GERMRM,
Please accept my apology. I didn't mean to come off in a condescending manner. I read your posts and couldn't really tell how much you knew about these machines so I went into a very long dissertation on what I thought.
My wife has been sewing for a very long time (over 50 years) and she's never experienced a machine jammed like that.
I've watched her and my mother sew for as long as I have memories, and have never seen one jammed like that. So, I just went into "overkill mode" and started typing.
As a matter of fact the only machine I have had jam with the needle down had bobbin tension problems caused by a bent spring on the hook. The spring was grabbing the thread and not allowing it to pass through the assembly and it tied the machine up big time. Once the spring was straightened out the machine sews properly.
I hope you get those machines figured out and that they are not damaged.
Joe