Biomek 2000

Long story short, our Biomek 2000 won't pick up P250 tips properly.  We are using an MP200 eight tip tool that works fine on another Biomek 2000.  It lowers itself onto the tips, picks up anywhere from 4-6 tips, then drops them.  Have tried repositioning the tip box, trying some different tips, etc.  Any suggestons are welcome. Thank you.