You may need to replace the USB port. We have a detailed guide of how to do just that here [guide|72377]
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You may need to replace the USB port. This is fairly easy to do. It is soldered onto the circuit board with 6 contact pins. If you do not know how to solder iFixit has a great guide here. https://www.ifixit.com/Guide/How+To+Solder+and+Desolder+Connections/750
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Make sure the soldering iron reaches temperatures higher than 300 degrees Fahrenheit. Hope everything works well for you.