Energized, I am measuring about 2.17V across that Zener diode which hangs off the emitter of the MPSA18.
I don't have anything that would have a Zener in that location. It's in series with the gate/base used as a low-voltage protection.
Also theres a pretty thick trace going to the zener diode's anode, and I am only getting 0.5V there to ground. I need to see what that bus is supposed to be.
Edit: that trace is going to primary ground, i was measuring from secondary ground. Disregard.
Edit: that trace is going to primary ground, i was measuring from secondary ground. Disregard.
Yeah the circuitry differs. the MPSA18 doesnt have a base zener at all. it does have an emitter zener.