[Coco] drive motors

[Gene Heskett]

On Saturday 13 July 2013 11:47:11 Robert Hermanek did opine:

> Ah, well here you touch on another topic that I've had trouble with:  I
> try on and off, but have never successfully connected any 3.5" device to
> my system.  The situation is...
> 
> Coco3, standard disk controller.  Using original ribbon cable that came
> with 5.25 drive, so all connections are card-edge style, and there are
> two connectors available for drives.  I picked up a second 5.25 drive at
> some point, hooked everything up, and have confirmed that with 2 5.25"
> drives, drive 0 and drive 1 respond normally, work perfectly.  So all
> controllers/cable are A-OK.
> 
> Next step:  I've been led to believe that pretty much any 3.5" drive
> will work... so I ordered a very clever little adapter that is female
> 34-PIN IDC style connector one one side, and nice shiny gold card-edge
> male on the other.  So this give me a 5.25" style connector for any 3.5"
> drive.  I've been careful to double check PIN 1, making sure I don't get
> anything backwards.  I set all this up as drive 0.  At this point I can
> power up, and confirm that remaining 5.25" drive (drive 1) works
> perfectly still.
> 
> So:  controller to stock cable to card-edge adapter to 3.5" drive is the
> full connection for drive 0.  Drive 0 appears to respond normally,
> meaning drive select is correct, when I do a DIR0 the 3.5" drive lights
> up and heads move around.  I get an IO error of course, no formatted
> disks.
> 
> I've tried both new HD disks, as well as a factory sealed set of DD
> disks that I picked up, and have this result every time:  Try DSKINI and
> I get an IO error half way through.
> 
> Clarification on DSKINI:  What does it do exactly?  As anyone knows that
> listens to their drives, DSKINI sounds like it runs the heads down to
> one end, then slowly ticks through the tracks.  Then their appears to be
> a "stage two" where it again repositions the heads, and runs through the
> tracks more quickly.  Then the process is complete.  If we call this
> stages one and two, then I can say that my DSKINI operation always fails
> after stage 1 -- the heads position, all tracks are slowly advanced
> through, the heads position again, IO error.
> 
> Then I gave up for a  while.  More recently, I took a floppy emulator
> that I could not resist buying, and configured that in the exact same
> fashion as the 3.5" drive, and had the exact same result -- it appears
> DSKINI succeeds for some amount of time, then fails part way through.
> 
> I'll attempt a link to the emulator:
> 
> http://www.amazon.com/Updated-Version-SFR1M44-U100K-Floppy-Emulator/dp/B
> 00C4PCK9S/ref=sr_1_1?ie=UTF8&qid=1373726291&sr=8-1&keywords=SFR1M44-U100
> K
> 
> I've tried both HD and DD media.  I've tried both 1.44 and 720k images
> on my emulator.  I've tried three different physical 3.5" drives -- one
> brand spanking new, the other two from the oldest PC systems I could
> find.  Always have the same experience.
> 
> ...but I hear others simply hook up 3.5" drives and away they go.
> Thoughts?
> 
> Thanks,
> -RobertH
> 
Generally since all 3.5" drives are made pc compatible, all of them are 
actually addressed as drive 1 AT THE DRIVE.  So if you have a full teeth 
cable, it should function on either plug of a twisted pc cable, with the 
drive on the end connector being drive 0, its after the cable twist that 
translates the address.  Going this route means you need to remove the pc's 
IDC connector on the controller end and replace it with a 34 pin card edge.

DD disks are a must as the coco cannot do the data rate required for an HD 
disk, and if the HD hole is covered, then the drive turns down the write 
current to DD specs, and may or may not complete the formatting operation.  
Data written to an HD disk with the hole taped over generally has a very 
short lifetime, fading rapidly into unreadability.
> On 7/12/2013 7:20 PM, Robert Gault wrote:
> > Maybe it is the controller or the way you set jumpers and resistor
> > blocks in your drives. On my two floppy system, the only floppy that
> > turns on is the one in use.
> > 
> > I have tested this with a Disto SC-II and two Tandy controllers using
> > the stock DOS1.1. One floppy is a 3.5" the other a 5.25" drive.
> 
> --
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> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


Cheers, Gene
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