Questions regarding an external JBOD

We have a TrueNas installation running on a Dell vxrail e560. All of our drive bays are full, and the server is at around 80% capacity right now. I’d like to add a JBOD to the setup out of an old Fortinet “Fortianalyzer-3500F” (Model: FAZ-3500F) which has 24 hard drive bays on the front… what I am trying to do is make this as easy as possible with the least amount of equipment, but I want to make sure that I’m not missing anything.

So we have a few dell SAS controller cards. (Model 342-0910) that allows for two incoming SAS cables. Am I correct in assuming that if I remove the motherboard from the Fortinet unit entirely, and keep only the backplane and PSU, I should be able to just use this as a JBOD? I purchased a couple Mini SAS SFF-8088 (external) to SFF-8087 (internal) adapter cards to put into the JBOD.

I tried to attach some photos here, but I can’t. And I can’t link offsite either. Copy and paste, and remove the space, for additional photos of the equipment:
ibb. co/album/7JLKhb

Any insight would be greatly appreciated. Thanks!

Yes. Just ensure there are no other connections other than power and the mini-sas connector (back plane).

The one issue you may find is how to turn that extra box on.
When I rigged my HP Gen8 micro server as an external SATA enclosure (SAS can do SATA), I rigged it so it would simply be on (wire/bridge between 2 psu pins).

Awesome! Also, I really appreciate the heads up about jumping the pins on the PSU! Much obliged.