[83_Silberpfeil]

Thanks to Armand, ossiblue, and brads for chiming in. Very helpful info!
Your assessments are SPOT ON! The pin on the mechanical portion (that connects to the electrical) broke off! It's a little 'aluminum tab' that broke off.

Ossiblue, your explanation of how the elec/mech portions work together is excellent. When I got old broken part back from the shop, it painted the picture you described with words. I'll post pix here shortly.

I ended up going with a spank'n new ignition assembly --- $$$$$.

My problem now is that I have an ignition key and a separate key for everything else. I am going to try to open up the old ignition key tumbler and try to use the 'wafers' to mod the original door locks to match the new key.

Thanks again to everyone here!