Hi Francois,

I work mostly with 3494s so I am not sure what a 3575 looks like.  On 3494s
there are windows on the top and sides of the library.  One day I decided to
clean the top of all the dust.  Afterwords we noticed that on one side of
the library tapes would have trouble checking in.  I noticed that there was
a brighter light over one side of the library.  Sometimes when checking
tapes into the library the barcode reader would retry 3 times and then kick
the tape back out.  Sometimes it would take several tries but eventually the
tapes or tape would go in.  In April we had the library moved to a larger
area to expand it.  Afterwords the problem went away.  I'm not even sure if
the light was the cause but the problem does not happen anymore.

Jack