For some reason the pictures appeared dirtier than the machine, but I did clean (again) and oiled (again). Haven't been able to pinpoint the actual cause of the problem, but the hang-up hasn't shown up yet today. I also cleaned (again) the zig-zag mechanism at the needle bar.
Oh, and it is a Coronado Countess, not Princess, so I think it is a little more stubborn.
