Default [Q] No dislplay after replacing screen

Hi everybody, I have problem with this phone. I tried 3 difference screens (replacements without chassis) and everytime was the same syndrome. Can not turn on the screen and after touching digitizer, can feel vibration so touch screen works. Its not possible I have 3 broken screens.Under youtube disassembly tutorials I also have seen many feedback form people who have the same problem. Anybody know what can be wrong ?
Thanks a lot for all comments