As this system is so new I doubt anyone even has access to the schematics yet.
But lets look at this from a different direction... I assume you have an RV or boat that you want to use your system in. So getting real AC power is not easy to find or get.
Sadly, you're between a rock and hard place here as desktop systems are designed for AC power use only. While some have tried altering the power supplies in older models they often hit the problem of needing their systems fixed and no-one will service an altered system like this. Besides, you won't get any warranty repairs as you have effectively voided it.
I should point out your system is not a true DC device! It still depends on the clocking of the AC line to work properly. A laptop on the other hand IS a true DC device!
So what to do?? You may want to get an older 2011 system to play around with as its easier to open and you can find full documentation for it (repair & schematics). If you can get it to work then you have a chance to get your newer system to work. Frankly, I think this is going to far but if you must then thats what I would do.
The better approach is to put the time and money into getting a good DC to AC converter. Leave the system intact and use it this way if you want a desktop system.
Or, look at getting a laptop and get an external display if you want something bigger to view. It will likely need a DC to AC converter but you might find a display that runs directly off of DC as well.