Glad you found the HDD functional. Let us know what kind of HDD Maxtor put in the enclosure.
Any time you have HDD trouble, back up your data completely to another HDD, so if there is a problem in the Maxtor HDD electronics, you won't be out of luck.
Also run a S.M.A.R.T. appl to see if there is a problem with the HDD, like ActiveSmart, or Passmark DiskCheckUp. If there are no alerts in the report, then you know it was the PCB interface.