Check the ribbon cables inside the phone. I found one that was not snapped in all the way, pressed it into place, and voila!, the phone powered on & charged correctly. As an added bonus, my LCD graphics got brighter and more colorful! P.S. USE ONLY THE TORX star-shaped screwdriver that comes with phone parts repair kits. Some idot stripped 6 of the screws in my phone, I spent several hours getting those stripped screws out, & about 5 minutes to fix my problem. They have those phone repair tool kits for a couple bucks on E-Bay, little more expensive at RadioShack etc....USE THEM!!
Thanks, hope it helps you too,