device doesn't on need a battery

Start with a battery or seeing if will charge . If it doesn't charge replacing the battery is only as good as a new batterys life. plug in the phone and see if it can be recognized by your computer if not it could be a charging cord problem or the charging connector port. If you have access to another cord try that also try wiggling the cord in the port to see if its making contact. Look into the charging port for dirt or debris if it does have dirt in it use a toothpick to clean it so the plug doesn't get broke off .If it does charge but dies right away then replace the battery. Hope this helps