Hey Guys,

currently I have a WD750AAVS-00D7B0 as a patient drive and a WD750AAVS-00D7B1 as a donor for head replacement, because one head does not read.

When I get the donor drive, I connected the drive to PC3k to check the heads, but I got this Information on screen:




There is said, that heads are switched off. In comparison here is the output of the patient drive:



Does it mean, that someone has already messed with the donor drive? Well, I just need the data from Head6, but I payed a high price for this donor and the seller claimed it to be OK.

Seems that Hdd with 6 heads where a 1TB disk, but for some reason someone (factory maybe?) turned the head off. IMHO you can use it as donnor with great chances that H2 works properly.

Best

F

Well,
Patient has head 2 enabled hence 6 out of 6 heads are in actual use .Donor says it has 6 heads you can verify after opening but only 5 are in use ,If the head 2 is there physically but not in use you can swap heads

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Amarbir S Dhillon , Chandigarh Data Recovery Labs [India]
Logical,Semi Physical And Physical Data Recovery
Website-> http://www.chandigarhdatarecovery.com

This is a great (and very old) feature of PC3K. It helps in donor choosing.
H2 is there but not in use.
It is very common that the head is switched off in factory, because it is a trimmed down 1TB model. It doesn't mean someone played with your donor.

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Good to know.
However, I've never used anything other than PC3K.

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Marketing shortcuted model. You can use it as the donor.

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Hey guys! Thank you for your support.
The Recovery was successful, but nevertheless I have some questions about the drive.

The donor drive had physically 6 heads, but head 2 was switched off. On the patient drive, all 6 heads were used. In my case head 6 wasn't reading any data. So I swaped the heads. The drive came after a while up and ready. Head 6 was reading, so the DR was successful. But head 2 wasn't reading. The same head that was switched off on the donor drive.

And here comes the part, I don't understand. The donor and the patient drive had 750GB. So on the patient drive I had 750GB / 6 = 125GB per head / platter. On the donor I had 750GB / 5 = 150GB per head / platter.

Does it mean, that on the patient drive I also have theoretically 150GB platters and only 125GB are used. And if during manufacturing one head gets defective, they switch off the defective head and use the whole platters instead of "just" 125GB?

During manufacturing a head cannot and will not be defective. It would not make sense to manufacture a drive with a defective head. I cannot confirm this, but I would expect a head stack with a defective head would automatically be rejected. The reason a head is disabled [or physically missing] on a drive is because of the quality of the disk's surface [in terms of amount of defects found]. So, the focus should be on the quality of the disk, not the head.

Now, in regards to refurbishing a drive [vs manufacturing], then a head could be defective. Depending on who is doing the refurbishing, they may think, therefore decide, that if a surface could not be read at all or it is read poorly, by a head then the respective head can be disabled and new max capacity configured.

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Hard Disk Drive (HDD), Solid State Drive (SSD, SATA, NVMe, etc), USB Flash Drive and RAID Data Recovery Specialist in Massachusetts

When selecting a donor for WDs I try and find one that is older than the patient, that way you can be fairly sure that it has the same number of heads, or more.

For example an old 3.5" 1TB patient might have 6 physical heads, you have a donor that's manufactured quite long after it (still same family) and you find out it's only got 5 heads. Making sure your donor is older than your patient usually shields you from nasty surprises. Either way, if the physical head maps are the same your donor should work fine.

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Ok guys! Now I'm really confused and need some help to understand, what's going on.

After the head swap, I still had the donor with patients heads laying around. So today I tried to activate the Head 2. But first of all, I ran a Head Test on the heads. Just to remember, on the patients drive the Head 6 was not reading. The result of the test was:



Head 6 is reading again. But why?

Ok, so I tried to activate the Head 2. I did it, but the drive didn't come back ready. When I tried to force it a little bit, loading SA from Profile, I get this message:



Does it mean, that I have no servo marks on this platter with Head 2?

And I still have another question.



Ok, I get your point. But my problem is that the Head 2 was physically on the HSA. It was there. But Head 2 was not reading on the patient drive. It can't be a coincidence, that the deactivated head is not working. Or?

If I, you, and anybody else with sanity, including Seagate, would we put a product like this on the market? Would it be worth the customer complaint and bad press for cents profit off of one customer? I say no.

Tying in with answer to first question, if the head itself is damaged (not the surface with errors, which implies lower capacity manipulation), it should be an automatic rejection. I would expect so. Matter of fact, I would expect a batch of head component or disk rejection, as it implies a manufacturing process problem for the either the heads or platters themselves.

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Hard Disk Drive (HDD), Solid State Drive (SSD, SATA, NVMe, etc), USB Flash Drive and RAID Data Recovery Specialist in Massachusetts