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Install the GPU power distribution board

Use this information to install the GPU power distribution board.


Ensure you have “SD650 V2 or SD650-N V2 Neptune DWC Waterloop Service Kit “ in hand to install components.


  1. Align the connector with the slot and place the GPU power distribution board into the node.
    Figure 1. GPU power distribution board installation
    GPU power distribution board installation
  2. Insert and fasten the five screws.
    Figure 2. Screws installation
    Screws installation
After you finish
  1. Apply the new thermal grease on GPUs.

    1. If there is any old thermal grease on four GPUs and the cold plates, gently clean the top of the four GPUs and the cold plates using an alcohol cleaning pad.

    2. If you have cleaned the top of the GPUs with an alcohol cleaning pad, make sure to apply the new thermal grease after the alcohol has fully evaporated.

    3. Apply gray thermal grease to the top of the four GPUs with a syringe by forming four dots spaced as shown below, with each dot consisting of about 0.5 gram (about 0.225 ml) of gray thermal grease. Each syringe contains 1 gram of thermal grease, sufficient for two dots of thermal grease.

    Figure 3. Thermal grease application
    Thermal grease application
  2. Replace the existing putty pad with the new one.

    Figure 4. Putty pad
    Putty pad
  3. Check the gap pads on the water loop, if any of them are damaged or missing, replace them with the new ones.

    Figure 5. Gap pads on the water loop
    Gap pads on the water loop
  4. Reinstall the water loop.

    1. ❶ Carefully rotate the top side of the water loop.

    2. ❷ Carefully insert the quick connect into the tray opening as shown.

    3. ❸ Carefully align the water loop with eight guide pins on four GPU cold plates; then, gently put the water loop down and ensure it is firmly seated on the GPU board.

    Figure 6. Water loop installation
    Water loop installation
  5. Loosen all water loop carrier screws (15x Phillips #2 screws).

    Figure 7. Loosening water loop carrier screws
    Loosening water loop carrier screws
  6. Carefully lift the water loop carrier up and away from the water loop.

    Figure 8. Water loop carrier removal
    Water loop carrier removal
  7. Reinstall water loop screws (7x Torx T10 screws) with a torque screwdriver sets to the proper torque.

    For reference, the torque required for the screws to be fully tightened/removed is 0.5-0.6 newton-meters, 4.5-5.5 inch-pounds.
    Figure 9. Water loop screws installation
    Water loop screws installation
  8. Reinstall GPU cold plate screws (4x Phillips #1 screws per GPU cold plate, total of 16x Phillips #1 screws) with a torque screwdriver set to the proper torque. For reference, the torque required for the screws to be fully tightened/removed is 0.34-046 newton-meters, 3-4 inch-pounds.
    Figure 10. GPU cold plate screws installation
    GPU cold plate screws installation
    1. Push down the GPU cold plate with your palm to reduce the gap between the GPU cold plate and the GPU.

    2. Press the torque screwdriver against the screw so that the screw is engaged with the GPU.

    3. Follow the screw sequence specified on the GPU cold plate label and fasten each screw for 720 degrees.

      GPU cold plate installation
    4. Make sure that the GPU cold plate is lowered into the node and its surface is flat without tilting. If the GPU cold plate is tilted, unfasten the screws, and repeat Step 1 to Step 3.

    5. Repeat Step 3 until the screws are fully tightened.

    6. Make sure the height of each screw is 12.5±0.3 millimeter (0.49±0.01 inch) and is fully compressed. If not, repeat the GPU cold plate installation steps.

      Height of each tightened screw
      Inspect the screws to make sure they are fully compressed.

      screw height inspection
  9. Reinstall the four Torx T10 screws (per node) to secure the quick connect.

    Figure 11. Screws installation
    Screws installation
  10. Reinstall the clamp plate or the drive depending on your configuration.

    • Clamp plate installation: Install the two screws to secure the clamp plate.

      Figure 12. Clamp plate installation
      Clamp plate installation
    • Drive installation: see Install the drive in the GPU node.

  11. Remove the connector cover if necessary.

    Figure 13. Connector cover removal
    Connector cover removal
  12. Connect GPU power cable.

    Figure 14. GPU power cable installation
    GPU power cable installation
  13. See Cable installation order to connect and route required cables accordingly.

  14. Reinstall the front and the rear cross braces (14x Phillips #1 screws).

    Figure 15. Cross brace installation
    Cross brace installation
  15. Reinstall the tray cover (see Install the tray cover).

  16. Reinstall the tray (see Install a DWC tray in the enclosure).

    For safety, use the lift tool to install the tray into the rack.
  17. Connect all required external cables to the enclosure.
    Use extra forces to connect QSFP cables to the enclosure if Mellanox ConnectX-6 adapters are installed.
  18. Check the power LED on each node to make sure it changes from fast blink to slow blink to indicate all nodes are ready to be powered on.

Demo video

Watch the procedure on YouTube