It needs scratching.

I would look at the obvious first like poor solder joint at coil lugs, dig around the tiny wires coming off the coil for breaks or cracks.

I'd also pull it's fuse be sure the fuse holder is good and metal caps on the ends of the fuse are on tight.

Be sure flipper button points are clean.

And wires for the coil are in IDC connectors real good.

Things like that.

LTG

I guess the definition of "randomly twitch" needs explanation. If the flipper is up and twitches while holding it up, I'd say it's an issue with hold power and eos. Is the flipper is down and randomly activates it could be related to the button or something else.

I would go into switch test and see if the flipper button shows up there when not in use. Pound the table and see if that triggers it. Also look at the leaf switch on the side. Perhaps it's too close together and touching when it shouldn't. Of course you want these close so the flippers respond with a light press but perhaps its too close and vibrations are causing it to trigger sort of. I suspect a flipper switch issue.

Did that really solve the issue? Does it make sense that peripherals plugged into the auxiliary 5v and 12v would cause the flipper twitch? My IMVE and TWD both all of a sudden started having a slight twitch every now and then on the right flipper only. Switch gaps seem to be fine. I just dont see how the fuse would be the issue or even poor wiring to the coil, something seems like it must be shorting or something super fast to trigger it. I dont know these SAM systems very well.

Yes I'd say it is possible. Seem this type of problems with other mods installed in games. The make the 12 volts dip too low and the 12v runs optos. So I've seem coils fire because the opto thinks there is a ball blocking the beam when it is just the opto failing. I've not heard of flippers before, but there are coils triggered by opto flipper boards so it is possible.

Unplug the light, if it does not happen it is the light. So if you really want light find a different 12 volt supply like a power brick.

Hmmm... well, TWD and IMVE use leaf switches not optos. Is the switch matrix on 12V? Then that makes total sense to me. I have interactive back box kits in both of mine that might be causing that and were both installed in the last few months. Ok, now its really starting to make sense. Thanks much.

Any other suggestions other than an external power supply? Other work arounds people have found for their games and lots of mods for SAM systems?

I was thinking it was opto flipper boards. If it is leaf switches then just make sure they are not gapped to close.

For alternate power you can rewire the service outlet so it is powered with the game switch instead of always on. Then plug a 12 power supply into the outlet. Or wire and old PC power supply to the switch. Search on that, there are a few good ways.

Has this always been the case? Have you fitted any mods, eg shaker? Sounds like back feed however I am not an expert. We experienced that issue when we fitted a shaker and forgot to put the filter in.

just picked up a star trek LE that is modded out and am seeing that on the right side upper and lower from time to time.

Update on mine, added a new 12v power source by rewiring the service outlet to power a power supply and removed most of the 12v stuff from the game power. issue is gone.