Table of Contents - 

Document Change History - 

Document Scope & Audience - 

Document Scope

The intent of this document is to walk-through the process of accessing, removing, and replacing/upgrading the backplane on the SuperMicro 4028GR and 4029GP series chassis should it fail or more functionality is needed.

There have been instances that as a system ages and is repurposed the amount of needed drives changes. Some versions of these particular systems,do not see all 24 drive bays and in order to change this the backplane needs to be swapped out and a RAID card added to the system. 

The steps below walk through a full backplane swap which is the more complicated than a replacement, please, use this as a reference for either procedure just know that a replacement will have less wiring than when compared to a swap.

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Identifying the System and Prepping for the Procedure - 

Picture 1 - System Sticker located on the top of the system

Picture 2 - Front of the system

Picture 3 - Rear of System

Accessing Internals - 

Picture 4 - Side of system 

Place the system on a sturdy and open work environment and locate the screw located within the red square above and remove it from both sides of the system. At his point the silver buttons on the top of the lid and slide back away from the drive bays to gain access to the internals.

NOTE: the anti-static pink foam piece that minimizes static issues but also allows for the system to be turned around on the bench much easier allowing the job to be completed easier and saving backs in the process.

Internals and Gaining Access to the Backplane - 

Removing Backplane Top Cover

Picture 5 - Additional Backplane Cover

In the image above, you can see that the internals are now accessible, however, we need access to the backplane as well which is under an additional cover indicated by the red rectangle, the two screws securing this panel are located next to the two screws removed for the main top cover from the previous step. I have also indicated the position of this screw via the red circle in the picture above.

Note: Two different systems were used while making this guide, one fully built and one barebones chassis. Please, do not focus on the components that may or may not be in the reference pictures unless specifically mentioned. 

Picture 6 - Removed Backplane cover and Fans

Picture 7 - Removed fans off to the side in a anti-static bin

Removing Fan Bracket

Picture 8-10 - Unsecuring Fan bracket assembly

Picture 11 - Lifting Fan Bracket Up out of Side Guide rails

picture 12 - One option to lift and lay fan bracket down on heatsinks (this minimizes having to rewire the fans)

This option does minimize the amount of wiring when putting the system back together, however, the trade off is more complicated wiring between the controller and the back plane

Picture 13 - Option 2 fully removing the Fan bracket to gain unhindered access to the backplane although fan wiring will need to be fully redone.

I ultimately suggest a full removal of the fan bracket to allow for easier wiring and complete access to the backplane.

Removing NVMe cables and SATA/SAS Cables - 

Picture 14 - Identifying the SATA/SAS cable to be removed, connectors have locks be sure to disengage appropriately 

Picture 15 - 2 removed Mini SAS to SAS cables

Picture 16 - NVMe connectors backplane side

Picture 17 - Unseated NVMe connectors from backplane 

Picture 18 - Unseated NVMe connectors motherboard side 

Picture 19 - Two Removed NVMe cables from system

Disconnecting Power to Backplane - 

Picture 20 - Six Power Connectors to remove

Picture 21 - All 6 Power Connectors disconnected from backplane

Remove/Unseat Drives -

Picture 22 - Unseated drive carriers 

Often overlooked if attempting to perform this procedure without any reference, any drive carriers actually containing drives need to be removed or unseated as shown above. Otherwise the backplane will not come out of the chassis. I personally prefer to unseat the drive, close the handle and slide the drive back into the slot. Not only does this minimize the potential of damage to the drive. but it also minimizes the amount of space needed to perform the procedure and keeps all disks in their same exact slot, just incase they were not numbered previously.

Removing the Backplane Subassembly - 

Locate the 10 screws securing the backplane and bracket into the chassis as indicated below.

Picture 23 & 24 - Top screws securing backplane subassembly

Pictures 25 & 26 - sides screws securing backplane subassembly; 2 per side 4 total

Picture 27 - 4 Bottom screws Backplane Subassembly

Picture 28 - 4 Bottom screws removed backplane subassembly

Picture 29 - Backplane Subassembly fully removed from chassis

Picture 30 - Backplane Subassembly removed and placed on workbench

Swapping Backplanes - 

Picture 31 - 4 Screws to remove to release Backplane

After removing the indicated screws the backplane should release from the bracket, the bottom is only held in by tabs and the backplane should rock/pivot out.

Picture 32 - REPLACEMENT/Upgrade Backplane to swap in

Insert the bottom of the backplane into the bracket before securing the backplane via the 4 screws from the previous step.

Reinstall the backplane subassembly back into the system so it can be wired up before restoring all other components to the system. Be sure to secure all 10 screws for the bracket as well as fully reinsert the drives for additional support before wiring.

Picture 33 - Backplane subassembly reinstalled into the chassis

Wiring the newly added backplane - 

Picture 34 - Layout of the backplane bpn-sas3-216EB

If looking at the system from the I/O panel, I typically wire the power connections to the left of the fan assembly that will need to be installed. In practice if pairs are grouped together it allows for easier wiring. Once securely connected, please, secure the loose cable with zip-ties or other methods to minimize damage during transit.

Picture 35 - Location of the two ports that will need to be wired to the add-on card

Please be sure to know which cable is attached to port 1 and which is attached to port 2 as they will need to be connected to the respective ports on the RAID controller. For these cables they tend to run best around the right of the fan assembly much like the originals that were swapped. See picture 13 and 39 for an example for routing. Picture 13 is how the original was routed and picture 39 show how I routed the new cable.

Reinstall Fan Bracket - 

Depending on what option you choose when gaining access to the backplane the steps to reinstall this bracket/subassembly can differ.

If the subassembly was not fully removed and simply lifted up out of the guiding rails and carefully laid within the system, be careful when lifting the bracket back up and sliding back into position within the guiding rails. Pay close attention to the cables as none of them should be pinched or pulled. There should be plenty of space for the power cables on the left. The right side is rather tight but doable, again, be careful and take your time so that a mistake is not caused or overlooked by rushing. Once the bracket is fully inplace, please, check all connections on the motherboard, especially the fan connectors.

On the other hand if the bracket was completely removed, please carefully reinsert the bracket into the guiding rails on the chassis while watching all wiring to avoid any pinches, cuts, or damage of any sort to the internals. Since the bracket/subassembly was completely removed, all fans need to be reconnected to the motherboard. This can be achieved in multiple ways, the end goal is to have all fans connected to their respective headers. Please see the two pictures below for reference regarding fan and header relation.

NOTE: If the fan wiring needs to be reconnected to the motherboard, I find it easier to remove the heatsinks and DIMMs for more access and better cable management.

Picture 36  -  Motherboard diagram indicating fan header location and numbering

Picture 37 -  Fan numbering

Fan number shown in picture 36 for reference to ensure fan wiring is correct.

Installing the Add-On RAID Card - 

These chassis are designed for multiple GPUs therefore the location of the RAID card is critical to ensure the system is used to its fullest potential. Although the card could be installed in any slot it could take away the possibility of a GPU being installed if it is placed anywhere besides slot 6 located in the very center of the machine.

Picture 38 -  Slot 6  Location to install add-on RAID card

Picture 39 - add-on RAID card installed into slot 6

Final Outcome - 

Picture 40 - System post Backplane swap and rewiring

At this point of the procedure, the backplane has been accessed, replaced/swapped, and reinstalled. The wiring has been piped leaving the connection of the cable to the add-on RAID card. Once this has been completed the system can be booted to check that not only is the RAID card seen but that all drive bays are now seen.

IF the system behaves as expected the two top covers can be reinstalled on the system before returning the system to its rightful home.

However, should the system NOT behave as expected, please create a support ticket at www.exxactcorp.com/support. Any pictures and descriptions that you can provide can help us determine the next best steps to take towards identifying the root cause and therefore the optimum solution.