WD5000AAKS dies on power brownout, board swap requirements?

[dw860]

I have a WD5000AAKS that was running in a system when a power brownout hit. When the host system went to reboot, the drive was no longer recognized by the BIOS. The heads can be heard sweeping around for a few seconds before the BIOS gives up and moves on. I cannot hear the drive spinning.

When I bought this drive, I bought two of the same model at the same time. I have not put eyes on the other drive as of yet, but I do have access to it and will have it in a few days. It is currently in a working system.

Having read what I can find on recovery methods for this drive, I have a few questions... Here is a picture of the board from the failed drive.

http://aercomm.net/pics/WD5000AAKS_controller_board.jpg

As you can see, U12 is populated. Assuming that the other drive has a populated U12, it is my understanding that I can remove U12 from the failed drive and transplant it onto the donor board from the working drive. Is this all that is necessary?

It is also my understanding that the code following the hyphen in the model number indicates the firmware revision running on that drive and that the firmware is loaded from the negative sector "system area" upon bootup. Given this, is it a requirement that the code following the hyphen in the model numbers of the two drives match?

What else do I need to be aware of when attempting a U12 transplant?

Finally, I am concerned about possible head/platter damage from the 4 or 5 startup attempts that I made before determining the drive was not spinning. How likely is it that head or platter damage occurred while trying to read the SA without spinning?

Thanks in advance to anyone who can help me through this procedure.

[BlackST]

If you hear the drive spin up then "heads move" then drive STOPS SPINNING, there's no board swap that can revive your drive as the failure is elsewhere. If this is the case, sorry for the bad news.

Your post is unclear as first seemed that the drive spin up then heads move then you don't hear it spin (anymore ?), then :

"Finally, I am concerned about possible head/platter damage from the 4 or 5 startup attempts that I made before determining the drive was not spinning. How likely is it that head or platter damage occurred while trying to read the SA without spinning?"

... unless motor is not spinning while HEADS move anyway (?!?) , in this case you get a "good" radial scratch.

Before all, a good analysis is needed.

[dw860]

From what I can tell, it does not sound as if the platters are spinning at all.

[Nick_CT]

I'm not sure how you can hear the heads 'sweeping around' if the platters aren't spinning?!

If it's not spinning up at all (and most likely the heads aren't moving as they will be parked) then a PCB swap might help with a U12 swap. As said above if it spins up, heads move around and then spins down, then a new PCB won't help at all.

You can also check the resistance of D3 and D4 on the board. If they measure 0 ohms then you could try and remove them and have another go. Remember though that the PCB now has no protection against bad power.

Search for TVS on this forum for more info on that.

[jono-ats]

The combination of numbers and letters after the basic model number reveal the family of the drive and the OEM customer, if any. Specific WD models often use a wide variety of firmware versions; there is no way to ascertain particular FW rev. from the model number, or anything else printed on the drive's label.

The voice coil can still move the heads from park in a drive that is not spinning.

Maybe the motor driver circuit is bad. Swapping the PCB and U12 might do the trick in this case. It won't help if the damage has extended to the preamp.