Cassettes not rewinding

The heads could also just need a good cleaning, either professionally or using a head cleaner dv tape. It's important to remember to always use the same manufacturer dv tape all the time. Evidently, Sony and Panasonic do not mix well, and the lubricants from those two tapes combined will gum up the works. If you use Sony dv's, always use a Sony head cleaner and vice versa. Cold can also cause those lubricants to gum up. Sometimes simply fast forwarding will loosen things up.

Defective rewind sensor. You need
professional service to
fix it. I suggest you buy a rewinder-forwarder than sending it to the service center, it is more practical and you are prolonging the life span of your camcorder video head ( rewinding and forwarding eats around 40 % of vhead life span.)