Hello -
It is likely that your USB charging connector is faulty or the inner pins are bent preventing it from getting a connection. This is actually a really common problem, more so than a faulty board. This is in part due to the fact this component goes through a lot of wear and tear from amount of insertions and withdrawals. If your phone has ever fell onto the ground while being plugged into the charger, that is another common cause of damage to the inner pin contacts. Anyways, if you are still experiencing problems with this phone, I would suggest replacing the USB connector first to see if that fixes it. It would be cheaper than replacing the boards and more likely to be the issue.