Posted by Sam on December 08, 2014
This is normally a sign of your LCD cable not being plugged in correctly. Reattempt the repair from the beginning. At the point where you plug in your new screen to your main board, check both your connector plugs, and verify that none of the pins are bent or missing. If the pins are damaged, plugging in your new screen again will not solve the problem. You will need to bend the pins back into place before your device will start working again. Once the pins are straight, and the screen is plugged in again, try powering on your device without closing it up. This will allow you to troubleshoot your repair without the need to remove every screw all over again.
If your device is still (or is just now) showing no image, but there is a glow from the back light, follow these steps:
If no image appears, you have a battery that is dead or dying. In either case, your battery no longer is sending a strong enough charge to your phone to allow the screen to make an image appear. You will need to replace your battery. Should an image appear on your phone, you are ready to go. Close it up, and enjoy your device as Apple intended!