Also have you tried it in another computer with another PSU and data cable?
Given the drive doesn't exactly (or shouldn't) make any noise, you are relying on the detection of the drive via BIOS and then the OS right? hence, guessing you've ruled out other points of failure too?
Indeedy. It would be useful for these things to have some kind of power indicator. No bios detector on known good controllers/cables etc. If this were a normal drive I would swap the controller board and have a go. Is this an option on these?