Hardware Need help with Vita repair

[NandoLawson]

Hey

Someone gave me a PS Vita Slim that wasn't turning on. It is in a perfect condition and the problem was the battery being dead.
The weird thing is that (after a battery replacement) the screen won't turn on when I start the device. I am able to hear sound so I can say that the console is booting just fine.
That sounds for me like a broken screen. But the thing is that the console has been barely used and, as I said, is in a perfect condition. Could other problems cause this problem?

 

[Leen]

might disconnected the screen when repairing it but not sure

 

[NandoLawson]

I only took the backplate apart as that is the only thing needed for replacing the battery. Am I able to check this without taking apart everything?