🚀 go-pugleaf

In <1992Sep13.151356.1307@mccc.edu> pjh@mccc.edu (Pete Holsberg) writes:
| The Trantor MiniSCSI converter gets its power from pin 38 of the SCSI
| device it plugs into, in this case, a WangDAT 1300. However, the W'DAT
| poops out only 2V amd the M'SCSI wants 5.
| 
| Could someone tell me about pin 38 before I start futzing around with 5V
| power supplies and piggyback connectors? :-)

Pin 38 on the centronics connector is termpower, on ribbon cables
it is pin 26.  Only one device on the SCSI bus is required to
supply termpower, and not all devices can be jumpered to supply it
(many assume the host will supply it).  When present, it only
needs to exceed 4.25 volts under SCSI-2 (not 5), and I think it
was only 4 v required under SCSI-1.  Since a diode is also required
when termpower is supplied, you will seldom see 5 v on the termpower
line.  Presumably the Trantor is able to accept that, since from all
accounts it mostly works.

As I recall, the WangDAT units *can* be jumpered to supply term
power, but you'll have to check your manual to see if this is true,
and which jumper(s)/switches to change.
--
Let no one tell me that silence gives consent,  |   Dave Olson
because whoever is silent dissents.             |   Silicon Graphics, Inc.
    Maria Isabel Barreno                        |   olson@sgi.com