iPod Powered Up, Black Screen?

Alright been sent in an iPod that was self-repaired by the customer.

They said they replaced the screen and all was well and they tested the new screen before sticking it down and it worked fine.

After they laid the adhesive and plugged the screen in again it was just white (white screen of death) and the hard reset didnt work. After hard resetting a few times the iPod's screen just went black.

Now i can't see the problem. The LCD connector on the board is intact. I've tried out test screens and they have the same result.

I cant see any damaged chips/caps/ics/resistors on the board but i am no expert.

Is there somewhere i should be looking? The iPod powers up, recognized in itunes, makes sound. I even updated it to iOS6 and restored it.