Quoted from jedi42:Just wondering if someone can point out the exact resistor that was replaced? Is it R20, R25, R27? Thanks.
I think jwilson was referring to transistor Q13 just below the resistors you mentioned. Looks like a 2N4401.
Hope he pops on and clarifies this but in the meantime have a look here...
http://www.firepowerpinball.com/downloads/DriverBoard.pdf