If you can find a Japanese 15 you can work on it yourself if you can follow directions in a manual. There are parts for them. They are CHEAP - they free motion and piece very well. Great machine. They do need a case or a cabinet. You catch and we'll help you clean it down at the Vintage Sewing Machine Shop - the only dumb question is the one you don't ask.
http://www.quiltingboard.com/vintage...ml#post5049306 that's a link to the shop
Here is a link so you know what a Japanese 15 or a 15 clone looks like.
http://www.quiltingboard.com/picture...p-t164361.html On there, you can find pictures, manuals, repair manuals, videos - all kinds of info. The bobbins are cheap and easy to find - it takes regular needles. Do a bit of home work before you buy anything. You can find replacement motors, foot pedals, lights, bobbin winder tires, slide plates - what ever. They are heavy to haul around but they won't dance all over the place when you sew.