Re: Apple II "Exerciser" Board

[mjmahon@aol.com (Michael J. Mahon)]

mrbrad@ll.net wrote:

>you need a 5.25 alignment disk and instructions would be nice...most people
>just toss a 5.25 drive away when alignment goes bye bye..but i have a
>similar board/with dysan align disk for an apple // w/ lobo controller and
>shugart 8" dual drives..they are more touchy and not common so not easy to
>replace

There is really only one track alignment adjustment on a single-sided
5.25" drive:  the head positioner.  If the head position is correct for any
track, then it will be similarly correct for all other tracks (within the
design tolerances of the drive).

Therefore, an "exerciser" seems redundant.  Software can easily
perform head positioning to any desired track (or between tracks),
and an oscilloscope can be used to examine the read waveform
so that head centering on the track can be observed.  An alignment
disk makes this centering easier, because of the special side-by-
side two-frequency track, but the process can be done with a little
patience using any known-good-alignment diskette by observing
the read amplitude.

Once the track center is found--usually somewhere near the
middle track ($11), then the head positioning motor is "locked
down" and the drive is aligned.  (Of course, track 0 position
should be verified, but that is a gross adjustment.)

-michael

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