ST3000DM001 and possibly bad TVS

[atomguy]

I have a Seagate ST3000DM001 drive which has stopped responding. Even in an external USB enclosure, the drive makes no sounds and the enclosure light just blinks forlornly.

As part of troubleshooting the drive in its original enclosure, I tried out different power supplies and think I grabbed the wrong one...after plugging in that adaptor no power, no spinning, nothing.

After some more research, a bad TVS seems to fit the symptoms I'm experiencing. Images of the PCB attached to this post.

Are there any additional tests I should try before removing one (or both?) TVS packages?

Would really appreciate another set of eyes and another brain to double-check my thinking before jump into HDD surgery.

Thanks!

Attachments

PCB, TVS focus

PCB Perspective view

[fzabkar]

Test the 12V TVS diode and the corresponding zero-ohm resistors:

http://www.users.on.net/~fzabkar/HDD/ST ... 01_TVS.jpg

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

[atomguy]

zero-ohm reistors registering < 3 ohms.

12V TVS passes 0.02V either direction with the diode test, ~7 Ohms forward/backward.

(for comparison the 5V TVS passes 1.2 V / 0.3 V diode test, 0.8 Ohms / out of range)

Am I right in thinking the 12V TVS should be removed?

[fzabkar]

Remove the 12V TVS diode. You can replace it with an SMBJ12A if you like.

Make sure your adapter is 12VDC, centre pin positive.

Best of luck.

[atomguy]

Success. Thank you!

Now to copy off the most important files first