On Tue, 30 Apr 1996 09:34:06 -0400 (EDT), LANCE TOST wrote:

>Other weird things having to do with spinup occur when i terminate, flip 
>the cable around, etc.. if you think you can help, i can give you more 
>details when you email.

>From your post it would seem that your SCSI cable might have the wrong
pin-out or might be bad in other ways. You should *not* connect every
numbered pin on the DB50 with the corresponding nr on the connector of
the SCSI-disk!

Also, I found that it in all cases I tried (very often) a Sun 3/60 with
1 drive will work fine without extra termination. BTW, you asked about
the termination in the Sun: there is termination which cannot be removed
or disabled as far as I know. It would not make sense to disable it: the
Sun is always at the end of the chain.

Below the correct pin-out for the cable is given. Please make sure
your cable conforms, remove the extra terminator (you should re-install
it when your problems have been solved) and make sure that if there's
a switch on the drive to provide TERMPWR that it's turned *off*.

Regards,
   Geert

SCSI Connector


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

        The pinout of the SCSI connector is:

            1   GND         17  GND         34  GND
            2   data bus 0  18  data parity 35  GND
            3   GND         19  GND         36  busy
            4   data bus 1  20  GND         37  GND
            5   GND         21  GND         38  acknowledge
            6   data bus 2  22  GND         39  GND
            7   GND         23  GND         40  reset
            8   data bus 3  24  GND         41  GND
            9   GND         25  GND???      42  message
            10  data bus 4  26  ???         43  GND
            11  GND         27  GND         44  select
            12  data bus 5  28  GND         45  GND
            13  GND         29  GND         46  command/data
            14  data bus 6  30  GND         47  GND
            15  GND         31  GND         48  request
            16  data bus 7  32  attention   49  GND
                            33  GND         50  input/output

        and the pattern of the pins as you look at the back of the Sun is:

            49    46    43  ....  19    16    13    10    7    4    1
               48    45    42  ....  18    15    12    9    6    3
            50    47    44    41  ....  17    14    11    8    5    2

        This pin-pattern is used because that makes it possible to 
        use DB50 connectors that can directly be clamped on the 
       flat cable.

    	Note that pin 26 (TERMPWR) is connected to ground on part
        numbers 501-1205-09 or lower, 501-1322-01, 501-1334-01, and
        501-1345-01. This can cause a short if another device in the
        chain is providing termination power!

---
E-Mail: geert@sun3.iaf.nl 
 Phone: +31-53-4303054