please, read this page:
viewtopic.php?f=1&t=124783&hilit=autochopand check this video:
dante lewis auto chop / beat making tutorial on the mpc 2000.
http://www.youtube.com/watch?v=QFXVl4BWp54MPC 2000 AUTO CHOP
1. make sure you have your sample selected
2. shift + 6 to open the program menu.
3. in programs hit f2 for parameters.
4. highlight decay and hit open window.
5. change the level to 0 and the start to 100 then close.
6. while in programs change your overlap to "mono" or "note off"
7. go to main screen and hit the sample u want to chop on "velocity" in the 16 levels mode. it's the button right under "full level" to the left of pad 1 then turn on.
8. now u got chops.
9. you can also tweak the chop start time by adjusting the start values.