三星 盖乐世 S8 Plus 屏幕 更换

I replaced my display with a another display with mid frame attatched already.all i did was change over my mother board,charging port and such and now if i power the phone on i feel it vibrate and see a blue led light up but that is all it does.screen is black and i can feel the vibration feedback if i touch the screen but nothing shows.going out of my mind trying to figure out what went wrong.