Seagate ST1000DX001 - DEAD/no signs of life

[pickleit]

This is the first of 2 sata hard drives that have come into my workshop this week and both present as "DEAD/no signs of life".

I need help in fixing the PCBs of these hard drives. I will try to explain as much as I know and what I am trying to find out, for each drive.

First..... The Backstory:
Both drives were connected to a semi-modular PSU. The PSU suffered a problem and 'died'; the PSU and only the PSU was changed for a new working one. The modular cables from the old PSU were left in place and when the NEW PSU was powered on, this is when the hard drives died; that's what I was told.hat I know / don't know:
---------------------------

Western Digital WD10EARS-00VWB0 (1TB 3.5" SSHD)
===============================================
[Pictures A & B]

PCB serial #: 100731495 REV B

Components Tested:
?? - TVS diode? ON 6LF VNE46

This PCB has very few reference designators.

I have tested both diodes circled in 'red' and 'blue' (shown in picture B). The 'blue' diode has continuity, but the 'red' diode does not. I believe the 'red' diode is on the 12V rail and the 'blue' diode is on the 5V rail. i believe both diodes are TVS diode.

Question:
1) Is the 'red' diode clearly dead and should be replaced?
2) Are there any other components that I should test.

Although the 'red' diode has markings on it, I can't seem to find any information about it, necessary in order to buy a replacement one.

Question:
3) Does anyone know what the specs of the 'red' diode are? or where I can buy one.

Attachments

Picture B

Picture A

[data-medics]

If you're reading continuity through the blue circled diode, you can simply remove it and the drive will likely work (pending any other problems). No need to replace if it's just to recover the data, just be sure you have a clean power supply while you're extracting the data out as it'll be more susceptible to surges.

And, FYI I'm pretty sure that's a PCB from a Seagate, not a WD as the title suggests.

[pickleit]

If you're reading continuity through the blue circled diode, you can simply remove it and the drive will likely work (pending any other problems). No need to replace if it's just to recover the data, just be sure you have a clean power supply while you're extracting the data out as it'll be more susceptible to surges.

And, FYI I'm pretty sure that's a PCB from a Seagate, not a WD as the title suggests.

Yup, I got the titles of the two posts mixed up. I would change the title, but I don't have the ability to do so.

[pickleit]

If you're reading continuity through the blue circled diode, you can simply remove it and the drive will likely work (pending any other problems). No need to replace if it's just to recover the data, just be sure you have a clean power supply while you're extracting the data out as it'll be more susceptible to surges.

And, FYI I'm pretty sure that's a PCB from a Seagate, not a WD as the title suggests.

Why would it be a good idea to remove the working diode, as it is the 'red' diode that is not working?

[fzabkar]

Mixing cables between modular PSUs often results in 12V being impressed on the 5V supply. This would explain the failure of the 5V TVS diode (QA). BTW, a working diode should not show "continuity" in both directions.

If the 5V diode is shorted (ie its resistance measures close to 0 ohms on the 200 ohms scale), then measure the associated zero-ohm resistors. If they are open circuit, then you can replace them with wire links ... as long as there are no other problems.

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

Attachments

5V_TVS_resistors.jpg (125.57 KiB) Viewed 13240 times

[pickleit]

If you're reading continuity through the blue circled diode, you can simply remove it and the drive will likely work (pending any other problems). No need to replace if it's just to recover the data, just be sure you have a clean power supply while you're extracting the data out as it'll be more susceptible to surges.

And, FYI I'm pretty sure that's a PCB from a Seagate, not a WD as the title suggests.

I would like to repair this board as a replacement board is neither cheap or easy to get where I am and; where as getting the components is cheap and easy.

[pickleit]

Mixing cables between modular PSUs often results in 12V being impressed on the 5V supply. This would explain the failure of the 5V TVS diode (QA). BTW, a working diode should not show "continuity" in both directions.

If the 5V diode is shorted (ie its resistance measures close to 0 ohms on the 200 ohms scale), then measure the associated zero-ohm resistors. If they are open circuit, then you can replace them with wire links ... as long as there are no other problems.

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

Thanks for the info, I will test and report back tomorrow.

[pickleit]

Mixing cables between modular PSUs often results in 12V being impressed on the 5V supply. This would explain the failure of the 5V TVS diode (QA). BTW, a working diode should not show "continuity" in both directions.

If the 5V diode is shorted (ie its resistance measures close to 0 ohms on the 200 ohms scale), then measure the associated zero-ohm resistors. If they are open circuit, then you can replace them with wire links ... as long as there are no other problems.

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

I have some results.....

The 'blue' diode, the one on the 5V rail has continuity in BOTH directions, has 00.5 ohms on cathode and 00.6 ohms on the anode. Both 0 ohm resistors (on the 5V circuit) are open circuit.

The 'red' diode, the one on the 12V rail has NO continuity in EITHER direction. Both 0 ohm resistors (on the 12V circuit) are closed circuit.

So... do I need to replace the 0 ohm resistors and the TVS on the diode on the 5V circuit. and the TVS diode on the 12V circuit?

[prasadsv]

Mixing cables between modular PSUs often results in 12V being impressed on the 5V supply. This would explain the failure of the 5V TVS diode (QA). BTW, a working diode should not show "continuity" in both directions.

If the 5V diode is shorted (ie its resistance measures close to 0 ohms on the 200 ohms scale), then measure the associated zero-ohm resistors. If they are open circuit, then you can replace them with wire links ... as long as there are no other problems.

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

I have some results.....

The 'blue' diode, the one on the 5V rail has continuity in BOTH directions, has 00.5 ohms on cathode and 00.6 ohms on the anode. Both 0 ohm resistors (on the 5V circuit) are open circuit.

The 'red' diode, the one on the 12V rail has NO continuity in EITHER direction. Both 0 ohm resistors (on the 12V circuit) are closed circuit.

So... do I need to replace the 0 ohm resistors and the TVS on the diode on the 5V circuit. and the TVS diode on the 12V circuit?

Replace 5V diode and resistors(0 Ohms)