MarkG - Nice explanation, as always! I'm not clear what the Motor 4D switch is doing. It's closed during the first pulse for Motor 4A. Doesn't that power the bonus stepper to step down, the same as the first pulse from Motor 4A would do?

During the double bonus, when the pulses #2 and #4 from Motor 4A are going through Motor 2D and 3B, why is it getting only 2 out of 4 pulses? Why isn't it 2 out of 5 pulses...or 3 out of 5 pulses if Motor 4D is making a connection with the bonus stepper? What happens with that first pulse from Motor 4A? I can see that the first pulse doesn't make it through 2D or 3B, but doesn't 4D send a pulse then anyway?

Great use of Audacity, @MarkG! I don't have access to a Solar City, but there's an arcade here that has a Target Alpha that I've worked on, which has the same bonus system. I've attached images of the TA circuit and sequence chart to be sure.

I'd be happy to go in and maybe use those lights/alligator clips again (like we did on Quick Draw) to see when that 4D switch is closing relative to everything else. There's a party there tonight, so I won't be able to do that until tomorrow, but I'd be happy to do it just so poor Mark can sleep peacefully again.

The only potential caveat is that the local machine does have its own bonus problem - intermittently giving 1 or 2 extra thousands to someone's bonus. Haven't chased that down yet, but hopefully it's just due to switch bounce and at the least the switch timings are correct.

You know, there's that lovely little 2B switch sitting up there by itself that would provide a perfect 6th pulse, wouldn't it? Could the 4D below be a misprint and possibly be 2B instead...or did I just enter crazy-town? 2B or not 2B, is that the question?

What you're suggesting is probably more likely - that the sequence chart marking for motor 4D is just incorrect. Although, why do a redundant switch as 4D and 2B would be doing the same thing? I'll try to find out tomorrow....stay tuned!
Target Alpha bonus circuit (resized).JPGTarget Alpha motor sequence (resized).JPG

Solar City bonus circuit alternate (resized).jpg

Hi Rolf,
I'm guessing that there would have to be 3 signals to turn the bonus stepper per 120 degree cycle of the score motor, with 6 signals going to the 1000 pt relay (2 1000 pt signals per each step of the bonus stepper) - so 5 120 degree cycles to complete the double bonus count. But I'll certainly count that out when I get to the machine tomorrow.

I only have 1 light/clip device - but I do remember this Target Alpha having a slow-counting bonus when I began working on it. The problem was that the G relay was not staying energized during the bonus countdown due to a 15th pos. switch on the bonus unit not closing ....it was alternating off and on with each bonus count. When I fixed it, I watched the G relay energizing and holding steadily through the entire bonus countdown - it's obvious visually - you can watch the G relay stay energized the whole time, then when the countdown is done, it releases.

Hey guys,
Yes, 4D is not marked correctly on the motor sequence chart. I've attached to photos, the first of the entire score motor at the home position, stack 4 is at the top, the switch we're concerned with is in the red box. You can see from the way the actuator is situated that it's not going to hit a post until late in the 120 degree cycle (the motor rotates CCW in the photo)....and sure enough, when I disconnect the motor and walk it through a cycle, I get 5 bumps from switch 4A, then the closure on switch 4D. That's two sequence chart errors in as many weeks, Mark - you're on a roll!

TA home position (resized).JPG

TA motor 4D at home pos (resized).jpg

Just for fun, I made 3 videos of Target Alpha collecting the bonus after balls 1, 2 and 3. After watching them, I realize this game may have some bonus issues, so maybe this isn't the best example to be watching for how things are supposed to work....but it doesn't look like the number of score motor cycles is as straight forward as I was hoping. Rolf wanted to know.

Alas, I don't have access to a Solar City (or any of the other permutations of this playfield). But the schematics are pretty much the same for the bonus section, yes? So I would think Solar City would have the same error.

I have to figure out my intermittent extra bonus error on this Target Alpha one of these days too! I'll probably take some of the switches off the motor 4 positions to get down to that 4A switch and look for improper gap - bouncing.