What does it mean that it won't spin down? Will spin all day long, even when it's not accesed? Or everytime the TC is mounted?
Well, none of us can be absolutely sure what is going on, but we're
assuming the drive platters stop spinning and maybe the heads are parked in some way and maybe the drive goes into some low-power "sleep" state.
What is
noticeable is an increase in sound and vibration of the TC when the drive is first accessed, and a decrease in sound and vibration 2 - 3 minutes after the drive is last accessed. We've been calling this "spinning up" and "spinning down".
Depending upon the drive installed, these changes may be very slight and difficult to notice, especially the vibration. My TC sits about 6 feet away from me in a quiet room, and when no other externals are being used I can hear the change in volume as the TC internal drive is accessed and as it "goes to sleep." To notice the change in vibration, I had to mount then unmount the drive using Finder, then go put my hand on the TC itself and waith 2 - 3 minutes. It was a slight change, but I could feel it.
I believe everyone's TC exhibits this desired behavior as it comes from Apple, but after hard drive replacement some people have had the result that the TC/drive never go into the quiet "spin-down" mode. I
assume that means the platters remain spinning, I guess as long as there's power to the TC, so yes, all day long.
This isn't necessarily a big problem: the slightly increased noise, power use, and wear(?) on the drives may well be negligible and unimportant, but it is just different than a stock TC. It still works fine for backups and restores.
