Hi
I have a bit of an unusual question.
I had an old (USB 2) external HDD and enclosure powered by a 12V brick. The computer (windows and Mate 18.04) stopped detecting the HDD but worked correctly with a different USB 2 enclosure on the same USB connection (but a different 9V psu). Since it was (very) old I decided to replace the problem unit with a new (USB 3) model. Because I am lazy I left the brick in place and used it to power the new housing/HDD (they are both 12V @ 1500mA and same barrel plug) and gave it a USB 3 connection. Guess what, I had the same problem, the OS's didn’t see the drive so I swapped the 12V brick for the new one and all I working as expected... I can only conclude the brick was causing the problem, unfortunately I discovered the brick issue after I had pulled the old housing apart so the theory can now not be tested with resulting pile of peaces...

A little while later I had identical symptoms from the 2 drives in a SATA connected removable 5.25" bay, I have 2 removable 5.25" SATA units in the desktop (these ones https://www.amazon.de/gp/product/B007X5 ... UTF8&psc=1). Each unit has a SATA connection per drive and the bays are powered by the PSU. I discovered the two drives in one of the bays weren’t being recognised (by windows and Mate) but the drives did work when swapped into the other bay. I replaced the bay and all is working as expected again.

I am curious, has anyone encountered the sort of power related enclosure failure I experienced with the USB drive and are there any ideas as to why I had what appears to be the same failure type on a SATA bay with a different power supply?

Thanks

Were the HDDs 3.5" or 2.5" models? A 3.5" HDD requires both +12v and +5V power, while a 2.5" HDD requires only +5V. A 9V PSU would imply that your enclosures are +5V devices with an internal step-down regulator.

Do the barrel plugs in your 12V PSUs have the same polarity, ie are they both centre positive or both centre negative? Reversing the polarity would either damage an incompatible enclosure, or it
may just not work (if there is a diode in series with the input).

_________________
A backup a day keeps DR away.