Re: Vista Solo disk drive

[ralphp@prysm.net (Ralph Wade Phillips)]

In article <4i1j8c$7at@Mars.mcs.com>, bird@MCS.COM (J. L. Walters) wrote:

> A friend has a Vista Solo disk drive. He tested its speed with Copy
> ][+ and found that it was slightly fast (but still within the 198-202
> ms spec). Unfortunately, he decided to fix the unbroken.

        An engineer, by any chance? <B-)
> 
> He pulled it apart and found two components on the single board that
> were screwdriver adjustable. One designated R78 had "wax" on the
> screwhead so he then turned to the other. (Which he says has a
> designation of Q?. I think the designation is for a transistor in the
> area, however, I didn't see it myself.)

        Could easily be.

> 
> In any case, he did not maintain a memory of where the adjustment was
> when he started and since turning it had no effect on the disk speed,
> he turned it more and more in different directions before giving me a
> call. There is little chance that the ajustment is back to where it
> was when he started.

        "The first rule of intelligent tinkering - KEEP ALL THE PARTS!" 
The SECOND rule - Notate ALL adjustments BEFORE adjusting.  Third rule -
If it ain't broke, don't fix it!

        Not for YOU, of course, but your friend could use these rules
emphatically engraved on his/her head.  Possibly with a 10lb sledgehammer
...

> 
> The question: Does anyone have any idea what the adjustment does on
> the Vista Solo and what he needs to do to get it correct?

        It's either the bias FREQUENCY or the write CURRENT adjuster,
AFAIR.  I have NO idea how to set it, save to be writing steady to a
diskette with an immediate read behind (as in doing a speed test ... ),
and adjust stop/stop until it gets flaky.  Mark the two end points, and
center.

        This could STILL be way off, tho ...


> 
> Kind Regards,
> -- 

        Ralph Phillips