MSD distributor issues

I am running out of ideas. The pickup is rusted but still measures within spec on ohms. Plug wires all check out. Turned the engine over - all valves appear to be opening and closing the right amount. Coil checks out. No changes in plug wire routing (not too close to the pickup wires).

At this point I have to wonder if the ignition box (Digital 6 plus) is going out.