There is an issue with the era vikings. They used the self lube stuff that was good for about 30 years, and then it hardens up. Only way to fix the problem is to carefully take it apart and clean ALL of the old stuff out. Don't try to force anything - it breaks very easily.
They are rather complicated machines, some of them require taking most of the machine apart to get at. There are some manuals out there, don't recall exactly where right now - but the main thing do NOT try to force anything, if it won't move easily and you try to move it, you will break something.