2 Feb
2009
2 Feb
'09
5:52 a.m.
On Sunday (02/01/2009 at 11:56PM -0800), Chuck Guzis wrote:
On 1 Feb 2009 at 10:11, Chris Elmquist wrote:
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
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.