Screen flickers for half a second then goes blank.

I just found a LED Cinema Display during spring cleaning that is not entirely working. The audio, charger, and usb all work on the display. The screen is detected by my 2011 13 inch MBP. About 40% of the time when I plug the thunderbolt cord into my laptop the screen will flicker for a half a second and then go completely black. I used my flashlight to look at it and I do see my computer's desktop on the display. From what I can see the backlight isn't completely broken, I figure it is either a problem with the thunderbolt connection or the logic board.

Thanks.