On Ballys of that era, there was a plug-in kit, that could be plugged into the appropriate spot (Jones plug jack)
to convert the game to a true AAB, as opposed to just an extra ball game.

Check out the schematic for details, it will make sense to you.

Nik,

I seek to photo-document on the IPDB every Bally and Williams EM game that has this option for the Add-A-Ball Relay Assembly. Look at our Bally Safari listing for pictures of the optional Relay Assembly and our Notes:

https://www.ipdb.org/machine.cgi?id=2044

A fellow is supposed to send me some Safari pics tonight so I can update the listing substantially on this topic. But, if you look before he sends, there is enough already there to tell you about it. I also update the IPSND.net with a Game Trait to track which games have this Assembly installed and which games don't.

You and I are collaborating right now on another game. May we work together on this one next?

Email me when you are ready, please, and I'll show you examples of what kinds of pics I am looking for, on your Dogies game.

Thank you,

Jay
IPDB

Dogies is listed of the similar era "convertible" games to the earlier Rocket III, you may find this thread of interest which lead to a DIY build of the added ball kit (it was also very similar for Wiggler we did thereafter). Some related pics were also updated for Rocket III on ipdb.
https://pinside.com/pinball/forum/topic/bally-rocket-iii-apron-credit-lamp-wiring

Then I wanted the replay knocker in use for "added ball" and pinside helped
https://pinside.com/pinball/forum/topic/adding-knocker-to-bally-aab-added-ball-kit-models

Pretty easy to make from some old parts and determine the wiring from the schematic. The added ball (well shoot again really) is a nice feature for home use.

It's a simple "shoot again" (no incrementing "balls to play" like true AAB) on Rocket III indicated by a lamp in the backglass and apron when active (the apron lamp could be unique to RIII). The "shoot again" (and Added Ball relay hold) then cancelled by the gate switch in the shooter lane arch. One nuance is that the game has a free ball gate on the shooter lane which cancels it out too. Surely will be slight differences on Dogies but it will be interesting to reproduce.

Are you sure about that? True AAB on a 4-player game would require a full bi-directional stepper unit plus the logic to subtract when the ball goes over the trough switch. (The "same player shoots again" relay, already present in the replay version, only needs to suppress the trough switch from doing anything on phony AAB.) The runway switch that cuts off the "same player shoots again" relay would need to be neutralized for true AAB, in favor of the re-purposed trough switch. Or in a cheesier implementation, the runway switch could activate the subtract logic, if changed from NC to NO, but you might get some false subtracts. And that doesn't even address the question of lighting 5 lights to show how many extra balls have been earned.
.................David Marston

Dave: You are likely correct.
I was thinking single player, not 4P multiplayer games.
Though I do own a True AAB Bally 2P Loop the Loop that has no credit/replay window
and a player could earn multi extra balls per ball in play,
that would have to be played off prior to the next players turn,
if i remember correctly.

I went deep into my archives to get my Dogies schematic, and I found the sheet that shows how to install the add-a-ball kit. Both that sheet and the schematic make clear that the kit has just one additional relay. Interestingly, the existing Shoot Again relay is retained to continue to represent an extra ball earned on the features, while the new Extra Ball relay represents an extra ball earned by score or a sufficient number of Cactus Juice points. I didn't study the reset of those two relays in detail, but it looks like you stack the two appropriately. Either relay lights the Same Player Shoots Again light. So it's not "true AAB" but at least you can get both one EB from the feature and one on score. If you get across more than one score level on a single ball, or get one score level and a Cactus Juice level on the same ball, you lose out.

The installation of the kit may not require any soldering, per the flyer, but you have to move several wires around, add a switch onto the switch stack of a relay, and change connections on the tie points that can be seen clearly at the top of this photo:
https://www.ipdb.org/showpic.pl?id=696&picno=18266
I think the relay comes with a tall-stack armature in anticipation of the extra switch being added. Uninstalling the kit would also be a chore. I did not see evidence that the kit was designed to be generic enough to be the AAB kit for every Bally 4-player that claims to have an "add-a-ball model" on the flyer (Dogies through Bally Hoo, I think).

As I think about it, a true AAB conversion should make the feature-earned extra balls increment the same stepper unit as the score-earned extra balls. Also, the reset sequence needs to step the Added Balls stepper down to zero, just in case the machine was unplugged at an inopportune time. See other threads about AAB implementation for additional ideas and issues.
.................David Marston