Re: 5.25 Speed Problems

["william strutts" <wrstrutts1@home.com>]

I have tried several different DDDS diskettes.

--
--
William R. Strutts - wrstrutts1@home.com - Whatever!

C'est moi!  http://www.facelink.com/wrstrutts

Just hacking away...
"Rubywand" <rubywand@swbell.net> wrote in message
3B246A20.CC87EFF5@swbell.net">news:3B246A20.CC87EFF5@swbell.net...
> william strutts writes ...
> >
> > Why would a 5.25" Apple Unidisk drive not be able to
> > maintain a constant speed?  Is the controller bad or
> > one of the drive motors?  I can get it to speed up and
> > I have adjusted the speed so that they appear correct.
> > There is one of those 50/60mhz black/white dashed (strobe?)
> > charts on the drive wheel.  I adjusted it like  you would
> > an old turntable so that the lines look steady when it
> > is spinning.  I also tried adjusting the pot using Copy
> > II Plus and the speed but the speed wavers up
> > and down like from 23 to 233.
>
>      That is an extraordinary variation. Since Copy II+ samples speed by
> writing to and reading a diskette in the drive, you may have a diskette
which
> gets stuck from time to time.
>
>      Or, you may have a diskette to which Copy II can not reliably write.
If
> the diskette is a high-density (HD) type, it will not work reliably in
most
> 5.25" Apple II drives. You need to use Double Density (DD) diskettes
> sometimes called "360K" diskettes.
>
>
> > I checked my other
> > 5.25 drive and it is a solid 200.3 well withing the
> > 198 to 230 range specified by Copy II Plus.
>
>      230 would be too slow for most purposes. A correct Copy II Plus
reading
> for normal use is in the 198 through 202 range.
>
>      If you are using the same diskette to check both drives, there are a
few
> reasons it may work in one drive but not the other:
>
> 1- The 'good' drive may be able to turn a 'sticky' diskette better.
>
> 2- The 'good' drive may be a later model 40-track drive which can R/W
> high-density diskettes (at least some HD diskettes and at least well
enough
> to work with the Copy II+ Speed adjustment).
>
> 3- The pressure pad may have become dislodged.
>
> 4- You mention (below) that you cleaned the heads; so, that is probably
not a
> variable.
>
>
>
> > I also checked the drive pulley but it doesn't appear
> > to be worn.  No cracks or anything like that.  There
> > doesn't appear to be any way to tighten the pulley any.
> > It is an Alps drive mechanism.  Any suggestions or is
> > the drive ready for the trash heap?  I also cleaned the
> > heads.
>
>      If you get a steady, no-jitter, no-jerk, strobe pattern (using the
> visual adjustment method) with the test diskette inserted, then, there is
> almost certainly something wrong with R/W to the diskette.
>
>      If the diskette does not seem to be turning steadily, you could try
> wiping the drive pulley and belt with an alcohol cloth (in case oil has
> gotten into the works).
>
>      You could check to make sure your pressure pad (which comes down from
> the top) has not become dislodged.
>
>      You could try using a different diskette.
>
>      You could examine the drive's circuit board for evidence of blown
> components (for example, blown electrolytic capacitors).
>
>
>
> Rubywand