Hard Drive Oddness

March 14, 2011 9:39 AM

Question about odd external HDD behavior--what, if anything, should I be replacing?

I have five Icy Dock external enclosures (like this one), holding various back up drives. My machine is a mid 2009 Mac Pro.

All of the drives have worked for a period of years (i.e., they're tried and true, but may be towards the end of their life). Over a couple of weeks, the HD that backs up my photos was having troubles that seemed to clear up when I used a different USB cable. Last week, the drive totally konked out. The drive (1TB Western Digital Caviar) was making a tapping sound, and failing to mount. I ran Apple's Disk Utility, it said there were errors; I told it to fix them, but the fix failed.

Got a new drive, backed everything up. The old drive is still in warranty, so I got a Rosewill external enclosure--figuring that with the new drive and the RMA'ed drive, I'd need one more encosure.

As an experiment, I put the "dead" drive in the new enclosure, it worked fine, and passed multiple scans, with no tapping sound. Put a different drive in the old enclosure--and the old enclosure and the different drive work fine, with no tapping sound.

Put the old drive back in the old enclosure, dead as a doornail, and the tapping is back.

Any ideas? Since I've already replaced it, I'd be happy to RMA it--but could it be the enclosure causing the problem? Will WD even check the returned drive, or will they just confirm that it's still in warranty and send me a replacement?

Bonus question: when running Disk Utilities, I found that it took about a minute to scan each WD 1TB drive I have, but it took about 4 minutes to scan a 500GB Hitachi (which came up clean on repeated scans). Same result even after reformatting the 500GB drive. They're all 7200 RPMs, and all formatted the same way. What gives? Should I be concerned?

posted by Admiral Haddock to Computers & Internet (2 answers total)

I've had weird errors with drives in external enclosures be caused by slowly dying power supplies and the bridge boards in the units going under. I'd wager, based on your description, that the power supply is going out on that particular Icy Dock unit, and the drive's just not getting enough power to spin up. if the others are the same model, you can try swapping the power adapter from one to the other to test. (I had a Rosewill enclosure that started generating errors and finally was unusable via FireWire when the power adapter went out; drive ended up being perfectly fine and I'm actually using it now for Time Machine - in a different enclosure, of course. I've resolved to start buying better quality enclosures - namely, the big RAID deals that OWC sells, that have real power supplies in them.)
posted by mrg at 10:06 AM on March 14, 2011

Thanks! I swapped the power supply for different one, and it spun up and passed its tests! That likely was the problem. It looks like I'll be getting another enclosure. Appreciate the input.
posted by Admiral Haddock at 6:53 AM on March 15, 2011