its under the playfield
see top right of photo (white wire with yellow band)
ignore the yellow capacitor which only has one lead connected in the photo

Diode on mine is there but I don't have a capacitor in the same spot. I'll replace the diode anyway and see if that makes a difference. I dont know much about diodes but I only have 4004's but I think the switch diodes are suppose to be 4148's, is there much difference? Should I also be adding a capacitor here? if yes what size?