Quoted from KenLayton:If you disassemble the spinner unit, you'll find the copper foil traces on the B-7470 (might be marked 1C-2001-66) contact board worn through to the phenelic. Over the years the pressure from the wiper finger switches have worn a groove into the copper so that no copper is left.
Is there a way to repair the copper traces when this happens? I just fixed one recently that had a groove worn through on the inner most trace. The machine would randomly not award the bonus and the score motor would constantly run and not eject the ball. I adjusted the switch inward so it would ride on what is left of the trace. It works for now but only until it wears another groove at which point I think there will be no more room to adjust the switch to.