[Coco] Chinon floppy drive and coco3

[Gene Heskett]

On Sunday 23 February 2014 00:48:58 Arthur Flexser did opine:

> Gene, I believe the index hole is used by the CoCo only for formatting. 
> So if that's the problem, it should be readily identifiable by the
> drive's working okay for reading and writing to existing CoCo disks,
> but giving an error when it gets to the verify stage of formatting.
> 
> Art
> 
You are spot on there Art.  I once had a drive with a doofy indexer, and 
had to move it about 5 degrees CCW to make it work.  The casting was in the 
way but I'm pretty good with a dremel, so I won that argument.  I checked 
with several brands of disks first though, and it simply did not align with 
the index hole in the sleeve.  Like Captain Kirk, I "made it so". :)  Its 
amazing what gets thru QC.

> On Sat, Feb 22, 2014 at 10:16 PM, Gene Heskett <gheskett at wdtv.com> wrote:
> > On Saturday 22 February 2014 22:06:50 Mike Howard did opine:
> > > Has anyone been able to get a chinon floppy drive to work with
> > > coco3. I can get it to read tracks but get io error when it trys to
> > > verify...How bout a nec drive. the nec is fd1177c ad chinon is 506l
> > > ?
> > 
> > ISTR I have used them ok.  But be aware that some Chinon drives could
> > be fugitives from an amiga, and have 2 problems, the first is the
> > head drive wire and its spring leaf to help it stay in the motor
> > shafts spiral groove is going to need cleaning back down to bare
> > metal & re-oiled, the second being that the amiga versions have no
> > "index" pulse which confuses the coco's WD1773 (or 93) FDC chip.  I
> > don't think its fixable.  The amiga did not read "sectors" but the
> > whole track was read into a buffer, and then the buffer was searched
> > for the correct "sector".  Ditto on writes, it read the whole track,
> > located the data to be updated in the buffer, and then wrote the
> > whole track back to the disk, leaving a small gap between the end of
> > the track and the same track coming back around as the disk was
> > spinning. So it didn't care where the disk was in its rotation when
> > it decided to write.
> > 
> > > --
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> > > Coco at maltedmedia.com
> > > http://five.pairlist.net/mailman/listinfo/coco
> > 
> > Cheers, Gene
> > --
> > 
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > 
> > -Ed Howdershelt (Author)
> > Genes Web page <http://geneslinuxbox.net:6309/gene>
> > 
> > NOTICE: Will pay 100 USD for an HP-4815A defective but
> > complete probe assembly.
> > 
> > 
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > http://five.pairlist.net/mailman/listinfo/coco
> 
> --
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> Coco at maltedmedia.com
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Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

NOTICE: Will pay 100 USD for an HP-4815A defective but
complete probe assembly.