I am looking for some help with my Pinbot. It has a problem which manifests as frequent triggering of at least one outlane and occasionally as a tilt during play or with a gentle to moderate tap on the lower half of the playfield.

I have noticed also that thumping the playfield is less effective at triggering the problem the more the field is tilted upwards towards fully vertical.

I have checked switch gaps, the diodes on the switches, looked at the wires for obvious shorts and even tiled the playfield up during play to jiggle all of the wires and tap stuff underneath with a wooden dowel trying to trigger it without success.

Does anyone out there have any thoughts/suggestions on how to go about tracing the cause of this issue?

Actually no, but I will give it a try. Could you explain how that would create a sensitivity to playfield vibration? I am not making the connection. (Sorry for the unintentional and BAD pun.) Really though - I actually am curious and do not understand.

Ok - checked to make sure all of the harness connections were seated well. Still doing having the same trouble.

Update - on the occasions that the problem manifests as a tilt, it seems to be a slam tilt since there is no warning and you lose the ball and your bonus immediately.

The outlanes and the slam tilt share a common wire (green with red bands that goes to 1J8 at the board). The outlane switches and slam tilt have different color coded white wires, all of which end up at 1J10.

If I bring the playfield fully up I have to hammer really hard with my fist to make it happen, and even then it dies not always happen. The lower the playfield, the easier it is to make happen. With the playfield all the way down, it happens with a super light tap (like if you were knocking that way on someone's door they would never hear it).

No. Or at least almost not at all. Putting it into switch edges shows that it is the left outlane that is getting triggered. Raising and lowering the playfield will trigger it until the field is tilted approximately 45 degrees or higher.

Interesting results - taping over the contacts for the left outlane did not make a difference. I next unscrewed the left outlane switch to take a really close look at it and left it dangling with its contacts taped over. This totally eliminated the phantom outlane triggering. I played a few games like this, banged on the playfield a bit and thought it was solved but then.....Pinbot says, "Tilt - all data lost". Still phantom slam tilting. Taped over the slam tilt contacts both under the playfield and at the coin door. Played a few more games to test and though not as frequent as the outlane issue was, it still gives a random slam tilt every few balls.

Another diagnostic question related to this: on a normally functioning pinbot in switch edges mode, does the ramp switch register only as down or both up and down? Mine registers ramp down but nothing when the ramp is raised.

I have never seen the slam tilt register in switch edges mode. Occasionally when banging hard on the playfield the ramp down will register. I attributed that to excessive vibration but it could be part of the same issue. The only reason that I am suspicious of the ramp switch is that it is the only thing I can think of that would be affected by a change in gravitational orientation. (Remember how the issue with the outlane would be worse flat with it raised up?)

I will try putting the outlane switch back on later tonight to see what happens.

Did not get to the next step before having to leave town for the next few days. More this weekend....

As with so many things in life, a little time away helps me to think things through more clearly. On my recent business trip I started thinking about how many issues with pinball machines boil down to seemingly minute changes, adjustments or barely perceptible defects. In particular, I staeyed thinking about this mysterious switch problem. Why did the outlane switch malfunction when it was attached but not when left dangling? The answer came when I also unscrewed the shooter lane switch (which was sometimes somehow causing a slam tilt). Turns out that I feel into an old trap. I read on Pinside once that when doing a playfield swap you should not bother keeping the various fasteners with their associated pieces because this assumes that whoever put each one in used the correct size. I had just finished a playfield swap on this machine but I had grouped all of the fasteners in with their parts. In unscrewing both the outlane switch and the shooter switch I noticed that one screw on each was a bit tighter than the other. When I came back from my trip I looked really closely at those screws. Sure enough, two were a tiny bit larger (probably #6 screws as commonly found at hardware stores which typically carry only even numbered screw sizes rather than the proper #5). I decided to put both switches back on each with an original#5 and a #4 since I did not have any extra fives laying around. Voila! All fixed! Seems that the slightly fatter #6 was fat enough to be intermittently shorting the switch.

Lesson learned. Thank you all for your generosity of time and knowledge helping me work this out by giving me ideas for various things to try. I really appreciate all of you who are miles down the road from me in terms of knowledge and experience.