First off, I will mention that according to the customer, this is a water damaged phone, though it was only for 5 seconds. I have disassembled it and cleaned all the connections.
Now, I get a Splash Screen, but then it goes black. The blue light in the upper left hand corner keeps slowly blinking bright and not bright, so that seems to be working.
I have factory reset the phone on the phone, wiped the cache, and used ODIN to reload the phone.
The screen displays just fine and all the buttons work when going to the options like update from ADB, wipe cache, etc. There seems to be nothing wrong outside of the OS but as soon as it goes past the splash screen when you are trying to boot it, it's just black.
Oh, I did have once when restoring it that it was optimizing apps and stopped at the end. I have ODIN'd since then.
This is a Verizon Galaxy S6