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 Post subject: WD6400AAKS clicking – weighing my options
PostPosted: February 22nd, 2018, 5:16 
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I have two WD6400AAKS HDDs, which used to be the main drives in my former computer (at first as a RAID1 array, then as a single drive + backup).
Last summer, I used one of these for quite intensive operations (extracting all files from several 40GB Norton Ghost images), letting it run about 15 hours a day, several days in a row (during the hottest days, using an non ventilated external enclosure – don't do dat). When I shut it down at some point, it made a weird noise, not a click, more like a slight screech, I knew that something went wrong, but still hoped that it was only a glitch. But indeed, when I turned it on the next day, it was clicking, with a regular pattern : two clicks, automatic shut-down, two clicks...
The data on it which hasn't been backed up is not valuable enough to justify the cost of a professional data recovery job (which would set me back about 800€ in my area, I believe). Still, I'd like to try a recovery. As I said, I have another drive of the exact same model which was bought at the same time, thus most likely an ideal potential “donor”. So, is there a slight chance of recovering this by myself ? I've heard (Scott Moulton's talk) about a procedure called "live PCB swap" : would it be worth trying this in that particular situation, on this particular model, considering the symptoms I described ? I've also read on this forum that it would require special tools to work. But here (and in Scott Moulton's talk) it's described as a quite straightforward operation which doesn't require any special material or software, and could indeed work if the failure comes from a scratch on the drive's system area – kinda contradictory informations.
If it does not work, that probably means that the heads are bad, so what are the odds of achieving a head swap (using the working unit as a donor) and a successful recovery, in the dusty environment of an apartment ? Are they so low that it's not even worth the trouble (except as manual training, so it'll still be worth it, as I have a growing interest in data recovery procedures, but of course I'd prefer to get an actual result !), or can it allow at least a partial recovery if done with utmost care ? Are there some known working tips that would increase the odds, some tricks to know about with that particular model ?
Thanks.


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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 22nd, 2018, 11:58 
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Short answer: No, you cannot do it yourself without the proper equipment and know-how.

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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 22nd, 2018, 12:20 
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abolibibelot wrote:
But here (and in Scott Moulton's talk) it's described as a quite straightforward operation which doesn't require any special material or software, and could indeed work if the failure comes from a scratch on the drive's system area – kinda contradictory informations.
.


:roll:

I find it fascinating that information like this is still readily available and that such bad advice is considered as an option - in reality, information like this should either not be available or should come with a number of disclaimers that list the actual risks involved with such processes.

Scott Moulton has given lots of bad advice via various videos and posts - it seems that he is a marketing genius, but not so much of a recovery guru IMHO...

In regard to your post, Jon's response was as simple and straight as you can get - seek professional advice if data is not important. (Anyone except Scott Moulton should be ok :wink: )


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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 22nd, 2018, 13:49 
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Well... could you please be a little more specific ? What would be the disclaimers regarding the risks of the live PCB swap procedure ? Is there a simple way to assess if this could be a possible workaround, or if it's totally pointless ? (The other link I provided seems to come from a legitimate data recovery company, so if information like this is bad, Mr. Moulton is not the only offender in the business...)
You meant, “seek pro help if data is important”, right ? I already said : not so much. I'd like to get it back, but it's kinda expendable, and I sure wouldn't pay more than ~50€ to recover that. I've read quite a few threads here where someone was asking for a 100% working DIY solution in a situation where failure was not an option, i.e., data was extremely valuable – this is not such a situation.
And seeking professional advice – that's what's usually provided here, right ? Maybe I shouldn't have mentioned that specific procedure right away – it seems to be rubbing you the wrong way, as if it was screaming “newbie coming up with recipe for disaster number four on the most talked to death recipes for disaster's list” ! :^p
In another thread, I was given some hope to recover data myself from a 2GB HDD by performing a head swap in a regular environment (I haven't had the time to deal with it yet, I found a replacement unit but still need a TTL adaptor). What would you say is the absolute capacity / platter density threshold beyond which this is absolutely bound to fail ? Or are there other considerations, beyond the dust issue, to worry about ? If so, again, could you be reasonably specific ? Or is this sort of “classified” information ?


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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 22nd, 2018, 16:18 
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@Spildit
Thanks for this constructive reply. Considering the way it happened, I wouldn't think that the PCB is causing the problem. In your (or anyone's) experience, what would be the most likely cause of failure, here, which would be consistent with the conditions I described (sustained workload, heat – I must add : no prior sign of failure, SMART status was absolutely pristine up to that moment, no warning whatsoever from HD Sentinel) and that faint screeching noise I heard just as it was spinning down ? Damaged system area, head failure, preamp failure ?
I've read that the preamp was either glued or welded to the head assembly, and excessive heat could make it malfunction : when that happens, what are the immediate symptoms, noise or otherwise ?
If it's head damage, it's unlikely that all heads get damaged at the same time in a case like this (no shock), right ? Then shouldn't it be possible to read something with the still functional heads ?
I know that clicking can be related to several distinct issues, but are there particular clicking patterns related to particular issues, or does the diagnosis always imply advanced hardware / software to access the ROM modules and whatnot ?

Read ROM with external programmer : that's some kind of very specific and expensive equipment, right ?

Quote:
Hot Swap would be pointless because you would have the translator loaded from the donor drive in the RAM so you wouldn't be able to properly retrieve data. You can do that to TEST only. If the heads still "click" and the drive doesn't read anything at all (you can't scan a single sector with victoria) and/or you can't read SA modules with something like a free DEMO of WDMarvel then most likely the head(s) are gone.

But isn't the live PCB swap precisely supposed to bypass the system area and allow a direct access to the data on the platters, if/when only the system area is damaged ? Or is the data in SA which is specific to a given unit necessary to its proper operation at any time, for that particular model ? (WD6400AAKS, Western Digital “Blue” 640GB from 2009, I can provide more detailed informations if needed)
Victoria is a Windows only tool, right ? But if any home procedure works at this point, the wisest course of action would be to clone the drive A.S.A.P. with ddrescue or HDDSuperClone running on Linux, right ?

Quote:
If i were to put a limit on drives that you can still open for some short time outside of a HEPA 100 clean room and still recover some of the data i would say 80 GB drives and only if you don't have a huge amount of dust particles on the air and if the dust particles are not going to get "stuck" to the platter like humidity and stuff that will be grudded to the platter. If it's just some particles of "dried" dust those will most likely "fly way" from the platter as soon as it starts to spin. If you live in a place that is very dry and have no humidity you will have more chances. But only with 3.5 drives that are 80 GB or smaller and also if they don't have special "problems" like Quantum drives or some older WD drives that will loose the head alignment if you unscrew the lid as it holds the head assembly as well.

Alright, that's not encouraging... But, considering that paying for a professional service is not an option here, I may still try it anyway, if only for pedagogic purposes, and as a personal cautionary tale ! In which case, are there specific details I should know about regarding that particular model, to optimize my odds of success, like, going from 1% to 2%, or from 0.01% to 1% ? :)


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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 27th, 2018, 8:59 
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I'm pretty new here, and I just wanted to drop in my two cents worth. I've been in the industry for a few years now, and though its impossible to be certain without the unit in hand to confirm, this is my best guess at the failure your drive suffered and the process someone would have to go through to salvage the data from it. This is by no means instructions or any form of encouragement for you to try this yourself, but rather an example of the kind of work that the pros get paid for. I've seen many drives of this and related models, and have found them to be reasonably robust.

Failure sequence, best guess: Drive running hot for hours on end, sudden power cut or unexpected disconnect from PC. Drive electronics initiate emergency unloading of heads. Minor distortion of parking ramp due to high temperature, one suspension assembly strikes edge of ramp, ripping slider off arm. Remains of arm no longer high enough to park correctly jam under ramp, preventing actuator from reaching parked position. Remaining intact heads rub against slowing platters causing screeching noise heard. Drive is free enough to allow spin-up on subsequent power cycles, heads knock and produce clicking noises as reading is attempted (and fails) from the damaged surface assembly. Damaged assembly rips into its associated surface with each sweep, potentially causing significant damage. Extent of damage depends on how many times drive was spun up.

Repair process, best guess: Drive is opened in clean room, and actuator assembly and platters are removed. All surfaces are inspected and cleaned. All surfaces have scattered contamination from breakup of slider assembly and subsequent damage to associated surface. Most damage restricted to area under parking ramp where heads rub during spin-up and spin-down. Decision is made regarding each surfaces chance of recovery, and all further work depends on either the primary or secondary (ideally both) of the drives System Area's remaining reasonably intact. If a good System surface remains, drive is reassembled, and platters are re-positioned to ensure they meet factory geometric tolerances (basically ensuring the data tracks are still perfectly circular with respect to the center of rotation). New actuator assembly from suitable donor drive is installed, with the suspension assemblies of the heads for any surfaces deemed beyond recovery removed. Manual initialization of drive can now be attempted. All critical system data is read from the drives most intact System Area, and pushed into drive RAM, modified to "hide" any missing heads to allow automatic initialization tests to pass while preserving zone table and translation mapping. This mapping is unique to every drive, and is generated during the drives assembly. It cannot be replaced with data from another drive without causing catastrophic data corruption. Once drive reports state "Ready", changes can be made to the drives RAM state to disable all of the drive self-repair functions which will hinder imaging. Imaging can then be attempted from the drives undamaged platter surfaces in accordance with the zone mapping.

And after that (assuming the imaging went reasonably well), the data has to be checked to see what (if any) of the original file structure remains, and repairs made where possible. Given that your drive has 2 platters, with all 4 sides in use (best guess, it is possible your drive is a "mule" unit, basically a cut down 1TB drive with 3 platters), and the zones (amount of data drive writes to one surface continuously before moving up the stack)are roughly 100MB, we can say that a single badly damaged surface will destroy any files over 300MB in size. If all surfaces are in reasonable good shape, then a very good recovery is certainly possible. But that possibility gets smaller with every click it makes.

But that's just my best guess, and feel free to try whatever you would like...


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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 27th, 2018, 11:46 
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Arigato Gozaimashita, Kuno.

Your generic advice is pretty solid.

Based upon the symptoms described, I am confident that the client's drive has a heads failure (with media damage).

What the OP doesn't know (we can't expect him to) is that the most important thing at this point is an accurate diagnosis that minimizes the chances of further damage. It's a safe bet that the more someone plays with a drive in this condition, the lower the chances of getting back anything.

So the next step, as Kuno-san noted, is to disassemble the drive in clean room and inspect the heads under a microscope. It may or may not be necessary to treat the platter surfaces, and it is risky to attempt platter extraction unless you have the proper equipment (platter burnishing tools) and expertise. Wiping them with a clean room cloth won't get the embedded particulate.

If the OP wants to try to figure out the cause and extent of the failure (but not really concerned about recovery), then I say, have at it.

People who are not in the business think that people who are are being unreasonable, haughty, greedy -- you name it -- when we discourage client interventions. You haven't seen the abortions that we receive nearly every day from clients who "watched a video" and made their drives [needlessly] unrecoverable.

A hard drive is not a toaster . . . all of these videos ought to have a HUGE disclaimer at the very beginning. It is irresponsible (if not negligent) not to.

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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 28th, 2018, 5:40 
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@Kuno :
Thank you very much for these very thorough explanations. (I'll have to re-read them carefully with detailed schematics next to the text to fully understand them – I'm not sure what some of the terms used designate exactly, like “ramp”, “suspension”, “slider” for instance.)

Quote:
Repair process, best guess: Drive is opened in clean room, and actuator assembly and platters are removed.

I thought that removing the platters was an exceptional measure, generally avoided even by the most seasoned professionals, unless there's an absolute necessity to do so (drive immersed in water for instance). Is the sequence of events you described (whether it does correspond to what happened in this particular case or not) a particularly severe kind of failure, despite the rather unimpressive way it happened, externally ? Is it potentially more destructive (or harder to deal with) than, for instance, a drive sustaining a sudden shock while in operation ? (I've recovered almost all the contents from a few drives which had sustained such damage by software-only means, namely ddrescue – for instance after my brother landed a punch on his laptop computer because Internet was too slow and he couldn't watch a Formula 1 race in live streaming...) The screeching noise I mentioned was very brief and faint, and no such noise could be heard the next time I turned it on (which I only did twice so far – the next day after the failure, while the temperature in the room was still very hot, and I gave it another try recently, hoping – foolish I know ! – that it could somehow “come to its senses” in a colder environment), only the regular clicking pattern.

Quote:
New actuator assembly from suitable donor drive is installed, with the suspension assemblies of the heads for any surfaces deemed beyond recovery removed.

In this case, that means that entire platters are not recovered, so the recovery rate must be very low, with many damaged files (especially the larger ones, since, as I've discovered recently on this forum, HDDs record data on platters “in serpentine fashion” (usually in strokes of a few hundreds megabytes as it's been demonstrated in this thread), not sequentially as it might be more intuitive.
[I hadn't read the last paragraph yet when I wrote this, see below.]

Quote:
All critical system data is read from the drives most intact System Area, and pushed into drive RAM, modified to "hide" any missing heads to allow automatic initialization tests to pass while preserving zone table and translation mapping. This mapping is unique to every drive, and is generated during the drives assembly. It cannot be replaced with data from another drive without causing catastrophic data corruption. Once drive reports state "Ready", changes can be made to the drives RAM state to disable all of the drive self-repair functions which will hinder imaging. Imaging can then be attempted from the drives undamaged platter surfaces in accordance with the zone mapping.

So :
– The “live PCB swap” is just a myth ? Or it doesn't work with “modern” drives ? (I'm aware that even if it could work theoretically, it would imply that all heads are still functional, the theory being that it is supposed to bypass the system area and the self-initialization process.) If the mapping is only related to the P-list (factory-reallocated sectors if I'm not mistaken) as it's been said above, isn't there a possibility to compensate for that corruption by crude software means like shifting portions of the drive's image, after analyzing the P-lists from both the failed unit and the donor unit ? Or is this not practically manageable ? Do all HDDs have reallocated sectors in the P-list, or is it not too unlikely to be lucky and have two units with an empty P-list ?
– Even if I did manage to swap the head assembly properly with very few dust particles landing on the platters, it is almost certain that it wouldn't work for those reasons ?

Quote:
And after that (assuming the imaging went reasonably well), the data has to be checked to see what (if any) of the original file structure remains, and repairs made where possible. Given that your drive has 2 platters, with all 4 sides in use (best guess, it is possible your drive is a "mule" unit, basically a cut down 1TB drive with 3 platters), and the zones (amount of data drive writes to one surface continuously before moving up the stack)are roughly 100MB, we can say that a single badly damaged surface will destroy any files over 300MB in size. If all surfaces are in reasonable good shape, then a very good recovery is certainly possible. But that possibility gets smaller with every click it makes.

Oh, right, I hadn't read this yet when I wrote the remarks above. That just confirms them. (Although, in the aforementioned thread, the “zones” were shown to be higher, like 263MB for one of the tested models, which would double the threshold.)



@jono-ats
Thanks to you too.

Quote:
So the next step, as Kuno-san noted, is to disassemble the drive in clean room and inspect the heads under a microscope.

So there's no way to say for sure if heads are damaged (and more generally to make an informed diagnosis) prior to opening the case ? If the above scenario is indeed what happened, is the damage likely to be visible to the “naked eye”, or not unless it's tremendously extended ?

Quote:
If the OP wants to try to figure out the cause and extent of the failure (but not really concerned about recovery), then I say, have at it.
People who are not in the business think that people who are are being unreasonable, haughty, greedy -- you name it -- when we discourage client interventions. You haven't seen the abortions that we receive nearly every day from clients who "watched a video" and made their drives [needlessly] unrecoverable.

Well, I would like to be able to recover some files which I stored there temporarily (and nowhere else – they were recovered from another drive which I then re-purposed and filled entirely, and considering their “track record” I was under the impression that those 640GB units were highly reliable), but they are certainly not worth the cost of a professional recovery (they're more like historical archives, and wouldn't serve any actual purpose). If my main HDD had failed in the same way (a few weeks later I also had trouble with it, a dreaded Seagate ST2000DM001, but managed to clone it in its entirety), with my most current working documents and pictures and e-mail archives and a gazillion other files gathered over the years, I wouldn't have taken any chance and would have paid the price, however harsh it would have been (although I did have a backup it hadn't been updated in months – bad practice I know, an automated online backup system would be much more efficient but my current measly uploading speed would make it highly impractical).
The problem is that this is an all-or-nothing situation : according to the informations provided here, there is nothing I could do with my current level of knowledge (which is definitely above average I would think, I'm often trying to explain technical aspects of hard disk drives' inner workings to people who see them as “toasters” as you say – although I realize that I'm still far from being an expert in that field) and equipment (quite basic and I couldn't affort the kind of advanced hardware/software interfaces that most regular contributors here use on a daily basis) to get a half decent result, or even just a few usable files, while paying for a full-blown professional data recovery service would be way overkill in that particular case. Considering this, what is the least stupid thing I could do with that drive ? :? Just store it in the hope that one day I could become skilled enough (and adequately equipped) to perform the recovery myself with a good degree of confidence ?

@Spildit :

Quote:
If your PCB have an EXTERNAL ROM chip you should be able to read it with a CHEAP external programmer and a SOIC 8 clip like this :

I tried to gather some informations with the two first links you provided, but could not find any mention regarding the price of those devices (external programmer). I haven't yet explored the two other links.

Quote:
Regarding that model just go buy an identical drive, remove the heads of that drive and place them back !!! I'm talking about removing the heads of an exact same drive and place the NATIVE heads back. Now try to read the sectors of the drive. Most likely you will not be able to do so and you did ruin the drive.

Just because of the dust particles, or also because of the required level of assembly accuracy ?

Quote:
And we are not even talking about head compatibility and the fact that heads have their own micro-jogs settings that are stored on ROM module, etc .... We are talking about removing the heads from a drive and use those heads tha are calibrated for that drive on it's own drive. Now if you figure out that it've very hard to do so imagine tryng to do the same but with diferent set of heads that are not calibrated for that specific drive, that might not even be compatible, etc.... Try it. But do yourself a favour and buy a drive to test with first. When you decide that you can do a head swap with some confidence then try to get another drive of the same model and swap the heads from one drive to the other, then practice. After some attempts and some heads destroyed let's say 50 or 100 times you can move to the drive with data that you want to recover. Untill you manage to do the head swap procedure on a drive that you don't care about don't even think in doing it on the drive with the data you want to recover.

Well, that seems kinda daunting... but I guess that everyone here who's speaking with confidence went through this at some point ! I found a used WD6400AAKS in perfect condition for 25€, I'm still wondering if it's worth it to buy it to almost certainly ruin it, and possibly not even gain significant knowledge in the process, which would require that I spend 10 or 100 times that amount... at which point, if I ever become proficient to do it, it would have been cheaper to have it done by an established DR lab, and at which point the hard disk drive technology may be declining to the point where I couldn't even turn the acquired expertise into a sustainable activity ! :)


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 Post subject: Re: WD6400AAKS clicking – weighing my options
PostPosted: February 28th, 2018, 10:11 
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abolibibelot wrote:
and at which point the hard disk drive technology may be declining to the point where I couldn't even turn the acquired expertise into a sustainable activity ! :)

Being successful in this business in saturated places offering this type of service has little to do with skills. Marketing and operation costs will pretty much eat the profits away. Kind of late to get in the game. In underdeveloped areas, yes, there is opportunity. Unless you know the language well, it is tough to go into a foreign market without, significant capital, connections and general help to get established.

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