Hi - I've changed screen on a lot of iphone 4S.

But I have a problem with 2 of them. When turning them on again the camera just shows a black screen and the flash does not work.

Anyone know what the problem could be ?

Thanks in advance

Hi - I changed the flex on a iphone 6 - and new screen.

But now my battery is draining really fast - over night. I changed battery, but same problem. Before I changed the felx I was using it with assistive touch, and no problem with battery?

What could have happened / solutions ? - really annoying since it's not my phone.

I tried charge new battery to 100% and then reset all settings .. but still drains battery. Could flex cable be the problem?

Thanks in advance.