I have replace the connector with a new, i think the solders are goods but i have always a black screen without backlight.
The motherboard seems to work fine, the restore on itunes is good but no display on screen.
Sometimes i can see some vertical lines but no backlight.
I have find a topic where a people give a solution for backlight with this picture:
I have check and i have continuity anywhere but not on the the blue line you can see on next picture: