black screen on galaxy s3

[robbie1944]

Hi

I have just changed the glass on my s3 when I turned the phone on all worked well but after about 5minutes the screen went black.
when you turn it on everything works except the screen
any ideas what can be the problem

 

[meyerweb#CB]

Possibilties include a defective screen, a bad connection where the ribbon cable plugs into the screen, or you damaged it during install.