My Avatar pinball will occasionally end the ball in the middle of play when there hasn't been a drain. This only happens once in a while, but if it happens once, it often happens again shortly thereafter. This is my first machine and I know almost nothing about the tech/repair side of things yet...Anybody have an idea of what might be going on in the machine to cause this or what a possible fix might entail?

Wow, thanks for all the fast responses! You guys are awesome. Losing my ball unjustly with only a few shots to go for Final Battle was definitely a feeling I hope never to repeat...

Ughhhh. I guess I really should blame myself for letting it happen four or five times to me in basically irrelevant situations before getting truly sheistering and actually bothering to fix it...

Yep - I found the plug for the opto switch at the trough and pulled it out and pushed it back in again really snugly, and haven't had a problem since, probably with another 500 plays at least. Very easy fix for me. With an older game, you may need to actually replace the switch itself, not sure.