i have a jvc svhs deck that needs help. The head does not spin freely - it spins 1/4 turn then stops. I can load a tape not very well then it stops. Any advice ???

I had this problem with a 6600-u JVC.
It turned out to be the video head motor. JVC only supplied it at the time as the head cylinder and motor together. It was expensive if I remember right. I used the deck until the motor failed again. From what I found out, this was common on a number of JVC's
The sad part was this deck gave incredible performance when working.