HDD power surge, removed TVS diode, still some more problems

[p83ot]

Hi all,
my dad put 19V on my hdd. HDD failed because of power surge. I openend it to see the PCB and at the 12V pins there was something burned.
I assumed it were inductors, so I repaired it by adding some solder over them (see picture). Then I read in this forum that it is necessary to remove the 12V TVS diode.
Indeed without removing it i measure a short circuit between 12V and ground. So I opened the right solder point of the 12V TVS diode.
When I put power on the hdd and make the USB connection to my PC. The drive appeared as 'removable device' in my windows explorer and in device manager. But when I click on it, it says to 'enter another medium'. The properties of it were 0 bytes used, 0 bytes free. My drive also didn't spin. But it was detected by the device manager.

So something else should be wrong. What else can I try or measure out on the PCB to make it word?

* did I remove the right component (=12V TVS diode)? There isn't much information on the little black component.
* also the 2 capacitors marked with blue rectangle on the picture measure each about 150 Ohms with my multimeter. All other capacitors measure infinity ohms (what is normal for a DC power). Are these capacitors broken? Should I replace them? Don't know what their capacitance is...

I feel that I'm almost there to make it work... but still another little problem on the print. But I don't have a clue what to check next... mayby you can help me

lots of thanks!
Ben

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[Nick_CT]

Your best bet to resolving this is to get a replacement PCB and have the ROM IC moved to the replacement PCB. This way, if the drive internals are OK you should have a perfectly functioning HDD again, along with the protection that the TVS gives you.

There are many places to source a replacement PCB.

[loki]

If you purchase the PCB through donordrives.com (if they have it in stock) you could send them your PCB & they will transfer the ROM for you for free http://www.donordrives.com/services


Loki

[p83ot]

thanks for the responses,
I have most of important data backuped so it's not a total disaster with the crash of this HDD, so I won't send the PCB to swap for another.
I just wanted to try to fix it myself. Curious if I could do it

So removing the TVS diode is the last thing you can do, if the drive doesn't spin after that lots more should be defect?
It's just hard to believe that the diode didn't do his job with the power surge. Or mayby he did it for 95% and a replacement of a small other component could fix the board...

Or isn't there much I could try next? Than it would be HDD in the trashbin.

[BlackST]

You can't "try to fix it by yourself" just looking at it or only with a soldering iron if the problem is deeper than "removing" or "replacing".

[SAjunky]

It's just hard to believe that the diode didn't do his job with the power surge.

Read the name TVS properly, "Transient Voltage Suppressor" - not a "Constant Voltage Suppressor". It does a job as designed - read - short pulses.

BTW, It wasn't a good idea shortening coil. Find replacement coil, but think about damage done if it was part of integrated SMPS. +1 to Nick_CT

[p83ot]

thanks all
I probably had bad luck and other components would be damaged...

Isn't the function of the coils at the 12V DC pins only to filter high freq noise? For DC power these are straight line connectors. I didn't have any coils to solder so I thought to quickly fix the print and replace the coils for solder.

[BlackST]

"I had no fuse of exact value so I bridged it / wired it , but it's a partial success and now I think I'm close to the solution because the new fuse / bridge / wire didn't break , just some smoke from another part of the circuit , so now I will replace/fix that part and it MUST work"

... more or less I hear it almost every day

When PCB is at fault I don't trust it, there are absolutely safe ways to check in order NOT to fry another one, then use another one. But this is a different story. Then make it work with the other one , and this is another different story.