4. Make sure that the heat-sink retaining clip is open.5. If you are installing a new heat sink, remove the cover from the bottom of theheat sink. If you are reinstalling a heat sink that was previously removed, see“Thermal grease” on page 149 for instructions for replacing the contaminatedor missing thermal grease; then, return to this step.6. If necessary, remove the cover from the bottom of the heat sink.7. Position the heat sink above the microprocessor, making sure that the word“Front” is closest to the front of the server; then, press the heat sink into placeand close the heat-sink release lever.FRONTHeat sinkHeat sinkretention clipNote: If you are installing an additional microprocessor in microprocessorsocket 3 or 4, you must also install a VRM.8. If necessary, install a VRM in the connector.a. Open the retaining clips on each end of the VRM connector.b. Turn the VRM so the keys align with the slot.c. Insert the VRM into the connector by aligning the edges of the VRM withthe slots at the end of the VRM connector. Firmly press the VRM straightdown into the connector by applying pressure on both ends of the VRMsimultaneously. The retaining clips snap into the locked position when theVRM is seated in the connector.9. Install the air baffle in the microprocessor tray.Note: Make sure that the air baffle lies flat and within the grooves on top ofthe microprocessor heat sinks and microprocessor baffles and that the airbaffle remains in place while you close the microprocessor tray. You might findit helpful to hold the air baffle in place with your thumbs while closing themicroprocessor tray.10. Install the microprocessor tray in the server:a. Make sure that the microprocessor-tray release latch is open; then, pushthe microprocessor tray into the server.b. Close the tray levers and make sure they are securely latched.c. Close the microprocessor-tray release latch.d. Reinstall the fans and memory cards in the server.11. Install the bezel and front cover (tower model only) (see “Replacing the topcover, bezel, and front cover” on page 119).12. Connect the cables and power cords (see “Connecting the cables” on page116 for cabling instructions).13. Turn on all attached devices and the server.148 IBM System x3800 Type 8866: Problem Determination and Service Guide
