It appears that many people have the exact same problem. The easiest way I can describe how you can replicate the issue it by Googling “black screen” on Google images and then clicking one of the pictures so that your screen is completely black, but is still turned on. Then go to a dark room, look at the screen, wait for your eyes to adjust and then see if you have small spots or lines all over the screen.
https://forums.motorola.com/posts/9030b1a2d9