CDC 9429 Floppy maintenance manual
phb.hfx at gmail.com
Sun May 8 16:02:06 CDT 2016
On 2016-05-08 5:49 PM, Chuck Guzis wrote:
> On 05/08/2016 01:30 PM, tony duell wrote:
>> They are considerably better than the Shugart drives with the plastic
>> disk with a spiral groove for the head positioner....
> Ah yes, the SA-400. When I was evaluating one, I wondered if Shugart
> was really serious about the things. Doubtless some engineer at Shugart
> was quite proud of himself for designing a ball-bearing follower for the
> spiral groove. Marks for being cheap.
> Oddly, my own troubles with the SA-400 (believe it or not, this was used
> as the original IBM offering for the 5150 drive) were with the tach
> circuit. Mine blew a small inductor.
> Among all of the 5.25" FH drives offered at the time, my vote still goes
> to Micropolis for designing the Sherman tank of drives. Leadscrew
> positioner with multiple steps per track. Probably among the most
> expensive 5.25" drives also.
> To their credit, Shugart did have the best hub-clamp setup.
Are you sure about the SA-400 being used in 5150s? All the ones I ever
saw where Tandon TM-100s which look very much like them and I saw lots
as a support person in an IBM lab in the early 80s. They have the same
sort of motor setup to turn the diskette, but use a different head
positioner. The TM-100s used a stepper with a taut band positioner.
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