[Coco] 5 1/4" drive
gene.heskett at verizon.net
Tue Apr 7 11:27:20 EDT 2009
On Tuesday 07 April 2009, Christian Lesage wrote:
>> Refresh my memory, please. Can an 80 track 1.2M 5 1/4" drive be installed
>> into an FD-502 case and work correctly? Will it act like a "standard"
>> floppy drive using the stock chip in the controller?
>Only if you can set it to rotate at 300 RPM. Normally, those 1.2Mb 5.25"
>drives spin at 360 RPM and have a 300 kbps data rate,
No, its 500 kilobaud.
>while 180k, 360k
>and 720k drives spin at 300 RPM and have a 250 kbps data rate. The CoCo
>needs the 250 kbps data rate. Some 1.2Mb drives have a jumper on their
>PCB that allows selecting the RPM.
>You could, however, connect a 3.5" 1.44Mb drive. These drives always
>spin at 300 RPM. They are plentiful and cheap. The diskettes are cheap,
>too. You would have to use DD media, though, or fake DD by covering the
>hole on an HD disk that allows the drive to detect media density.
I don't recall ever having an HD disk even successfully format here. Either
the ones I have are too hard to write, or the drives I have write too weakly
when the HD hole is covered. I happen to have a good supply of DD disks
because the old amiga used that format. Some claim covering the hole works,
but I've not found them to be usable here. Most of those drives auto set the
data rate to 500 kilobaud when the hole is uncovered and refuse to play nice
with a 250 kilobaud data rate unless it is covered, and then write too weakly
to write a robust signal to an HD disk at DD speeds.
One such place where DD disks are available yet is:
Another might be: <http://www.athana.com/html/diskette.html>
but no prices are shown on the front page. In the US, call 1-800-421-1591.
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