Original post by: Brian Wood ,
Try these few things. 1. Put your broken screen back on and test it to see if it works. If it does, its the new lcd. 2. Install the new lcd fully and do a hard reboot by pressing home and power for about 5 seconds or so. Then hold the power button to see if it comes back on. 3. I have run across and IC that can get blown that controls the lcd and backlight. This IC may be the problem and youll need to get it repaired. You can google iPhone IC repair to find a reputable company. I hope these suggestions help.