I'm trying to have my Revenge From Mars fully operational, but there's that issue that still remains.

When the pinball starts, the coil for "Right Lockup 1" keeps knocking. As if the opto saw something.
Checked the opto in the Switch Test, and it works fine.

Even stranger : I've connected that opto to another coil, thinking that coil would do the same thing, but this is still the Right Lockup that keeps knocking.

It should be the coil rather tha the opto, but it reacts correctly in the coil test...

I'm really puzzled, there. And stuck.
If anyone has any kind of idea, that's be jolly good