Possible TVS diode burnout on WD1001FAES?

I have a 1 TB WD1001FAES (SATA, 7.2kRPM, came as pre-installed component on a Dell XPS 9100) that I suspect has a PCB failure b/c it would not power up but had not shown any signs or made any noises to indicate physical damage.  Before coming to this site and seeing fzabkar’s helpful posts on TVS diodes, I tried the following:

I swapped the PCB on the dead drive for the PCB on a 1TB WD 1002FAEX (the current version of the 1 TB Caviar Black and visually an exact match to my damaged PCB).  With the new PCB, the drive spun up and Windows could tell there was something there (ATA device and generic disk drive) but could not read the drive in any way.  [I now know from fzabkar’s posts that this is b/c the PCB swap is not as straightforward as it appears].

So, it appears if I can get the PCB board working again, even temporarily, I may be able to recover the data on the drive.  There have been numerous posts about TVS diode failures, but my expertise is not enough that I can transfer that knowledge to find these diodes on my PCB.

Here is a picture of my PCB:  http://img713.imageshack.us/img713/8254/img3027sg.jpg

Any direction you all could provide would be most appreciated.  Thank you!

Here are the components that you should test:

See Q5: http://www.users.on.net/~fzabkar/HDD/TVS_diode_FAQ.html

Should the problem turn out to be somewhere else, then the good news is that your board has an external serial flash memory chip at location U12 below the Marvell MCU. This 8-pin chip needs to be transferred to your replacement PCB. Your local TV repair shop should be able to do this for you.

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Wow, that is insane response time, fzabkar!  You are a hero!

To further clarify:  Is there any part number ( or some other ID) I can check to verify that the ‘new’ board will operate with the dead drive once the 8-pin chip has been swapped?  The boards are visually exactly the same as far as I can tell; they are both “1TB Caviar Black, 64 MB cache” drives, but they have two different model #'s.  I just don’t want to brick the second drive in a futile attempt to save the data on the first. I know in previous posts you have linked to places that sell replacement PCBs and offer to transfer the drive-specific data, but I could not find my specific model # among their offerings.

Thanks again for your intelligent and well-written posts!

Sorry, I don’t know enough to be certain whether your two boards would be compatible. Even if there were no obvious differences, there could still be subtle variations in minor components. For example, I believe that some boards may use different programming resistors that configure the MCU for slightly different operation. I expect that the 2060-nnnnnn number on the PCB identifies the PCB artwork (ie the layout of the copper tracks), whereas the 2061 number on the sticker probably reflects the loaded components, including the optional ones.

I’d compare the marking codes on the major chips. Some differences would be significant (eg part numbers), whereas others would not (eg date codes). Differences in the part numbers of the RAM and flash ICs would be OK as long as the chips were functionally identical.

There are so many variables to fixing a hard disk that I can think of.

By suggestion, find a backup solution so that next time the unthinkable is not a problem

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