OK, here's a wierd one.  We upgraded our 996-600 to a 997-500
recently, which involves replacing the processor boards, the upper bus
converters and some power supply modules, as well as loading a new
PDC version.  Since then we have been unable to boot from tape.  It gets
to the "Interact with ISL?" question, we reply "Y" and nothing happens.  It
will sit there indefinitely with no visible activity on discs or tape.

I called the Response Center, who dispatched the field people.  We have
tried different combinations of processor and memory boards, several
different SLTs, including one from the factory, different media (DDS and
9-track), a new DDS drive, new DDS firmware, an older PDC rev, and
connecting the DDS drive to different channels and different card cages.

While I wait for the next idea from the Field Organization, I wonder
whether anyone else has run into this.  Any info would be appreciated.
At least this will make a good war story for the next SIGBAR meeting in
San Diego...