No picture after screen replacment only touch response

Hi, I have a Sony xperia z3 compact

The screen has been changed on several occasions without any fault

The last replacement the screen was put on there is no picture, although the touch screen works as you can connect it to tv and everything is fine except display on the phone

I found a little gold pin put I do not know it this is out of the phone and needs to be soldered back on or not?