Static and lines on screen after repair.

hello, i'm a IT tech and im doing a repair for my grandmother. this is my first ipad repair. although it went very well after ordering some parts, the original screen i started with which was fine; only the glass was broken in several places. now that same screen displays static and lines. i have checked the ribbon cable several times over and all connections and i cannot seem to find the problem on why its suddenly doing this just as im about to finish it up. any help would be appreciated. thnx.