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.

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.

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?

spring_(resized).jpg

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.

OK, it looks like a poorly aligned player-unit disc:
player-unit-2_(resized).jpgplayer-unit_(resized).jpg
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.

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?

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.

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?

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".

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.

john-

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.

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.

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...