Hello, I am glad to find this forum. I think my PSU blew and fried 2 of my drives. One is a Seagate Barracada 7200.10 500G and the other is a SCSI Maxtor Atlas III 10k 73G.

The Barracada short out the power supply everytime it is plug in and the machine will not boot with it plugged in. The machine boots normal if the Barracada is not plug in. I read the forum and the 2 TVS diode seem to be fried. I will check on that tonight.

The Atlas is not being recognize by the SCSI adapter at all. I believe the drive does not spin at all, but it is hard to tell. Any suggestion on this drive? Does it has a TVS system like the Barracada? I like to get some data out of it if not repair this boot drive... please help. Thanks

The Atlas was not in any RAID setting. It was in normal mode.

I took pictures of the drive, I hope this will help with diagnositic:

Where should I start?

The moderator is holding my pics. I took a picture of the back. I circled the components that might be TVS diode. Is it safe to remove them?

The pictures are at at:

http://www.kanio.net/atlas3_comp.jpg
http://www.kanio.net/atlas3_cover.jpg

The Atlas3 does not short out the PSU when it is plug in like my Barracuda does. Can it still the TVS diode that causes the drive not to be seen by the adapter?

Yap good place to start with volt meter. Test and remove but be sure once you put this drive back on after you have removed them and you do not have a good PSU it will burn more than you want.

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Iorana Haraharaini

... If you fry the preamp , as it is a Quantum, it will be 99% game over. Beware.
Your data your choice.

Thanks for the feedback. I hate to loose all my data... so unlucky.

I think you meant I do have a good PSU after I removed the diode.

At appears that the TVS diodes are connected directly across the supplies, ie no fuses or series resistors. If your PSU is not shutting down, then your diodes are OK, and your problem is elsewhere (TM).

I will test tonight. If it is not the diodes, what can it be? Is it DIY?

The rule of thumb appears to be that, if the drive doesn't spin or attempt to spin, then the problem is most likely on the PCB. If the drive spins, then the most likely culprit is the HDA.

You say that you are unsure whether the drive is spinning. That's your first step.

I already gave good advice. If you need professional help near you there are reputable members of this forum who can help.

NO this is not what it means. It means after you remove the TVS and your computer does not have a good PSU then you can fry more than you want to fry on this HDD and the game is over.

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Iorana Haraharaini

Thanks for all your help. I tested the 2 circled diode over the weekend. Both of them are good and have resistance across.

My new PSU has not come in yet, so I don't want to mess with it on my working PC. I am praying that the drive all of a sudden show back up in the SCSI bios.

If it still doesn't show up in the scsi bios, Is board swap an option?

A nice board member suggested to check few things. I checked the 2 diodes near the 5v and 12v pin connector. They were not shorted. I also checked another regulator near the 2R7D coil and it is not shorted. Is my board fried and need a transplant? The back of the drive can be seen here:

http://www.kanio.net/atlas3_back1.jpg
http://www.kanio.net/atlas3_2.jpg
http://www.kanio.net/atlas3_3.jpg

Any help will be appreciated. Thanks.

New update, now the drive spins and getting detected by the scsi card. However it is slowing the whole computer down because it takes a long time to be recognize and is in ASYN mode... any help?

Backup your data and replace the HDD.

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The two diodes across the +5V and +12V supplies appear to be Schottky rectifiers, not TVS diodes. As such, they only provide protection from reverse polarity, not overvoltages.

It appears that the onboard regulators may be OK, but I would still test them by measuring the Vcc pins of each known IC, eg the Atmel 24C16N and the Samsung SDRAM. I would also measure the voltages at the coils and flywheel diodes in each of the regulators. Just be very careful with your probes.

I would also determine whether it is the Fault or Busy LED that is lighting up. Refer to the FO (fault) and BO (busy) external LED pins at the front connector. See the pinout in the manual, or the writing on the PCB. You may be able to plug in an LED from a PC case.

Here is the product manual:
http://www.seagate.com/staticfiles/maxt ... manual.pdf

Maybe what you should be doing is making the user aware of the risks, not just the possibility of succes. Or maybe when DIY fails after your advice, you will cover the additional costs for a professional service following addiitonal damage.

FUD.

How does this one word (if its even a real word) help the user here?

It's not fud. HDDs are MALE. And It's not FUD (Fully UnDetected), the drive is seen . And it's not FUD (Fear Uncertainty And Doubt) ... but from FUD to BOHICA there's just FUBAR in between. LOL !