not responding screen black screen

hello,

i have bought new screen with the digitizer .. i had the iPad ready before the screen arrived it was working perfectly all i had to do is connect the cable for the new screen on the iPad and I'm done! what i didn't see coming is that the screen did not respond! its black i thought something must be not right with the screen so i plugged the old screen to check and it tuned out to work perfectly!!! when i tried with the new screen it still black and after a while the old screen didn't respond as well the new one either black or with lines .

what can i do ? what to replace etc!

this is the screen