Subject: RE: H89 CP/M hard-secored boot diskette

From: "Dwight K. Elvey" <[email-masked]>
Date: Fri Apr 4 12:11:06 2003

>From: "Patrick Rigney" <[email-masked]>
>
>> [Tony wrote:]
>> Very odd...
>>
>> You might try checkking the index monostables on the hard sector
>> controller (they only really do anything once per track, when the index
>> hole between the sector holes comes round), but I can't see why it would
>> then work for the first 4 cylinders.
>
>Well, as it turned out, the stepper motor on the drive was locking up.  The
>further towards the inner tracks it got, the more it struggled, and it
>wasn't close to correctly centering over any track beyond the first few.
>I'll mess with that later.  I was able to replace the drive with a spare,
>and I'm again up and running.  I produced several good test boot disks, BUT,
>I don't know how well that new drive is aligned, it's straight off the shelf
>from the As-Is room at Wierd Stuff.  Rotation speed is spot-on according to
>the internal diag, but I don't have a 5.25" alignment disk to check it
>otherwise.  Anyone who receives a boot disk from me is, therefore, going to
>be my "canary in the mine." :-)
>
>Next task... get the soft-sectored controller running.  Unfortunately I have
>no docs for this whatsoever, not even a schematic.  I understand that it
>requires MTR-90, and possibly a certain HDOS software distribution as well.
>Does anyone know?
>
>Patrick
>

Hi
 Old dry grease is quite common on these old drives, as
well as slight corrosion on the guide bars. You should
be able to relube and get it running, without changing
the stepper settings.
 As I recall, the H89's came with one of the snail track
type positioners. The biggest problem would be the guides.
Dwight

---

From: "Patrick Rigney" <[email-masked]>
Date: Fri Apr 4 12:12:10 2003

> type positioners. The biggest problem would be the guides.

Dwight, yes, the mechanism is very stiff, and I hope a little careful
lub'ing may restore its health.  Now that I think about, though, I wasn't
very smart by trying as many diskettes as I did... hopefully I didn't
strain/burn/damage the stepper during my experimentation.

This drive is worm gear rather than snail track.  It's one of the drives
with the gigantic door that covers almost the entire face of the drive...
Siemens FDD100-5.  I think this is the drive that's original to these
beasts, so I'd like to keep it alive if I can.

Patrick