Re: anyone know where I can find a service manual for Disk II

[Silicon Sam <SiliconSam@gmail.com>]

On Apr 9, 6:26 pm, Mike Willegal <m...@willegal.net> wrote:
> Hi Michael,
>
>         Are you sure about the analog recording thing?  I was speculating that
> whole track was simply written with some repeating pattern like 1s and
> 0s.  Last night I was looking at the signals coming from a regular
> formatted disk  and it shows many of the same patterns that are seen in
> service manual, with a lot of added noise and jitter. I figure that the
> noise and jitter came from the sector headers and actual data not being
> a consistantly repeating pattern.
>
> Regards,
> Mike Willegal
>
> Michael J. Mahon wrote:
> > Mike Willegal wrote:
>
> >> Hi Tom,
>
> >> Perfect,  just need to find or make a good alignment diskette.
>
> > Finding may be easier--it's an analog recording!
>
> > -michael
>
> > NadaPong: Network game demo for Apple II computers!
> > Home page:  http://members.aol.com/MJMahon/
>
> > "The wastebasket is our most important design
> > tool--and it's seriously underused."

 The cats-eye signal was written on a floppy by a machine that had a
wobble between tracks 15 and 17 (or whatever two tracks) and that way
you had a perfect sine wave on your scope on track 16.  As I recall
Dysan charged $50 each for them floppies back in the late 70's early
80's.  I wore out and messed up a few of them.