question for the hardware wizards

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Posted: Mon Dec 25, 2006 12:27 am

just how is the information stored on a HD with two disks?

I have a broken HD and bought a second of the same type.
now I'm planing to exchange the discs from one case to the other.
unfortunately it is impossible to install the discs with ecactly the same
rotation in respect to each other as they where when taking them out...

will this render them useless?

the blasted thing doesn't have to last forever, just long enough to read it once
and the data is not worth professional recovery

(I googled sectoring, but this describes only one disc)

Posted: Mon Dec 25, 2006 1:23 am

Agi, hard disk drives are assembled in cleanrooms so particulate contaminants don't settle on the platters. The RW head to disk spacing is so small nowadays, that if a dust particle or fibre from clothing were present, would likely cause a nasty head crash and further damage the disk. Disassembly of the case is therefore not recommended.

You are likely to have success transplanting the electronics from a working hdd to one with bad electronics. However, the manufacturers often revise the design during the model's production run. So, not only will you need the same make and model drive to salvage parts from, you will very likely need one from the same batch or production run.

With all electronic devices, suitable anti-static precautions will need to be taken (grounded mat on work bench, antistatic wrist-strap....).

You will also find the screws bolts or fasteners used to hold the various components together have odd heads. The appropriate screwdrivers may be difficult to obtain Sad

In summary: If the problem is with the drive electronics, a transplant from a working unit will give you a reasonable chance to recover your data. If the problem relates to the RW heads, then opening the case and transplanting heads from a working unit might work but the risk of losing all the data is much higher.

HTH

7/9

Posted: Mon Dec 25, 2006 5:33 am

I suppose you might have a chance at getting it to work. There's a video on youtube of a guy running an HDD without the cover, so if you work in a relatively clean room wearing gloves and work quickly, you could probably get most of the data back. And you have nothing to lose but an expensive hard drive.

Would it be possible/easier to transplant the electronics?

Posted: Mon Dec 25, 2006 7:57 am

if you go down this road (and as others say, its dodgy) try to minimise particles etc by :
1. go into the bathroom, close the door/window and seal gaps/vents with duck tape.
2. run the bath/shower so that a lot of steam builds up.
3. let the water run away and wait for the steam to condense.

this will remove a lot of the dust particles from the air and means the disk might survive the process.

I got this from when I was looking into serious case modding and thinking about putting a perspex window into a HDD (I didn't bother in the end because the concensus was that even then it wouldn't last long).

Posted: Mon Dec 25, 2006 11:34 am

@7/9
umm, let's say I know what I'm doing

I have swapped the electronics, outside and inside in a relatively clean room.
what I think the problem is, is the bearings on the part with the actual plates.
or the engine driving the plate. it looks as though the plates don't get enough speed, so the starting sequence is restarted over and over again.

Quote:

unfortunately it is impossible to install the discs with ecactly the same
rotation in respect to each other as they where when taking them out...

that is my only worry at the moment, for everything else it's too late

the HD inteior is self cleaning:
the spinning of the plates whipes the dust off and there is a filter in the path the air in the HD must take, so any particles left in there will be taken out b4
the heads move about the plates.

Posted: Mon Dec 25, 2006 6:53 pm

relatively clean room <> cleanrooms

class 100,000 (if your lucky in a well controlled environment) versus class 1,000 (bunny-suits)

Posted: Mon Dec 25, 2006 8:16 pm

Usual failure mode for a HDD are blown bearings. This causes a wobble that induces the physical crash. The servo driving the platters gets rotational velocity from info written on the disk itself. Not getting this info indicates physical damage with a disk or very remotely a WR head.
Removing and replacing platters is a very mean trick but may be a meaningless exercise unless the problem is a RW head. Good luck.

In the future, change hard drives at the first sound of bearing failure or after your second failed surface sector scan.

Not quite a Newb Joined: 17 Dec 2006 Posts: 22

If it is able to spin up put in the freezer for a few hours. Have the kit ready to mirror or image the disk as soon as you take it out. I would simply try and copy across the really important stuff like your my docs folder rather than try to copy the whole disk but you might just get lucky.

Sounds ridiculous but is has got me out of the poo more than once. It wont last long after you power it up but maybe long enough to get what you need off it.

Rinse and repeat may also work if the task is not completed first time round.

Posted: Tue Jan 02, 2007 9:26 pm

@geezer810

would have tried that before I opened it, though I'm not so shure how the bearings will take the cold Confused

now the humidity is probably going to condense on the disc

Baiting Guru Joined: 04 Jan 2006 Posts: 3193

It may be too late, and it's very expensive, but www.ontrack.com
Expect to pay around �1000.

419Eater Admin Joined: 30 Sep 2003 Posts: 7469

Exchanging platters I would suggest, would be a complete waste of time in this particular case. I think in the last 20 years I have only had three HDs die on me, but I still run weekly backups to a spare HD and optical storage. For very important data, I make two backups and keep them well away from each other!

I think you're going to need professional help, however it will be very expensive, and perhaps the data isn't worth it.

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