I've opened up a Lutron dinner, and I'm trying to understand how the microprocessor gets its DC voltage. With my limited knowledge I'm not seeing an AC/DC converter. I've attached pictures, can someone explain how this works?
There is undoubtedly an "AC/DC" convertor on the board, since the TI micro needs 3.3V DC nominally to operate. However, you're probably expecting to see an inductor or two, and a switching power supply control IC, which there isn't. That's because the circuitry consumes so little power, it's not necessary to go this route. Instead, I think the AC is directly rectified (D3, D4), and then probably "chopped" by a series pass transistor (Q8?) operating at a fixed duty frequency/duty cycle directly into the large electrolytic filter cap, with a paralleled zener diode for regulation (Z2?).
Of course, this is merely a guess, since we don't have anything approaching a circuit schematic to reference.
The AC/DC convertor is a rather crude circuit with dropper resistors, rectifier diodes and a Zener shunt regulator. After this there should be a regulator IC which supplies the MCU with a more stable voltage.
Due to the high voltage drop it will only be capable of supplying a very low average current, but the large filter capacitor may hold enough charge to pulse a latching relay on and off.
Your images are too fuzzy to trace reliably, however I think the circuit may look something like this:-
Note that the 'ground' symbol in this diagram is just to satisfy the simulator. In reality the entire circuit should be considered live!