Hi All,

I got a case which requires heads swap for Hitachi 1TB 3.5 drive Model: HDS721010CLA332 1TB 3.5 date AUG 2011.
I have the same Hitachi drive as a donor - > Model: HDS721010CLA332 1TB 3.5
The donor drive has the same MLC and P/N as the patient has and it is from APR-2011 so the heads seems to be compatible.
The patient drive has 4 heads while only head 1 (0,1,2,3) is dead while all the others are good without even one single bad sector on their reading zone.
So I transfer the heads from the patient drive to the donor drive and from the donor drive to the patient drive the heads swapping was quick and smoothly.
Before I power on the patient drive I powered on the donor drive with the patient heads stack on it.
The donor drive couldn't be recognize by PC3K. But instead it just started to make unpleasant sound with clicking scratching and choking sounds.
I can't think about what went wrong during the heads replacement procedure. What cause the drive which was perfectly worked before (so there is nothing on the platters which could kill the heads) to act like that.
This behavior happen to me before with 500GB Hitachi 3.5 drive.
I have got an hunch that it belongs somehow to an alignment issue that went wrong during the operation or the top magnet got now any change or maybe one of the screws has to be put differently.
I can't think about other way to put the magnet, screws, heads differently.
Before I closed the lid of the drive I checked carefully that there is nothing on the top platter (nothing like a dust or something).
After the donor drive act like mentioned I opened it's lid drive to see If there are new scratches over the platters but nothing. The platters were clean.

Can't think of any reason why the drive was acting like that after heads swapping with heads which seems to be compatible.
Please give me some tip or advice were should I look into.
I didn't connect the patient drive to the power yet so if there is something wrong that I made with the donor drive I will still have the chance to fix it with the patient drive.

Best Regards,

Did you check the heads that were making the noise with microscope AFTER the swap ?

+1 BlackST...

Always check your heads under magnification if you want the best results... The little buggers can sometimes come loose (especially after a fall) but appear to be sitting OK to the naked eye...

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But the donor drive never fall before and not after. More over it was worked perfectly before the swap.
I can't think about even the smallest thing that went wrong.

Lets think about that, what are the parts which combine that drive which are envolve with the swap opertaion:
1) Top magnet -> hold up by 3 screws. -> what can goes worng with that??
2) Little magnet with black rubber which prevent the heads from falling out of the ramp. -> what can goes worng with that??
3) heads stack. -> They are located on a ramp and were smoothly taken out and back to it. So what can goes worng with that??
4) Screw under the heads which tight it to the drive's body. -> what can goes worng with that??

All those were placed in their native location.
What can goes wrong with those during the operation which ends up with such bad noises and unrecognize drive?!
By a simple look it should be very easy to get a working drive after swaping the heads since there is no any risk to heads during the swaping.

Honestly without attending the procedure I can't tell what could be the problem, but being logical, things are :

1) Something mechanical happened
2) There is hidden media damage
3) There are differences in the parts (even unnoticed) that prevent the procedure from working.

Still unknown what was the outcome of the swap and analysis of the headstack after swap (damaged ? where ?)
I am also sorry to confirm that it is not an easy drive to work with.

@Scorpion
Want to verify your work is error free and understand what the issue is generally speaking? If yes, buy 6-10 drives of the same kind like your customer's, ideally from different sources so that you do not receive a number of drives that were manufactured back to back on the same assembly line. Of course follow typical compatibility rukes. Do head swaps between them and follow BlackST's suggestion. Record results. See if you can conclude a pattern!

Best wishes

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I am sorry - are you talking about possibillity that head/slider de-glue itself from a steel part during swap?


@thread author: you have few valid questions, looking forward to see answers on those by emminent data recovery experts.

Seems that knowledgeable people here, tend to be evasive with answers to exact qusetions.

Understandable is that is difficult to take stand in this field (DR), but....


Nevertheless, why is commonly stated that head/slider must not touch each other?


And if I hijacked topic a bit, my sincere apologies...


Haltec

Like pcimage said, this is hitachi Arm. Head swap -even with perfect donors- in most cases doesnt work. Few amongst us know why but wont tell
Still looking myself fot the answer.

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Not a cheap offer.. Such experience will cost me at least 800$-1000$ (in the ideal way) not including the shipping and the costum..



For those who got the answer PM to me I would like to buy the magic answer from you.

If we are evasive, then give the correct answer without seeing the drive.