6s screen lcd does not work after replacement, works for 1 sec

I changed the screen on a iPhone 6s, when I was to power on the device there was no apple boot logo. I know the phone is on because of the sound it makes when I connect to the charger, and it is recognised by my computer, sometimes the lcd flashes on for one second then goes dark. the touch works as well since I can unlock the phone and hear the buttons being pressed on for the passcode. This problem now happens with the old screen as well and also with other new screens.