I have a Seagate Barracuda 7200.7 120Gbytes ST3120026A. Here are the info of my disk:

Model: ST3120026A
S/N: 3JT1RM8S
P/N: 9W2083-311
HDA P/N: 100264020
Config: D4B-01
Firmware: 3.06
Date code:04103
Site code: AMK
Product of Singapore
Photo: https://docs.google.com/leaf?id=0B-zEfH-vZBmBOTBiZjg1ZjQtMjAyMy00ZmM4LWFhNzYtNmI0NTA3YTNjZmUz&sort=name&layout=list&num=50

Due to a power surge while attached to an external USB enclosure it seems that some element was burnt on the disk's PCB. When I plugged the disk on my motherboard it don't even power up looks like a short circuit.

Here is the PCB of my disk, I have circle in red the burnt element: https://docs.google.com/leaf?id=0B-zEfH-vZBmBMmFiZjJlMmEtZTliNC00OWVhLWJmYzAtNTRkYTE4NjZkODIx&sort=name&layout=list&num=50

My first thought was find a similar disk (same Model, P/N, etc) and replace the PCB. I found one disk with same P/N but a more recent firmware version. Here are the info for the replacement disk:

Model: ST3120026A
S/N: 5JT56PP2
P/N: 9W2083-311
HDA P/N: 100316765
Config: D4B-03
Firmware: 8.01
Date code: 05357
Site code: WU
Product of China
Photo: https://docs.google.com/leaf?id=0B-zEfH-vZBmBZmRhYzA5ZmEtMDI1OC00ZjZhLWFhZjItMjEwOGUyOTQ0MWM2&sort=name&layout=list&num=50

After replace the PCB, my disk seems to rotate (I can hear it) but BIOS disk discovery never completes and BIOS hangs.

While searching the web for what to do next I came across this forum and this topic reporting exactly the same problem on a similar disk: http://forum.hddguru.com/seagate-120gb-st3120026a-pcb-burnt-diode-t13061.html

Someone suggested there to simply remove the burnt diode, but there are no replies if this fixed the problem.
Can the experts suggest me want are my next steps?

Should I remove the burnt diode?
Is the firmware / config difference that important for the disk not to be discovered?
Is it possible something else (beyond PCB) to be also burnt?

Thanks in advance!

Follow the instructions in that thread. It is certainly possible for there to be additional damage, but the odds are on your side.

The reason that the replacement board didn't work is because each board stores unique, drive specific information in a serial flash memory chip. This chip, or its contents, needs to be transferred to the donor.

BTW, I need your email address and password in order to see your Google pics. :-)

_________________
A backup a day keeps DR away.

Thanks for the reply!
So you suggest to simply unsolder the burnt element (diode) and leave its position on the board empty?

I made photos shared to everybody, hope to work!

That's the 5V TVS diode. Just remove it with flush cutters, but make absolutely certain your power supply is OK, as you will no longer have overvoltage protection on the 5V supply.

_________________
A backup a day keeps DR away.

This worked, I save my data!
Thank you fzabkar !!!
I 'll pay the beers next time