Why wont the screen display anything?

I was attempting to fix an ipod 5th gen that had a broken screen as i had done the same with my iphone 5s. But after putting in the screen and powering it on, it was just gray with a few darker vertical lines running down it. After turning it off and reattaching the screen again, it won't even light up, but my laptop is able to recognize it. Is there a problem with the screen I got or did i damage something while replacing the old one? I can also feel the motherboard getting just a little warm if that means anything.