Install the Lenovo Neptune(TM) liquid-to-air (L2A) hybrid cooling module

Follow instructions in this section to install the Lenovo Neptune^TM liquid-to-air (L2A) hybrid cooling module. The procedure must be executed by a trained technician.

About this task

Attention

• Read Installation Guidelines and Safety inspection checklist to ensure that you work safely.
• Touch the static-protective package that contains the component to any unpainted metal surface on the server; then, remove it from the package and place it on a static-protective surface.

CAUTION

Do not touch the radiator fins. Touching the radiator fins might damage the L2A.

Note

Make sure you have the required tools listed below available to properly replace the component:

• Phillips #1 head screwdriver
• Torx T15 head screwdriver
• Alcohol cleaning pad
• SXM5 PCM Kit
• SR675 V3 water loop putty pad kit
• SR675 V3 water loop service kit

Important

Putty pad/phase change material (PCM) replacement guidelines

• Before replacing the putty pad/PCM, gently clean the hardware surface with an alcohol cleaning pad.
• Hold the putty pad/PCM carefully to avoid deformation. Make sure no screw hole or opening is blocked by the putty pad/PCM.
• Do not use expired putty pad/PCM. Check the expiry date on putty pad/PCM package. If the putty pads/PCM are expired, acquire new ones to properly replace them.

Procedure

1. Make sure the SXM5 GPU board assembly is installed in the GPU tray. See Install the SXM5 GPU board assembly.
2. Turn the L2A upside down.
   Note

   If the L2A is already in the shipping box, skip to step 2c.
   1. Hold the radiator by its upper edge and hold the cold plate assembly by its lifting handle; then, put the L2A into the shipping box.
   2. Place the top cover of the shipping box on top of the L2A and ensure it is firmly seated.
   3. Hold the shipping box and carefully turn it upside down.
   4. Remove the bottom cover of the shipping box.
   5. Remove the plastic tray and the bottom of the cold plate assembly is facing up.
      Figure 1. Turning the L2A upside down
      
      
      
      
3. Replace the PCM to the cold plates.
   1. Align the PCM with the marking on the bottom of the cold plate, and place it onto the cold plate; then, apply pressure on the PCM and hold it for three to five seconds until it is firmly attached.
   2. Repeat to replace the PCM on the four cold plates.
      Attention

      After PCM is replaced, there is an expected short duration of throttling before the GPU returns to normal operation. This is due to the PCM requiring a break-in period after being replaced.

      Figure 2. PCM application
      
      
4. Replace the putty pads to the SXM5 GPUs.
   1. Align the five putty pads with the GPU VR (1) and the markings on the GPU, and attach them to the GPU.
   2. Repeat to replace all putty pads on the four GPUs.
      Figure 3. Putty pad application
      
      

      1 GPU VR (Cover the GPU VR with putty pad)

5. Turn the L2A right-side up.
   1. Place the plastic tray on top of the L2A to secure the L2A in place.
   2. Place the bottom cover of the shipping box on top of the plastic tray and ensure it is firmly seated.
   3. Hold the shipping box and carefully turn it right-side up.
   4. Remove the top cover of the shipping box and the cold plate assembly lifting handle is facing up.
      Figure 4. Turning the L2A right-side up
      
      
      
      
6. Hold the radiator by its upper edge and hold the cold plate assembly by its lifting handle to remove the L2A out of the shipping box; then, align the L2A with the sixteen screw holes on the SXM5 GPU board assembly and the two guide pins on the GPU tray, and gently place the L2A onto the SXM5 GPU board assembly.
   Figure 5. L2A installation
   
   
7. Install the six Phillips #1 screws (M3 x 5 mm) to secure the radiator to the GPU tray.
   Note

   Loosen or tighten the screws with a torque screwdriver set to the proper torque. For reference, the torque required for the screws to be fully loosen or tighten is 0.3±0.03 newton-meter, 2.7±0.27 pound-inch

   Figure 6. Phillips #1 screw installation
   
   

   1 Radiator

   2 Cold plate assembly

8. With a Torx T15 head screwdriver, follow the sequence (cold plate 1 → cold plate 2 → cold plate 3 → cold plate 4) to install the cold plate assembly.
   Important

   To prevent potential thermal issues, make sure to complete the following steps.
   1. Follow the screw sequence specified on the cold plate label, and fasten the sixteen Torx T15 screws for 720 degrees.
      Note

      Make sure to follow screw installation sequence to prevent cold plate tilting.
   2. Follow the screw sequence specified on the cold plate label, and repeat to fully tighten the sixteen Torx T15 screws.
      Note

      Loosen or tighten the screws with a torque screwdriver set to the proper torque. For reference, the torque required for the screws to be fully loosen or tighten is 0.4±0.05 newton-meter, 3.5±0.5 pound-inch.

      Figure 7. Torx T15 screw installation
      
      
9. Remove the interposer card from the chassis. See Remove the interposer card.
10. Install the GPU-L2A assembly.
    1. Pull the SXM5 GPU board assembly latch outward until it stops.
    2. Hold the radiator by its upper edge and hold the cold plate assembly by its lifting handle; then, align the GPU-L2A assembly with the six guide pins on the chassis, and gently place the GPU-L2A assembly into the chassis.
       Figure 8. GPU-L2A assembly installation
       
       
11. Route the SXM5 GPU board assembly power cable through the cable clip and cable guide, and connect it to the SXM5 GPU board assembly and the SXM5 GPU power distribution board in the rear of the chassis.
    Figure 9. SXM5 GPU board assembly power cable connection