This Whirlwind has developed a switch error, and I am having trouble diagnosing it.

When the top and middle 3bank drop targets, either or both, are down, when the top single drop resets, it triggers game credits. I think from the middle chute. Coin door switches are not indicated in switch edges/test mode so I can only test this in gameplay.

I’ve replaced diodes for the three bank board. The coin door and can switches don’t seem to have diodes.

I’ve visually inspected other switches in the “rectangle” indicated by the triggered switches on the switch matrix, but this has some differences from the normal switch matrix puzzle so wanted to check to see if I’m missing something…

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Thanks! You are suggesting to check the interface board? This doesn’t seem to have one for the coin door, like a WPC game, say.

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I should mention I’ve swapped out the MPU entirely, so if there are diodes on there for dedicated switches it’s not that…

Bumping this for ideas from System 11 minded techs!

Amusingly the switch for coin chute 3 doesn’t exist, that would be on some euro door configurations I believe but not on my US coin door. No other vibrations including the other drop bank cause this — I agree it’s odd that it happens on reset.

The drop switches are all optical, wondering if the single target board is the culprit now since it’s hacked up by a previous owner, but it’s a pretty simple board and clearly that one opto functions when dropped, it gives the proper reward. Just gets goofy on reset.