I brought a non-working iPhone 2G and thought it would be simple fix with replacing the old battery with a new battery since the original owner couldn't (or should I say wouldn't) exactly tell me why the phone was failing to turning on and function properly. I've ordered & replaced the battery but the iPhone still fails to turn on even after charging the new battery for a few hours. How do I test the motherboard and/or communications logic board to determine whether these parts a fully functional before ordering replacement parts?