Hi Taylor/Kelvin,
I remember in the past that I would sometimes have to replace switches when their console ports would stop working. I haven't had to do it in a long time, but I did back in the EWare days. Not saying this is necessarily the case, but its possible that its the situation here. I'd say if the same USB/console/computer/terminal emulator settings are working with another Extreme switch, I'd say the console port may have a hardware issue.
Thanks
Brad