WD7500AAKS pretty sure its a Head swap. Symptoms included

[cgallery]

Any ideas. Please

Still not too late to send it to East African Data Handlers.

Sorry, couldn't resist.

[Doomer]

Any ideas. Please

Send it to professionals

[Doomer]

Still not too late to send it to East African Data Handlers.
Sorry, couldn't resist.

That could work too if you want to laugh

nice one cgallery

[mediaman]

hhhaaa
well done!

doomer: i'm trying to be professional but the learning curve is steep. This is the first failure i have had in the past 20 disks. good thing it's mine and not a customers. Come on, what would you try next?

[Doomer]

Come on, what would you try next?

I just remembered one good Russian book
Here is a quote from it - "Maybe you even want a key from the appartment where money are lying?"

[mediaman]

hmm, thanks a lot! (I'll assume for the purposes of this thread that something got lost in translation)

Actually I am suspecting static produced by the hepa filter set up may be the cause? My whole bench, and me, and chair etc is grounded, but could the airflow have a static charge? I know WD,s in general are very sensitive. I am going to put the heads back on the donor to see how it works. As I say, the head swap went really really well, you would have been proud!

[cgallery]

As I say, the head swap went really really well, you would have been proud!

But, it didn't work. How well could it have gone?

Do the heads fasten from the bottom of the drive? Or are then clamped by a fixing screw through the top. If they aren't fastened from the bottom, you're very likely have an alignment problem, aren't you?

[mediaman]

thanks for the feedback. my point is the swap went so well something else must be missing, you are prob. right re alignment.
The heads have no bottom screw. They swivel on a pillar and are fixed only from the cover plate screw, ie. there is no internal screw at all. Even the magnet/retainer assembly has no internal fixing screws. The only internal screw is on the ramp.

Alignment tips?

[cgallery]

Alignment tips?

I'm been working on a technique, but I'm not ready to announce anything yet.

[Russwinters]

As far as the lidscrew/head alignment, your best bet is probably to attempt something like Dmitry shows in this article; at the bottom of the page

http://hddguru.com/content/en/articles/ ... k-Q-and-A/


Obviously, you would want to do this while it is within the flow bench to reduce the chance of particles landing on it (although if it is spinning this should also help alleviate this)

Also, you will want it connected to whatever imaging device you are planning on using WHILE it is in the flow bench and you are doing this, because if you find the alignment positioning you may not get it back, so you must be ready to image right away.

*Edit* A note to make is that as Dmitry mentions; the drives he was working on are much lower BPI then the drive you are working with. This is going to make alignment much more difficult =(

[mediaman]

Hey Russ. I really appreciate the feedback. THis disk is still sitting there messed up. I Screwed up basically, not with the HSA swap itself, which went well, but by not realizing the almost impossible alignment problem. The density is so high that micrones will prevent track reads.

Someone out there know's how, or can do it, but I haven't been lucky yet. Painful learning curve mistake....

I should have sent it to east africa..

[Russwinters]

Yeah drive density levels are getting very high and causing a lot of problems. Not only are the drives more delicate (a small knock can set them out of alignment). But recovery can be near impossible, if not impossible.

[BlackST]

No it's not impossible. I have a solution for alignment but unfortunately is rather complicated so it's neither commercially exploitable :S anyway it was a good experiment and worked decently.

[magneto]

hmm, thanks a lot! (I'll assume for the purposes of this thread that something got lost in translation)

Actually I am suspecting static produced by the hepa filter set up may be the cause? My whole bench, and me, and chair etc is grounded, but could the airflow have a static charge? I know WD,s in general are very sensitive. I am going to put the heads back on the donor to see how it works. As I say, the head swap went really really well, you would have been proud!

I highly doubt that you did 20 recoveries in a row in the same cleanroom with no issues and then had an issue with static charge. What made you think static charge? Was it not cleaned correctly or were you rubbing it with dry paper towels for extended periods of time prior to the swap? What happened when you put the parts drive heads back into their original case? Though the sound isn't good, I wouldn't rule out firmware issues; at least if you are positive that your headswap went well. The heads are sensitive but I think with them ramped you could get away with this drive. Alignment is crucial but I've personally pulled headstacks out of many, many WD series hard drives and put them in donors. Then when the swap didn't work I placed them back into their original cases and the heads worked fine with no crazy contraptions or methods. Firmware adaptives are crucial after a swap, instead of the quasi-random guessing of alignment. Does the drive ever "come ready"? Even into it's "safe mode"? What equipment do you have available to you, i.e., firmware manipulation?

No it's not impossible. I have a solution for alignment but unfortunately is rather complicated so it's neither commercially exploitable :S anyway it was a good experiment and worked decently.

Complicated or not, if you're not willing to share why post about it? I imagine there are some pretty intellectual people on here that might be able to comprehend that intricate details of the task. As well as many who will attempt and fail. I know you've mentioned an NDA on several occasions and that is understandable. But IMO "No it's not impossible" would suffice, instead of talking about methods that can't be shared with others.

[mediaman]

hmm, thanks a lot! (I'll assume for the purposes of this thread that something got lost in translation)

Actually I am suspecting static produced by the hepa filter set up may be the cause? My whole bench, and me, and chair etc is grounded, but could the airflow have a static charge? I know WD,s in general are very sensitive. I am going to put the heads back on the donor to see how it works. As I say, the head swap went really really well, you would have been proud!

I highly doubt that you did 20 recoveries in a row in the same cleanroom with no issues and then had an issue with static charge. What made you think static charge? Was it not cleaned correctly or were you rubbing it with dry paper towels for extended periods of time prior to the swap? What happened when you put the parts drive heads back into their original case? Though the sound isn't good, I wouldn't rule out firmware issues; at least if you are positive that your headswap went well. The heads are sensitive but I think with them ramped you could get away with this drive. Alignment is crucial but I've personally pulled headstacks out of many, many WD series hard drives and put them in donors. Then when the swap didn't work I placed them back into their original cases and the heads worked fine with no crazy contraptions or methods. Firmware adaptives are crucial after a swap, instead of the quasi-random guessing of alignment. Does the drive ever "come ready"? Even into it's "safe mode"? What equipment do you have available to you, i.e., firmware manipulation?

have you ever heard that "static sparkly sound" when you turn off your filters? Mine do that. The air, rushing past certain elements, create a charge. My setup, as are many, are for medical purposes where static is not an issue. I have heard (forgotten where) that a grounded mesh at the air outlet helps. It IS an issue. Static IS unpredictable. 100 times it will go right, 1 it won't. I would like to remove the variable.

To be honest though, if you read the thread through, in hindsight, alignment was the main problem. The static issue was a possibility, that is retrospect in not a big player here.

I have chatted via PM openly with BlackST and he has been very kind. I don't think he feels he has anything to share that would help me at the moment. I am sure that if he could he would have helped.

[Steve]

does it still make the same sounds?
Sure sounded like media damage

[BlackST]

Simple: in-lab developed solutions like custom servo track writers are capital assets, could work only operated by the people who built them and, to be replicated commercially, will cost thousand $. A cnc machined fixture with necessary precision cost about 2500$ alone, not mentioning the rest. Many parts were bought from surplus stock, and anyway the price was very high. It's not worth the study, the handwork, the design and all the rest (the only 'plus' is the challenge)

[Odiferous]

hhhaaa
well done!

doomer: i'm trying to be professional but the learning curve is steep. This is the first failure i have had in the past 20 disks. good thing it's mine and not a customers. Come on, what would you try next?

If you've achieved a success rate of 19 head swaps out of 20, then ..... (not quite sure what to say)

Duncan

[magneto]

Simple: in-lab developed solutions like custom servo track writers are capital assets, could work only operated by the people who built them and, to be replicated commercially, will cost thousand $. A cnc machined fixture with necessary precision cost about 2500$ alone, not mentioning the rest. Many parts were bought from surplus stock, and anyway the price was very high. It's not worth the study, the handwork, the design and all the rest (the only 'plus' is the challenge)

Thank you! I wasn't trying to bag on you directly, BlackST. It was really aimed at the common answers given to users trying to become better, i.e., "send to pro" and "exists but can't tell you". I agree with your statements above. My question is do you believe, theoretically, that it is possible to rewrite servo in a drive that already has user data and still recover the user data? I definitely see how this is not a cost-effective solution for the majority of the forum users. Just to reiterate, I do understand if we get into conversation that cannot be discussed openly and I hope that all can understand that I, like BlackST, have signed an NDA and am very limited in what I can say. I will help when and wherever I can.

[pninja]

FAILURE!
well, to be honest, it did not work out
after a text book head swap (yes all 8 of them) nothing. The H swap went very smoothly, probably the best and cleanest I've done. ESD precautions all way through, cleanbench perfect.

But, disk does same. Maybe one of the lower platters has some damage. Maybe still PCB.

Any ideas. Please

Hi mediaman,

Just to double check the head and your skill, put it back to its original place and align it.
If it worked then your H swap was perfect. Look for possibility of incompatible head assembly,
bad PCB or F/W problem.
If it didn't work, conclusion is there...
I have done HS on this model 3 times. One complete fail. Other two partial success.
In one case I had to disable a head to clone the drive. In another case cloned with
tons of bad sectors.

Regards