OK! I think that worked! I adjusted both the top and bottom tension, tightening both, and also found that either the bobbin or the way I wound it was intermittently refusing to move. I used a different bobbin and we seem to be in business! It does bunch periodically as I start off, but I'll keep fiddling with it. Thanks, all, for the advice!!
Now on to the Adler 67 I also picked up to refurb!!