I have an iPhone 3GS that simply will not charge. When plugged into a wall charger/dock, it will not charge yet it played music from the same dock when it still had battery. My question is, why will it not charge yet play music through the dock connector? It has done this before but started charging after awhile. I do not have a warranty left on it either. I would just simply like to know if I can fix it without opening it up (if so, please give solutions) or if I should trash it. Thanks.