Hey all, I've been searching the web and my local support for a while now, and I'm really stuck. My World Cup Soccer table has this issue where (most of the time) it works great, but occasionally, while in play the ball trough will start trying to eject balls into the shooter lane. Sometimes the ball will make it out, sometimes the solenoid seems to only half fire, and the ball just shows its head and falls back into the trough. It's not just one ball either. I frequently end up having all 4 remaining balls in the shooter lane while I am still playing the 5th ball. This tells me that it is not just one opto acting up, although I have tested all of the opto emitters and receivers in the ball trough, they all check out fine. When it starts to happen, I open the cabinet and make sure that all the connectors are firmly attached at both PCBs, and then upon closing the door again, it keeps going.
I really am at a loss for what could be causing this, but I sure would like it to stop. What is it in the logic of the game that tells that solenoid to fire? Could there be a switch somewhere besides the trough that is shorting and producing a half-fire to full fire response in the solenoid (I didn't think half-fire was an option, but looking at the solenoid while this is happening and listening to it, it sure seems like it.)

Anyway, any help on this would be much appreciated.

Thanks for the reply. I have cleaned all the optos and checked the boards for loose solder points etc. I also used the switch test to confirm that the opto pairs were each working when I rolled a ball down the trough.

How big would a divot in this trough need to be? I assume the ball would need to be getting stuck there for this to be the problem? There is barely a rough patch in the trough, but certainly not what I would call a divot.

The switch at the plunger checks out fine, and all the switches in the row/column with the "trough stack" opto all seem to be working great. Not sure what the heck is going on here, but just played through 5 games without a problem. I guess I'll post again when it happens again.

Thanks Pinmeister, that trough guide is on its way, sounds like a great idea even if it's not whats causing the problems.

I think I finally found the problem, and as NM pointed out, it was an opto in a ball popper up top. Not sure why that popper would lead to the trough kicking out a bunch of balls, but there was a broken wire. After the fix, it hasn't done anything. I'll start up T-1 and let it sit for a while and see if anything fires.

Thanks so much