Well, nothing crappy with this schematic. Connections look legit. Now you can lift ballast cold lead and lamp hot lead connection (black wires) from the ignitor board, disabling the ignitor, and probe the circuit safely. I would just use ~100W incandescent with two wires to probe, as multimeters can be sometimes misleading having too high input impedance and picking capacitive interference instead of a true voltage.
First, connect the incandescent lamp across the lampholder. It should light up at about half brightness. If it does, okay, ballast and photocontrol is good. If it does not at all - there is a circuit break somewhere. If it lights up at full - the ballast is shorted.
Next, I would try the trick with an incandescent and a fluorescent starter as a makeshift ignitor across the sodium lamp.
There may be tough cases as the choke partially shorted, hard to diagnose without some specialized tools. You can try to connect the choke right across 120V line directly and measure short circuit current. Should be around 2-2.5A AC I assume. Be careful as if the choke is really shorted, you can expect some fireworks ) Use some current-liminting in the circuit, at least 10A breaker, better something like 1KW heater or large lightbulb. Better use something short circuit resistant as a current clamp, as you can blow multimeter 10A input that way.