Why isn't my Galaxy S4 charging?

A

AC Question

Galaxy S4 not charging

Hi, I have a problem with my S4 not charging. When I plug the cable in, the red light comes on and the phone does say its charging but does not gain any power. Now the phone is completely dead and will not charge which means I can't turn it on. I have tried another battery in this phone and the phone does turn on however still won't charge. I have also tried different chargers. I took the phone to a repair shop and they changed the charging port however still no luck. They suggested that it could be a problem with the motherboard? Anyone know what this issue could be and how I could fix it?

Thanks