DARK (on 2 brand new) screen on iPhone 4!

I've had this problem on one iPhone 4..refused to take new screen. Old screen worked fine and new screen worked in another broken iPhone. I did all that you have done and the only fix was a new screen from another company, I can only assume that there is some "version" of screen that will only work with a certain iPhone...just like the battery problem in the iPhone 3GS causing reboot loop, and some other mobile phones that have 3 versions of the same phone, I'm guessing that these phones are a release date that only matches the same release screen??

Where did you order the screens from? There is a always the possibility to get a bad screen, I have gotten 3 bad ones in one box before, but your problem sounds like there is something else that you are doing wrong. Did you make sure NOT to pinch the LCD cables on each of the new screens. When you bring the cables from the front of the phone through the mid-plane assemble, it is easy to pinch them. Sometimes when this happens, you can break the cable internally, without seeing it. Most iPhone screens don't come with the cables prefolded, so the reason your original screen still works is most likely since the cable stayed folded at the perfect angle once you took them out. Before you push the glass onto the front, be sure to check the LCD and digitiser cables to avoid pinching them. Make sure they are completely through the housing. Examine the new screen's LCD and digitiser cables and see if you can spot any obvious damage.

Hope this Helps