replacing platers & heads

[cooltechman]

I have many hard drives that have gone bad & wanted to give it a try at data recovery
i know you need a class 100 clean room but i figured nothing to loose
i have 8 drives all seam to do the same bios recognizes them but gives hd fail message they all make steady clicking sound which has allways been attributed to the armature either being stuck or something
when i oppened them they all seem to spin fine and armature mooves freely but on power up they just jump back & forth
is this heads not reading info for servo mottor or controller chip not responding
can anything be done as swap out from 1 drive to the other
it would seem that servo info is being passed on as on the wd drives if i force servo to edge of platen it stops spinning would seem to indicate it knows where heads are located
if anyone has info regarding what the cause of heads swinging like that would be greatly apprecated

 

[KimberTech]

There are many causes for the heads to crash into the platters in the hard drive. I will attempt not to get too technical here:

One is the actuator,which basically the motor that drives the head stack using magnetism.

Another is the drive controller which may give improper direction to the arm.

Yet another is a power problem on the logic board of the drive itself.

It could also be tiny dust or dirt particles interfering with the clearance which is miniscule between the head and the platter.

It could also be a mount failure of the platters, if they dont spin correctly, or slightly out of place, the head will bang.(Saw this on a dropped drive once)

Once you have the heads clattering, you almost always end up with physical damage to the platters. If you run it like that for long, damage is imminent.

I am technical ...and I can assure you that hard disk drives are not an end user repairable part. You can not effect any kind of reliable repair unless you have the know how, and the clean room you mentioned.
IMHO...a complete waste of time.

I can post some reading material for you if you are interested in the anatomy of hard drives and how they work.

Good question though.


Kimber

The more I learn,I realize how much more there is to know!

 

[cooltechman]

thanks kimbertech
but i believe that head crash is not what im expiriencing
and its not the heads clattering at all rather the actuator is moving back and forth very quickly as if it cant find any of the data on the drive
i have opened 8 drives all are doing the same thing
the platers dont seem to have any physical damage as they are clean and damage free
i have suspected the controller boards which i have replaced with known good on 3 of them
so in my opinion it leaves only the head itself or the tiny chip on the acuator that controles the servo action
i tried opening good drives to find one that the head assembly matches but unfortunatly didnt have any exact matches
any help would be appreciated
if any way to test head and servo chip

 

[Grenage]

Well if it wasn't in a clean room, I imagine the "good" drives are no longer good.

As Kimbertech says the Hard Drive really isn't serviceable past replacing the board.

 

[cooltechman]

i didnt have a clean room but did it inside a new plastic bag as carefully as possible
i set a norton disk doctor to make surface test in loops
its bean running for 24hr
so far not a single eror
though i know that it may cause premature hd failure they were old garbage anyway the data is more important than all the drives combined but im not going to pay for data recovery as they charge per MB and i have a total of 25g of data i need recovered
thanks all

 

[Grenage]

Well if you're determined, good luck to you and I hope you prove us wrong

 

[mudskipper]

cooltechman -- I, too, wouldn't expect that it would work. However, if you are successful (and I seriously hope that you are), then please post back and let us know how much YOU charge for data recovery! LOL I might need your services sooner or later! ;-)
Mudskipper
-----------------
Groucho said it best- "A four year-old child could understand this!
Quick! Run out and find me a four year-old child: I can't make heads nor tails out of this!"

 

[KimberTech]

If I were as determined as you are, and with no expectations at all, I would get my hands on an identical drive and put the platter in the new one. If you have corruption on the platters themselves then even a good head and arm will not find the tracks it needs to read the data.

If you are looking for testing for the components specifically, I have no idea.
I am technical but I do not design or troubleshoot components that deeply.

Have you tried any software stuff prior to dissassembling the modules?

Anyways...
Good Luck! Kimber

The more I learn,I realize how much more there is to know!

 

[stevejo595]

"don't do that" "you need a clean room" ...etc...

Have you ever tried it?

I had an old 20M MFM that wouldn't spin. I cracked it open right there on the desk, wiggle everything a bit and Whala! it worked! I did have to keep smacking it with a screwdriver now and then but I got my data off!

I suspect your drives have a bad controller bd. and I would replace that with a known good one before I started opening them up. The platters, actuators and heads can go bad but so can the electronics on the controller. I have a 30 GB Quantum fireball that has that exact problem. Worked fine, no noise, no lost sectors........then Wham! PC wouldn't boot, drive clunks a couple times when bios is trying to recognize it. I think I can get the data off with a new controller bd and afterwards, toss it in file 13

 

[Peahippo]

The clean-room aspect to working with hdd is over-rated.

True, the speck of dust is able to crash the head onto the disk, and cause data loss and catastrophic drive failure. But this is primarily a concern if you are making a drive you want to sell for $100, with warranty, to a user who expects to run it for years. This is NOT a concern if you are the end user trying to recover data from a drive which is going to be trashed anyway.

As long as you take reasonable precautions against dust and dirt (opening the drive in a clean plastic bag is smart) then you have done all that you can do to open and work with it safely.

My particular concern with this kind of activity is that if you choose to remove platters from one drive and put them on another. Even if you move all the platters between the same model of two drives, you can't be sure the design of the drive DIDN'T include a factory alignment of heads-to-platters.

As for platter rotation ... I've dis-assembled drives before, and noted that the platters are held in by friction ... they are stacked onto a hub with seperation rings. It is possible they can rotate on the hub over their lifespans, hence I conclude that the drive electronics probably adapt for it, hence moving platters may not involve data loss due to the angular orientation of them.

 

[Peahippo]

Cooltechman, I have some very bad news for your platter-moving idea. Surf to:

http://www.geocities.com/thestarman3/asm/mbr/DataRecovery.htm

... OR, to its Google cache:

http://216.239.33.104/search?q=cach...m+forensic+"hard+disk"+platter&hl=en&ie=UTF-8

... and you'll get this quote:

"Despite claims to the contrary, technology does not exist to remove the platters (without extensive control measures) from one device and read them back with another machine.

At the time of manufacture, control signals (servo information) are written to every drive after it has been assembled. Any attempt to recreate or read back these signals once the exact alignment and relative positioning of the platters and the head stack have been altered is virtually impossible.

Commercial data recovery companies (including ourselves) have invested heavily into research to overcome some of these problems. At Data Recovery Labs, we have been successful in many forms of platter transplants - but in every case - the removal of the disks must be done with exacting measurements to maintain the positioning in relation to the spindle that they are mounted on. If the platters are removed - without strict engineering methodologies - the surfaces are useless for data recovery purposes.

Industry sales reps routinely boast of removing platters and reading them in another drive and often allude to mysterious capabilities, but when specifically questioned on their success with physically removed platters they claim that each case is different and must be handled on a one by one basis. If pressed for examples of successful platter removal and recovery, they will usually claim it's a matter of not wanting to violate company confidentiality or reveal trade secrets."

(Citation: "Data Removal and Erasure from Hard Disk Drives." Copyright(c)1992-1998 Nicholas Majors & Data Recovery Labs. Toronto, Ontario, Canada.)

It's as I suspected ... the platters are closely aligned to the heads, and any rotation of a platter on a hub renders the data out-of-reach. This alignment is likely to be on the order of a thousandth of an inch.

Instead, don't remove the platters! Try to get the controller running. Hopefully there's a driving problem that can be resolved by changing the motor.