cannot seem to get rid of the annoying audio buzz in this world challenge soccer machine
re attached missing ground wire on the ac plug - this dropped the buzz volume a little bit
tested continuity of ground from the newly reconnected plug to several places inside machine - all is good
replaced VR1 7809 & VR2 7805 on the aux sound board, buzz volume dropped a bit more but still annoying
checked for ground continuity on chip legs of the aux sound board and it is good

not sure where else to look, my google skills reveal very little info on this topic

sounds like 60 cycle hum to my untrained ears