Chosen Solution

i’m fixing a friend’s phone, because after he dropped it the screen was broken so i replaced it with new lcd but it went black, the weird thing is for less than a second i can see the lock screen but then i goes black again , so apparently the phone is working the lcd is working because i could see the lock screen with the clock and stuff but then it goes off to black, how can i fix it, and what is the problem here?

@engsarah hopefully you disconnected the battery before replacing the display. If not then there is a chance you blew the backlight filter on the logicboard.