My Sony M-729 All Of A Sudden, Stopped Working..?

My Micrcassette-corder M-729V all of a sudden stopped working. It hasn't been used that much, and never was dropped.. I actually bought it years ago, but it was put away until about a couple months ago. Now after only 2 - 3 months of use, it stopped recording.. "It acts like it wants to work"... It makes noise/sound like it's working but nothing goes around. I opened the cassette door, took out the cassette and watched, I can see the little spindles move a little, maybe like a 1/4" and then I'll hit the other button and the spindles reverse themselves a 1/4" back. The lights all go on.. I've changed batteries multiple times thinking that might be it, but nothing!! This Sony M-729V is such well made machine! For such a little machine, it is solid with a heavy duty feeling, giving someone the feeling of QUALITY!! And for NO REASON, NONE, "it stops working?? There's got to be reason why and I really do want to get it to work again, I can't and won't just throw it away... No way! That's why I'm contacting you guys.. Can you please help me??? Thank you ! ... Art