The place to start would be to follow the wiring for the autoplunger looking for a short.

Also check the switch that triggers the auto plunger.

Trough and shooter lane switches, yes

The game is confused about where the balls are. Trough, shooter lane, lock switches need attention and checked via switch test.

You need to go into the switch matrix test in the Portal menu. First, keep it running without doing anything for a few minutes. If you hear a beep and keep an eye on the matrix to see what switch just activated, this will mean that there's a bad opto. Next, I would start pressing down every switch on the game. If you activate a switch and see that another switch is also activated when you do that, it means that you have a crossed wire somewhere. Lastly, you may want to give the machine a few taps (or kick one of the legs a few times) to see if anything activates in the matrix. If something does here, then you have a switch that is too sensitive (possible since when there's a lot of action on the pin, shaker action becomes more frequent).

You checked to see if the switch in the shooter lane is too sensitive?

Is there a permanent ground from a bad transistor? I only know this because my bumper lights on LOTR were permanently on. My tech traced it to a permanent ground from a bad transistor. I don't know this stuff well, just passing my experience. Do you have the manual? what other switches are on that matrix? I don't have the manual or game anymore. Check everything on the same daisy chain.

I believe if he had a permanent ground that the auto-plunger would always be plunged and would blow the fuse and maybe burn up the coil.

It sounds like the switch in the shooter lane is activating and causing the auto-plunger to think a ball needs to be put into play.

Makes sense to me. I took the bulbs out or they would've fried or melted the plastics. And that was on the flasher matrix. Thumbs up. The coil would've been red hot. And why would that cause the ball to end. I think. Just saying great point. Might be more the trough Stern is infamous for that.

That is not the problem...works installed either way...BUT All coils should be installed with the wires as far from their coil stops as possible to make everything more reliable. And it sounds like a bad /failing maladjusted switch to me. As others have mentioned I would start switch test with the glass off and tap on the playfield or the rails by the ball launch with your hand and see if anything activates .Then try to activate it by hand with the coin door open . You should be able to 'feel' the switch activate manually and if it seems to easy to press it probably is.

Doesn't sound normal and this may be your problem.

This is normal, the machine in "attract" mode will try to direct any balls in the shooter lane into the trough.

It sounds like either ball trough switches 1 and 2 are not sensitive enough or are defective.

For the shooter lane switch here is an example picture of a switch. The contact point is towards the left end (the little white bump under the switch arm). You need the arm to be bent upwards away from the contact point to stop it from switching on its own if that is what is happening. You would need to hold the arm on the left side of the contact point (where the arm is attached to the switch body) while bending upward slightly near the contact point on the right side of it.
rolloverswitch.jpg

If he doesn't hear a click on the shooter lane switch that is a really bad sign correct?

You should be able to hear a click in a quiet room. If you don't hear a click then either the switch is always depressed or is defective. If it is always depressed then it usually can be fixed with the bending I described a couple posts above.

^ TY!

If you can hear the click then that should be ok for the position of the arm, especially if a ball rolling onto it causes the click.

See if tweaking/fixing the ball trough switches solves your problem.

If none of those things fix the problem then it may be worth your time to replace the switches.

One other thing, make sure all of the wire connectors under the playfield near the ball trough are connected firmly.

I agree ... check your ball trough switches and wiring and also replace the shooter lane switch and check its wiring. They are cheap and have a hard life. After all it is one of the most often used switch in a game.

Yes ..should be a click easily heard and felt as mentioned ..or it is worn out and needs replacing. It may work from time to time BUT not every activation is registered when they get old like that and/or they activate from gravity alone.

Check the trough adjustment and wiring as mentioned above because tapping the playfield and setting off ball trough switches is not normal unless you are actually moving the balls. Check trough wiring and switches to make sure that everything is adjusted correctly.

go into switch test and activate the switches in question. If you do not see it register or see more then one when you hit only one you found the problem. Or if one stays activated [ the palantir sounds like it is ] that is another problem that will confuse the matrix and cause issues you mention. Also if the daisy chain from other switches does not reach the trough switches [or intermittently] that could also be the problem. Check for continuity from switches in question.
Also see what switches are on the same row/column [manual is your friend] and check them and you should find the problem.
Good luck!