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

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

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

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

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