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 Post subject: Re: Deformation of dishes?
PostPosted: December 10th, 2018, 5:20 
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I have collected some information about shock sensors, particularly those made by Murata.

Hard drive shock sensors:
http://www.hddoracle.com/viewtopic.php?t=2637

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 Post subject: Re: Deformation of dishes?
PostPosted: December 10th, 2018, 22:40 
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mhp666 wrote:
In none of these cases there were scratches on the HDD, so I assumed that it is due to deformations in the dishes.

2.5" platters are made of glass, deformation is highly unlikely, even if some "potato chip" effect can be observed, it's probably minimal and can be ignored

the WD model you have has special servo-to-data position calculation that depends greatly on original bearing being intact, which is often not the case on old or even dropped drives.
Very possible that vibrations you applying move disks packet inside the bearing just enough to bypass the read errors. Keep in mind that vibrations could cause heads to come near or even touch the surface, which is not a good thing.

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 Post subject: Re: Deformation of dishes?
PostPosted: December 11th, 2018, 17:50 
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Doomer wrote:
the WD model you have has special servo-to-data position calculation that depends greatly on original bearing being intact, which is often not the case on old or even dropped drives.

Thank you for this clarification I had not thought about this detail.
Doomer wrote:
2.5" platters are made of glass

I think they are usually made of aluminum, and there were a number of HDDs that were made of glass and that had more drawbacks than advantages.
Dommer wrote:
Keep in mind that vibrations could cause heads to come near or even touch the surface, which is not a good thing.

I totally agree, right now what I'm doing is very risky, I've only used it 3 times and when I did not know another way to read the sectors that I had left. In the last I spend a little and stick heads to the dishes.

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 Post subject: Re: Deformation of dishes?
PostPosted: December 11th, 2018, 17:58 
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mhp666 wrote:
I think they are usually made of aluminum, and there were a number of HDDs that were made of glass and that had more drawbacks than advantages.

I would be really surprised if you can find 2.5" drive with aluminum platters

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 Post subject: Re: Deformation of dishes?
PostPosted: December 11th, 2018, 18:08 
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Doomer wrote:
I would be really surprised if you can find 2.5" drive with aluminum platters

Thanks for the clarification and sorry for my confusion.
You're absolutely right I just checked with 3 HDDs and all three of glass.

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 Post subject: Re: Deformation of dishes?
PostPosted: December 11th, 2018, 18:55 
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mhp666 wrote:
You're absolutely right I just checked with 3 HDDs and all three of glass.

I don't know how accurate it is, but SA module C5h contains DCM information, including heads, media and preamp vendors and part numbers.

http://www.hddoracle.com/viewtopic.php?f=86&t=1036&p=4555

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 Post subject: Re: Deformation of dishes?
PostPosted: December 11th, 2018, 19:28 
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fzabkar wrote:
http://www.hddoracle.com/viewtopic.php?f=86&t=1036&p=4555

Very good work

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 Post subject: Re: Deformation of dishes?
PostPosted: December 12th, 2018, 8:05 
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fzabkar wrote:
the WD model you have has special servo-to-data position calculation that depends greatly on original bearing being intact, which is often not the case on old or even dropped drives.

When this problem happens again, I will try to change the dishes to another HDD, to see if it reads those sectors without problems and the deformation of the dishes could be discarded.
Thanks again for the indication.

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 Post subject: Re: Deformation of dishes?
PostPosted: January 16th, 2019, 17:19 
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It seems that I am again faced with an HDD that may be that the bad sectors are read with vibrations (I'm not sure, at the moment I'm taking out the information).
I put a picture of the vibrators that I got to perform the test. They are stuck only by the front to the HDD.


Attachments:
IMG_20190116_221050.jpg
IMG_20190116_221050.jpg [ 2.19 MiB | Viewed 7456 times ]

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 Post subject: Re: Deformation of dishes?
PostPosted: January 16th, 2019, 17:35 
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@mph666, what were the vibrators removed from or from what were the constructed?

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 Post subject: Re: Deformation of dishes?
PostPosted: January 16th, 2019, 17:45 
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I bought them on Aliexpress.
https://es.aliexpress.com/item/DC-12-V- ... 63c07apijP
I hope to be able to do a test with the HDD that I am recovering, because it has all the looks to be a candidate.

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 Post subject: Re: Deformation of dishes?
PostPosted: January 16th, 2019, 20:50 
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Thanks. Good luck with your experiment!

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 Post subject: Re: Deformation of dishes?
PostPosted: January 19th, 2019, 5:23 
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I just tested the vibrations in a HDD WD10JMVW and they do not help me to finish reading the approximately 64k sectors that it reads with errors.
Any ideas to try to recover these sectors?


Attachments:
2019-01-19 at 10-18-38.png [11.71 KiB]
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 Post subject: Re: Deformation of dishes?
PostPosted: January 19th, 2019, 16:01 
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Spildit wrote:
Can you tell use the full models of the drives where vibration did actualy helped you out to recover the data ?

If in the last 2 cases I had, if I managed to recover the data 100%. In one of them I think I remember that there were about 2400 sectors and I read them in less than 1 minute.
In this case where I am I can not recover a single sector, I will wait for an HDD to come out with these conditions and I will try to draw conclusions.

Greetings.

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 Post subject: Re: Deformation of dishes?
PostPosted: January 21st, 2019, 10:47 
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I do not remember the HDD models (badly done by me).
But I think it happened to me with wd and toshiba.

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