Tony,
   See if you can "ping" the SCSI addresses the tape drives are set to using the
AIX diagnostics SCSI bus analyzer service aid.  You can get to the service aids
by typing in diag at a root prompt.
   You should also verify that the SCSI adapter is placed in the correct slot in
the H50.
I've seen this problem before (diagnostics run fine to the adapter, but can't
talk to the
tape drives) when the SCSI adapter was placed in an unsupported slot in the
server.
You can check which slots support the SCSI adapters in the Installation and
Service
Guide for the H50, or in the PCI Adapter Placement Reference Guide.

Good luck!
'Chel

Michel Huber
Consultant
Gresham Enterprise Storage

Leo Humar wrote:

> G'day Tony,
>
> Is the differential controller a Low Voltage differential controller ?
> Do you have the correct LVD cable and LVD terminators ?
> You can also connect LVD/SE devices to a single ended controller with single
> ended cables and terminators.
>
> Leo Humar
> LCS Pty Ltd
> lhumar AT bigpond.net DOT au
>
> No trees were killed in the sending of this message. However a large
> number of electrons were terribly inconvenienced.
>
> -----Original Message-----
> From: Tony Rynan <tonyr AT AU1.IBM DOT COM>
> To: ADSM-L AT VM.MARIST DOT EDU <ADSM-L AT VM.MARIST DOT EDU>
> Date: 28 November 1999 15:55
> Subject: QUALSTAR 46120
>
> >Good morning All,
> >
> >Has anyone configured a QUALSTAR TLS-46120 to an AIX 43 Box.
> >
> >I have a QUALSTAR library with 4 * AIT-2 tape (LVD) drives connected to an
> >RS/6000 H50 on scsi differential adapter.
> >The SCSI addresses are unique but I am unable to see any devices on the
> >scsi bus at all. The scsi adapter has been tested and is working fine......
> >
> >Any ideas ??
> >
> >regards Tonyr
> >