My CSI has been dogged by a very intermittent trough issue since I bought it, and I finally figured out the problem (but not the solution). Sometimes when I lock a ball in the Skull, the 3 balls still in the trough get into this configuration:

IMG_7090.JPG

When this happens, trough switches #2 and #3 don't register - because the balls are just beyond the physical switches. Ball 1 registers at the "Trough Jam" switch, but apparently the software doesn't act on this. The game does 2 ball searches, goes to "end of ball", and only then pops ball #1 into the plunger lane. This makes it unfit for league play, of course.

I caught the game "in the act" today when this happened - as soon as it went into a ball search following the skull lock, I opened the coin door and went into switch diags. Only the "Trough Jam" switch was registering.

Since this is a mechanical problem, I assume there can only be a mechanical solution. I don't see anything about the trough mech that looks "wrong". Any advice would be appreciated.

Yes, the scoop is cracked on both sides:

IMG_7094.JPG

I also reproduced the ball position with the scoop removed (sorry for the poor focus):

Trough-jam.jpg

I think what's happening is that the balls and/or the trough have become magnetized. I thought I installed carbon steel balls, but maybe I missed the one magnet in the game. I'll try carbon steel balls and see if I can reproduce the failure mode manually.

How did you zip-tie your scoop to repair it?

BTW, thanks, fellow Duluthian!

I used several layers of foil tape to shore up the scoop, and added a layer of mylar to the trough. I'll reply if that didn't fix the issue.

I can see it - thanks for the pic!

The switches and optos are working fine. The problem is that the game software ignores the "trough jam" switch when it does a ball search. The fix is to avoid trough jams (until I can rewrite the code with a P-ROC).

Bummer - the problem is still happening (but less frequently). We used CSI in league play Saturday, and it happened twice.

I'll try both tonight. Belt and suspenders.

So tonight, I finally caught the culprit red-handed! I'm certain now that the remaining problem (much more intermittent) is that either the trough or the balls have become magnetized. Two failure modes, both mechanical in nature - and probably due to not using carbon-core balls.

magnetized-balls.jpg

I just ordered new carbon-core balls for all of my Sterns. It was about time to replace them anyway.

I just proved to myself that magnetized balls were my entire problem. I removed the trough and took it to my desk. Then I used a level to hold it at a 1 degree angle. The balls stuck to the wall! Then I redid the "experiment" with balls that I knew were carbon core. They moved freely.

I really feel dumb for putting Chrome Steel balls in this game - I'm usually more careful about that. Just glad that the issue is resolved!