I had a similar problem with my 1958 United Big Ball Bowler, on the score motor where the rivets go through the board they where cracked across on about 90% of them. Rather than take it out and redo it I moved all the wires from the bottom tab to the top and it has been running like a clock for the last two years with no issues. You can see what I have circled in the picture and an arrow to one of the more obvious breaks in continuity.