[comp.sys.hp] scsi bus

root@siihp1.epfl.ch (03/06/91)

    I'am currently trying to install new disks on the SCSI bus of
my hp 9000/400t workstation. I have already a hp660S box with 2
disks and a dat inside. The problem is the following : it seems
that the scsi bus ends inside the box, it is not possible to add
other peripherals after the box on the bus. More, the two scsi
plugs on the back are not symetricals, there is an entrance and an
exit, you cannot interchange. But it works perfectly when i put
the 660s box at the end on the bus. There is probably some strap
or switch to set or unset in or out the box, but i have no idea
and neither my hp hardware specialist. Anobody has an idea ?

    Thanks very much for answers.



                    Claude Lecommandeur
                    Service Informatique Central
                    Ecole Polytechnique Federale de Lausanne
                    1015 LAUSANNE (SWITZERLAND)
                    E-Mail : lecom@sic.epfl.ch
                    Tel : (41 21) 693-45-86

kinsell@hpfcdj.HP.COM (Dave Kinsell) (03/10/91)

>    I'am currently trying to install new disks on the SCSI bus of
>my hp 9000/400t workstation. I have already a hp660S box with 2
>disks and a dat inside. The problem is the following : it seems
>that the scsi bus ends inside the box, it is not possible to add
>other peripherals after the box on the bus. More, the two scsi
>plugs on the back are not symetricals, there is an entrance and an
>exit, you cannot interchange. But it works perfectly when i put
>the 660s box at the end on the bus. 
>

The 660S box is designed as a straight-through bus, with the external
connectors being symmetrical.  From the symptoms you describe, it sounds
like the internal SCSI bus has an open circuit near one of the connectors.
The bus is routed on a flexible PC board.  You need to work with the local
support people to see what the options are for replacement.


Regards
Dave Kinsell