I chased down the flash lamp problems on my Monte Carlo.
The flash lamps next to the roulette wheel were locked on. I found a out-of-spec transistor on the driver board. The under-playfield transistor (MJ2955) tested fine once the driver board was disconnected, so I just left it.
The other one was weirder. The “left dome” flashers did not work. Lamps themselves were fine. The transistors tested okay, and there was voltage at the lamp socket, but grounding the lamp socket did not cause the lamps to light.
I found that the two lugs of the lamp socket were shorted together. Apparently the resistor in circuit that steps down the voltage is good enough to protect the transistors from failing, or I just got lucky.
I might have caught this sooner if I’d noticed that the last person to re-rubber the game had looped rubber around 89 sockets rather than reading the manual for the correct rubber ring sizes.