tape speed

i recently got a ivc m50, I noticed the tape speed is a little slow. Is the a speed ajustment pot on the motor? or do i have to replace the belts? Right now it is fully functional even the track skipping feature on the cassette deck.

I have a Pioneer sk-21. I am having a problem with the tape speed being way to slow. I adjusted the motor speed about 5 or 6 times and each time there was no change in the speed of tape. All belts appear to be in good shape and present. I bought another motor thinking the motor i had was bad...