Update regarding my problems. I replaced all USB cables.
-Problem with random firing shooter coil still there. It just pops once in a while... (every 1-2 minutes or so). I think it only does it with balls in play.
-Infinite ball saver problem not tested yet.
I did Averells recommendation to make the outlet of the through straight. I don't recommend this, they bounce back in in my case. But also my ball through seems to have some mechanical flaws (it is not straight).
Anyone who has a spare trough, please contact me.
-Flippers going briefly dead gone as far as I could test BECAUSE new problem:
During play IO board 1 goes missing (where the scoop is). It doesn't come back unless you hard reset the entire machine.
Of course I checked if the cables are well seated; they are. I ordered extra wire harness standoffs to zip the USB cables to.
It happens repeatedly and within 3-4 minutes of play. Before USB cable replacement, this was not an issue....very strange.
Any other suggestions then already mentioned in the forum (keep away from amplifier, keep away from high power coil wiring etc.) I have ferrite chokes on both ends of the cables.
I guess IO board 1 is the one in the back that has also the worst connector.
Does anyone know why it does not come back to life? As I understood from Ferret the software should reconnect to the IO board automatically after a few seconds.
I have a Pinbits jam protector and modified it to fit the trough,thanks for the tip.