my mpc xl data wheels getting knackered.... help!

my data wheels been playing up pretty bad. rotating it anti clockwise will initially give the effect of rotating it clockwise , you have a turn it for a few seconds before the data starts gong back the right way! very annoying when chopping samples etc. Has anyone else had this problem? Anyone know how to fix it or roughly how much it will cost to sort out? I havent taken it down to sound control yet cos im very very broke... thanks!!

I think the only way to fix it is to get it serviced, there's a thing inside that gotta be changed when it goes bad, I think they call it a rotary encoder or whatever... save your pennies, I think it's not so cheap...