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OldGuy · Active contributor Joined: 09 Nov 2008 Posts: 9

A friend brought in a Seagate ST3320620A (firmware 3.AAE) drive from a Maxtor Personal Storage device (TM3200). The drive would not spin up, and when removed from the Maxtor case and placed into a PC, the PC itself would not boot. This failure to boot eventually turned out to be very significant in diagnosing the problem.

The story behind the drive was that it was purchased about a year ago and had been used by his future wife to backup her artwork and family photos. At some point, she misplaced the power brick for the unit and had not attempted to use it for several months. Recently, she needed to access the drive because there had been a problem and she needed to restore her backup copies. Whe eventually found a power brick that had a connector that fit, so she plugged it in. The drive did not spin up after she plugged in the power. I was assured that the drive had not been dropped or subjected to any other abuse and that it had been working before she misplaced the power brick.

This went a long way towards assuring me that the problem was most likely on the PCB and not the drive itself, so I noted the drive model and the firmware and started trying to find a replacement PCB. I spent several days sending emails to various Ebay sellers and other organizations trying to find the same drive with the correct firmware. I was unable to locate any source for the PCB on this drive.

I was doing some additional searching one evening when I came across a couple of links talking about failed zener diodes on hard drive PCB drives. I don't remember the exact links, but at least one of them was an Anandtech forum. Most of the references on this issue were late model Seagate drives, including the specific model I was working on. The PCB has zener diodes on both the 12 volt and 5 volt lines that provide overvoltage protection. If one of these diodes fails short, it creates a dead short to ground that is seen by the PC power supply when you try to boot the system. Thus, a telltale symptom is that the PC won't boot if the drive is installed in the PC. This began to sound a lot like the problem I was facing. Interestingly, most of the posts I found on this issue talked about seeing smoke or seeing signs of damage on the PCB itself. I looked at the PCB with a magnifying glass and could see no real damage. After locating the zener diodes, I did notice that the 12 volt one had what appeared to be a very small crack in the plastic insulator that surrounded the diode itself. This part, by the way, was labeled KVP69A. I was unable to locate any zener diode with this number, so I don't know if it is unique to the drive or not. I then decided to try to test the diodes. Having a little electrical knowledge, I knew that if you check the resistance on a diode and then reverse the leads, it will show a high resistance in one direction and a low resistance in the other direction. If the resistance is very high in both directions, then it has failed "open." If the resistance is zero in both directions, then it has failed "short." On my PCB, the 12 volt zener showed no resistance in either direction, indicating a short. This was consistent with the "failure to boot" problem with the PC.

Since the zener diode is there primarily to provide overvoltage protection, the circuit should still work if it fails "open" or is simply removed. I decided to try to desolder one end of the zener so that it would be connected. When I gripped the diode with a set of pliers while I heated the joint, the insulator around the diode crumbled. This is usually a sign that the insulator has been overheated. After disconnecting one end of the diode and confirming that I no longer had a short between the two points where the diode was connected, I put the drive in my computer and hit the switch.

I heard the drive spin up and the computer booted and detected the drive. Windows saw it as not having been initialized and wanted to format it. I declined that option and loaded what I had always felt was the best file recovery software, GetDataBack from Runtime Software. I tried both the FAT and NT versions of the software, and neither was able to recover more than a few files. Since the drive had been used to copy files from a MAC, I got some software to allow me to read an Apple drive from a PC, but still was unable to recover anything significant.

The friend who brought me the drive then produced a copy of RecoverMyFiles. We loaded that and it immediately saw all of the files on the drive. The result was full recovery of all the files on the drive.

I think that what initially happened was that his future wife found a power brick with a connector that fit, but it was not the right voltage for the Maxtor enclosure. When she connected the power brick and turned it on, she blew the zener diode. If you have a similar drive that you're relatively sure has not suffered any physical damage, exhibits the "no boot" symptom when placed in a computer, and will not spin up, then a failed zener diode may be the problem.

The zener diodes on this drive were connected to the pins where the power is plugged in. The 12 volt zener was a rectangular plastic package, about 5 mm long and 2 mm square in cross section. The 5 volt zener was slightly smaller. If you don't have a volt meter, then try to find a friend who does have one. After testing the diode and determining that you think it is bad, try desoldering one end and pulling it away from the board. If this doesn't fix the problem, you can always solder it back.

Because the zener diode is there for overvoltage protection, that protection has been lost if you disconnect the diode. If you want to reuse the drive after recovering your data, I would replace the diode before trusting it for long term storage. Since it has already experienced an overvoltage on at least one occasion, then it could certainly happen again.

I hope this helps some of you out there.

Mike

harddrivespecialist · Posted: Fri Nov 21, 2008 8:48 pm Post subject:

Very good story with a lot of details.
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ojay · Officially active! Joined: 09 Dec 2008 Posts: 4

Hi, I have read your description about the damaged hard drive. I have the same problem but have no electronic expierience. Could it be possible that you make a small how to... for this case! So I can see how I have to disconnect this diode.

The reason for my defect is that I had a few AC connector on my desk and choosed the wrong one.

Thanks for your help

Botan_Rain · Officially active! Joined: 10 Dec 2008 Posts: 2

Agreed, a How To might be the very trick needed here!

OldGuy · Active contributor Joined: 09 Nov 2008 Posts: 9

I'll try to put something together that might serve as a guide. I found some good pictures in another thread, so I might "steal" those to help.

adeon

This also happened to me.

One of the diodes failed me, so now I am looking for a replacement PCB. I could try and find someone who can replace it, but in doing so the warranty will be voided, so for now I am searching for a matching HDD in stores. After I get my data back I will switch the wrecked board back to the old HDD and return it. While it is true that the new harddrive will (eventually) be susceptible of this kind of failure some time in the future, I will try to update the firmware on it and hope for the best. Apparently there are some more people experiencing this particular kind of sh*t (burnt diodes) in their Seagate drives.

Oh, and I will back up my essential data at least once every 2 weeks.

Will keep you posted with updates as they unfold.

ojay · Officially active! Joined: 09 Dec 2008 Posts: 4

@old guy

Thanks for your coming HOW TO... I'm looking forward to it.

adeon · Posted: Fri Dec 19, 2008 2:33 pm Post subject: Yesss

Yes it worked!!

After busting my a*s trying to find a replacement PCB I took OldGuy's advice (thanks a million) and searched for a 12V Zener diode and had the burnt one replaced. I must say I was lucky to find some guys of unbelievable talent in electronics, who taught me exactly what to buy and replaced the defective one. I am backing up my essentials as I write this. Mind you, the replacement is a 12 Volt, 1 Watt Zener diode. Very easy to find. I would advise against trying to replace it yourselves, unless you are a professional and have the right tools for the job.

I wish you best of luck

ojay · Officially active! Joined: 09 Dec 2008 Posts: 4

Hi, great news.... I'm still hoping that oldguy make his tutorial. I am not certain where this diode is on my disk, could you help me and make a picture so that I can see on you disk what you have done.

Thanks

adeon · Posted: Sat Dec 20, 2008 1:26 pm Post subject: Sure

Yes, please PM me with your e-mail address and I'll send it over. I'm not that familiar with online image hosting, so once you receive the photo I hereby encourage you to post back link should you have such an account; so others can see why we all grief when we hear "Made in China".

adeon · Posted: Sun Dec 21, 2008 12:17 am Post subject:

Okay, pictures sent.

ojay · Officially active! Joined: 09 Dec 2008 Posts: 4

Hi@all,

it's done Smile

The description of oldGuy and the pictures which adeon convinced me to do it. And I can say it was sucessful and I could recover my 20 GB private pictures!!

I am really thankful that I found this post and the fast help!!!

Now I am on the turn and the only thing what I could do is to upload the pictures which adeon sent me.

So here are the links:

Before:
http://img19.imagevenue.com/img.php?image=55069_100_0071_122_629lo.JPG

Replaced
http://img239.imagevenue.com/img.php?image=55065_Replaced_122_514lo.jpeg&loc=loc514#

The only thing what I have done was to disconnect the diode and the disk runs as before... Laughing

adeon · Posted: Sun Dec 21, 2008 11:00 am Post subject: Yeeeee...

Alright, nice to see it's done.

Be very careful though, as OldGuy also mentioned: by removing the diode you have lost the overvoltage protection. This means that if you have a power surge, the smoke coming out of your HDD will be much more expensive. So the idea is either to use a UPS Power Supply or a set of anti-surge power plugs (with fuse), or to reinstall a working diode.

Oh, and both pictures that I sent you are after the replacement, I sent two of them in case the flash was too powerful. You can remove one of them or edit your post.

Good work
and
Happy Holidays
Very Happy

IBROX · Officially active! Joined: 20 Jan 2009 Posts: 3

I have the same problem with my drive it’s a

Seagate Barracuda 7200.11 1000 Gbytes
S/N - 3Q0AZNW
St31000340aS
P/N: 9BX158-568
Firmware - 8D81
Date Code: 08412
Site Code: AMKSPR
+5V 0.065A
+12V 0.6A
I would appreciate anyone that can get or have a replacement logic board.
Thanks
IBROX

RussWinters · Posted: Wed Feb 25, 2009 10:00 pm Post subject:

IBROX, are your certain you are having the same symptoms? The drive you have is a 7200.11 which are having MASSIVE failure rate with firmware. Basically the symptoms are that the drive will not identify in windows or any other software your will try to run.

The drive WILL power on, and it WILL spin up, but nothing else will happen.

If your drive spins up but is not being identified you have this firmware issue. It is fully repairable. Seagate will replace the drive for you but if you have valuable data you will need to firm repair this issue.