so pull the unit and debug it at a bench. this has been the traditional method of working on large scale cluster deployments for decades, why do it any differently for mining? Commie's example is the ideal way of running a large group of mining rigs.
because pulling the unit with two PSU and (insert the number of GPUs) is a job for two people hehe.
besides pulling out and putting back in is a waste of time. look at what i said above, i fixed my hanging rig faster than you can pull that bar bell from a rack LOL.
Wrong. Hint: rails. It has rails.

Then it's just a matter of few screws and top cover.
So you pull it out like a drawer. Then screws? Screw that. It maybe lighter with rails but it is a waste of time.
How about a rack with rails? You pull the whole rack to troubleshoot and push it back(column of racks) to the air pathway(vent)
A rack with rails is better than a drawer with rails hehe
I'm a bit lost now. A rack is shown on the first picture, what's the point of pulling it (yes you can, it has wheels)? Or do you mean something else?
This is a classic server room setup, each rig equals to a server. Sure if you only have 4-5 rigs you don't need a rack, just use separate cases or hang them to the wall if you wish LOL But when you run dozens of rigs then it's completely different picture. Container setups for 500+cards/250+ asics with hot/cold zones, monitoring systems, security etc are in the market for a reason.
It is a closed rack, that' why i called it drawers, if you want to mine in drawers in the tropics then go ahead hehe
What i mean by racks is open air racks...just google and youtube big gpu farms, they don't mine in drawers with fans.....aaaand they are not in the tropics