Hi there, I've had the same trouble with my new VZ-2000. changed out all the belts and then the turntable ran slower than a wet week.
all you have to do is adjust the speed of the motor with the two tiny trim pots on the circuit board behind the turntable.
undo the two screws to remove the turntable from the unit, pop the turntable out and lean it towards you, then adjust the two trim pots which should be almost in the center of the board. the one closest to you is for the 45rpm the lower one for 33's. you will need a record in and playing to adjust it to your liking. then simply reassemble and Rock On!!!!!
Cheers
Dave