Help on HDD board repair

[davidovv]

Hi
I have a problem with SEAGATE barracuda 1TB HDD. My hdd was in external usb rack and (i believe) the cause of malfunction is bad power supply of rack. Attached, here is the image of part of hdd board near the power supply connector.
The red box is the component that burned. it seams to be the same as other five connected with blue lines. and i want to try to replace it. when i try to measure the value of other five components, that i think are shunt resistors, instrument shows like short circuit. I want to connect the 2 purple dots with wire but i am just not so sure of myself, i need "green light" from someone more experienced that i can do that.
Does anyone know what exactly are these components, do they have some filter function or what...,
and can y try with wire between 2 purple dots or i need to find the exact same component.

Best reguards

Attachments

[fzabkar]

It appears that your drive has sustained an overvoltage on the +5V supply.

I believe the red component is an inductor. Its function is to filter the supply. You can replace it with a wire link. However, you will find that a 5V TVS (transient voltage suppression) diode has shorted. This should be the leftmost of the two diodes at the bottom of the photo. The rightmost diode is the 12V TVS diode.

Remove the shorted diode with flush cutters. The drive will work OK without it, but it will no longer have overvoltage protection on the affected supply. Be absolutely sure your PSU is OK.

If, for continued protection, you wish to replace the diode, then a 5V TVS diode can be substituted with an SMAJ5.0A, and a 12V diode with an SMBJ12A. They can be ordered from Farnell, Mouser, Digikey.

If the drive has sustained additional damage, and you wish to replace the board, then you will need to transfer an 8-pin serial flash memory from patient to donor. This chip stores unique, drive specific information.

If you need help to identify any component, post its markings, or refer to the following URLs:

http://hddscan.com/doc/HDD_from_inside.html
http://www.users.on.net/~fzabkar/HDD/HDD_ICs.txt
http://www.users.on.net/~fzabkar/HDD/TVS_diodes.txt

This vendor offers a board for US$40 plus $10 for a ROM transfer:
http://www.onepcbsolution.com

Here is another:
http://www.hdd-parts.com/seagate-barrac ... -sata.html

[robbie]

You can use a PCB from a donor, swaping the ROMs of course

[davidovv]

I couldn't wait for answer and i burned something else on board, and i gave my hopes up. It was fortunately only additional inductor (the first one from the left with blue line) . I totally forgot to check those two TVS diodes, that looked OK, (is the term zenner the same as TVS?).
Now, when i saw this post, i replaced both of inductors and removed the 5V TVS, that was shorted. Then I connected external rack to separate PC power supply (created the connector myself) and... miracle... it works.
I will definitely replace 5V TVS, but for now it is great that i get to save some data.

Few months ago i tried to find replacement for HDD board and i found it on ebay, somewhere in Canada, i bought it but it never came. It was surely lost in transport because the seller gave me full refund, so i hesitate to by things from Internet for now, and that is why i decided to try to repair it myself. It is really a shame that things now are cheap and that it is cheaper to by new hdd than to repair old one (for 50$ + shipment i can buy new 1TB hdd)

I also found 1TB same model same firmware (from a friend that bought the drive at same time) but it didn't work. Why do they have so many differences with drives, I remember the time when you could, for example, take 10GB board and repair 5GB HDD...

Anyway, fzabkar, You have my deepest thanks, You really saved the day.

PS: robbie, thank you too for taking you time and participating in this thread

[fzabkar]

is the term zenner the same as TVS?

A TVS diode can be thought of as a very fast acting zener.

Congratulations, BTW.