I have a 4th gen 20G ipod whose hard drive has died. Are replacement hard drives available through the apple store?

Question

I have a 4th gen 20G ipod whose hard drive has died.  Are replacement hard drives available through the apple store?

Answer 1

I don't think Apple will do that repair for you, because the iPod is too old.  I believe the hard drive type used in 4th gen and older iPods is no longer produced.  There may be non-Apple shops who can do the repair, but they may be using a working part salvaged from a used iPod.
If you want to do the repair work yourself, and you are good at such things, this web site has repair guides
http://www.ifixit.com/Device/iPod_Original
(There are probably also YouTube videos on the topic.)
NOTE:  There are two hard drive physical sizes.  The thick version has two platters, and corresponds to the "thick" iPods (with double storage capacity).  A 4th gen 20GB model should be the thin version.  The hard drive used in iPods up to 4th gen should work interchangeably, but 5th gen and later iPods use a different type.
I have a 4th gen iPod that started out as a 20GB.  The hard drive failed, so I put a compact flash card on an adapter in there.  The adapter is like this one (I bought it a few years ago so it's probably not the same seller)
http://www.ebay.com/itm/NEW-Compact-Flash-CF-SSD-To-Toshiba-IPod-1-8-inch-Adapte r-Black-/121174875639
The compact flash card is standard; I bought the cheapest one.  I currently have an 8GB card in there, but prices have come down, so I may get a 64GB card soon.  It works great with the 8GB card.  No more hard drive spin-up delay.  Battery lasts longer.  It's lighter.  And it should be more shock resistant.
The only mod I needed to make on the adapter was to bend over two pins 90º, where you place a jumper to set the drive to "master."  The adapter plus CF card is actually smaller and thinner than just original 1.8-inch Toshiba hard drive; I used some thin foam packing material (cut to the right shape) to take up the excess space and ensure the adapter and card did not become disconnected.
The 4th gen iPod has excellent sound, compared to some later iPods.