Paul:  I had the same problem with my Autopiano some years ago.  It
only squeaked when the take-up spool was full and, to make it even more
elusive, only when playing large rolls.  Lubricating the bushings that
the take-up spool pivots on fixed the problem.

DON'T use oil or grease!  Use fine powdered graphite or graphite mixed
with naphtha (cigar lighter fluid) or rubbing alcohol.  Put a little on
both bushings.  No guarantees that this will cure your squeak, but it
did fix mine.

Good Luck

Tim Mattice