after screen replacement the iPhone screen will not turn on
i work in a repair shop and have recently been working on a iphone another shop worked on. they replaced the screen but some how they put in a old battery by mistake during the instillation. We replaced the battery and the screen immediately died. we have replaced the battery with 3 different ones and we have also replaced the screen with two different ones. itunes is picking up the device but the screen will not turn on.
do any of you have any ideas?