Problem solved!
Barny thanks for putting me on the right track, The bobbins I was using were unscrewed maybe 1/4 turn. The bobbin being loose was just enough to close the gap on the bottom and cause the jams I was getting. It sews beautifully now. It seems to actually be a little more complex and capable than my 648 (possibly a built in cam stack along with the disks?) so now I get to spend some quality time with the user's manual so I know how to operate it correctly.
Thanks,
Rodney