Hi Tom.
It's nice to hear that you are still in business with the CDI tester. I need to take a day to reacquaint myself with the project. While I'm doing that, can you explain a bit more about what you are doing with the AC output. Is this related to the ignition pulse, the charging pulse, or is a a new third output?
Any wiring diagrams and more information about what you are trying to do will be of help. How will you be working the DAC?
Are you needing to add two switches which will be read to determine the output? Like the mode switch and charging switch set a program path take?
Any wiring diagrams and more information about what you are trying to do will be of help.