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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 13th, 2018, 19:55 
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VCM is part of head stack assembly.

Heads need replacement if FW matches (as it does).

This is where things get a little trickier . . .

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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 13th, 2018, 21:49 
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From the manual ...
http://www.fujitsu.com/downloads/COMP/fcpa/hdd/mhv2xxxah_maint-manual.pdf


Attachments:
MHV2100AH_rev_A3_field.gif
MHV2100AH_rev_A3_field.gif [ 55.36 KiB | Viewed 927 times ]
MHV2100AH_rev_A2_factory.gif
MHV2100AH_rev_A2_factory.gif [ 55.86 KiB | Viewed 927 times ]
MHV2100AH_rev_fw.gif
MHV2100AH_rev_fw.gif [ 56.61 KiB | Viewed 927 times ]

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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 14th, 2018, 11:08 
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Ok, same revision / FW then.....

Drive should need head stack replacement as already mentioned ....

This is NOT a DIY case anymore. If you need the data then the drive should be send in to a specialized professional data recovery firm and NOT an ordinary computer repair shop.

:( :( :(

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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 14th, 2018, 11:22 
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Joined: January 9th, 2018, 13:34
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Thanks for all your input, I've learned a lot.

So, this is what I measured:

Vio on both PCBs: 3.3V (connected or not to drive)
Resistance from Vio to gnd:
- donor PCB: 5.33k not connected, 4.9k connected to drive
- failing PCB:5.25K
No continuity from Vio to HDA pins.

Vcore on donor PCB: 1.24V, failing PCB: 3.44V (connected or not to bad drive) .
Not a BD9109FVM regulator I think, but has matching pinout.
Resistance from Vcore to gnd:
- donor PCB: 166ohm does'nt change connected or not to drive
- failing PCB: was first 98ohm, 48.5ohm after powering a few seconds to read voltages, then 15.3 ohm after powering another time ( :shock: sign of melting MCU?)
No continuity neither from Vcore to HDA pins.

There is 6.6ohm between VCM pins on both drives. On both disconnected PCBs, its near 160k, so servo winding should be OK.

Interesting thing: good drive spins up even when HDA disconnected -> it does'nt need to detect preamp.

My deducing is: failing core voltage regulator -> dead MCU + dead preamp, servo winding OK (does'nt help much...) :arrow: Head stack replacement needed :(


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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 14th, 2018, 11:51 
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repfanatic wrote:
My deducing is: failing core voltage regulator -> dead MCU + dead preamp, servo winding OK (does'nt help much...) :arrow: Head stack replacement needed :(


Agree ...

:cry: :cry: :cry:

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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 14th, 2018, 16:01 
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Sorry, the hires scan identifies the Vcore regulator as a BD9102FVM.

BD9102FVM, Rohm, Synchronous Buck Converter with Integrated FET, 4.0V - 5.5V, MSOP8, Vout = 1.24V:
https://www.marutsu.co.jp/contents/shop/marutsu/ds/bd9102fvm-e.pdf

You might also like to measure the Read/Write Channel test point voltages (T3/T4 & P15/P16) on the donor PCB when mounted on each of the donor and patient HDAs.

Preamp Block Diagrams:
http://www.hddoracle.com/viewtopic.php?f=59&t=229


Attachments:
Read_Write_Channel.jpg
Read_Write_Channel.jpg [ 170.74 KiB | Viewed 875 times ]

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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 15th, 2018, 12:11 
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Joined: January 9th, 2018, 13:34
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Thanks again for all your help :D .

Anyway, even if we know now it is not a DIY situation, I am very willing to go on for a head swap...

The most important files on this drive are some work I could do again, so losing them is'nt dramatic. It's already some years this drive broke and I never needed it really since.

Also:
- I have access to a clean room,
- I am conscious some training would be needed: planning to do this first with old 3.5' dead drives without needing the clean room,
- this would show me what are the issues, and let me search how to solve them (if possible).
- probably I would need appropriate tools, some are already identified:
+ a stable workbench (could be DIY one),
+ a system to unmount cleanly the VCM magnet (I know how strong they are, surely my fingers remember it :lol: )
+ the corresponding headcomb I can't build myself, but some are not really expensive (even for a one-time use)

Last but not least, supposing a perfect head swap can be done, is there another necessary step then, like adjusting some parameters in RAM,
or would the drive straightforward work again :?: .


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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 15th, 2018, 15:12 
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repfanatic wrote:
(...)
Last but not least, supposing a perfect head swap can be done, is there another necessary step then, like adjusting some parameters in RAM,
or would the drive straightforward work again :?: .


It should work ...

If you have something like an hardware based imager (like DDI, PC3K-DE, etc) the better but if not and assuming you did your job well and there are no dust particles on the platters/heads and the new heads don't get "dirty" by reading damaged surface on platters, etc ... you shouldn't need to "adjust" anything (firmware related) on your drive.

Also if there are NO adaptives on that PCB ROM as you were already told then you don't have much to worry about .... You just need to swap the heads and of course return here to tell us if you did manage to do so with sucess or if it was a complete disaster !

Regards and good luck.

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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 16th, 2018, 13:46 
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Thanks for your support, this is is a great forum :good: and shows the best side of internet, where everyone can contribute and help others.

In a modest way, I will try to keep you informed of the progress of this repair, even if it is not for tomorrow.

Best wishes to this forum and all of you :beer:


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 Post subject: Re: Fujitsu MHV2100AH: head fails
PostPosted: January 16th, 2018, 16:17 
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repfanatic wrote:
Thanks for your support, this is is a great forum :good: and shows the best side of internet, where everyone can contribute and help others.

In a modest way, I will try to keep you informed of the progress of this repair, even if it is not for tomorrow.

Best wishes to this forum and all of you :beer:


Ok !

Will be looking forward to ear from you in the future.

Good luck and do post back the results of your attempt !

:D

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