2 Seagate Momenti

[acforensics]

Hi Gurus,

I just changed heads on one seagate momentus after another. Both give the same symptoms post-headswap: Spins up, heads never leave ramp, stays busy.

I've checked and double-checked the connection from head assembly to PCB. Is that the only thing it could be? Any other ideas?

Thanks,

A

[phishin_ca]

Can you post the terminal log?

[acforensics]

It is basically:

Buzz
Head Mask FFFF


But no clicking(obviosuly since the heads never leave the parking ramp)

[phishin_ca]

I was looking for messages related to unknown preamp. Are you sure the swapped assembly was good, and compatible?

[BlackST]

Incompatible headstack, uncertain connection - but the log? Or defective pcb.

[jono-ats]

Strange.

I've been working on a 120 GB Momentus that reports can't read APP Code. It won't read any cylinders, either. It has the original PCB, but just to be sure, I reprogrammed two others with no improvement.

I located another donor with same country, same first 3 letters of S/N, and same model no. I got the Head Mask error after I transplanted the heads. I didn't check it with the cover off, so I don't know if they were in the ramp or not.

I put the replacement heads back into the donor, and they worked perfectly.

I'd be inclined to say that the head stack is incompatible, but I can't tell you why. Maybe another donor will shed further light on the problem.

I hate these puppies . . .

[acforensics]

Wow. The donor was about a close a match as I could get. Model, Site, FW, Date Code and first FIVE of the s/n matches!

I doubt that Seagate would manufacture two different headstacks/preamps with everything matching so close. They would lose money in the manufacturing process if they customized every hdd that left the plant. So I suspect headstack/preamp mismatch is out.

I'll move the headstack back onto the donor to see if it works. I suspect connection problem at this point.

Thanks for the healthy discussion...

A

[jono-ats]

Hey, if you find out, please let me know!

Seagates usually aren't that picky about heads.

Jon

[BlackST]

Pm me.

[msurgeon]

Check one simple thing before going too crazy: make sure you don't have double thickness of rubber gasket under head/PCB connector. This will elevate the connector enough to avoid contact.

[acforensics]

ms - I did check the gaskets. In fact, I removed them both just in case that was an issue.

[phishin_ca]

The 2 gasket thing was why I was asking the question. Last one I did (momentus), I inadvertently left the gasket there. I can't remember the terminal log exactly it was along the lines of "no compatible preamp found". How did things go after moving the heads back?

[acforensics]

Moved heads back to donor and it didn't work either on the donor either. So now I'm thinking the head/preamp assembly is not working. For kicks, I put the heads of the patient(which I assume are bad because of clicking and searching activity and other diagnostics), and they still clicked, but they did move off the ramp. Another odd thing: The numbers on the sticker on the small pcb of the that is part of the head assembly shows different numbers than the sticker on the pcb on the head assembly of the donor. Are we supposed to match these???

I had another pair of Seagate 2.5 drives sitting around and they matched.

It may be that the donor was refurbished(even though it didn't say it was refurbished) and a different head assembly was put in accompanied by programming changes(ROM?).

What a nightmare...

[narro]

I hava an identical issue.

Seagate Momentus 5400.2
ST9120821AS
FW: 7.24

Drive remains on busy, and it seems the heads won't leave the parking zone.

Terminal shows:

***************************
F>Interface task reset
4096k x 16 buffer detected
MERC2 - 1_Disk 0.05 03-17-06 15:55
Head Mask 0F,01 - Switch to full int.
Spin Ready
Dwell Cyl - 084F/072C/0765
ERR Read App Code

F>
********************

[BlackST]

Dwell Cyl - 084F/072C/0765
ERR Read App Code
F>
********************

That's it.

[jono-ats]

If heads won't move from the ramp, even after a swap, is this most likely a motor speed / stability issue?

[BlackST]

No. SPIN READY. Check if the VCM is properly driven.

[narro]

Check if the VCM is properly driven.

How ?

[acforensics]

The saga continues...

Here is the terminal log of the other Momentus:

Reset
4096k x 16 DRAM
GALILEO - 1_Disk S-0E 10-09-07_17:41

Buzz HM HM HM HM HM HM HM HM HM HM HM HM HM....

Heads still do not move from the ramp.

A

[drc]

That does sound like a potential VCM problem. I usually see that error with extreme head or platter damage, but the heads are always at least moving. Sounds like it might be failing to move the heads for whatever reason... (stuck? VCM failure? beats me)