iPhone 6s Black Screen After Screen Replacement

I recently got an iPhone 6s with a pretty badly damaged screen. The screen worked, however it was completely cracked and there was a black bleed mark on the LCD. I ordered a screen and began replacing it.

After replacing the screen and hooking everything back up to the logic board I got a black screen. I absolutely made sure to disconnect the battery before ever touching any other part of the phone. I have also tried connecting it to iTunes and got as far as it asking for the passcode which I cannot enter as the screen does not work.

Now here's where it gets hairy and I'm stuck, after looking through the various other similar questions I attempted to test if thew screen was bad by replacing the severely cracked screen, which I knew worked. After taking all the assembly parts off the new screen and putting them back on and trying to plug it in, I got nothing.

It's still being recognized by iTunes, but now no matter which screen I have plugged in I get a black screen. I have a sinking feeling it's going to require board level repair (which I can't do, yet) but I'm hoping maybe someone here can see something I can't.

If there's something you think may help me get this problem remedied or you need more information on what all I did to it, just ask and I'll happily provide more info. Thanks everyone.