iPhone 5 new screen black after screen replacement, old still working

I replaced my broken iPhone 5 screen and the screen was black, so I put the old broken one back which worked as before. I ordered another screen and when it arrived, I put that one in and that one is black also. I put the old broken screen back in, and that works.

I have no idea what to do. Both of the new "bad" screens kind of look like change from a deep black to a bit lighter black when I push the power button, but it is so slight, it is hard to even notice.

I tried:

- Disconnecting the battery, holding the power button in, changing the screen, connecting the battery back on and nothing.

- I moved the foam things on top of the connectors over to the new screen, still nothing

- I tried the phone without putting the metal cover back on the connectors, still nothing

- I tried to hold the power button and the power button down at the same time for 15 seconds, still nothing

- I have the newest iOs 10 on the phone.

Everything I read on the internet about these black screen cases were related to black screen with any screen. But my phone works with the old screen still, but nothing with the 2 new screens. Very unlikely that both new screens would be faulty...

Thanks