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Seagate PCB swap help!

Last response: in Storage
June 6, 2008 10:39:20 PM

Recently my external Lacie hard drive failed to power up. It had a slight burnt smell to it.

I cracked it open and inside was a Seagate Barracuda 7200.10 320gb.

So I ordered a new Barracuda ( identical ST3320820A ) with the intention of swapping out the PCB which I did. The hard drive is now spinning but I can't get the bios to recognize it.

The only difference between the two boards is the firmware. The old one is 3.AAC and the new one is 3.AAE. Could this be my problem and if so, can I fix it?

More about : seagate pcb swap

June 6, 2008 10:59:57 PM

If you had a compleat new HD why did you not just use the whole thing?

The way you are doing it will never work with your old data (new controller firmware). You now most like need to format the HD.

Befor you changed the controller you should have checked to see if it would still spin. If it did still spin you should have run SpinRite 6.0 on it.
June 7, 2008 1:16:18 AM

Whats wonderful about harddrives is that you need the same pcb, firmware and all, for a swap like you did to work.
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a b G Storage
June 7, 2008 1:23:10 AM

I do hope the OP had backups of his files. He defenetely voided warentys for both HDDs.
June 7, 2008 2:36:46 AM

damn dude iam in the same exact place as you besides the fact that my harddrive is an old ide 60gb! consider yourself lucky. Iam gonna try and use magnifying glass and see if i can find the bad traces....yea...i hope.
June 9, 2008 3:35:48 PM

First off, the use of SpinRite would have been a huge waste of time. Before doing anything, I strongly suggest you consider the value of the data to you. Any attempts you make now can and will most likely increase the cost of professional data recovery services. It is my recommendation that, if your data is worth $300 or more, you get take advantage of the free evaluation that most data recovery labs offer.

If you want to do the recovery yourself, you may get lucky with getting a PCB that is an exact match. But, the damage could be more severe than just the PCB and could also be with the head assembly and/or the SA tracks. If so, you'll need tools that will far exceed your budget.

Have fun!
a c 342 G Storage
September 1, 2010 6:54:50 PM

Flawed procedure at the very start. Too late for OP, but for others who might read this thread ....

OP reports burned smell from an external drive, opened the case and found a Seagate HDD unit inside. First step should have been to identify whether the failure was in the case, or in the HDD:
(a) Mount HDD inside a computer as an internal HDD, test to see whether it works there.
(b) Since OP bought a replacement HDD of the same type, IF the first test above says the original HDD does NOT work as an internal, then mount the new one in the old case and test whether that works.
After these THEN we know which component needs to be fixed.
a c 288 G Storage
September 23, 2010 5:28:56 AM

The first thing the OP should have done was to remove the damaged board and examine it for obviously burnt components. The usual culprit is a 12V or 5V TVS diode which can simply be removed. The drive will work without it, but it will no longer have overvoltage protection on the affected supply rail. You need to be sure that your PSU is OK.

These URLs should help you identify the components:

You can replace the 12V diode with an SMBJ12A, and the 5V diode with an SMAJ5.0A. Both are available from Farnell, Mouser, Digikey.

January 31, 2013 10:02:53 AM

Seagate PCB's donor PCB just need the same board number as the damaged one. The board number is etched on the PCB, begin with 100******

When you get it, you also need move your original PCB's BIOS to the repalcement PCB. You can move the BIOS from your original PCB by using hot-air gun, then solder it on the replacement board. Please refer: Or you can find the electronics repair shop to help you.
February 6, 2014 8:15:59 PM

Hello, for certain disks, just swapping the PCB would do the trick. For newer model hard disk, the bios chip also needs to be transferred to the replacement PCB.

However in both cases, you can rely upon who provide PCBs for almost all hard disks. Also they do the bios chip transfer for you at just $10. Data recovery is not costly anymore.

My hard disk PCB got burnt and it was an older model. I just ordered an identical PCB from and swapped. It just worked like a charm. Millions of thanks to

Advantages of
1. They have PCBs for all brands and models. Even if they don't have with them, they arrange from external vendors.
2. Low cost firmware transfer. Just at $10.
3. Excellent support. You can just mail your queries and they respond immediately.

I strongly recommend to everyone who have damaged their PCBs. Save hundreds of dollars.