Suicidal ST

[kaxi]

An ST3500320AS (SD35) is clicking for some time, then stops spinning after having parked the heads arm in the middle of the plater, leading to a nice sticktion, every time.
I haven't seen such a case before. First thought was corrupt ROM. Does anyone more experienced have any idea what could be the cause of such behavior?

[fzabkar]

Have you tried a different PCB???

Does the headstack sweep over the full surface when it clicks?

Could it be that the MCU and/or motor controller are hanging?

Is there any clue in the terminal output?

[BlackST]

90% - the customer knows why
10% - hardware problem .

ROM is less than 1% if so the problem should be replicable, try and see.

[kaxi]

fzabkar and BlackST thank you for replying.
I did try another PCB, with original ROM (it is the original ROM, checked S/N), same behavior.
The head arm sweeps over all the platter when clicking, and parks in the middle. Doesn't move to the parking zone when motor spins down.
It does the same think every time.

[fzabkar]

IIUC, the headstack is positioning itself in the center of the platter when the drive is performing a controlled spindown. I'm wondering whether the drive behaves the same way during an emergency retract, ie when the power is shut off. I don't know whether playing with the drive in this state would be advisable, though.

[kaxi]

It does the same in a power cut-off. For some reason it seems convinced the middle of the platter is the proper parking place.

[fzabkar]

If you isolate the VCM contacts at the HDA connector, this will prevent the motor controller from driving the headstack. The headstack will then be free to find its own position in the airstream. If you now spin up the drive and the headstack moves toward the centre ... ???

[kaxi]

Isolating the HDA conector leaves the headstack unmoved on parking zone. Seems the auto-return mechanism in power-down is for some reason missing. Cannot think if there is something mechanical to check.

[hhddrec]

Hi kaxi, can you send us pics from Platters and Headstack. maybe usefull

The HDD is internal drive or external Drive?
what are simptoms to Fail?
i think in this case in important to know how the HDD was used.

bye

[BlackST]

fzabkar and BlackST thank you for replying.
I did try another PCB, with original ROM (it is the original ROM, checked S/N), same behavior.
The head arm sweeps over all the platter when clicking, and parks in the middle. Doesn't move to the parking zone when motor spins down.
It does the same think every time.

Then you have always the same problem. I wonder if there is servo calibration or not at start and I would like to see a pic of heads under microscope...

[kaxi]

I'm afraid this is the best I can do for now.
The drive was an internal one, and it has been opened before elsewhere. This is all that I know for the drive's history.
The headstack clicks swapping the whole platter radius, and pausing momentarily for 2-3 times at positions about the middle, until "parking" at the middle before spin-down.

Attachments

[hhddrec]

I think this HDD will not be recoverable, if HDD was opened in other sites, is very difficult to work, you do not know opening conditions, and what testing, pieces exchange, ... they do it, hard to work in this condition.

But i think you have heads problems or maybe media damage.

As BlackST says, a pic from heads under microscope will be good.