I had a PSR 4000 between 1996 and 1998. I bought it brand new directly from Yamaha (stores didn't carry it ... Yamaha in LA had a couple b-stocks laying around) and when I got a PSR 9000 in 1998, I gave away the 4000. The 4000 was the "smaller brother" of the 8000. One of the nice things it had was scroll wheels beneath the screen, instead of the up-down buttons on the other PSRs.