I have a Williams System 6 pin and I notice that sometimes when the ball goes over a rollover switch it will sometimes register multiple times, at worst sometimes adding three "hits" (easily noticed when the bonus counter rapidly lights up). It doesn't occur on all the rollovers and on the ones it does happen on it doesn't happen all the time. I tried gapping the switches very far and then very close but no dice either way. I also tried burnishing the contacts with a burnisher that's safe on gold contacts but still seems about the same.

My guess is that the switch is bouncing open and closed ever so slightly to register multiple hits on a single rollover of the ball (it seems to occur more often when the ball is fast). If so I'm guessing the switches are just fatigued and need to be replaced. I'm guessing that adjusting them several times didn't help with the fatigue either. Have any of you ran into this before and found any good solutions? Thanks!

After a bit of searching around for some ideas I ran across swampfire's awesome little guide to upgrade early SS rollover leaf switches to microswitches. Guide is here: https://pinside.com/pinball/forum/topic/guide-upgrading-early-ss-rollover-switches-to-microswitches

I should note that I had to align the diode to the column line wires as the switch didn't register when facing the row line wire (My game was a System 6 as opposed to 7 so maybe that's why?). Another thing I should note is that some of the microswitches' rollover wires are bent a bit differently/aren't consistent. I actually had to adjust some of them a bit to make them work without getting the ball stuck and/or not register hits. After a bit of finessing however these microswitches work fantastic!