert
the PHM into the processor socket.
Attention: To prevent damage to components, make sure that you follow the indicated
tightening sequence.
b. Fully tighten the Torx T30 captive fasteners in the installation sequence shown on the heat-sink
label. Tighten the screws until they stop; then, visually inspect to make sure that there is no
gap between the screw shoulder beneath the heat sink and the microprocessor socket. (For
reference, the torque required for the nuts to fully tighten is 1.4 — 1.6 newton-meters, 12 — 14
inch-pounds).
After installing a PHM:
1. Complete the parts replacement. See "Complete the parts replacement" on page 178.

System board replacement

Use this information to remove and install the system board.
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ThinkSystem ST550 Maintenance Manual