Hi

I accidentally plugged in the wrong power supply into my Maxtor 400gb External Hard drive - Stupid I know!!

Now there no power going to the enclosure or the drive - no green light or spin up

Try the hard drive in a new enclosure - still no joy

The Hard drive is a Seagate 400 gb Barracuda 7200.10

Model: ST3400620a
F/w: 3.AAE

I guessing that there is damage to the PCB but I personally cant see any damage

Any help greatly appreciated on identifying damaged parts - I havent yet removed the board just inspected the components on the board as it is.

I read somewhere that the TVS diode may have taken the hit but I dont know where it is or how to identify it damaged

thanks in advance

mg3np1

Sorry if this is posted in the wrong place

This forum is very helpful in this mater. You have a button at the top called Search. You can search here for TVS or controller board, power supply or a number of other search names to find the answer on this one. Or you can try and search for a guy named Frank who is not a DR guy but loves to talk about TVS and give his copy and pasted answer to all OPs who ask for help on this issue. He goes by fzabkar you can even search on him. I think you will find 1000+ post in the shortest period of time on this forum all on the same subject from this guy. OH well you can find a lot of help on this issue here and Frank I sure would love to put his notes here for you. Please search now you will find what you need here.

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Iorana Haraharaini

hi,
here you go the reference pic. help it can help you. if you can't repair it you can change PCB and replace ROM chip original PCB to good PCB. i have such PCB in stock. please feel free to contact me if need.

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data recovery service[/b]

The most common result of an overvoltage with the wrong adapter is a shorted 12V TVS diode. That's the bigger of the two diodes. In most cases you can recover the drive by snipping this diode. Just be careful not to overvolt your drive a second time, as you will no longer have any protection. You can replace the diode with an SMBJ12A from Farnell, Mouser, Digikey.

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A backup a day keeps DR away.

Hi Thanks for replies!

I have further question is the 12V TVS the black component (circled white) parallel to the screw hole in directly above the Power connector

and the 5V TVS is at right angles to it? (circled blue)



Sorry its difficult to read the ratings on my components

To test these diodes components - I remove the PCB flip it over and use the solder points for the TVSs as contacts for the multimeter probes

Is there any ribbon type connection I need to be aware whilst removing the board, or does it simply just unscrew - on that note what screwdriver do I need?

Sorry for the elementary question(s) I just trying to be clear

Thanks
mg3np1

Hi again,

Are these valid replacements for the TVSs:

12V:

http://cpc.farnell.com/fairchild-semico ... dp/SC07219

5v:

http://cpc.farnell.com/fairchild-semico ... dp/SC07218

cheers

mg3np1

You have correctly identified both diodes. Farnell's SMBJ12A is the correct replacement for the 12V diode. However, the SMBJ5V0A is a slightly larger part than the original. This is because the SMBJ series is rated at 600W, whereas the SMAJ series is 400W. If the SMBJ fits, then use it.

You don't need to remove the board. Measure the resistances on the component side where the diodes are soldered to the PCB. In any case they are surface mounted components (smt or smd), not leaded, thru-hole parts.

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A backup a day keeps DR away.

Thanks for all your help....HDD now fully operational it was a blown 12V TVS (open) diode as suggested ...

Thanks

does not explain the original symptom of:

since an open TVS diode would not affect normal drive operation...?!

Is there some other piece of info which is missing?

Vulcan you have totally misunderstood how the tvs diode functions in typical operational scenarios. What usually will happen is it will go short circuit and immediately shut down the power source. Unfortunately if the power source dosn't for some reason shut down the tvs will burn out very often causing further damage to the pcb and also to other critical components. As has been pointed out the tvs is not required at all for normal operation.

Open = not connected

Closed = connected

One or more posters are having a terminology issue

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

Thanks for the reply, dick, but I haven't misunderstood at all - as your reply kindly confirms what I already knew, so thanks for that.


Yep, I've seen that many times.

Yep, I've seen all that before several times too - but the OP has not reported any other faults than the 12V TVS, therefore there is no evidence being given by the OP of other damaged components. That's why I previously asked if other info was missing.

Also, we have circumstantial evidence that at the start of the thread, the 12V TVS was (as you said, and I agree) shorted. That fits with the initial symptom of no spin-up (due to the (likely) shorted TVS being a crowbar across the input power source).

The only scenario I can think of, where the initial symptom and the OP's latest report that the 12V TVS was "open" both match, is that things changed e.g. the TVS burned itself out (while shorted) so much that it became open circuit, due to a power source which didn't shut down. However, as you said (and I agree from my experience), that length of short would likely make a mess of the PCB, and that isn't reported by the OP. Again, that's why I previously asked if other info was missing.

If the OP had said the TVS was found to be shorted, then everything fits of course, and this is just a typical scenario - but they didn't say that...

If you can explain how an open TVS (as reported to be the cause by the OP) prevents spin-up (which is the initial reported symptom by the OP), then I'd be very happy to learn.

drc - thanks for that possible highlighting of ambiguity. I interpreted the OP's mention of an "open" TVS being the problem, as meaning the TVS was "open circuit". However if the OP meant "open" to be that the 12V TVS was "not connected" then that still does not explain the initial symptom of no spin-up, does it?

Perhaps the OP will be kind enough to give some more clarity - but perhaps they'll never be heard from again...

ISTM that OP mistakenly referred to his blown/shorted/closed TVS as "open" and then dick got his terms backward

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

Ahh yes Vulcan as I do see what you mean. Well spotted! And thanks for politely explaining.
I think we have to presume the op got his terminology incorrect as he probably meant to say 'short' instead of 'open'.
Maybe he will report back in the near future.

drc and dick - all agreed and thanks for your replies.

It was only because the OP seemed to be describing a contradiction (no spin-up reportedly caused by an open TVS) that I made any comment in the first place

I firstly apologise for the confusion I seem to have caused... I merely wished to thank the forum for helpimg me get my HDD operational again. The overvoltage caused the 12V TVS diode to blow, with no apparent other damage to PCB I replaced the TVS it for continued voltage protection and the drive is working again


I apologise again but thanks for the recommendations

mg3np1

Hi

I am new on the forum, your help would be appreciated. I have managed to plug 19VDC into my Maxtor Personal Storage 3200, the polarity was in the correct sense! The green light just flickers now, but nothing else. Just wondering if I stand any chance of a similar recovery to your solution to the same problem above on a Maxtor Basics 400G?

I am hoping that snipping a diode might get me back up and running?! Please advise if there is any temporary solution without needing components, and also what full repair components I might need?

Many thanks

Davro

Remove the drive from the enclosure and examine the 12V TVS diode on the drive's PCB.

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

Also see the photo clips here:
http://www.users.on.net/~fzabkar/HDD/

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A backup a day keeps DR away.