The piece of advice about power cycling the phone by disconnecting and reconnecting the battery proved crucial to the success of my repair (camera and lens replacement). At first when charging the phone after closing it, I got a dark, blank screen with an intermittent buzzing noise. After re-opening the phone and making sure all cables had been properly reconnected, I ignored the advice to power cycle the phone. Still all I got was a dark, blank screen (and intermittent buzzing if charging t). Then I opened it a third time (leaving the screen connected and attached at a 90 degree angle) and I only disconnected and reconnected the battery. Voila! When I closed the phone and powered it up, I got the screen to light up!