I have a 3g motherboard that i was saving for when i got a good back housing. It was working good except for wifi being out. So i got a back housing assembly put together and i installed motherboard. Itunes will recognize phone so i know its working but LCD wont work ....i have put two working LCD on it and it still doesnt work. I have checked the connections between LCD and motherboard when installing and no go. It was working fine before; minus wifi. What could be the problem?