How to Install a CPU and Heatsink Assembly (FRU)

Use this procedure to install a CPU. A CPU replacement kit contains a CPU, an alcohol wipe, and a syringe of thermal compound. When you replace a CPU, the heatsink is reusable. Do not discard the heatsink.

Before You Begin

• Sun Fire X4800 Server CPU Module (CMOD) and Filler Module Overview

• CPU and Heatsink Assembly Overview

• CPU Designations

1. Prepare the server for service. See How to Prepare for Service.
2. Remove the CMOD from the server. See How to Remove a CPU Module (CMOD).
3. Set the CMOD on a flat antistatic surface with ample surrounding space and light.
4. Remove the CMOD cover. See How to Remove the CPU Module (CMOD) Cover.
5. Remove the CPU and heatsink assembly. See How to Remove a CPU and Heatsink Assembly (FRU).
6. Use the alcohol wipe that comes with the CPU replacement kit to remove the residual thermal compound on the underside of the heatsink.

   The underside of the heatsink contacts the top of the CPU.

7. Ensure that the CPU retaining cover and the release lever are in their fully open upright position.
   
8. To ensure correct installation, align the keying on the CPU with the keying on the socket.

   One corner of the CPU is marked with a triangle, and one corner of the CPU socket is also marked with a triangle. These two triangles are the key and must align. When these are aligned, other keying notches and trims line up as well.

9. Carefully set the CPU in the socket ensuring that the notches and indents in the socket and CPU line up and that the CPU sits flat within the socket.

   When properly installed, the CPU fits snugly within the socket.

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   Caution - Possible component damage. The pins in the CPU socket can be easily damaged if touched or if the CPU is installed incorrectly. Do not drop the CPU onto the socket. The CPU sits atop the socket and does not require insertion. Do not press down on the CPU.

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10. Close the CPU retaining cover.
11. Lower the release lever and secure it under the retaining clip.
12. Evenly apply the entire contents of the syringe of thermal compound (included in the CPU replacement kit) to the top of the CPU.

    To ensure an even application of compound apply the contents in the shape of an asterisk.

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    Caution - Possible thermal-related component damage. To ensure the proper transfer of heat away from the surface of the CPU, apply the entire contents of the syringe.

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13. Position the bottom of the heatsink over the CPU so that the captive screws in the heatsink align with the threaded standoffs on the motherboard.
    
14. Lower the heatsink onto the top of the CPU.

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    Caution - System thermal failure or component damage. Once the bottom of the heatsink contacts the top of the CPU, do not move the heatsink. Excessive heatsink movement can cause the thermal compound to smear and become uneven. This can result in voids in the compound that can negatively impact the transfer of heat away from the CPU.

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15. Press down on the center of the heatsink to engage the captive screws with the threaded standoffs on the motherboard.
16. To secure the heatsink, alternately tighten the captive screws until both screws are fully tightened.

    Turn each screw one-half a turn at a time.