speaking of 3.5" floppies, is 720K R.I.P.?

Chris Halarewich halarewich at gmail.com
Wed Feb 4 13:58:22 CST 2009


you might try here
http://www.newegg.com/Product/Product.aspx?Item=N82E16821103116
according 2 what i can find it will do 720



On 2/2/09, Chris Elmquist <chrise at pobox.com> wrote:
>
> On Sunday (02/01/2009 at 11:56PM -0800), Chuck Guzis wrote:
> > On 1 Feb 2009 at 10:11, Chris Elmquist wrote:
> >
> > > What's particularly nasty is that I chose these drives, Samsung
> SFD-321B,
> > > because I had a recent datasheet that clearly showed they supported
> > > this mode--  until of course they arrived and the switch/sensor is not
> > > even installed!
> >
> > Chris, the OEM manual for the SFD-321B is online at:
> >
> > www.techtravels.org/amiga/SAMSUNG-SFD321B-070103.pdf
> >
> > I note that they do use pin 2 as a density select pin and the OPA and
> > OPB PCB jumpers to determine the operating mode.  You might want to
> > play with this a bit to see if you can coax it into operating in 2D
> > mode.
> >
> > Whatever, please report back because I note that these drives are (1)
> > cheap and (2) have a provision to supply a READY signal instead of
> > DISK CHANGE.  That could come in useful.
>
> yes... I studied the OPA and OPB jumpers, hooked them up, and no joy.
> The actual density selector switch or optical sensor is missing from
> the drives I received.  So, there is no way for it to know that the
> low-density media has been installed.  It needs this input along with
> the density select coming from PIN 2 on the interface to decide what
> mode to go into.  If all the parts were there, then the PIN 2 would
> choose between 2.0 MB and 1.6 MB (raw) modes (and actually change the
> RPM to 360 when going to 1.6 MB mode) but that would only happen if a
> low-density disk could be detected.
>
> So, I think they have cheaped out on us with these particular drives.
> I mean, they are cheap to start with ($7 ea) but this appears to be an
> extreme situation.  I think they can only do high density, 1.44MB format.
>
> I've also found a warning in the CatWeasle documentation that this drive
> is not compatible with it and a claim that they are high density only.
> Which, I think I have proven again.
>
> I'm now exploring both Sony MPF920 and Alps 635H drives...  they look
> like possible candidates at about the same price point.
>
> Chris
>
> --
> Chris Elmquist
> mailto:chrise at pobox.com
>



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