Hello I'm quite new posting here but I have lurked a bit, I have an issue with my Western Digital drive.
- To keep this very brief I did the stupid thing of being lazy with a new PSU on my computer and left one of the cables which shorted three HDD's various models.
- Looking up information and reading the amazing Fzabkar's information on drives in-depth, I was able to bring back two of my drives back to life, one by replacing the TVS diode and another by PCB replacement and swapping the chip.
- My most important drive (Subject) which I left until last in my tinkering still wont work (TVS diode and PCB board switch), though I'm not sure how to move forward.

At the moment I've powered it up three times to get this result:
It powers on via external HDD caddy then clicks 5 times, after that windows detects the drive in the device manager under disk drives as "External USB 3.0 SCSI Disk Device".

I'm afraid to turn it back on unless advised as I'd like to recover the data from the drive.

Thanks for reading this any advise would be appreciated.

Though before ending this post I'd just like say I'm very grateful for the advise and information freely give from the community as well as other places around the net.

Hello,

your last patient likely has damaged preamp, 771698 pcb has stupidly designed overvoltage protection, so the 12V coming in on the 5V line toasted the internal preamp circuit most probably. The subsequent powerups may have caused damage to the user data and servo system, if the damaged preamp drove current thru one of the write heads. This is the worst scenario, don't power it up again. My advise is to seek pro help and have them pledge they won't power it up either without swapping the heads.

pepe

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Adatmentés - Data recovery

If you can upload a photo of your PCB, I'll show you how and where to test your preamp.

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A backup a day keeps DR away.

Hello and thank you for the reply, how much would it likely to cost to fix this kind of issue if I'm not able to do it myself?

Also here are the images of the new PCB board with the chip swapped.

Back - https://ibb.co/56FRTJB
Front - https://ibb.co/ZJjhqgH

if drive clicks after pcb replacement (with rom swap) preamp damage can be considered for sure.

PIN4: -5V,
PIN6: +5V on preamp connector,
check these on the HDA against GND (chassis or PIN2) using a multimeter in diode mode, in both directions(black to GND, red to PINx and vica versa)
write values here.
you can also check R67 on the original pcb, it is normally shorted, now probably open, possibly a visible burn on the top.

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Adatmentés - Data recovery

I've only just seen the response now.
The previous board I think died maybe due to heat damage from hot air station replacing the TVS diodes and resistors (I had a bad station) so it would not power up after the changes, though with the new board it power on after doing the necessary changes correctly but now it turns on with five then clicks stops as mentioned in my first post.

I will report back with the values ASAP thanks again for looking over my issue.

I'm just replying to this thread saying thank you for all the advise given and just giving an update for any future visitors to this thread.

I sent my drive off to get fixed professionally, I gave instructions as advised from this thread in what the issue potentially was which was correct.
It was a quick fix on there end but was not cheap I sent my drive off around September got my drive back around Christmas last year (after several payments (Wasn't cheap!).
PLEASE PEOPLE BACK UP YOUR DATA IF IT'S VALUABLE.

My data was worth the money spent recovering and I will be doing more diligent back ups in the future and taking extra care when doing PC maintenance or upgrades, although it was a costly lesson I know some others won't be as fortunate as I was.

Make sure you do all checks before doing critical and you can save your cash and use it towards something else.

Thank you again.