87 Classic 50 4-Cyl Ignition System Testing Help

[DuckOfDeath]

I replaced my stator and switchbox before I got a DVA adapter for my meter. Still have no spark on any cylinder. I disconnected the black/yellow kill wire from the switchbox and the two yellow rectifier leads and still no spark. Stator tests good, and I suspect the old one is fine too. I'm getting 35 volts between the red and red/white. 280 on the blue/blue/white. I get identical readings whether or not the leads are connected to the switchbox or not. The trigger tests good when not connected to the switchbox (4.3v on the purple to white and 6v on the black/white to brown). When connected to the switchbox the volts on purple to white drops to 2.3v and on brown to black/white drops to 4.6v. Based on the CDI guide, if the voltage drops below specs on the trigger leads (4+v) when connected to the switchbox, the switchbox should be replaced. My problem is that I already replaced it and when I installed the old one back on it acts the same way except the voltage on the purple to white only drops to 2.8v. Wouldn't I at least get spark on the two coils controlled by the brown and black/white trigger leads that do come up to specs when connected? I'm literally getting zero volts from any of the four coil leads.

 

[DuckOfDeath]

I found the switch box bench test card in another post and spent some time learning about how to test diodes. It appears my new box has a bad diode to the Grn/Wht terminal, as it's passing current in both directions. The old box seems to have issues passing current in the proper direction between the red/wht to blu/wht and on to the black/yellow terminals. I feel better knowing the same diodes aren't toast. I'll try and return the new box for exchange.