Odd problem with new large WD drives

[drc]

I've run into this so far with a WD3200BEKT-22F3T0 (7200 rpm 2.5" drive) and a WD3200AAJS-00VWA0. On scanning or imaging, the entire first half of the drive shows UNC errors about every 5-6 blocks on MHDD. At or around the halfway point in the drive the errors completely cease and the second half of the disk is fine. The errors do show up in the same place on multiple different scans.

Anyone else experienced something similar? This seems like a really strange issue to me.

[BlackST]

What's strange ? a head is weak ot a zone is full of bads.

[msurgeon]

I have had similar scenarios on a couple of occasions where it turned out to be translator related. Even though trans. modules check out good, try re-generating and see what happens. Can't hurt.

[BlackST]

May also be (unlikely? rare?) ... before doing transaltor regen, make a backup of the SA. You'll never know what happens

[drc]

I guess what seemed strange is that it would be at such a regular and small interval, with the sectors in between being completely normal (not slow or anything). Usually with typical bads or a weak/failing head I would expect the bads to be at semi random intervals with other slow sectors in between.

[BlackST]

No. The 'zones' assigned to a head are interleaved between surface(s) so the bads appear when switching to that weak head

[drc]

I understand about the interleaving, what I was trying to say is that usually with bad/weak head drives I would expect to see something like:

[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][]XXXXXXXXXAAAX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX[][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][]XXXXXXXXXAAAXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX[][][][][][][][][][]

etc., whereas this drive looks like

[][][][]X[][][][]X[][][][]X[][][][]X[][][][]X[][][][][][][][][]X[][][]
[]X[][][][]X[][][][]X[][][][]X[][][][][][][][][]X[][][][]X[][][][]X[]
[][][]X[][][][][][][][]X[][][][]X[][][][]X[][][][]X[][][][]X[][][][][]

When I get back to work tomorrow I'll post a photo.

[Zorb]

Looks like a head.

[BlackST]

It's strange. For me, the diagnose would be - in this order : SA, Translator, PCB, HEAD.

[Doomer]

probably drive doesn't have original adaptives in ROM it might cause such behavior in first User zone
Also it may be weak heads or alignment problem - on the outer diameter density is higher and vibration is stronger

Last edited by Doomer on February 18th, 2009, 20:05, edited 1 time in total.

[Russwinters]

I understand about the interleaving, what I was trying to say is that usually with bad/weak head drives I would expect to see something like:

[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][]XXXXXXXXXAAAX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX[][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
[][][][][][][][][][][][][][][][][][][][][]XXXXXXXXXAAAXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX[][][][][][][][][][]

etc., whereas this drive looks like

[][][][]X[][][][]X[][][][]X[][][][]X[][][][]X[][][][][][][][][]X[][][]
[]X[][][][]X[][][][]X[][][][]X[][][][][][][][][]X[][][][]X[][][][]X[]
[][][]X[][][][][][][][]X[][][][]X[][][][]X[][][][]X[][][][]X[][][][][]

When I get back to work tomorrow I'll post a photo.

I would see example one as being two bad heads (that read consecutivley)

example two, this is just one bad head.

Also different manufacturers/models likely distribute data somewhat differently amongst the platters

[macman]

I have a similar problem but my scan shows

[][]![][][]![][]![]![][][]![][!][]![][][][][][][][]![][][][][][][][]
[]![][]![][][][][]![][]![]

the drive continues like this until about half way through the drive. However where the ! are shown the drive spins down then spins back up.
I am currently trying to image the drive in reverse all the way from the back of the drive. Its the only way i can find to get an image. Just got to wait to see if it will work when it gets to the beginning of the disk.

[pepe]

[][][][]X[][][][]X[][][][]X[][][][]X[][][][]X[][][][][][][][][]X[][][]
[]X[][][][]X[][][][]X[][][][]X[][][][][][][][][]X[][][][]X[][][][]X[]
[][][]X[][][][][][][][]X[][][][]X[][][][]X[][][][]X[][][][]X[][][][][]

for this pattern I would think of a radial 'scratch' on one or more disk surfaces. It usually looks like the drive has one or two damaged sectors in regular intervals (SPT).

pepe

[N.C.]

Agree with pepe.

This is one damage on the surface (phisical or logical, like damaged servo information), but can be weak head, bad adaptives, or translator issue too.

But my first vote is for surface problem.

Janos

[pcimage]

Now I got virtually the same. WD5000-AAKS

From 0-~67% the drive is virtually unreadable, but after this it's more-or-less perfect.

All mods in SA read OK, translator regenerated, ROM regenerated from SA.

Still the same

[CK]

Sean,

I had a similar problem recently, heads and SA seemed perfect.

Solution in my case was to modify Data Extractor config to set "Block size for reading" from 256 to 2 or 4 and I got a 100% image, albeit slowly!

-CK

[pcimage]

Wow, that would be slow!

I'll give it a go now

[pcimage]

No dice

Even 1 sector at a time (stays BSY for 5-10 secs then ABR)

[hddguy]

Are all heads physically OK? maybe there is damage to at least 1 head. I know that Head Test function in PC3K is not very good and will usually say it has passed anyway....

[pcimage]

I would assume so, as it images the remainding 33% perfectly.