[comp.sys.sun] Odd problems with Miniscribe 9380S and 3/50

KLBY@vax5.cit.cornell.edu (04/27/91)

I am having an odd problem with Sun 3/50's and my Miniscribe 9380S disk
drive and my cable.  This is an interesting problem, and I will do my best
to explain it.

I have a Miniscribe 9380S disk drive that I wish to use with my Sun 3/50.
I built a SCSI cable from a db50 and a 50 pin header strip.  First of all,
I checked my cable with an ohmmeter, and verified all the pins went to the
right pins.  Next I took my disk and cable and went to a friends to format
it.

At that point in time I found that my cable did not work with any Sun
3/50.  I thought this was odd, but the Sun just would not find the drive.
Next I attempted to use my friends cable, and again, no luck in finding
the drive.  Odd.  I began to wonder if the drive was alive.

Next, we went and tried my friends drive on a few 3/50's and they all came
up.  I was really beginning to think my drive was DOA.  Anyway, next for
the hell of it we put my drive and his cable on his 3/60, and it found it
right away.

So, my cable did not work with any drive on any Sun.  My drive would work
with his cable on his 3/60.  His drive would work with his cable on any
Sun.  I should mention we where using the same power supply for the drives
through all of these tests.  I also checked my cable against his to make
sure they where the same, and they where.  I bought a different brand of
ribbon cable and I am going to try building another cable, but the big
question is:

Have any of you ever ran across a disk drive that will not run on one
model of CPU?  any ideas?

wolfgang@wsrcc.com (Wolfgang S. Rupprecht) (05/10/91)

KLBY@vax5.cit.cornell.edu writes:
>I have a Miniscribe 9380S disk drive that I wish to use with my Sun
>3/50.  I built a SCSI cable from a db50 and a 50 pin header strip.
>First of all, I checked my cable with an ohmmeter, and verified all
>the pins went to the right pins. [...] So, my cable did not work with
>any drive on any Sun.  My drive would work with his cable on his
>3/60.  His drive would work with his cable on any Sun.

Does he have SCSI pin-26 connected in his cable?  Do you?  Many early
model 3/50's shorted SCSI pin 26 to ground.  This tended to upset the
disks that tried to source +5 onto this pin.  The simplest solution was to
not hook up pin 26 on Sun SCSI cables.

Wolfgang Rupprecht    wolfgang@wsrcc.com (or) uunet!wsrcc!wolfgang
Snail Mail Address:   Box 6524, Alexandria, VA 22306-0524