Remove the B200 NVSwitch and retimer cold plate module

Follow instructions in this section to remove the B200 NVSwitch and retimer cold plate 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.
• Power off the server and peripheral devices and disconnect the power cords and all external cables. See Power off the server.
• If the server is installed in a rack, slide the server out on its rack slide rails to gain access to the top cover, or remove the chassis from the rack. See Remove the server from rack.
• Two people and one lifting device on site that can support up to 400 lb (181 kg) are required to perform this procedure. If you do not already have a lifting device available, Lenovo offers the Genie Lift GL-8 material lift that can be purchased at Data Center Solution Configurator. Make sure to include the Foot-release brake and the Load Platform when ordering the Genie Lift GL-8 material lift.
• A torque screwdriver is available for request if you do not have one at hand.

Note

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

• Torx T15 head screwdriver
• Torx T15 200mm extension bit
• Phillips #1 head screwdriver
• Phillips #2 head screwdriver
• Alcohol cleaning pad
• 2 x B200 PCM
• 2 x B200 SXM6 PAD-1
• 2 x B200 SXM6 PAD-2
• B200 GPU F&R Shipping bkt Kit
• B200 GPU Service Kit
• B200 Retimer NVSwitch Service Kit
• B200 Retimer NVSwitch Shipping Kit
• B200 NVSwitch PCM
• B200 NVSwitch PAD-1
• B200 NVSwitch PAD-2

B200 (GPU & Retimer NVSwitch) (service & shipping bkt) Kit are reusable and mandatory when servicing GPUs and GPU cold plate modules. It is recommended to keep them at the facility where the server operates for future replacement needs.

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.

The following illustration shows the B200 GPU numbering and corresponding slot numbering in XCC.

Figure 1. B200 GPU numbering

Physical GPU socket	Slot numbering in XCC	Logical number in nvidia-smi
GPU 1	Slot 21	4
GPU 2	Slot 24	7
GPU 3	Slot 22	5
GPU 4	Slot 23	6
GPU 5	Slot 17	0
GPU 6	Slot 20	3
GPU 7	Slot 18	1
GPU 8	Slot 19	2

The following illustration shows the components for NVSwitch and retimer cold plate module.

Figure 2. NVSwitch and retimer cold plate module components identification

Table 1. NVSwitch and retimer cold plate module components

1 Retimer cold plate torque label	2 Leakage sensor module
3 Handle	4 Hose tie
5 NVSwitch cold plate	6 TIM breaker screw
7 NVSwitch slot number label	8 NVSwitch cold plate torque label
9 Retimer cold plate

Procedure

1. Make preparation for this task.
   1. Remove the front top cover. See Remove the front top cover.
   2. Remove the rear top cover. See Remove the rear top cover.
   3. Remove the fan cage. See Remove the fan cage (trained technician only).
   4. Remove the CPU complex. See Remove the CPU complex.
   5. Remove the power complex. See Remove the power complex.
   6. Disconnect the cables and remove them from the GPU complex if necessary. Before disconnecting the cables, make a list of each cable and record the connectors the cable is connected to. Refer to Internal cable routing.
2. The following illustration shows the hose holder location.
   Figure 3. Hose holder location
   
   
3. Remove the rear fan cage support bracket.
   1. Unfasten the eight M3 screws that secure the rear fan cage support bracket to the the chassis.
   2. Unfasten the four M3 screws that secure the rear fan cage support bracket to the fan cage.
   3. Grasp the rear fan cage support bracket to lift it from the fan cage.
   Figure 4. Removing the rear fan cage support bracket
   
   
4. Remove the rear B200 cold plate module. See Remove the rear B200 GPU cold plate module.
5. Remove the front B200 cold plate module. See Remove the front B200 GPU cold plate module.
6. Unfasten the two captive screws that secure the hose holder in place; then, remove hose holder B/C. Repeat to remove hose holder B/C on the other side.
   Figure 5. Removing hose holder B/C
   
   
7. Release the hoses and cables from the hose ties that secure them to the hose guides.
   Figure 6. Release the hoses and cables from hose ties
   
   
8. Follow the screw sequence specified on the cold plate label, and repeat to fully loosen the eighteen Torx T15 screws with a torque screwdriver set to the proper torque.
   1. Set the torque screwdriver to 5.22±0.2 inch-pounds, 0.59±0.024 newton-meters.
   2. Loosen the NVSwitch cold plate screws by 360 degrees following the screw sequence: → → → → → → → .
      Figure 7. Removing the NVSwitch cold plates
      
      

      Note

      • Ensure the captive screws are completely loosen before removing the cold plate module.
      • Make sure to follow screw sequence to prevent cold plate tilting.
   3. Loosen the retimer cold plate screws by 360 degrees following the screw sequence: → → → → .
      Figure 8. Removing the retimer cold plates
      
      

      Note

      • Ensure the captive screws are completely loosen before removing the cold plate module.
      • Make sure to follow screw sequence to prevent cold plate tilting.
   4. Repeat until all screws on the NVSwitch and retimer cold plates are fully loosened.
      Note

      • If necessary, use the Tim breaker screw to separate the cold plate from the GPU. Ensure to fully loosen all the cold plate screws before fastening the TIM breaker screw.

        • Open the lid of the TIM breaker screw.
          
          
        • Fasten the TIM breaker screw to separate the cold plate from the GPU.
          
          

      • After usage, return the TIM breaker screw to its original position.

        • Loosen the TIM breaker screw to return it to its initial position.
          
          
        • Close the lid. If the lid cannot be closed, the TIM breaker screw needs to be further loosened.
          
          
9. Install the shipping brackets.
   1. Align the guide pins on the shipping brackets with the guide holes on the manifold and cold plates; then, lower the shipping brackets onto the NVSwitch and retimer cold plate module.
   2. Tighten the fourteen captive screws (PH1, 14 x M3, 0.5 newton-meters, 4.3 inch-pounds) to secure the shipping brackets to the NVSwitch and retimer cold plate module.
      Figure 9. Installing shipping brackets
      
      
10. Removing the NVSwitch and retimer cold plate module.
    1. Secure the hoses to the manifold with the hose ties.
    2. Secure the leakage sensor cable with the cable clip.
    3. Hold the handles to lift the NVSwitch and retimer cold plate module out of the chassis.
       Figure 10. Removing the NVSwitch and retimer cold plate module
       
       
11. Immediately clean the PCM and putty pads off from the NVSwitch and retimer with alcohol cleaning pads. Gently clean the PCM and putty pads to avoid NVSwitch and retimer damage.
    Attention

    • It is recommended to clean the PCM while it is in liquid state.

    • The electrical components around the die on the GPUs are extremely delicate. When removing the PCM and cleaning the GPU die, avoid touching the electrical components to prevent damage.

    Figure 11. Cleaning PCM and putty pads off from the NVSwitch and retimer
    
    
    
    
12. With alcohol cleaning pads, wipe off any remaining putty pad and PCMs from the NVSwitch and retimer cold plate module.
    Note

    Keep the shipping bracket attached to the cold plate module if it is to be reinstalled later.

    Figure 12. Wiping PCM and putty pads off from the cold plates