Hi I have a WD Cavair SE 200gb WD2000JB that was used in an external enclosure. At one point the enclosure over volted and toasted this drive. I am hoping it is just the TVS, as the drive does nothing when plugged in. I would like someone to point out the TVS for me on the pic in the link I provided below. Hopefully its just the chip and I can replace it.

https://skydrive.live.com/redir.aspx?ci ... Bsrc=Share

Thanks in advance

It appears my link broke. Anyway there is a black square chip near the power plug labeled L4.. And a little further up right across the head contacts is another similar, smaller one labeled L2. Are these the TVS chips, if so which do I remove?

Here is a pic of the board, someone else luckily posted the same model before

download/file.php?id=4758&mode=view

I would like to revive this drive, if the TVS is the issue. I have a couple dead WD800 that I could get the chip from if it's compatible.

You don't need to replace it, just remove it (observing usual precautions, and accepting the consequences of no over-volt protection).... But if your board looks anything like the one in the picture, then it's certainly NOT just a TVS issue....

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Thanks for the reply. No my board don't look that bad, however I don't know exactly what chip to remove, can you point it out for me? L4 is right by the power plug, and L2 is across the head contacts. I imagine L4 is the 12v? Likely the one I need to remove? I would appreciate it if you could point out what I need to remove.

Thanks

I can't see numbers on the picture. Just a warning: coil L2 (whatever) is usually part of DC-DC converter. Next to the coil is usually a Schottky diode, it works as rectifier. If you remove this diode (thinking of TVS) and connect power supply, you can make more damages.

I will upload my own photo tonight for you. I think L4 and L2 are not what I'm looking for, I think it's D3 and D4.

Ok here is my board, please show me the 12v and 5v TVSs, and advise me on which to remove

http://photos-c.ak.fbcdn.net/hphotos-ak ... 0328_n.jpg

First at all, your PCB contacts look terrible!
Remove oxidation with soft pensil eraser, keep your fingers on the edge of PCB to not cause static electricity discharge. Then try if it works.

L4 is connected to the power line, check continuity with multimeter. Use the lowest range, usually <200 OHm.

L1 and L2 are probably part of DC-DC converters with associated two Schottky diodes D4 and unmarked (between C82 and C89). Don't touch these diodes, unless continuity test shows close to 0 resistance.
The only possible TVS is D2 on the right side (next to C46). Once again don't remove it, unless it shows close to 0 resistance.

Thank you for your reply. I will try this tonight. Do i check with power applied to the board, or without? And what would be an approximate good reading from this diode?

I believe you should know this things. When you meassure resistance, you musn't connect power to the tested equipment. It would give incorrect reading. Good reading will be out of 200 OHm scale. Suspicious - anything on the scale.

I measured resistance of D2 and it gave approx 107.xx and fluctuated a bit from there.
I don't have the best multimeter though, also it only has a setting for KOhms, the other settings are for AC and DCv and DCmA.

What do you gather from this reading?

Not conclusive, on this range normal diode could start conducting from the testing voltage (supplied by multimeter). Is the same readings in both directions? I don't know this board, therefore not sure it is TVS at all.
Please post markings on the diode.

IIRC the reading was les than 10 reversed. As for markings, they are so tiny that I can't make out what they are, but it does say G30 GP 526. The other two diodes are identical to this one.

I am affraid, it is Schottky diode STPS2L30A http://www.st.com/internet/com/TECHNICAL.../CD00001633.pdf
Your multimeter is completely not suitable for testing TVS and even worse, it could damage low voltage chips on the PCB. I never seen such meter - 10 Ohms on diode?
Give up with such meassuring device, besides I don't see any TVS on your PCB
Did you clean PCB contacts as aviced?

I have not cleaned them yet, but only because I know that is not the issue. This drive was inside of an enclosure that shorted and started smoking a bit. The enclosure has since been long gone in the trash.

And lol, yes the multimeter is a POS, its a Micronta, I believe an old Radioshack one.

OK

I don't mean to disregard your advice, or to offend you by that. Upon closer inspection last night I can see its not just oxidation, but rather scorches and burns.. So now I'm thinking the whole PCB may be bad. I did clean the contacts with an eraser but the scorch marks did not come off.

I am not upset if you don't follow my advice, it is your interest and your risks involved, by example by using wrong multimeter.
These marks on contacts are burns? Then situation is clear, expect also damages inside HDD. Almost sure.
Your data is still on platters, but cost of service will be high.