(Topic ID: 154681)

Aztec legs and ball count

By padarjohn

3 years ago

Topic Stats

  • 23 posts
  • 6 Pinsiders participating
  • Latest reply 3 years ago by padarjohn
  • Topic is favorited by 1 Pinsider


Linked Games

Topic Gallery

There have been 5 images uploaded to this topic. (View topic image gallery).


#1 3 years ago

I recently acquired a Williams Aztec. The machine was restored a while back (maybe 10 years ago) and working well (mostly) when I picked it up from the previous owner. But with the rear legs extended as far as they'll go the playfield still has very little slope, and play is very slow. I was wondering if there are any other owners who can tell me if the rear legs should be longer than the front ones, and/or what a good slope angle should be.

I also have an issue with the ball count - it advances after every play, even multi-player (i.e., 5 balls total, or 1 ball per player in 4-player mode). It worked OK before I moved it. I have some ideas to check out before I get serious about asking for help, but this is my first EM machine and the inside is a giant jigsaw puzzle to me so if anyone has any pointers before I jump in they would be appreciated.

#2 3 years ago

Regarding the legs...there are 3" levelers you can buy. I've put those on most of mine to increase the pitch. Really makes a difference.

#3 3 years ago

I would look at the coin unit; make sure it is making it back to zero position. When it steps that the wiper fingers are not in a MID position, make contact with more that I contractor.

When you start a single player game the Coin unit is at home position, and the red line below is the path. As you add more players the part changes, you need to check this happening.

Since this worked until you brought the machine home, also check the Jones plugs. As there are in-between the Coin and Player units.


#4 3 years ago

Opps, missing the red like.


#5 3 years ago

Supposedly, manufacturers made two of the legs on the back of the machine slightly longer, maybe 1/2 inch longer. But, as time goes on, legs get switched, mixed up, etc. So, if you have four legs of the same length, that's fine. 3" casters on an EM machine can greatly alter the gameplay from its original design if you extend the 3" caster all the way. Might end up breaking something on the playfield also... I have my Aztec set up with 2" casters with the front caster at their lowest position and the back casters at half-way. Plays fine and fast... Going higher than halfway on 2" casters could result in bent or broken caster bolts. Technically, the casters on EM machines were designed to level the machine as a whole, and they weren't designed to alter the playfield angle. So, if all the playfield casters were at the same height, you should still be able to have a fast playing machine...

There are many variables, other than playfield angle, when trying to get an EM machine to play faster:

1) Condition of playfield: worn playfield, is the playfield cleaned and waxed?
2) Condition of game ball
3) Condition of playfield devices: pop bumpers, slingshots, kickouts, etc
4) Condition of playfield rubber rings
5) Condition of shooter lane and ball arch groove

#6 3 years ago

Thanks. I'm at GDC this week, so I won't be able to check these things until I get back.

The legs look new, so I doubt they're original.

#7 3 years ago

28 1/2 Chrome legs for Aztec, all the way around.

1 month later
#8 3 years ago

I finally got enough other stuff out of the way that I could get back to trying to figure this out. I was doing a quick inspection to look for loose wires, etc. and found this. It couldn't be that simple, could it?


Nope. I put it back where it belonged, and it's still advancing the ball count.

Hopefully I'll get time to do a more in-depth look tonight, after I've had a chance to study the schematics for a while.

#9 3 years ago

OK, it looks like a poorly aligned player-unit disc:
Took me a while to find it, I didn't realize it was in the head.

I've never done this before. Can someone give me some pointers before I go jumping in with wrenches, etc.?

I also found a loose machine screw in the base. I don't like finding things like that. But I haven't found any place missing a screw yet.

#10 3 years ago

Hi John
please give a detailled description of "what happens when You play a 4-player-game".
I assume - but I am not sure -
AAA: player-1-ball-1 -> player-2-ball-1 -> p-3-b-1 -> p-4-b-1 (-> p-4-b-1 and on and on ?) ?.
BBB: p-1-b-1 -> p-2-b-2 -> p-3-b-3 -> p-4-b-4 (p-4-b-5 or p-4-b-4 and on and on ?) ?.
CCC: Your description.
(How about: Writing about "Lights in the Backbox - 1 can play / 2 can play / 3 can play / 4 can play, player-1 is playing / pl-2 / pl-3/ pl-4, ball-1 is in play / ball-2 / ball-3 / ball-4 / ball-5)

The manual: http://mirror2.ipdb.org/files/119/Williams_1976_Aztec_Instruction_Manual.pdf -> page-12 (ori-10) tells us: Player-Reset-Relay is mounted on the Mech. Panel - down on the bottom in the Cabinet.
Start a ONE-player-game -> lift the playfield and have a look at this relay -> You loose the ball -> the Ball-Count-Unit should step-up - immediately after: This Player-Reset-Relay should pull-in - and stay pulling for a while question: Does it ? EVERY TIME You loose a ball ? ALSO: The Player-Unit-RESET-Coil should fire - EVERY TIME You loose a ball (actually not needed in a ONE-player-game --- but Williams pins act this way). Greetings Rolf

#11 3 years ago

Hi Rolf,

The ball count works fine for one-player games. And the player count works correctly.

When I started having this issue it was always advancing the ball count when a ball drained, regardless of the number of players. E.g.,
Two player: p1-b1 -> p2-b2 -> p1-b3 -> p2-b4 -> p1-b5
Three player: p1-b1 -> p2-b2 -> p3-b3 -> p1-b4 -> p2-b5
Four player: p1-b1 -> p2-b2 -> p3-b3 -> p4-b4 -> p1-b5

Last night I was cycling though trying to watch what was happening, and it seemed that with the playfield up it was working better than with it down. It wasn't advancing (incorrectly) until p3 -> p4. So I spent some time looking for loose wires. But after a while I realized it was pretty random - without moving wires or playfield it would sometimes do that, sometimes always advance like before. And it acts the same now with the playfield down.

So I started to think it was the act of running through a lot of cycles that had changed the behavior, which points pretty strongly at moving parts.

You can see in the pictures above that there are several places where it's very close to (or possibly is) bridging contacts. I figure I should correct that before looking for other problems.

How do I adjust the alignment of the disc? Do I loosen the nut on the shaft, or is that going to open another can of worms?

#13 3 years ago

Hi John
I am irritated - first impression was: ALWAYS same faulty behaviour - second: You write (post-11): "with playfield up it is a bit better the playfield down" -> do You SOMETIMES have the fault - and sometimes NOT ?

A very good site: http://www.pinrepair.com/ -> 1930s to 1978 EM ...: http://www.pinrepair.com/em/index.htm - it has three parts -> click on "2 Part Two, 2d. Stepper Units -> http://www.pinrepair.com/em/index2.htm#steps -> scroll down 14 pictures - below comes title "Cleaning a Stepper Unit" -> read the text following -> below the third picture -> text about "really weird game behaviour" -> look out for bakelite disk screws -> are they loose ? want to loosen and adjust the bakelite plate when the player-Unit is in Zero-Position (ALL THE WAY stepped back (Zero-position = ready for player-1) -> fingers shall rest squarely and centered on the rivets -> then tighten the screws -> try out -> report. Greetings Rolf

#14 3 years ago

Hi Rolf,
Sorry for the irritation. Before last night the ball count behavior was very consistent - it always advanced. Now it still consistently has a problem, it's just more random in when (it always advances when player 3 finishes, but not always for player 1 or 2).

Thanks for the links, I'll follow up and report back.

#15 3 years ago

OK, bear with me. As I said, this is my first EM machine and my brain isn't wired to think this way. But as I study the manual and schematics it's starting to make sense.
The screws to adjust the Player Unit bakelite plate are under the disc, so to do it right I'll have to remove the disc. But I was able to push on the plate and shift it slightly so everything aligns perfectly, and it had no effect. The contacts are shiny and bright, so there doesn't seem to be any issue there. If the alignment was wrong it would score the wrong player, turn on the wrong light, etc. So I think it's safe to assume that's OK. I'll take it apart and tighten the plate later on.
So the Ball Count Unit Stepup depends only on the relative positions of the Player Unit and Coin Unit. Chrisbee tried to make that point in posts 2/3 above, but it didn't register with me before. But now that I've watched the mechanical parts work and matched it to the schematic I can see that. So now I'm thinking it's with the Coin Unit, I'll check that in a bit (sorry, I have a job that I have to pay attention to.. )

Meanwhile, can anyone explain what "C 1-C" and "C 2-B" are on the diagram in post 3? I understand they're "cam actuated switches", but how do I figure out what motor(s) they're associated with?

#16 3 years ago
Quoted from padarjohn:

can anyone explain what "C 1-C" and "C 2-B" are on the diagram in post 3? I understand they're "cam actuated switches", but how do I figure out what motor(s) they're associated with?

OK, this is now more relevant. I electrically isolated the relevant wipe on the coin unit. In 4-player mode it still advances the ball when transitioning from p3 -> p4. That means whatever is doing it is coming over the R-W wire from the player unit. Also, in 1-player mode when the ball drains I would expect nothing, but instead it triggers the player unit stepup which, according to the schematic, can only happen if switch "C 2-B" is closed.
I've been trying to understand the theory of operation... the outhole switch triggers several things which then triggers the outhole relay, and if the ball index relay is active (based on no extra ball and maybe other stuff) then either the ball count unit stepup is triggered or the player unit stepup is triggered, based on the states of "C 1-C" and "C 2-B".

#17 3 years ago

Hi John
the last part of the last sentence in Your post-16 is wrong - correct is: ... (... other stuff) then EITHER (only) the Player-Unit-Step-UP-Coil fires OR*+*: TWO things happen - Ball-Count-Unit-Step-UP-Coil fires, immediately after that the Player-Unit-RESET-Coil fires.
In the lower half of my post-10 I was asking You to do a test - the test is about these "TWO things happen ...". So do the test starting with : "Start a one-player game -> lift the playfield ..."

Maybe (Your post-16): "Also, in 1-player mode when the ball drains I would expect nothing, but instead it triggers the player unit stepup which, according to the schematic, can only happen if switch "C 2-B" is closed."
Maybe, maybe You wanted to write player unit RESET which ... (?). So do the test starting with: "Start a one-player game -> lift the playfield ..."

Your Score-Motor-Switches work fine - when the Score-Motor does a turn: EVERY SWITCH ON THE SWITCHSTACKS ON THE SCORE-MOTOR WILL BE ACTUATED. Every feature calling for "help of a Score-Motor-Turn" does actuate "own Switch(es) mounted on the relay" so the help gets through. The many other features (not interested in SCM-help) simply do not actuate "their" switches - they say "Score-Motor You can turn and actuate all switches so You actuate "switches for me" - but at this time I am NOT interested in Your help".

You asked about SCM "C 1-C" and "C 2-B": The first letter "C" is not needed - it stands for "Switch will CLOSE when actuated (and this information we also see in the drawing of the switch in the schema). The "1" or the "2" tells us "which Nylon-Wheel" - the first Nylon wheel after the Score-Motor or the second Nylon wheel or 3rd, 4th etc. The "A", "B", "C" etc. is the position in the Switchstack - "A" is "Bottom-Switch". Look at the ipdb-schema -> A/B-11,12,13,14,15,16 -> drawing of the Score-Motor. Irritating -we must live with this fact: Score-Motor-Nylon-Wheel "1" is in reality the SECOND WHEEL (!) - Williams said: INDEX-Wheel is so special and important - we use a UNIQUE TERM -> whenever somebody is looking up something in the schema -> at first glance he sees: Hey, the INDEX-Wheel is involved ...
No use to argue about this fact -> when You want to look-up a switch on "O (for open) 4-D" -> Count the Nylon-Wheels starting at motor -> INDEX-Wheel -> 1st -> 2nd -> 3rd -> 4th Wheel.
The example "O 4-D" is in schema at C-2. Greetings Rolf

#18 3 years ago

Hi Rolf.
I will re-read what you said, and look some more tomorrow. I'm incredibly tired tonight.

I looked through the schematics last night until very late, and finally (mostly) understand the relationships between the ball count stepup, player unit stepup, and player unit reset. Basically, the outhole relay will always trigger the player unit stepup, and the matching connections on the circuit in post #3 will trigger the ball count step-up. If the player reset relay is active it will also trigger the player unit reset relay (setting back to player 1). I'm too tired right now to remember what conditions do this, but it made sense last night.
So,... if we eliminate the coin unit from the circuit (post #3), each ball drain will trigger the player unit stepup until player 4. Because the player 4 setting on the player unit bypasses the coin unit, when player 4 drains it will trigger the ball count stepup and the player unit reset.

I isolated the coin unit by putting paper under the wiper contacts associated with this, essentially removing all of the connections on the right side of the coin unit in the circuit in post #3. If I hit the start button once and then activate the outhole, it works exactly as expected - the player unit advances and the ball count does not increment - until player 3. The ball count stepup is being activated for both player 3 and player 4 (the player unit reset works correctly after player 4).

As you can see in post #3, the ONLY way for the ball count stepup to be activated with the way I set it up is through the R-W wire from the player unit. The only way for it to happen with player 3 is for R-G-I wire from the player unit to be shorted to the R-W wire. I checked with an ohm meter, and don't see any short. The only other explanation is the wiper in the disc momentarily bridging the rivets for those wires.

Maybe tomorrow I'll know more.

Thank you very much for your continued help.


#19 3 years ago

Hi John
I advice: First make sure a 1-player-game works - I want do be sure: whenever changing to next ball: The "Player-Reset-Relay must pull-in - stay pulling for a while - the Player-Unit-RESET-Coil fires.
If so - I then would look at a 2-player-game. -> http://mirror2.ipdb.org/files/119/Williams_1976_Aztec_Instruction_Manual.pdf -> page-17 (ori-15) -> (in the picture: lower end - to the left) -> sneak-in a piece of cardbord under the two wipers (so they cannot make connection) -> the unit can move -> Start a game -> then press Credit-Button again -> NOW use a Jumper-Wire to permanent connect Lug-R-Y Lug-R-W (You eliminated "maybe faulty-connection because of the cardbord" and You established connection needed for 2-player-game "using permanent the clipped-on Jumperwire").

Well, I do not understand (post-18): f I hit the start button once and then activate the outhole, it works exactly as expected - the player unit advances and the ball count does not increment - until player 3. The ball count stepup is being activated for both player 3 and player 4 (the player unit reset works correctly after player 4).

When I hit the Start-Button ONCE -> I do play a 1-player-game -> ONLY the Ball-count-Unit steps up - on the Player-Unit I can see the (actually useless) pulling of Player-Unit-RESET-Coil. and about this (actually useless) pulling: I would like to read - does it happen - or not ? Greetings Rolf

#20 3 years ago

Hi Rolf,

Everything always worked fine in 1-player game.

WRT my last post, I was doing what you just suggested, minus the jumper. Removing the coin unit from the circuit like that basically simulates 4-player game.

Thinking about things more, because the player reset relay is activated by the ball count EOS switch, if the erroneous ball count stepup was related to the outhole (ball drain), the player unit would HAVE to be reset back to player 1. Instead it advances correctly to the next player. That would imply that it can't be related to anything to the left of the player reset relay switch in the schematic at D-6.

Since there's no other way to get power to the ball count stepup relay, it implies something else is applying power to the R-W wire somewhere between the player unit in the head and the ball count stepup relay in the base. Given that this behavior started after unplugging and removing the head I'm going to start with the connectors we pulled and check for short circuits.

#21 3 years ago

Hi John
do not get angry - I would like You to do the tests I suggest - from the results I then could proceed to my next test.

Well, OK - Your post-20: "Since there's ..." IF (if) it is a 4 player game and the player-3 has played the ball -> pin wants to step -> look at Chris' JPG in post-4 -> if the wiper in the player-Unit is faulty - it should connect "side-wire-blue-and-something" "side-wire-R-G-I" --- but it faulty does connect "side-wire-blue-and-something" "side-wire-R-W" then the Coin-unit is bypassed (already) at end of player-3. Greetings Rolf

4 weeks later
#22 3 years ago

Sorry to be away so long. We spent a lot of time looking at the player unit, and didn't find anything. The real mystery to me was how the ball count stepup relay could be activated without triggering the player unit reset when going from player 3 to 4.

Eventually I decided that I wasn't making progress, and rather than have the machine sitting here frustrating me for months I took it to the place that originally restored it to let them fix it.

On a positive note, while I was there I picked up an NBA Fast Break and committed to buying a Bally Eight Ball that he was restoring.

When I get it back I'll come back here and update the thread with the resolution.

2 months later
#23 3 years ago

Back at last. Sorry for the long delay. I told him to take his time since I had picked up two more machines and didn't really have room for the Aztec anyway

It turns out the problem was a stuck switch on the score motor. It was bent and never breaking contact. Bending it up slightly so that the contacts would separate cured the problem. Honestly, I never would have suspected the score motor.

Now to find that switch on the schematic so I can understand exactly what was going on...

Promoted items from the Pinside Marketplace
From: $ 18.00
Apparel - Men
Pinside Shop
$ 99.00
Gameroom - Decorations
Pinball Sales
$ 4.49
Yorktown Parts and Equip
$ 22.00
$ 189.00
Boston Pinball Company
$ 89.99
From: $ 200.00
Lighting - Interactive
Professor Pinball
$ 125.00
Cabinet - (Alt) Translites
FlyLand Designs
$ 84.95
Cabinet - Shooter Rods
Super Skill Shot Shop
From: $ 99.99
Cabinet - Other
Lighted Pinball Mods
From: $ 7.00
Playfield - Protection
Pinball Haus
$ 248.85
From: $ 24.99
Lighting - Led
Lee's Parts
$ 48.00
Playfield - Toys/Add-ons
ModFather Pinball Mods
From: $ 9.99
$ 15.00
Playfield - Plastics
Pinball Haus
$ 100.00
Lighting - Interactive
Professor Pinball
$ 29.95
$ 30.40
$ 89.99
Lighting - Led
Lighted Pinball Mods
$ 160.00
Cabinet - Toppers
Id Rather Play Pinball

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside