EMs do draw a pretty good amount of current. You list the voltage of each game, but not the current load (watts/amps) You may want to check that breaker if it starts to trip rather than just dim. The breaker may be a wimpy 10 Amp that will not support a large load. Do not simply install a larger breaker either as the wiring may not be heavy enough gauge to support a larger load. You pinball machines may want to be on their own circuit.