SA-400's (was: Heatkit 5 1/4 floppies

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Wed Apr 7 18:32:26 1999

On Wed, 7 Apr 1999, Richard Erlacher wrote:
> I don't believe those were the earliest of the 5-1/4" types. The early
> SA-400's I remember used a lead screw just like the 8" drives, but that was
> too costly for the competition that followed. When Apple started buying
> "partial" drive mechanisms in order to implement their more software-driven
> approach, with the idea of saving a few bucks . . . multiplied by a milion
> or two drives . . . other manufacturers including SIEMENS and BASF, among
> others, tried a two-phase stepper on a helically-tracked drive wheel as
> opposed to the stepper driving a lead screw. Most makers later went to a
> band-actuator system using a small stepper.

Interesting. All of the SA400s that I've seen used the spiral groove on a
rotating disc. The only 5.25" drives of that vintage that I have with a
helical lead screw were the Micropolis 35 track 48TPI and 77 track 100TPI
(NOT 96TPI!!). Was there any sub model designation for the Shugarts to
differentiate different positioners?

--
Fred Cisin                      cisin_at_xenosoft.com
XenoSoft                        http://www.xenosoft.com
2210 Sixth St.                  (510) 644-9366
Berkeley, CA 94710-2219
Received on Wed Apr 07 1999 - 18:32:26 BST

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