Quoted from John_C:Actually, I have been working with Spooky support for the last few weeks while I tried everything I could think of to identify the source of the problem. I've replaced the servo extension leads, braided the servo flat wire leads, replaced the 12v/5v power supply (at my own expense), etc. All along, Spooky has tried to offer guidance but they've been unable to determine the cause of the problem.
It wasn't until I changed out the servos that the problem seemed to go away.
MK6PIN - You suggested this issue might be some sort of inductance loop. Can you shed some more light on this?
I've watched how you were addressing the issue, and several on here nailed the culprit. Strictly speaking for myself, with the intent of helping others, as I love this game, Spooky rocks, and possibly clarifying would help others find what I did....
EMI - electromagnetic interference (noise)
Induced voltage - can be transmitted OR received depending on what the intent is by creating a coil or in this case a loop to amplify the desired result.
While both have similarities, the resulting effects are generally different.
In this case, the servo motor wiring UNDER the playfield have managed in some cases to create an effective inductive loop (due to overall length and parallel nature underneath). When this happens, it's not noise, but rather an induced voltage (from whatever) that it picks up. That small voltage is then "seen" by a Michael but only briefly, hence the creep. Also explains why there are many games that don't even experience it. Servo is simply getting induced voltage at random times, and energizes. Completely random, Michaels behave differently, with the exception as #1 always seems to be the worst culprit. Why? best shot of getting the full effect of the pulse, as the wiring ABOVE the playfield is parallel.
So...as others have touched on, the simplest way to "break the loop" is to go UNDER the playfield, unlace all the servo wiring (carefully, but quite easy) leaving each 3 wire servo twist in place, hanging. Once accomplished, locate an easy area under the playfield to relace, with each servo trio oriented 90 degrees from each other. The wires are long, and took me about 15 minutes to address once I figured out what was happening.
These are hand laced, again explaining why some games do it, and some don't. Simply been assembled/ laced differently. The 90 degree part actual creates rejection to any induced voltage, as opposed to amplifying it. You may have actually done it when you changed your servos and not even realized it. I had the issue, corrected, replicated, and corrected using this method 3 times...enough to convince me I'd found what was happening.
Easy, but just be careful to not cut an actual wire. Secure, and done. There are several games out now dating back to WOZ where proper wireway/ lacing is very important. This is one of them.....(ferrite chokes are sort of hit or miss as they generally help w rejecting noise)
Yes, I've interacted w Spooky (quite a bit) as I went through this...again, not speaking for them, just wanted this lifted so everyone just doesn't pile on, blaming bad parts or something....this works, and hope some find it helpful.....