TSM 4.1.3 on NT 4 with at IBM 3483 (ADIC scalar 100) LTO tape library.

We used to see 18 slots in our tape library, now we only see 17 (and that is
all we can use now).
The library itself seems to be OK, and things are still working, but missing
one slot in our library
can be a big deal some days.

We have rebooted (powered down and brought back from totally off, both the
library and
the TSM server), and had TSM audit the library.  All seems OK except we are
missing a slot
in the library (in an 18 slot library missing one is over 5%).

Any suggestions on how to 'get it back'?

... TIA ... Jack