How Fisher & Paykel Smartdrives get rid of lint is that the drums are designed so that lint goes out the holes/slots but doesn't come back in - theoretically. During the rinse and spin cycles the lint tapped on the outer skin of the drum is flushed away.
If the machine is fairly old and "someone" has been using too much soap powder, then a thick buildup of scale can form on that outer skin thereby blocking the holes/slots.
I fixed one by take the drum out and scraping, almost chiselling, out the the buil-up in the grooves of the outer drum skin and using coat hanger wire to clear the holes/slots. Crappy job to do but it worked for me. Hope this helps. :)
Mark
Mark Garvey, September 2006