[Skipping the introduction]

HDD model: ST3250820AS, firmware 3.aae

Problem:
- ATX Power supply burned out, and burned the HDD.
- TVS diode burned.

Actions I took:
1. Changed the power supply. Result: Working PC, but hdd still not recognized in BIOS.
2. TVS removed. Result: HDD still not recognized in BIOS.
3. I found similar HDD (ST3250823AS), and tried exchanging the PCBs. Result: HDD still not recognized in BIOS.
4. I resoldered the flash ROM chip from the original pcb to the PCB of (ST3250823AS), and tried exchanging the PCBs. Result: HDD still not recognized in BIOS.
5. I found exact the same model of HDD with the same firmware(3.aae) on it, and exchanged the PCBs. Result: HDD still not recognized in BIOS.
6. I did NOT try to solder the flash rom chip to the identical replacement pcb. Should I try?
The reason i did not try this is because it was a borrowed pcb, and the owner didn't felt good about soldering on his board However I can buy that hdd from him if you think it's worth it

My question:
What do you think should be my next step ? How would you diagnose my problem ?

Any help is greatly appreciated.

Send the drive with the original PCB returned to its original state to a data recovery pro. Assuming that your efforts didn't kill the ROM, they will be able to properly diagnose and quote you to recover your data. If you killed the ROM, then expect most labs to call it unrecoverable while others will quote an insanely high price.

_________________
Luke
Recovery Force Data Recovery

Had the TVS failed??. Did you check it??


Different models , pcb not compatable.
Did the Hard disk spin, make any noise,??


Different models , chances are that pcbs are not compatable.


Did the drive spin up?
If it did, then you will have to swap the rom and try.
But there are chances that something else might have failed due to the power surge.
As you have done this much, you can as well swap the rom to the exact model pcb and check.

Try to answer the above to get a clear idea as to what is happening to the drive
Try to post the picture of the faulty board.

Do it If you are sure about yourself, know the risks of DIY ,
else seek professional help.

sorry
my post got delayed (while typing) and lcoughey has already answered to it.

@Sty
if data is very important ,do seek pro help. DIY can spoil the chances of recovery later by DR or it can make recovery costly as pointed by lcoughey
your choice, choose wisely

"Insanely high"... exaggerating a bit !

Just a bit.

_________________
Luke
Recovery Force Data Recovery

This is older series, even if ROM is killed it is not adaptive to the HDD so shouldn't be huge problem.

It depends...

Yes, I measured the resistance with multimeter, it was 0 ohm in each direction. Also, there was little bit of smoke from it when I powered it.


No.


No, as i remember.


What else could go wrong ? Maybe the preamp inside the HDD ?
It has to be some electronic, since the bios don't recognize it, no ?


I will try, but before I try I need to buy that old HDD.


Here you can find the pictures: http://imageshack.us/g/1/9843968/
You will notice that ROM is missing because it is on replacement board at the moment. Also you will see a damaged TVS. It is still on board just because it was damaged so hard that I could remove one half of it, so now there is no connection at all between it's pads.


:S
Little story behind my problem: I wanted to thank a friend for one favour so I installed SSD in his old computer. After I installed it, while driving it in my car to his place, I stepped on a brake, and it's pc on the backseet fell.
First thing my friend did is he also connected his old hdd, and turned it on.
First it was working for a minute, and then turned off. After that he couldn't turn it on.
The rest is history. Both HDD and SSD burned. Luckily SSD was new with warranty and without important data.
If it was mine HDD somehow I would could say goodbye to memories, but now I can't do it...

If after you swap PCB with a compatible one and it doesn't spin, possible inside damage...

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This is the first part that I don't understand. If the 5V TVS diode were shorted, as your measurements appear to confirm, and if you hadn't yet removed it, then the new PSU should have shut down. You would have seen a single kick of the fans and then nothing. "Not recognized in BIOS" suggests to me that the PC POSTed, otherwise you would have said that the PC did not power up. Could you please clarify this?


Elsewhere you say that the HDD did not spin up with the new PCB. If you place a card between the PCB and the preamp connector (of a compatible PCB), does the HDD spin up then? If so, then this would suggest a preamp problem.

It sounds silly, but I have to ask this question -- did you verify that +5V and +12V were present at the SATA power connector?

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A backup a day keeps DR away.

Hi, you have a very good point there. It was in different order:
After I changed the power supply, I got the symptoms like you described(only signle kick of the vents and then nothing).
Then, after a few seconds I noticed the smoke from the TVS, and realized that probably it was burned out already from the old power supply. Then I removed TVS and only then it powered up normally, but it didn't show the hdd in bios.


OK.
Question:
Is this preamp the only thing (except from the PCB) that could cause this invisibility of the HDD to bios ?
Could a mechanical failure of the head also cause invisibility ?


Well I checked it like this: I put a new SSD drive on the same connectors, and it reads it normally. I also tried to connect that identical disk that I've found and it recognized it. So I am assuming the connections are fine.

What would you do ?
What chances would you give me with this ?

You can try this, what fzabkar suggested.(isolate the preamp connection to the pcb and power on the drive)
IF the hard drive spins up, then serious damage to preamp on HSA,
then surely not DIY, you need proper tools and clean room and experience to continue.

@sty, just to rule out other remote possibilities, measure the resistances between the motor terminals. You should see something like 1 ohm.

Also, place your ear against the HDD conver and listen for any sounds, however soft.

_________________
A backup a day keeps DR away.

Really ?

Hi guys,

thank you so much for a useful advices. I know i sound like a dinosaur when I say this, but it's really incredible how we can exchange such a specific knowledge from all around the world in such an easy way.
Yesterday I left a disk to a professional store so they can make a diagnostic, so we'll see.

I will keep you updated with all updates, so stay tuned !

Hi,

here's the feedback.
They made the diagnostic for me for free, and said that there is a problem in PCB, and also in preamp of the head.
I agreed that they try to save the data.
The price they suggested was around 340USD + VAT if they managed to save the data. If they fail then it's for free

So I accepted the deal, and they managed to copy all the data from the drive to my external hard drive (it took all night to copy everything).

So, it ended up good in the end.

To make a small commercial for those guys, since they are pretty new: the company name is "DataSector", based in Zagreb Croatia, webpage:www.datasector.hr

All in all seams like a good service, and nice people.

To all of you who gave me a good advices here, and especially to the ones who prevented me from DIY on opening a hard drive - a big thanks!

Good result!

Congratulations on taking the correct professional route

_________________
PC Image Data Recovery
http://www.pcimage.co.uk

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So they charged you US$340 plus tax for a head swap? Including parts? Wow, that's a good deal !!! Most other people in this forum charge US$1000+++ for head faults.

_________________
A backup a day keeps DR away.

Some people do it for even less, go figure ! Each case is different, anyway.