22 Apr
2015
22 Apr
'15
11:09 p.m.
On 4/22/15 5:04 PM, David Gesswein wrote:
On Tue, Apr 21, 2015 at 10:54:42PM -0700, Josh Dersch
wrote:
That makes sense.
So, I suppose this is somewhat good news in that
I may be able to
use the drive, but I wonder what would cause the data on the disk to
fail in such a manner (and I'm still hesitant to reformat the drive
without recovering stuff off of surfaces 2/3...) Any thoughts?
Head alignment off on those heads. Can the drive microstep or any other
way to change the head alignement? You might be able to recover the
data that way.
According to the service manual one of the surfaces contains servo
tracks used to position the heads, and all alignment is based on these
tracks. If some of the heads are now out of alignment with those tracks
I don't think there's anything to be done about it (but I've only
skimmed the manual thus far). There does not appear to be anything I
can do at the interface level, at any rate. I wonder, though, if
perhaps running the drive in a different orientation (it's currently on
its side) might have an effect on the wayward heads. Probably not, but
it's worth a shot. I may try that tomorrow...
I have seen an MFM drive with a few heads so out of alighment that
you got data from track n+1 on one head and n on another. Not sure
how you cause that without more serious damage to the drive.
Yeah, I know nothing
of the history of this machine, it seems to have
been well treated aside from being left in a somewhat damp and
rat-infested environment, no evidence of it being dropped. But then,
the chassis on the Ridge is built like a tank so it might very well have
been dropped a few feet to no obvious effect...
For MFM
drives orientation or finger on the stepper motor helps to recover
data when the heads are off. Probably doesn't work with your drive.
Yeah, there's no stepper to grab onto here. And if there was, it'd
probably take my finger off when it moved, this drive means business :).
Thanks,
Josh