Screen Change Worked for a few seconds now black

Hi All

I was changing my iphone 6S screen last night (Done plenty of these so experienced doing it) I was having conecting the top 3 connectors I dont know whether the cheap aftermarket screen had poor manufacturing on them. Anyway as I was trying to clip in the top of the two horrizontal connectors it started smoking. (I didnt disconnect battery before)

I continued on my way and screwed the cover clamp down, turned phone on and screen came on, but after a minute or so it went black. (Phone still on and making noises when text arrives etc)

I decided to plug the old screen back in but still black.

I then tried without proximity sensor i thought maybe if that was faulty it thinks im making a call etc but to no avail

Any suggestions!

Thanks Guys :)