Recently I have a failed Toshiba case & I am keen to know where I am wrong or if any alternate way of recovery is there.
Hard disk is 1Tb Toshiba Desktop hard disk model - DT01ACA100 . currently it is not supported in Toshiba and has to be accessed through Hitachi utility.
Disk has 2 heads. Disk got normal detection and Head 1 was working fine with Imaging speed of 50Mb/s , however Head 0 was giving lots of read errors.
We swapped heads as we thought that may improve situation , but after head swap read speed of Head 1 has increased to almost 90Mb/s with no change whatsoever from Head 0. Is there any way I can do something ? Where we went wrong. In general how to correctly diagnose disk thoroughly.
I read Dr-Kievs advice on using commands sensibly , I think we will have to change diagnostics steps .
I know Pros like Dr-Kiev work on firmware level manually and it is truely professional. Unfortunately this part is not listed in any manuals and you will have to learn it hard way.Besides small DR persons cant devote required time only for r&D as he is like one man army and has to look into other aspects of the business too.
In big established firms its teamwork and one can focus on speicific issues. Payout to large companies is also high so they can afford to spend time.

Likely there is just media damage on the bottom platter surface. It probably got the new heads dirty already. Try the heads back in the donor and see if head 0 is still working fine. Some cases just require multiple sets of heads or repeated cleaning of the heads. Other times, the platter could be just badly damaged and you'll never get a great read of it.

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Data Medics - Hard Drive, SSD, and RAID Data Recovery Service Company

Well,
Please Inspect Platters ,There is Nothing Like Dr Kiev Can Do And some of Us Cannot .Bad Media Has Nothing To do With Firmware .Secondly Pardon Me but There is Nothing Till Date i Have Seen Or Experienced That Some of us cannot solve here and the man you are talking about can .RIAD is what they stress on .I know some of you will talk about a few professionals that they can do this and that but other then Einstein Sir i have never come across anyone great other then spildit and frank both are very good in firmware ,Frank specially is good in electronics and rom .Others like us are all plus minus each other .There are three to four more that i know but i have never seen just heard they can do better work .The way to do this is when you remove heads just do not swap heads ,Inspect them then take a decision you can definitely find if platter is damaged or not ,Heads speak for themselves

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

My vote: its bad head/media

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There is no substitute for education and experience
THANK YOU
SHAHI
shahi.mahbub@gmail.com

Thanks all of you for valuable suggestions. I would like to stress following --

1) Donor heads are 100% compatible as both disks were brought at same time and except SN every other parameter is same.
2) Head transplant was successful because after transplant speed of other working head 1 has doubled.
3) There is not a single bad sector for head 1.
4) Is it possible that only single surface is degraded more than other one ?
5) We cant use Toshiba utility to correct G-list and reading through utility as spildit has pointed out this is not actually a Toshiba hard disk.

I think correct way to diagnose was to check platter degradation and defects in zones before head transplant.I dont know whether that is possible in hitachi utility.
If this option is not availble or cant be checked then there is no way to check whether the issue is with Heads or Defective zones and surface defects,
there are many super Gurus like Doomer ( for seagate ) , Guru , etc.
I have mentioned Dr-kiev because he has pointed out a crucial issue about commands . Only few posts are there in this regard.
He has shown how a master technician will do recovery than rest of the amature players who are ever ready to fire command like regenerate translator (before that erase NRG list ) and hidden dangers in this type of work.

Hi Spildit
Thanks for detailed explanation which has thrown light on this model. Since Large no. of these disks are sold ,this information will be surely helpful for other members too.
Here is my observation to points you have put forward --

2) Regenarate translator was specific for Seagate drives only as Dr-Kiev has pointed out risks in using these commands. Here I was not talking about Hitachi Arm drives.
3) Yes your assessment is right , all modules can be read flawlessly not a single error.
5) Loss of adaptive for Head 0 -- How can I check in depth , I can read partially from Head 0 (even before and after transplant) but no. of defects are too large .
Is there way in general (not specific to this case) to check Defective zones and files affected ? This Routine must be implemented before head transplant otherwise like this case its useless as problem was not with heads.
6) If Head restored in donor again , Head 0 works fine.

I think there is nothing left now to try. But I am wondering how only one surface of platter has gone bad ,non affecting other entirely ? Is there any specific reason for this ?
Thanks a lot for all the help

Twist In the Tale

Its a TOSHIBA hard disk which is actually HITACHI and is manufactured by WD. I think this erratic and senseless behaviour has something to do with this fact.
Required data (aprox 25 Gb ) was on D drive , unfortunately Head 1 which was fully working has covered only 9Mb out of it and rest by failed Head 0.

This work is closed. Anyone keen to have look at defects patterns and perform R & D through pc3000 , pls. PM. me.
Only option left is to study Head specific Adaptives. which might is responsible for head 0 errors.