Thanks for the pic, Judy.
I had that problem when I first started working with this machine. That is what I was talking about when I said "
And the position finger is in place in the notch of the position plate."
Miriam, I have the tension unit back together all nicely cleaned up and shiny. I have been following the diagrams and instructions in the original user's manual. Tools for Self Reliance is a wonderful organization, isn't it? The thread follows the proper path for threading, ending at the needle where it goes from right to left. The needle is placed with the flat side to the left. Fortunately, at least according to the manual, that is fool proof as it will only fit in one way 
After working with the tension unit, the stitching is still exactly as it was regardless of how I set the top or bottom tension. The only thing I haven't done is disassemble the bobbin case and clean and reassemble it. Will wait until tomorrow to tackle that as I'm completely worn out at this point. I've been working on this for over two weeks, reading and researching and trying first this and then that with no good outcome. I'm not a quitter but this is about to beat me.