Quoted from songofsixpence:
My understanding is that the small transformer is mostly about powering the displays. I have seen replacement LED displays become available for the Sys1 and 80. I assume these run on 5 volts, so I wonder if the small transformer is necessary if these are replaced?
If so, then there is a final workaround for that last early-Gottlieb problem. Not necessarily cheap though.
LED displays would need at least 5v and 12v.
The only LED displays being produced that I'm aware of are here:
The small transformer carries a bit more than just the high voltage for the displays:
The two transformers convert the 120 volts AC input to other voltages needed for the game. The large transformer outputs power for the solenoids (24 volts), general illumination light power (6.3 volts), and CPU controlled light power (6 volts). The small transformer outputs the main score display voltage (60/42 volts), the computer board voltage (12 volts which ultimately ends up as +5 volts), and the score display offset/reference voltages (8 and 4 volts).
But, depending on what the LED displays actually require, and as long as you install a power supply for the 12v, it could be something worth exploring. If this turns out to be a viable workaround, it sure could save a fair number of games with dead small transformer.