craftgrrl | Montgomery Ward sewing machine problem

Does anyone here know about this vintage machine? It doesn't have a model name, but it is olive green, has an external motor, and comes with a plastic case.

I have figured out how to thread the machine, and it is sewing fine.

The problem is winding a new bobbin. When you open the top right portion of the lid, there is a little bobbin arm that folds out. It has a wheel that locks against the armature. Apparently, it is seized up. I have put penetrating oil in and around the mechanism in hopes to get it moving again, but I wonder if there is some button/knob/lever that allows for bobbin winding. Just disconnecting the needle from the armature did not do the trick.

Any ideas?

I did check the FAQ, but found nothing on this brand.