Hello, this week I got a Samsung GT-I9300 (S3) which was dropped by the owner and since has a black screen. It is still possible to boot the phone to the point the blue LED is switched on, but thats it. There are lots of reports for this kind of damage in forums, usually giving advice to replace the entire LCD/screen/upper case unit which is about 135 Euro here in Germany if you do it yourself.
In this case the glass as well as the LCD screen do not show any visible damage. I wondered if anyone ever tried to disassemble the screen unit to get to the actual cause. I cannot do this on my own as this is not my phone and in the screen unit everything is glued together with makes it impossible to open it without further damage.
Regards Jens