Chosen Solution
Hey. I have changed the screen twice and now the screen is black. First time it hade dead pixel so i got a replacement screen. And now its all black. I’ve switched to a screen that I know works but it’s also dead. I can charge the phone and pair it with itunes but it asks for a code but I can not write it on my phone. I can turn off the sound using the up button on the left side and then vibrates it and sometimes when I press the home button then it also vibrates. I think I’ve disconnected the battery at every change of screen Does anyone know what might have happened??
You may have forgotten to disconnect the battery, it happens! The iPhone 6S is very prone to blowing the backlight circuit if the battery is not disconnected. Ideally you should even wait ~10 secs to insure that the output caps on the backlight line are fully discharged. If you attempt to connect the backlight connector and it is misaligned while there is still voltage, the backlight circuit can get damaged. Unfortunately for you, this will require a micro-soldering repair and is not a DIY fix.
