Can you describe it in a bit more detail? GO through the sequence of events from the time the machine is turned on with two balls in the trough, to the time it kicks them into the shooter lane.

Does the kicker fire even when balls aren't in the trough? Or is it a one-time kick when you first turn the machine on?

That's... really odd behavior.

So, when there are balls in the trough, closing their respective trough switches, you turn the power on. The coil that kicks the front ball into the shooter lane kicks once, and then retracts. It does this onece more for the next ball, and then kicks over and over again for the third ball, because it's not able to get that third ball out of the trough.

Then, when you take all three balls out, that same kicker energizes one last time and stays locked on?

Now, I'm not super experienced, but this behavior kind of goes against everything I know about how System 11 pins work. The machine has no reason to kick a ball into the shooter lane unless a game has started. The coil locking on makes more sense by itself, but the act of the coil pulsing on and off like that can only really be explained by some seriously funky issues with your game ROMs.

Is there any way you can record video and upload it somewhere?

So, power comes on. Game kicks a ball out. Game kicks a second ball out. Then there's some kind of sound callout. Is that part of the game's attract mode? I also didn't see the kicker try to kick the third ball out, nor did I see it lock on. Can you get some video of that?

The initial kick when you turn the power on reminds me of a Taxi I had where the bell coil would fire right when the machine was powered on, before the CPU had even booted. Turning the machine off and then right back on again would fix the problem until the machine had been off for a while.

https://pinside.com/pinball/forum/topic/taxi-bell-rings-on-power-on

It also makes me sad that I never wrapped up the thread with my solution. I hope I can remember it. Also, anyone can feel free to correct me if I'm wrong about something. (I'm probably wrong about something.)

The general story is that there's a board-wide signal that limits when the coils can fire. This signal acts in conjunction with the signals sent from the PIAs (which are, in turn, driven by the CPU). There's a timer chip that's designed to wait until the CPU is in a stable state before opening the gate for these coils to fire. I think this is the "blanking signal" that you see people talk about. Or maybe it's related to it.

Somewhere in the PIA-to-Coil equation is a logic chip that examines the blanking signal and the signal from the PIA. If both of those are in a certain state, then this chip sends a signal to the transistor that drives the coil. If that chip is faulty, then neither the blanking signal nor the PIA's signal will matter. The coil will just fire as soon as that logic chip gets power.

I have to go right now, but I'll be back later. For now, scrounge up the manual and grab your logic probe. Find a nearby coil (schematic-wise) and check the pin from the logic chip that drive's that coil's transistor to see what it does when the machine is first turned on. I'm willing to bet there's no signal at any point during that process. I'm also willing to bet that the pin leading to the transistor that drives the kicker coil is high for a bit of time as the machine first turns on.

Please note that all of what I just said could actually be completely wrong. I'm still kind of new at this stuff. Hopefully it helps!

It's hard to tell with the camera moving back and forth, but am I seeing that whenever the outhole kicker fires, the shooter lane kicker fires at the same time?

If so, then we appear to have two issues: one where the shooter lane coil fires right at machine power-on, and one where the outhole kicker firing seems to also cause the shooter lane kicker to fire.

Does that seem accurate?

I think you and I are talking past each other, here. Let's tackle one thing at a time.

I've watched the videos again, and it really seems like the outhole lane kicker and the shooter lane feeder coils are firing at the same time. It looks like the game freaks out until there's nothing pressing the outhole switch, and possibly also nothing pressing the two trough switches furthest from the shooter lane. (The manual calls these switches 55 and 56, but it also calls them right and mid, which is weird.)

Put the balls in the trough with the power off. Push them in there with your finger if you need to. Turn the machine on when there's nothing pressing the outhole switch, and all three balls are in the trough. What happens?

Transistor Q25 traces back through a pre-driver transistor, and then into pin 11 of U20. Pin 12 and 13 are the blanking and PIA signal. I can't remember which one's which off the top of my head. I do know that if pin 11 is high without both 12 and 13 being high, then the 7408 chip at U20 is busted, and you need a new one. I had that problem with my Taxi's bell-ringing coil. However, the consistent nature of the coil firing (once per ball, rather than just straight locking on or sputtering) means the problem is somewhere else.

Does the fire-twice-then-lock-on thing happen every time you power on the machine with three balls in the trough? And does the first kick happen right as you power on, or is there a second-or-so delay first? In addition to the fact that it's firing when it shouldn't be, it's odd that it would fire normally twice and then lock on at the third fire. If that pattern repeats five times out of five, then there might be something going on with the game ROMs. Otherwise, there could be a transistor or IC failure somewhere.

If the lane kicker is firing with all the other coils, then there's a possibly short somewhere that's causing the return line from the lane kicker coil to go to ground whenever one of the other coil return wires goes to ground. The manual says that this should be the violet/red wire. I believe power is always supplied to a coil, and it's the grounding of that wire through the transistor that causes it to fire. That would mean that the violet/red wire is completing its circuit at the same time any other coil is.

Given that, I wouldn't think that the ground wire from that coil is just shorted directly ground, otherwise it would be locked on all the time and you'd have a melted coil. It's possible that pin 11 on U20 is going high at the same time any other coil goes high. You can get out your logic probe and see if that's the case. The outhole kicker, left ramp raise and left ramp lower are also driven by U20 on pins 3, 8 and 6. Put the outhole kicker on coil test. You should see pin 3 on U20 go high every time the outhole coil fires. Leave the outhole coil firing and check pin 8. That one shouldn't be going high while the outhole coil is firing.

Now, check pin 11. If that one's going high while the outhole kicker is firing, then you need to check pins 12 and 13, which are the inputs for pin 11. Pin 12 is the signal from the CPU (by way of a couple of other chips) and pin 13 is blanking (which should generally always be high while the game is powered on). I'm mainly interested in pin 12. If pin 11 is going when it shouldn't be, then either U20 is bad, or it's just doing what it's told by a chip further up the chain.

I would also make sure the diode for the shooter lane coil is working properly. That may or may not be contributing to the problem, but I know that I've had transistors get fried after too much reverse current from a coil, which lead to things locking on and acting weird.

NOTE: Again, please take everything I've said with a grain of salt. I may not know as much as I think I do about this stuff. I'm just the only one helping out, it seems.