I replaced the screen on my Iphone 4s. Screen didn't work. I reseated all the connections and nothing so I suspected the battery may have been dead. I put it on my charging dock and it turned right on. It said the battery level was 100%. Removal from the dock causes and instant power loss, or perhaps just the screen turns off. I reseated everything again, same thing. I tried placing it on the dock with the battery disconnected, it wouldn't go past the power on screen with the Apple logo so I don't think it's a problem with the battery connection, plus the pins look good. Any ideas?