iPhone 3G won't turn on after screen replacement?

[Randolpfcouture]

So, I bought a iPhone 3G to use a ipod/back up back phone. I ordered two white LCD/Digitizer assemblies. One for my broken 3GS, and the other for this 3G. Both had broken screen. Thought it would be an east fix. The 3GS went on smoothly without a hitch. Now, the 3G on the other hand.. I have been replacing screens for a while, this was routine. I did everything correctly. But now it's not coming on, it's not being recognized in itunes... I took the battery off for 20 minutes and left it alone. Put the screen back on.. no luck.. I cannot fathom what happened. it was working fine with the old screen. now, neither screen work.

Any ideas? :/

[danielh3410]

try checking ur internal parts arent loose-as there should be a metal-plate section near edge of ur battery which if loosened or not connected properly will stop u receiving a signal