replacement of screen and possibly LCD, how to determine

@ottohye what do you mean by "does not completely light up"? Lights up a little bit? One side only? To/bottom? Or just not very bright....What have you checked

What's the model of this phone? Are you saying you are still using a 1st generation Galaxy S Epic 4g? I took a quick look around, Samsung is on Galaxy S8. I am not sure if you can get a legitimate high quality screen for an S1. I'm sure you will find "a" screen but quality wise, I can't be sure about it. If this is the Sprint model, you may be better buying a whole new Galaxy S 4g, as the phone refurbished looks to be cheaper than repair.