Hi All,

following up on two of my previous posts:
http://forum.hddguru.com/seagate-barracuda-7200-think-its-electrical-failure-t13358.html
http://forum.hddguru.com/help-with-disconnecting-tvs-from-seagate-barracuda-7200-t15313.html

I am pretty sure I failed miserably at trying to repair my HD. Here is a quick recap:

1) Based on my first post, I learned that my issue was a blown TVS
2) Based on my 2nd post, I learned how to remove the TVS
3) Using ohm-meter, I discovered that the 12V diode has a value of 0, so I removed it
4) I tried the H/D and STILL, my entire PC would not power on (same story as in my 1st post).
5) So then, I removed both the 2nd TVS diode, i.e. the 5V one.
6) At first, I was ecstatic, because this time, my PC did power on........BUT then I soon found out that the BIOS is not recognizing my Seagate H/D.

Note, upon listing carefully, I notice a faint sound coming out of the damaged H/D; its a repetitive (~0.5 Hz) pattern of faint whisper followed by faint beep.
when I disconnect the damaged H/D from the power, I no longer hear the noise.
???? any thoughts on what is going on???

Although I am upset at my botched DIY repair, thankfully, I did not have any critical data.
Barring any expensive data recovery solutions, does anyone else know of any feasible "last ditch efforts" I could try?

Don't despair. Keep calm. I don't believe you have botched anything. Removing those two diodes would have done no harm.

That said, you may have an additional problem. :-(

The first thing I would do is to verify that there is continuity between the power pins in the SATA connector and the solder pads of each diode.

Once again, set your meter to the 200 ohms range and measure the resistance between each of the four diode pads and the power connector.

Here is a pinout:
http://pinouts.ru/Power/sata-power_pinout.shtml

Best of luck. Don't give up.

Hello fzabkar, Many thanks for your continued help!

So, I tried to follow your instructions. Here are my results:
(Note, in case my notation is not clear, image below may help clarify)

Based on the ohm-meter, continuity was positive for the following combination:
(all other combination showed no continuity)

* 12V (Pad A) and Pins 13,14,15
* 12V (Pad B) and Pins 4,5,6,10,12
* 5V (Pad A) and Pins 7,8,9
* 5V (Pad B) and Pins 4,5,6,10,12

NOTE: No continuity was found between 12V (Pad A) and 12V (Pad B), or between 5V (Pad A) and 5V (Pad B)

Thoughts?

If the power damage occurred while the drive was in spin, it could have caused the heads to become stuck to the platters.


You will need a clean room to fix that though.


Regards,

Thanks for the heads-up. Is there any way to confirm if the heads are stuck?

btw, to clarify how the drive sounds: it sounds as if there is some movement (almost like an attempted spin that lasts for about half a second), but then it stops, then repeats on and on.
overall, it sounds a like faint "beep/buzz" that has a frequency of about 0.5Hz .

also, I have verified that the HD is not recognized by the BIOS in 2 independent machines.

You can check head stuck with another pcb.
But if you want to be 110% sure, only START to spin up the drive, and DON'T wait until it spins up completely!!!
(different fw adaptives + more in the pcb vs the version in the platter can be dangerous)

If the drive can start to spin up, you need to swap the 2 eeprom, and you will get your data.

Janos

It is NEVER a good idea to "force" damaged PCBs to work.
Unless you have the right equipment and know how to do it SAFELY, it is NEVER a good idea to make a potentially damaged PCB work without ANY protection (TVS are put on for a reason, and if they failed, the cause may have damaged something else too...).
At present you have 2 scenarios : badly damaged PCB, stiction, AND/OR preamp damage too. Further damage on PCB could have been avoided. If you have damaged section on the PCB that is a DC-DC converter, 90-99% you have fried preamp too.
This is why extra care and special equipment is needed when incoming drives with fried input section come in - protect data and avoid further damage.
At this point , your data = your choice.

Note, upon listing carefully, I notice a faint sound coming out of the damaged H/D; its a repetitive (~0.5 Hz) pattern of faint whisper followed by faint beep.
when I disconnect the damaged H/D from the power, I no longer hear the noise.

sounds like the platter is stuck and the headstack can not move


which of course seagate drives it does happen a lot
possible crappy factory made


so the only way now is a recovery company

to open the hard drive up and unstuck the motor
then possible headstack damaged has happen allso

Hello Everyone,

THANKS so much for all the feedback.
Following PM info I got from fzabkar:

I have successfully just performed the "Percussive maintenance" and - I can't believe it! - but it worked. I am totally stunned!

I am backing up the data as we speak.

For those who may run into this in the future, here is what I did:

1. While the damaged HD was unplugged,
2. I powered on my PC.
3. I then plugged in the sata power cable only
4. During this time, I still heard the sound I described above.
5. Following the lead from this post http://forum.hddguru.com/samsung-portable-500gb-dead-t14351.html#p99445
6. I then held the HD with my left hand. The HD was in the horizontal orientation with the Seagate label facing up.
7. I then struck my HD to my right palm.
8. At first it did not work, so I tired a couple more times, about 5 total.
9. Miraculously, the buzzing/beeping sound was no longer heard. However, I did hear some clicking for about 1 minute, which then stopped
10. Thinking that the HD might now be recognizable by my PC, I connected the Sata data cable, and "walla", it was recognized by my OS (windows 7)

DISCLAIMER: Please note, from what I have read, the above "shock method"/"Percussive maintenance" is not recommended by many on HDDguru. So please perform at your own risk.

Special thanks to fzabkar, and again thanks to everyone else.

Lord, now we will be getting cases by the truckload that mysteriously don't work anymore after being hit on the table a few times

Congrats but don't buy any lottery tickets anytime soon as you have used up your luck for a while

_________________
You don't have to backup all of your files, just the ones you want to keep.

Looks like a I called it.


Of course, this method of repair is 100% bad news.


Only safe way to remove stiction (heads stuck) is in clean room with lid off. (NO, you do NOT pry the heads off with a tool.)



Regards,

If you have had any experience of the specific problem, or any knowledge about the mechanics behind the hard disk, you will understand the potential damage you were very very lucky to avoid on this occasion.

It is fortunate for you in this case that the problem was incorrectly parked heads, and not spindle siezure. Also, you are fortunate that heads did not scratch suface during the attempts to hit it.

I am happy you have your data back, but now am wondering how many users will read this and use it for encouragement to attempt their own DIY repair unsuccessfully....

if i was this guy I would seriously consider buying a lottery ticket.

Sure, I was shocked when the OP stated that he hit a powered-up drive, but on what basis can anyone state that he was lucky to have succeeded? There are plenty of success stories all over the Net, whereas the DR labs would only see the failures. In fact, I would suggest that the OP would have been unlucky if the method had not worked, and extremely unlucky if it had resulted in more damage.