We're having an issue with a Mustang Pro, where sometimes a ball gets stuck in the through, and the pinball registers it as missing.
The issue is that the through jam opto, which works in the test menu, never engages the VUK when the ball gets stuck, never clearing the jam and leaving the pinball stuck.
The optos themselves work fine, as they don't show any issues when placed in another machine. In the test menu, all switches and optos in the through register fine.
Other Stern machines we've seen try to engage the VUK as soon as you interrupt the opto, this one doesn't. We thought it could be a software issue, so we updated from 1.20 to 1.45, but no changes there.
Does anybody have any suggestion?