I'm experiencing a similar issue. I've been scratching my head after replacing a screen on a customer's device for several days now. When I power up the device, everything appears to work except for the AT&T network (not sure if has been disconnected or not). Though, once the phone goes to sleep on it's own, or it's left alone for too long, things start to act funky. I wake the phone up after falling asleep for the first time since boot, the home screen appears, but there is no sense of touch/the digitizer isn't functioning anymore. Once the screen falls back asleep due to no interaction, it will not wake back up by pressing the power button and the LCD remains completely black. When I put the original screen back into the phone, however, the phone works as it should. The only way to reset the device is to unplug the battery, which results in app optimization after every trial (time consuming). There is also a bit of heat coming from the middle of the phone. I'm running out of ideas. Please help!