I have an older 1998 portable Bernina with feeder...

Question

The control k**b for the drop feed won't move the machine won't move the material forward when I sew. I opened the bottom and oiled all the parts between the k**b and the feeder plate. I tried to move the bullet shaped part back and forth which is very difficult to move. The "U" shaped part that wraps around it will move back and forth. Is there anyway I can fix it myself and if so how? Many thanks for your time.