First off, let me applaud my fellow Marylander, Enochsmoken, for putting all this effort into trying to repair this board and being able to use an oscilloscope.
But if you are successful in repairing this dinosaur, that's just what you'll have: repaired 1976 technology.
Please keep in mind, a Weebly MPU is $167 shipped, 2021 technology. Just a thought.