Quoted from Zigzagzag:
Maybe the switches (almost) touch a coil lug ?
If the vibrations cause an occasional contact between the high voltage from the coils and the switch matrix it could cause this.
I assume you have tried taking out and reseating U20 before changing it, just to make sure the problem isn't in the IC socket or on the PCB ?

I would agree that it seems like there is a switch wire shorting to a coil lug. Spend a lot of time really looking close at all of the coils to see if any switch wiring is in close proximity.

1 week later

#25 3 years ago

EJS

Eric_S

Pinside+ Frequent

Oshkosh, WI

11y 131K 1,719

Really look over the wire bundles to see if something is causing a short, like an errant screw. Any wiring hacks on the game? Look really close at those. Get a friend to look it over. A fresh set of eyes may see something you're missing.

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