iPhone 3GS - No Picture, Just backlight / Gray Blank screen

[JonoSmallridge]

So im repairing a iPhone 3GS and the front Glass is pretty Mangled.
And i took the Digitizer off and put a new one on. Suprisingly easy!
And after all screwed in the top wasnt clipped on so i pushed the top left back down. It made a nice click as it snapped in place. Only thing is, the screen went bright white and lost all picture. i put this down to software straight away, as the sleep button performed correct turning the LCD on and off.
Then after a power cycle the LCD is now gray. again no image just the backlight. I can just replace the LCD but im pretty sure this wont fix mutch. Its not damaged in anyway, And i have seen my fair share of broken iPhone LCD's.
But i have never had this problem. Also the digitizer doesnt seem to be working
Is this linked with the LCD? So yeah.. Iv tried a Hard reset and power cycles. Nothing seems to work. Oh and the iPhone isnt mine!
Any one else had this problem?

 

[Crystal-RX]

So im repairing a iPhone 3GS and the front Glass is pretty Mangled.
And i took the Digitizer off and put a new one on. Suprisingly easy!
And after all screwed in the top wasnt clipped on so i pushed the top left back down. It made a nice click as it snapped in place. Only thing is, the screen went bright white and lost all picture. i put this down to software straight away, as the sleep button performed correct turning the LCD on and off.
Then after a power cycle the LCD is now gray. again no image just the backlight. I can just replace the LCD but im pretty sure this wont fix mutch. Its not damaged in anyway, And i have seen my fair share of broken iPhone LCD's.
But i have never had this problem. Also the digitizer doesnt seem to be working
Is this linked with the LCD? So yeah.. Iv tried a Hard reset and power cycles. Nothing seems to work. Oh and the iPhone isnt mine!
Any one else had this problem?

Can you connect the iphone to your PC/Itunes to see if it detects the Iphone?

If Itunes gives you all the information about iphone, then either you damage the LCD or connection was not tight. There are only 3 wires attached the top assembly to the iphone.

#1 to LCD, #2 to digitizer and #3 to the ear phone