Screen blacks out for about 5-30 seconds when using.

Hello, all.
I recently purchased a used Surface Pro 4 online. At first when I was using it, it was fine. After about 2 or so days, the screen would simply go black for about 15 seconds, before it would show video again like nothing happened. I use this Surface for meetings and appointments, so the screen is definitely required for this. I've worked on 2-1's before, but I haven't opened this system up yet, and i would like to know of any possible causes and maybe fixes.
Thanks!