great article.i was always wanting to know what that 3rd pin was for.also,i would like to add that another source for power would be the old 9 volt ac adapters that were used to power handheld games and calculators in the 1970's.just cut the small plug off of the end,bare the wires,screw them onto the pachinko terminals,plug in to an ac outlet,and you are set.that is what i use on my vintage machines.