Coincidentally a similar question just came up about Jungle:

https://pinside.com/pinball/forum/topic/confused-about-something-that-should-be-simple

On Jungle and Orbit the P relay doesn't fire the Score Motor so the O relay may be needed to do that.

/Mark

If you do it manually, i.e. where you activate the outhole switch with your finger and let the kicker fire, then activate the trough switch with your finger, do you get the same result where O relay pulls in again right when you activate the trough switch?

Hmm how about do the same manual method, you activate outhole switch...but then you disconnect the motor and then activate the trough switch. Does O activate then too? Might turn up something but probably not especially if this is indeed how the game was designed to work. But the guy with the Jungle said *sometimes* it did it, not every time, soooo.....

what is really needed is to verify, by someone else with a gottlieb orbit, that can just test to see if their trough switch triggers the ball return coil. Anyone???

I think it is becoming clear (to me at least) that this is how the Gottlieb multiplayer ball return/players unit design worked in the early 70’s

During this era, P has no motor or hold switches, the P switch in the circuit serves to re-fire O and then performs the P hold function in series with the O hold switch. In other words, without O being on, the motor won’t turn and P would turn on and off with the trough switch. The (tolerated for a time) consequence of this design is that the ball return fires a second time.

Near the end of 1974, the design began to change (Super Soccer, Far Out, Out of Sight, …) and switching was added to P to inhibit the second return kicker firing. A few machines later (Fast Draw, …) a P motor switch and P hold switch were added (using the P switch that formerly fired O, just connecting it to the Motor 2B conditioned power source that O runs off of).

I could be wrong (wouldn’t be the first nor last time), but others seem to feel this way also - MarkG above AND, as is usually the case on anything I look into, Rolf (two/three years ago) here and here:
https://pinside.com/pinball/forum/topic/the-many-problems-with-my-gottlieb-hot-shot#post-4084881
https://pinside.com/pinball/forum/topic/gottlieb-king-kool-player-unit-not-working-correctly#post-4845077

I think you're exactly right. If the P relay is held in and the O relay is held out (can not energize), the score motor never turns on, and the player/ball never advances. So hence the P and O relays go together to turn on the score motor, and you get the double tap from the ball return coil (via the O relay.)

but to be honest, i can't remember any other game that does this. i went down the row on other games like Hot Shot, Big Indian, Jumpin Jack, 300, Fast Draw, etc and could not find a single example that double tapped the ball return via the O relay. Admittedly though, all those other games are later (1973/1974), where Orbit is 1971. i wonder if the 2player version (Outer Space) does this too? probably not...

Guess need to look at King Rock, Now, Sheriff, Jungle (all 1971/1972) and see if they do this. I did look at Lawman (2player version of Sheriff) and it did not do a double tap. Unfortunately I don't have any other 1971/1972 four player gottliebs in the stable.

Ah! Jumping Jack is an interesting one (mostly because I have a clean schematic of it...), it has a slightly different design - still no P motor switch though. I don't see [yet] why JJ doesn't fire the ball return coil a second time, but I do see that they've taken measures to not fire the big target bank resets more than once (fire on O and not P, O and P switches in series).

Big Brave (and I presume Big Indian) have a P switch to filter out the second pulse to the ball return coil... also Far Out/Out of Sight, Soccer, Super Soccer

These No_P_Motor_Switch-based designs continue through 1974... including Duo/Magnotron. Fast Draw is the first machine I've seen with [what I used to call "the standard"] P Motor and P hold switches.

I have Outer Space set up in the garage at the moment and will check it tonight.

i'll have to check Jumping Jack again... but it's 2player not 4player... maybe that's the reason no double tap... i don't have Jack in the Box...

The other problem is that some of the games that do it only do it sometimes.

The 2 player/4 player differences were minimal with regard to this logic... at least, based on the differences between Duotron and Magnotron. I've also checked with another pinsider with a Duotron (2p) - it definitely does the ball return double tap

One other point - the standard P motor and hold switches were used in 2p/4p games up until, at least, Snow Derby (1970-12). Then came this period of alternate designs from 1971 - 1974. What was Gottlieb trying to do? Although, I could be over thinking this, it could be some new electrical designer, under Krynski, who wanted to make his mark with some new design variation, right up until the point they fired him...

I revisited it and this is what I found...

Jumpin jack 2p -double tap
Lawman 2p - no double tap
Hot shit 4p -double tap

Sorry I think I misidentified a couple on the above post. but this I just checked now and it is correct

Thanks, found a snippet of Lawman (1971-10) schematics in a thread... it has the standard P motor and hold switches, so that checks out. Lawman is the last machine with that design (until Fast Draw, 1975-04) and Lawman is the machine immediately prior to Orbit (1971-12) where the double tap starts.

It could be that you think it rekicks because of the trough switch, but it could be unrelated to it. This could be the problem (this is the same advice I posted for another post recently - I've seen it happen numerous times):
Check the ball kicker for "mushrooming" and then take a file to it. When the kicker blade gets shroomed, it can catch the plastic switch arm and close the outhole switch as the kicker arm returns back to it's resting position. That of course re-energizes the O relay which will re-fire the kicker.

Outer Space does double kick.

Thanks, Mike... and Clay... and Mark,

By my count, of the 18 two and four player machines released in this "No P motor switch" era - from Orbit (1971-12) through Soccer (1975-03), there are at least a dozen machines in which a ball return double tap is the legitimate, designed mode of operation. I'll try to write a summary up of what we've found and post it here...

TL;DR By design, these twelve early ‘70s Gottlieb machines fire the ball return kicker twice per ball - Orbit, Outer Space, King Rock, King Kool, Jungle, Wild Life, Jack In The Box, Jumping Jack, Hot Shot, Big Shot, Magnotron and Duotron.

Background:

Several owners of early ‘70s Gottlieb multiplayer EMs have noted that their machines fire the ball return coil twice per ball in play. The first coil firing ejects the ball from the outhole towards the shooter lane as expected… but, as the ball activates the trough switch, the ball return coil fires again. Examination of the schematics for these particular machines revealed that they do not utilize the “standard” logic that Gottlieb had used both in earlier and later designs. This second ball return firing is a consequence of deviating from this standard logic. The motivation for this deviation is unknown, but they did switch back to the standard design in 1975 with Fast Draw.

Specifically, the “standard” Gottlieb design used independent O (Ball Return) and P (Add Player Unit) relays, each with their own dedicated hold and motor switches. Both O and P relays are independently activated (by the ball return and trough switches, respectively), activate the motor via their own motor switches, and remain activated throughout the motor cycle using their own dedicated hold switches (serving to deactivate the relays late in their motor cycles when their work is done). See attached schematic from Fast Draw.

However, ALL Gottlieb multi-player games (18 in total) between Orbit (1971-12) and Soccer (1975-03) do NOT have P motor and hold switches. Instead, P re-triggers O to turn the motor and taps into O’s hold circuit for its timely deactivation. This additional retriggering of O results in the second firing of the ball return coil. See attached Jungle schematic.

Other things to note:
- All games of this era with drop targets (8) use an additional P switch to inhibit a second drop target reset on the second O firing.
- Some games of this era (6) use an additional P switch to inhibit the second firing of the ball return coil when the ball is crossing the trough switch (Big Brave, Big Indian, Far Out, Out of Sight, Soccer, Super Soccer).

Fast Draw ball return (resized).jpg

Jungle ball return (resized).jpg

Excellent information!! Thanks for doing the research @DaMoib!

As one of the consulted (Duotron) this thread is both engaging and impressive - the drive to figure out the design and whether something is an issue or a feature.

I'd never notice the double tap before, but I certainly do now. I wonder if there might be some benefit in terms of a ball not making it all the way to the shooter, kind of a belt and suspenders thing.

Duotron in particular has another weird kicker thing - when the ball exits via a lighted outlane (which scores the hole bonus) then center kicker also fires. Being relatively new to pinball ownership (all EMs), there are a lot of various clunks and clicks going on between balls so I never really thought to untangle the sounds and link to the circuitry. Until now. So thanks a lot!

Yeah, my point is moot if the game is designed to do this. I'm really surprised Gottlieb even did this. Yes, it might have saved a couple of bucks, but not worth it if it makes your product look like it has a mechanical flaw right from the factory. At least it didn't take them too long to see the error of their design.

I don't see the benefit. A "normal" Gottlieb game will re-kick the ball for eternity until it successfully gets over the trough incline.

So what is the problem if you can hear the ball return mechanism fire but it will not kick the ball up on to the return ramp? I’m currently having this problem with my 1975 Gottlieb super soccer.

Can you remove the apron and watch what's going on? If the coil is energizing something mechanical could be at fault.

I can see that the mechanism is firing. I can even put my finger in the hole and activate it and feel it working. The ball just doesn’t kick high enough to get on the return ramp. I am having the same problem with the kicker for one of the bonus holes.

Fantastic Info….I was about to dig into my Wild Life that does this….now I don’t need to!