Help testing USB connectivity

[morbid88]

Just bought a replacement 6700 off fleabay and found it to be a reconditioned unit. (ripped off again). Using the tools in the kitchen, can someone give some advice on how to make sure USB is working on the phone. Bootloader reads Serial then USB when plugged in but all RUU's throw a connection error or unsupported RUU version. Would like to test in bootloader mode and give some commands to verify communication. Never had issues like this with my old 6700. Bootloader is 2.02, Does charge through USB, tested data transfer so cable is good. At a loss and starting to thing it's hardware related.

Thanks in advance