Well I'm experiencing my car's first-ever no start after replacing all of the original ignition components, including rebuilt transistorized switching unit, transistorized (low impedance) coil, ballasts, condenser, etc. The car will start and run fine when swapping a conventional black-top coil for the silver, transistorized-friendly coil. But I've been led to believe that these switching units are designed to operate only with the low resistance coils. Both coils have their expected terminal resistances and unique +15 terminal voltage values (which for transistorized only appears when points are closed).
I'm doing troubleshooting on the fender-side with jumper cables to the rebuilt switching unit and the two coils. Old switching unit had to be returned for core. Timing and dwell were verified after briefly re-wiring the connections to operate as a conventional points-based setup (bypassing the trans switching unit). This is a baffling problem that prompts consultation with the experienced community -at-large here. Thanks much ... Hans