I bought a 600E at a garage sale before Christmas. The owner said it worked fine, but I found one big problem -- the lever to raise and lower the feed dogs and the little buttons that hold the throat plate down was disengaged. We checked it out and could see that someone else had already had the bottom of the machine off, since it the cover was bent and held on loosely.
The good news was that if you didn't need that lever to work, it sewed very nicely. It also filled the bobbin like it was supposed to. I didn't get a manual, but it was easy to operate.
Because I didn't need the machine, I sold the cams and some of the attachments and gave the machine to our local sewing machine repair shop. They accept donations, refurbish, and donate the fixed machines to charity.
Good luck with yours!
Dayle