Samsung is pretty notorious for the black screen problem. So far I've tried the "1-2-3" method of removing the battery, holding down the power button for one minute (if that didn't work, 2 minutes, then 3 minutes) to discharge any lingering electrical charge, replacing battery and turning on.
That didn't work.
So I ordered a new screen digitizer assembly. Took the phone apart, replaced the new screen assembly.

That didn't work.

Wondering what my next course of action should be here. It's important that I get access to this phone.