TLDR:

In this thread I will provide my circuit analysis and description for the entire schematic of the 1973 Bally Monte Carlo 4-player pinball machine. This is my second attempt at such a project. The first one is for the single player 1974 Bally Bon Voyage as seen here:

https://pinside.com/pinball/forum/topic/em-schematic-fully-described-from-beginning-to-end-bally-bon-voyage

Table of Contents

1. Long Boring Intro
2. Reference Materials
3. Power Supply
4. Schematic (and that "POGSUP" thing)
5. The Score Motor
6. Power On
7. Coin Chutes and Credits
8. Start New Game Player 1
9. Start New Game Players 2-4
10. Game Play (10, 100, 1000 Points)
11. Mushroom Bumpers and Gates
12. Get Those Roulette Numbers, Playfield Holes, Extra Ball
13. Special, 100,000 Points, High Score Award
14. Tilt, Pop Bumpers, Flippers
15. Ball Drain - You Totally Missed Everything
16. Ball Drain - Bonus Collection
17. Ball Drain - Next Ball and Next Player
18. Ball Drain - Last Ball

THE END!

LONG BORING INTRO

This MC (Monte Carlo) project was done using some different methods and improved procedures based on what I learned the first go-around with the Bon Voyage, these will be described as it goes along.

I hope my circuit and process descriptions are even better this time around, that is, more easily followed, clearer to understand, and more complete and accurate. My goal is to make every description as clear as possible so it can be understood by any reader with just a minimum of basic background knowledge. In order to achieve this, this work will feature:

---> THE Monte Carlo Schematic <---

This MC schematic has been completely redrawn in vector format from the original scanned version, so it has perfect resolution and can be blown up to any desired size while still keeping 100% perfect detail.

See the latest version right here (bottom of this web page):

http://www.xsvtoys.net/monte_carlo_pinball_documents.htm

As the thread progresses, please feel free to post with any questions, comments, or corrections you have. If there is any doubt or confusion about how something works, I would like to try to update it and get it as clear as possible. If I have something wrong I would like to correct it, so don't worry about posting corrections.

There will be a pause between sections so I can get things in order for the next uploads and also wait for questions about the latest section.

WHY DO THIS?

I like to know how stuff works. No other reason. People here seemed to enjoy the BV thread so I am posting here again for fun.

WHAT GOOD IS IT?

If you have a Bally 1973 Monte Carlo, you are golden. You should be able to get a solid understanding of how everything works and you will be able to quickly troubleshoot practically any problem that comes up.

If you have a Bally EM of similar vintage this should help to understand how it works. Many of the sub circuits use the same logic from machine to machine. For example, many of the circuits are very similar if not identical to the ones described in the Bon Voyage thread.

If you want to know more about how an EM works this could be a good illustrative example. Many of these subcircuits are used over and over in different machines, usually with slight modifications but once you understand the details in one specific subcircuit it is much easier to figure out a similar one in a different machine. This will especially apply to Bally EMs. I am not sure how well the information will translate over to other brands such as Gottleib which may use different schematic layouts, but the general ideas should be somewhat consistent.

REFERENCE MATERIALS
As a relative newcomer to the pinball world, I ride on the shoulders of giants who have already set the standards for everyone. This is a list of some of the resources I used. There probably isn't anything actually new in my work, it is just presented in a different way and is specifically detailed for one single pinball machine.

The PinRepair web site by Clay Harrel is completely awesome. If anyone wants to work on and understand EMs, I think they should read this, then read it again. And keep reading it again and again! I have read through it entirely at least 5 times and I learn something new every time I go back. Thanks again Clay for posting that great resource.

http://www.pinrepair.com/em/index.htm

This section has the basics about EM schematics. I don't repeat the details of the basic background information in this document, so this is worth reviewing as an introduction.

http://www.pinrepair.com/em/index3.htm#schematic

I also recommend to sign up and pay for the Pinball Ninja web site, where there is a ton more good information about working on EMs. And the video series called This Old Pinball is also worth getting for more knowledge and some good entertainment.

http://www.pinrepair.com/donate/

http://www.pinrepair.com/top/

The PinWiki of course is also filled with tons of useful information. There is an EM section that covers all of the basics.

http://www.pinwiki.com/wiki/

The various parts catalogs and schematic books that were published over the years by the different manufacturers are very valuable for all sorts of information about a specific machine. Many are found here:

http://www.planetarypinball.com/mm5/merchant.mvc?Screen=BOOK

The Bally 1976 Parts Catalog is the go-to for this Monte Carlo:

http://www.planetarypinball.com/reference/partsmanuals/BLY_Parts_1976/files/mobile/index.html#1

Here is another web page with some nice pinball document downloads.

https://www.funwithpinball.com/resources/parts-catalog-list

The Bally book An Introduction To Bally Flipper Games is full of excellent information for this vintage machine. It is chock full of all sorts of details about how schematics work, how stepper units work, how the score motor works, and so on.

Of course you want the operating manual and the schematic for your specific machine. You can often get these from the Internet Pinball Database, such as here for the Monte Carlo.

https://www.ipdb.org/machine.cgi?id=1621

If your machine doesn't have the documents available there, then you can almost always get them at a reasonable price from The Pinball Resource:

http://www.pbresource.com/mansch.html

POWER SUPPLY

Part 1 POWER SUPPLY

The power supply in a EM pinball machine is as about as simple as it gets, predating modern power supply boards and modules that produce a variety of voltages in AC and DC. There is a transformer, and that is basically the entire power supply circuit. A transformer uses coil windings and magnetic induction to change one voltage to another. For the Monte Carlo and many EM machines, everything in the entire machine is AC (alternating current). There is no DC (Direct Current) anywhere in the machine. Since there are no semiconductor parts at all there is no +5DC, +12VDC, and so forth. There is just incoming 120 VAC which is turned into two separate branches of AC current, one for the lamps and one for everything else.

Some of this power supply wiring can vary between machines depending on where the machine has been in the past. For example, if the machine was installed in Canada or Europe, it may have modified parts and wiring for the source power in those areas. This part describes a typical USA version.

The power supply includes fuses which will protect the machine against electrical shorts which could otherwise cause damage or even fire. This machine has 4 fuses.

15 A
15 A
10 A
8 A

These fuses are of the type known as 3AG. This designation describes the physical size of the fuse. In addition to needing to be the right physical size each fuse has a voltage and amperage rating. The amp rating is critical and only fuses of the proper matching amp rating should be installed. The voltage rating for the fuse can be the same or higher than the rated voltage. The most common 3AG fuses are 250 V, and these will work fine. The original fuse holders on this era of Bally machines have a reputation for being unreliable, so it is recommended that they be replaced.

fuse block original (resized).jpg

Theis MC will be soon replaced by this FUS-HLDR-SNAP from Pinball Resource. I have it in hand I swear I will do it!

fuse block pbr FUS-HLDR-SNAP (resized).jpg

This section of the schematic shows the entire power supply. For a typical USA 120 VAC input there will be a 3-conductor power cord with a green ground wire, a neutral wire, and a hot wire. The green wire goes to ground. The neutral wire goes to the bottom of the transformer on lug 5. The hot wire goes to a tie point on the insert board (big black dot), where it is connected to a brown wire. That brown wire goes to the power switch. On the other terminal of the switch is a white wire which goes to an 8 amp fuse, and finally on the other side of the fuse is an orange wire that is attached to lug 1 of the transformer. So if the 8A fuse is good and the power switch is turned on, the transformer will get an incoming supply of 120 VAC as shown.

ps-1 (resized).jpg

As shown in the drawing the transformer actually has two separate internal wirings on the left side to handle the incoming voltage. Because the transformer lug 1 is tied to lug 3 and the neutral wire is tied to lugs 5 and 7, there will then be 120V across each of those wiring pairs, as shown in green.

The design of the transformer is set up so the other side will give us the voltages we want to run our machine. In this case these voltages are lower than the incoming 120VAC, so this is a called a step down type of transformer. For this machine, there are just two AC voltages that are used to run everything, 6 VAC (nominal) which is used for all the lamps and 50 VAC (nominal) which is used for everything else. These are highlighted in green. From this point we will just use "V" instead of "VAC" since it is understood that everything in this machine is AC voltage. We say "nominal" because the actual voltage will vary depending on the incoming voltage, this is not a regulated power supply like modern ones are. It is typically a bit higher. The voltages can vary by several volts but this is OK, the machine tolerates this and will work fine even with those variations. These old mechanical machines are very robust, almost bulletproof, in this regard. On this Monte Carlo the voltages are measured at 6.8VAC and 55.2VAC with an incoming supply of exactly 120VAC as measured by a volt meter.

There is a drawing of the transformer on the bottom part of the schematic that shows all of the wiring. On the top part of the transformer, a yellow-brown wire is connected to lug 10 and a yellow is connected to lug 8, these 2 wires form the 6V supply for all of the lamps. Another yellow wire on lug 8 matches up with the red-white wire on lug 4 to provide the standard 50V power for all of the other parts of the machine. The actual voltage will vary depending on what the input voltage is, since AC voltages can vary from place to place and even time to time in the same place, then this 50V supply can also vary. As is common in EM machines, the higher voltage can be set for two different settings. This so-called "high tap" is provided on lug 2 of the transformer, if the red-white wire is moved from lug 4 to lug 2 then you will be on high tap and you will get about 4V more. This was originally intended as a countermeasure to low input voltages from the wall supply, but some people like to set their machines to high tap even if their voltage is a good 120 VAC in order to "juice up" the machine. The various solenoids will react more strongly to the high voltage thus providing more power to the ball and speeding things up. As shown in the picture, this MC is set for low tap.

Monte Carlo Schematic Transformer Wiring 120V (resized).jpg

ps-2 transformer labeled (resized).jpg

As to whether your machine should be set to high tap or not when you have solid 120VAC power, that is a matter of debate. Some feel that it makes the game play more lively and therefore better, while others say this makes the game play faster than was originally intended and therefore not as good. It can cause the ball to move too fast and even possible damage plastics or cause air balls due to the higher power. Also some point out that the higher voltage causes more stress on all of the components, although the actual effect of this is probably minimal.

Going back to the schematic, the last parts of the power supply are the other three fuses. The 6V side is split into two branches that are each protected with a 15A fuse, and the 50V side is protected by a single 10A fuse. All of the fuses are highlighted in yellow here to make them easy to find.

You will notice that the fuses on the right side of the transformer are of higher amp ratings than the 8A fuse for the main power on the left side. There are two 15 amp fuses which protect only two branches of lamp circuits. It might seem odd at first that the fuses on the other side of the main 8A fuse are rated at a higher amperage.

As an example if you have a lamp circuit with 40 incandescent bulbs and they are each drawing 250 milliAmps or 0.25A then you will have 40 X 0.25 = 10A of current draw on that circuit. Thus the 15A fuse is needed to provide short-circuit protection while giving enough current overhead to run all of the lamps.

The left part of the transformer does not see that same 10A though. If it did then the 8A fuse would blow. This is a characteristic of step-down transformers. In this case the incoming voltage is 120V and the step down voltage is 6V. The current draw on the step down side is reduced by the ratio of those voltages, so in this case 120/6 = 20. That means the left side sees 1/20 of 10A or 0.5A of current draw (at 120V) when the right side is seeing 10A of current draw at 6V.

These numbers are assuming a theoretical "ideal transformer" so it is not exact, but it is close enough for this example. There is plenty of transformer theory to study and it gets to be a somewhat complicated subject. But this is enough for us to know to keep the pinball machine flipping.

After this Part 1 of the circuit description we have covered the area in the entire schematic that is highlighted in yellow.

Monte-Carlo-Schematic highlights 1 power supply (resized).jpg

SCHEMATIC (and that "POGSUP thing")

Luckily the original designers of the machines laid everything out in a schematic that has been preserved and available to us many years later. The schematic is always overwhelming when you first look at it, but (almost) everything you need to know is there once you break it down into parts and start to understand the concepts.

At the very start, it is important to understand the "state" of the machine as shown by the schematic. When the schematic is drawn, it is showing all the different switches as open or closed. Since any given switch could be open or closed depending on the state of the machine, the way the switches are drawn on the schematic represents an arbitrary decision by whoever drew the schematic. The "state" of the machine as represented in the schematic is also the "normal" state. So when we say a switch is Normally Closed (NC) or Normally Open (NO) we are referring to its position in the default schematic state. It seems to be the general consensus in pinball schematics that it everything is drawn to represent this state:

Machine power was switched on, a game was started, then the machine was unplugged.

I call this POGSUP for short. Power On Game Started Un Plugged.

mnemonic (resized).jpg

Be sure to remember this when you are working and looking at switches, because if you turn the power on the state of some of the relays (and switches) will immediately change from the POGSUP condition which can throw you off if you are not ready for it. This will be covered in detail.

Since this tutorial covered the power supply before coming to this topic, we know that there are two separate voltages for the machine, the 6V and the 50V. When looking at the schematic, the first thing to grasp is that the entire thing is a series of subcircuits that are hanging between these two voltage supplies. This is shown in the picture below. On the bottom part there are the 2 lines (or wires, or branches) that form the 6V circuit, and all of the lamps are controlled in subcircuits there. On the top part there is a stack of two 50V circuits and everything else is controlled in subcircuits there.

Monte-Carlo-Schematic 2legs (resized).jpg

It is helpful to understand that there is just one grand power circuit for the 50V and what you are looking at in the schematic is a "folded over" representation. That's why there are red arrows on top of each other. If you follow the 50V wires you will see that this 50V circuit is folded over about in the middle so that one half is shown on top of the other half (the bottom branch then loops around and goes on top). This is done for convenience of working with the schematic. If you just laid out the entire 50V branch in one long lump it would create a really wide and skinny schematic that would be awkward to work with, like shown below.

The original schematics were all on paper and completely hand-drawn, as there were no computers with CAD software at that time. The best schematics are the original paper schematics. Luckily these are available for most machines from Pinball Resource and other places. However sometimes these are photocopies (or copies of copies), and also they are folded up. This means the quality of detail can vary quite a bit.

There are also electronic versions of the schematics available for many machines, such as posted at IPDB. These are scans of the original paper schematics. Again the quality varies quite a bit depending on factors such as the quality of the original source, the scanning parameters, and further shrinking and treatment of the digital files. Some of the digital files are low resolution, blurry, and difficult to read.

It is personal preference as to whether you like to work off a digital file or a paper schematic. I like having both worlds. If you have a good digital version you can view it and manipulate it easily on a computer. You can then print it out (in sections) if you want a physical piece of paper to work with while you are at the machine.

For this project I decided to recreate the entire schematic in vector form (for no other reason than why not). This means it is no longer a bitmap file that gets grainy when you want to expand it and look at detail. It always will be perfect resolution no matter how much you zoom. The vector schematic was created in Adobe Animate software, previously known as Flash. Details on that are available up request.
schematic-1 zoom (resized).jpg

It is also common to see errors in the schematics so these will be corrected as they are found if there are any.

For this circuit description I am taking a different approach than was done for the Bon Voyage. For that project I mapped out in a spreadsheet every relay, solenoid, etc, and then accounted for and mapped out every switch, including the colors of the wires and where those wires were going. This makes for a great map of the system, but that job is very time-consuming and tedious so I decided to try a different route this time.

For this project, I have supplemented the schematic with some details about the relay switches that will make it easier to do a circuit analysis. Then, by virtue of describing each subcircuit in detail with snippets from the schematic everything should be easily available down to the last detail.

In the schematic Coil Locations Chart I have added information about the switches for each relay. First the total number of switches in shown in parentheses, then the map coordinate locations of all of each switch is listed. Now you instantly know the important information for each relay - how many total switches does it have and where are they? If you look at the first relay in the chart, the All Evens Trip Relay, you can see that it has 9 total switches and then the map locations for all 9 are listed.

Monte Carlo Schematic Coil Locations Chart (resized).jpg

Within the schematic, each switch is also labeled with its count in relation to the total for that relay. So here we see that this part of the schematic shows switch 4 out of 6 total for the 10 Point Relay, switch 5 of 6 for the 10 Point Relay, switch 4 of 5 for the 100 point relay, and switch 3 of 6 for the 1000 point relay. The switch numbering sequence for each relay is arbitrary loosely based on working left to right on the schematic. Note that the switch number does NOT correspond to its actual physical position on the relay.

schematic-2 switch numbering (resized).jpg

Another schema I will use it to change switches and other things from black to red colored when they are different than the POGSUP "normal" state of the schematic. This is just to keep things clear when we are talking about a condition change that occurs for whatever reason. Examples are shown in this picture.

schematic switches red explanation (resized).jpg

THE SCORE MOTOR

Before continuing on with a schematic analysis, it really pays off to consider the score motor in some detail first. The score motor is integral to many of the subcircuits in an EM pinball machine and if you have a good solid mental image of how it works it becomes much easier to decipher and understand circuits.

The Score Motor, shown in the picture below, consists of a series of cams on a shaft which is connected to a motor that rotates the shaft, and therefore the cams. Mounted on top of the cams are stacks of switches. When the Score Motor is resting all of these switches are in their default POGSUP state as drawn in the schematic. Some are NO and some are NC. Each cam has a different shape via some protruding lobes so that as it rotates, it causes the switch stack above it to swap states as the cam rotates. This means all of the NC switches on the stack will open and all of the NO switches will close. The various cam shapes are used to provide timing for the switch changes as the motor turns, or to provide multiple pulses for some switches. The Score Motor looks intimidating with all of those switches and wires, but if you work on it logically one step at a time you can figure it out.

This drawing from the Introduction to Bally Flipper Games document shows the shapes of the score motor cams.

score motor drawing (resized).jpg

Also included in that guide is a description of how the cams relate to each other. It seems a bit confusing when you first read this, but it actually does make sense once you relate it to how the cams are shaped, which we can elaborate on.

score motor bally description (resized).jpg

The Score Motor itself is shown below in the schematic highlighted in yellow, in its normal resting state. It is connected across the 50V leg of the power supply like all action circuits are. If you look carefully at its circuit you can see that normally there is no connection to between both legs of the 50V supply, so the motor doesn't have power to run, it just sits motionless.

There are a number of switches that are found in the score motor circuit such as Evens Hole Relay, Odds Hole Relay, Bonus Score Relay, and so on. These are all wired in parallel between the score motor power input and the 50V supply line. So if any of these switches closes, the score motor will get 50V and it will start turning. As an example below, the Evens Hole Relay has been closed and as shown it now completes the 50V circuit to the score motor, which then will make the score motor start turning. Any of the other switches in the parallel chain will work the same way to start up the score motor, but the problem with any of them is that they are typically just closed for a short period of time. We need to have a longer AND controlled duration for the score motor in order for everything to happen in an orderly manner as is necessary for reliable operation.

There is one special Score Motor switch on the first cam that controls the Score Motor itself. This is switch 1E (also yellow) which is actually a make-break switch. One half of it is Normally Open at rest. The Score Motor can be triggered to start running by a variety of switch inputs. Once it starts turning, switch 1E will immediately move to the other position which due to the shape of Cam 1 then provides continuous power to the motor, keeping it turning. Thus, the score motor takes over and powers itself. This is needed because the switches that trigger the score motor to start are generally only closed for a short duration, so on their own they would only move the motor a small amount. But we need it to make a complete half-turn for everything to work right, and that is the job of switch 1E. Once it has rotated around 180 degrees (halfway), the shape of the cam is such that switch 1E will move to the opposite position or back to its NO state, which cuts off the power to the motor and stops it, unless there is still some other input telling it to go. Thus, the Score Motor is naturally set up to make a one-half revolution whenever it gets a signal to go. During this turn all of the switches will move up and down with their cams and every switch will change states, that is, all NO switches will close and all NC switches will open. But each switch will only make something happen if it is connected via some other switch in the entire circuit within a specific subcircuit. By going through the entire circuit diagram as we will do here we can eventually figure out all of the actions of the score motor.

score motor circuit resting (resized).jpg

These next 2 diagrams show how the score motor cams work to cause things to happen with different timings. First is the Sequence of Operation of Score Motor Switches which is shown on the Bally schematics. This gives you a picture of how each cam changes state for each half-rotation of the score motor.

Monte Carlo Schematic Sequence Operation Score Motor Switches (resized).jpg

Next here is another way to look at the same information. This is in the form of a pulse diagram. The shapes of the 12 cams are shown on the left and this is translated into their timing as they rotate. The dashed lines represent the two "parked" positions of the score motor, when switch 1E is in the rest position as described above.

score motor cams (resized).jpg

Use any of these pictures or a combination of them to get the image of how the score motor timing works. If you know how a pinball machine works, it should start to make some sense if you think about the layout of the timing.

- Cam 1 is used to control the score motor itself as we have seen. It can also be used for any situation where we want a switch to change state the entire time the score motor is turning.

- Cam 2 provides a series of 5 pulses in a row. This is handy for 5X scoring events, for example if you want to score 500 points there is no 500 point relay, but you can trigger the 100 point relay 5 times and to get this. This cam is also used for situations where a lot of pulses are needed to get something taken care of, an example being resetting the score reels at the start of a game.

- Cams 3-8 each just give one pulse, but these are staggered in relation to each other. These can be used to control the timing of events, for example if you want some things to happen before another, then put the earlier events on the lower number and the later events on the higher number.

- Cam 9 gives 3 pulses, so it can be used to give scoring such as 300 or 3000 points.

- Cam 10 gives the latest signal at the end of a score motor turn so it is used for things you want to happen last.

- Cam 11 provides 6 pulses that are slightly offset from the other cams, it is used mainly for adding credits but can also be used for score reel reset operations.

- Cam 12 acts as an alternator, so the switches will be in opposite states every time the motor makes its half turn. For example there might be two pop bumpers that switch between 10 points and 100 points "randomly" in this way.

All of these examples will be described in detail in the circuit analysis.

The last piece of the score motor puzzle is the switch naming protocol. The switches are labeled as SCM switches and they are labeled by their cam position and their position in the stack of switches on that cam, with A being on the bottom and going up the alphabet from there. So SCM4A is the bottom switch on cam 4. SCM8C is the third one up from the bottom on cam 8.

ADDENDUM POST:

Important note about the Bally score motor: There are typically slight variances in the order and the function of the cams from machine to machine, so be sure to analyze the specific score motor layout for each machine you work on. (Thank you to MarkG).

POWER ON

The first operation we need to perform is to flip the power switch to the On position. Typical of Bally machines of this era, the power switch in found underneath the front right part of the cabinet. The picture below shows the top of the power switch on the left (which is inside the cabinet) and the bottom on the right (the toggle which is underneath the cabinet).

Flipping on the power switch doesn't cause much to happen. There isn't much noise and the only lights that come on are the ones on the coin door.

power on 1 power switch (resized).jpg

If we are truly starting from the POGSUP condition, then we are starting with an unplugged machine. Note that the schematic shows the main power switch as being CLOSED, not open. That matches with the POGSUP description, which is Power ON, Game Start, UnPlug. So clearly if you follow that procedure precisely then the power switch stays closed when you unplug it. As trivial as that point seems, it does mean that if you plug it back in and have the power switch on, some things can change on the schematic, and they do. This can get somewhat confusing if you are not ready for it when analyzing the schematic, but here we will cover it all in detail.

Upon power-on, there may be a buzzing noise coming from the front door. If this is the case, it is most likely the Coin Lockout coil. As shown here, the Coin Lockout coil is always on when the power is on, except that each time the score motor rotates it will be turned off during most of that rotation, this is controlled by a Score Motor switch 1B which is NC . Remembering the lessons learned about the score motor, we can look at Cam #1 and easily see that it will cause any switch on there to change its state during the entire time the score motor makes its rotation. Since 1B is on Cam 1, that means it will change to Open while the score motor rotates. This would then cut off power to the coin lockout relay, except there is that pesky 8200 ohm resistor in parallel with the SCM 1B switch that seems to bypass it. The topic of this resistor in combination with the coin lockout coil has been the subject of much speculation in many threads at Pinside and other places. To save space I won't go into all of that here, I have been doing some work on this and am thinking about a separate post to revisit this topic.

power on-2 lockout coil (resized).jpg

The sole purpose of the Coin Lockout coil is to allow a coin reject bar to spring into place when the power is off, so anyone who puts a coin in while the power is off won't lose it. Then, when the power is on the coil activates and has to constantly hold the coin lockout bar open by its magnet. Because it is on all the time it eventually heats up and starts to buzz. The Coin Lockout coil is not needed on a home machine and it can be entirely disconnected if desired to make things simple. This is done by unsoldering the 2 wires to the coil and then closing them off with tape or wire nuts so they don't short.

power on-3 lockout coil (resized).jpg

For the lighting circuit (the 6V branch), we can see that as soon as the power switch is turned on the Front Door Illumination circuit is alive, getting 6V from R-B wire from one of the 10 A fuses. This R-B wire goes to the coin door to the lamps that are there, with the other half connected to the yellow wire which is one leg of the 6V power supply. This circuit is shown in green.

power on-4 front door (resized).jpg

We can confirm this by observing the machine and noting that no other lights are on. It is often easier to start with an observation of how things look and work before looking at a schematic subcircuit, it gives a good starting point to help understand what is going on. As you analyze a circuit, you will often find yourself returning to the machine to do a visual check on how something works.

As is typical in Bally machines, after turning on the power switch you can hit the left flipper button to turn on the lights. Upon doing so, we observe:

- All GI (General Illumination) comes on for the backglass and the playfield.
- No other lamps are lit on the playfield.
- In the backglass the last match number is lit and GAME OVER is lit
- Also in the backglass the score reels and 1-4 Can Play lights are lit, corresponding to the number of players that played in the last game. So if only one player was playing, only score reel 1 and player 1 is lit, if 2 were playing then both 1 and 2 score reels and player numbers are lit, and so on.

THE GAME OVER RELAY

It also should be noted here that upon turning the power switch on the game will always be in Game Over condition, even if the last game that was being played was not finished before the power was turned off. If you start a game and them don't finish it and turn the power off, you will hear a relay click when the power switch is turned on. This is the Game Over relay being activated. This is done so the game is ready to start from the beginning, and you don't get some "free play" of whatever balls are remaining just because the last person didn't finish.

This Game Over action is accomplished by the Lock Relay, so this is a good place to start for the power up. The Lock relay has a NC switch which is connected directly to the Game Over relay trip. This trip relay is used to put the machine into game over condition as soon as power is supplied. Note that it will KEEP tripping the Game Over relay (should it latch for whatever reason) as long as the Lock relay is in its default position. This won't work out well as we would never be able to start a game, but its OK, the lock relay will be energized as soon as we hit the left flipper button and that switch will change state.

power on lock relay game over trip (resized).jpg

THE "G TYPE" RELAY

The Lock relay is our first look at what Bally calls a "G" Type Relay. This is the most common relay used on this type of machine. Its function will be covered here and all subsequent relays that are discussed in this circuit description are assumed to be this same G type, unless specifically noted as otherwise.

Here is the drawing of the G type replay from the Bally 1976 parts catalog.

relay G drawing (resized).jpg

Here is the Lock relay from the Monte Carlo.

relay lock (resized).jpg

These relays have two possible states, unenergized and energized. This translates to two different states for all of the switches that are mounted on the relay. When there is no power applied to the relay coil it is in the unenergized state, which corresponds to the POGSUP condition. The switches will all be in their NC or NO positions as shown in the schematic. There can be different numbers of switches mounted to the different G relays and any of those switches might be NO or NC, whichever is needed to make their circuit work is what they will be. The Armature steel plate is held in that position by the force of the spring. When power is applied to the coil, it will cause a magnetic field which pulls in the armature (against the force of the spring). This will cause all switches that are connected to the Switch Actuator to change their positions, so every NO switch will close and any NC switch will open. This G type relay is the most-used coil in a Bally EM of this era and controls a majority of the machine's functions.

Below we see that the Lock relay coil is energized by a press of the left flipper button, as shown on the left. As shown on the right, there is a switch on the Lock relay that is tied directly to the Lock relay itself, this is the "Lock-In" switch that is used very often in these pinball circuits to hold a relay closed for a duration of time. In this case, the Lock relay will stay energized for as long as the power remains on, as there is no other switch in the circuit to break that circuit. This means that the Lock relay, like the Coin Lockout relay, is energized basically all of the time and therefore a special coil made for that purpose is required to keep it from overheating.

power on lock relay (resized).jpg

By energizing the Lock relay we now can note that the Lock relay switch 1/4 shown in the Game Over trip circuit above is now open, this is important as now it allows a game to be started (that is, it won't keep trying to put the game over relay into the tripped position like it does at power-on). This is shown below, now that switch is open (it is red to show that it has changed from its NC state).

power on lock relay game over trip 2 (resized).jpg

Note that even though we have now cut off the power to the Game Over trip coil, the Game Over relay STAYS in the tripped position for now. This is because this Trip function is a mechanical one. As soon as the trip coil is energized it pulls in its armature plate and this plate slides on top of a small white piece of plastic that then holds it in place mechanically. It can't be released until the other coil called the Latch coil is energized. This type of relay is called the G Type Interlock Relay by Bally. Here is a drawing of a typical one from the 1976 parts catalog.

relay g interlock drawing (resized).jpg

Here is a photo of the Monte Carlo Game Over interlock relay. The rest of its function will be discussed later.

relay lock (resized).jpg
relay game over (resized).jpg

There are two other switches on the Lock relay (3/4 and 4/4) that control the lights, and these are shown in this picture on the left side and labeled with red arrows on the top schematic excerpt.. The top part shows it as it is in POGSUP state, so those two switches are NO and there are no lights on since the power is off.

For the lower part the machine has been plugged back in and the power switch is on, AND the left flipper button has been pressed so the Lock relay is locked into the energized state as described above.. As we saw earlier, this will cause the GI for the front door to turn on. Now there are additional lights that are lit because those 2 switches on the Lock relay are now closed. The circuit paths that they now energize are shown in green.

Going left to right, first we see the GI for the Insert is now on. The insert refers to the backbox or backglass. The Number of Player lite for #1 is always lit. If the previous game had been played with 2, 3, or 4 players then those lights would also be lit. This will happen via the Coin Unit Disc which we won't go into now, saving it for later. The (note) is added by me on the schematic, because as observation tells us the score reels for whichever Number of Players are lit are also lit. Interestingly, this isn't really shown in the schematic anywhere. But a look at the back side of the backbox at the wiring for those lights shows that the wire colors correspond to the wires for the Lights themselves, so that explains how they are controlled.

Next there are 4 100,000 lights for each of the 4 players. If any of the players in the last game happened to exceed 100,000 points then this would close the switch 4/4 for the corresponding 100,000 Relay and this would cause that player 100,000 light to be lit in the backglass. This is shown for player one as an example, where the NO 100,000 relay switch 4/4 is shown closed instead of NO. The details of the 100,000 relay will be covered later. But we can note here that the 100,000 relays are interlock relays in the same manner as the game over relay.

Moving over a bit on the schematic we see the rest of the lighting that comes on when the left flipper button is pressed. The GI for the Panel (which is the playfield) is lit. Also, either the Left pop bumper OR the right pop bumper will be lit, this is just randomly determined by whichever half-position the score motor is stopped at, via the SCM 12C switch. The green line shows the left pump bumper being lit. Reviewing the Score Motor description should make it clear how this works! Finally, we can see that the Lower pop bumper will always be lit.

All of these lights correspond to what we observe so that is good.

lock relay light control (resized).jpg

There is one final piece to the power-up light control which is controlled by two switched on the Game Over relay. When looking at anything involving the Game Over relay, it is important to remember that if you are observing the machine after you have plugged it in and turned on the power, this relay will be in the OPPOSITE position versus what is shown in the schematic with the POGSUP state. This can be confusing if you are not aware of it.

One switch on the Game Over relay is shown below. It connects the 6V power that we previously looked at over to the Match lights, and disables the Ball Count and Player Up lights. As shown by the green circuit, if the Match Adjustment Plug is set to ON then whichever match point is connected to the 00-90 Unit Disc will be lit, in this case it is the 00. The function of the 10-90 Unit Disc will be described later. This circuit also lights up the Game Over light in the backglass as shown in green.

game over relay light control 1 (resized).jpg

Another Game Over relay switch shown below is switched to Open from its NC state. This then cuts off power to all of the various playfield lights (not the GI), so none of those are lit as we can confirm by observation.

game over relay light control 2 (resized).jpg

COIN CHUTES AND CREDITS

Assuming the game has just been turned on, the next action is to put in some coins to get game credits or to start a game. An important thing to know is that the arrangement of the coin chutes can vary between games as there were many different combinations used. Therefore, the wiring in the door of the coin chutes in a specific machine may not match the general schematic. This is the case with this specific Monte Carlo. It can get confusing if you try to understand your coin chute wiring and what you are looking at doesn't match the schematic.

Interestingly for this specific Bally Monte Carlo you can access a document on the IPDB called Bally Coin Chute Schematics. It shows 5 different schematics for the coin chute layout which offer a variety of options as to how many credits are offered. However my specific Monte Carlo example doesn't match any of the ones shown in that document. The only way to know for sure is to go into the coin door and look carefully at the coin chute wiring and compare what you see to the schematic, and sort out exactly what you have. You can also test the action of the coin chutes by dropping in coins or simply manually moving the switches to see what happens. (Always manipulate the small wire that activates the coin switch very gently so as to not damage it).

By observing the coin chutes we can confirm that for this specific machine we have two coin chutes, and they match up with the ones in blue in the schematic: "2nd coin chute" with a yellow and black wire and "3rd coin chute" with a white and red wire. The parts in red are not found on this machine, that includes what would have been the "1st coin chute" with a white and blue wire and also a stepper unit called the 2-coin unit and would have the solenoid on it called "2 coin unit step up solenoid".

coin chutes1 this Monte Carlo (resized).jpg

Here is how this Monte Carlo looks on the back side where the coin chutes are. Note that the white-blue wire which would be for the 1st coin chute if it were installed is hanging out near the top, cut off. So it could be reconnected later if it were desired to add the 1st coin chute into the mix.

coin chutes coin door back (resized).jpg

We also see that there are two adjustment plugs that are associated with this circuit, which are shown here in orange. These are the 2nd coin chute adjustment plug and the 3rd coin chute adjustment plug.

coin chutes 2 adjustment plugs (resized).jpg

Note that these two align with the sign that is stapled into the inside of the cabinet near where the adjustment plugs are so you have a handy reference if you are in there changing them around.

coin chutes 3 adjustment plugs sign (resized).jpg

All of these parts described so far combine with the rest of this part of the schematic to control what happens when coins are added. The operator can set different combinations depending on how many credits they want to offer per coin. The actual coins that would be used would be determined by the coin acceptors that are installed in the door, these aren't part of the schematic. So the coin chutes could be activated by a dime, a quarter, or whatever part is installed in the door.

So now we will look at different combinations of the adjustment plugs and see how things work.

First let's move the 2nd coin adjustment plug from over to the left (opposite as shown in the drawn schematic). This activates the circuit shown in green then the 2nd coin switch at the bottom is closed. So if a coin is inserted into the second coin chute, the Coin relay will immediately energize through the green path. As soon as it does this it will close its own switch #2/7 which is shown in the yellow path that goes down through SCM 8E. What will happen immediately is that a game will be started for player 1. This will happen through a series of events triggered by the Coin relay, but we will save that discussion for later when we go to the Start Game part of the schematic, so for now just take my word that this is what happens.

We can confirm by observation that if we drop one coin in then the game starts for player 1. If we then drop a second coin in it will add player 2. A 3rd coin will add player 3 and a 4th will add player 4. Oddly if you then add a 5th coin, you will get nothing for it, the coin will seemingly disappear. When this adjustment plug is in this position, no credits are ever added to the credit wheel, it just jumps directly to game start-up.

coin chutes 4 direct start 2nd chute (resized).jpg

Next let's move that 2nd coin chute adjustment plug back over to the right and assume that we have a machine with a 1st coin chute installed. In this case if a coin is dropped into that 1st coin chute, everything will behave exactly as described above. The Coin relay will be immediately activated via the green circuit, them lock itself in via switch 2/7 via the yellow circuit, and it will start a game (or add a player) by a circuit mechanism we will discuss later.

Over to the left shown will dotted lines is another optional circuit that would use a 2 coin alternator unit as shown below. I don't have one of these installed to test, but the circuit looks straightforward. There will be an additional adjustment plug called the 1st coin chute adjustment (shown on the left with dashed lines), and if we move that plug to the left position it will bring the 2 coin unit into the circuit. The first coin that is dropped will energize the 2 coin unit which will then move it to its alternate position and close its switch. That will mean the next coin will allow the path that energizes the Coin relay and everything will happen as described above. The only difference is that 2 coins are needed to start instead of one.

coin chutes alternator unit (resized).jpg

coin chutes 6 2 coin (resized).jpg

Next let's look at the effect of the 3rd Coin Chute adjustment plug. It has 5 different jumper positions that will control how many credits are added to the credit wheel when a coin is dropped into either of the coin chutes. It can be set up to add 2, 3, 4, 5 or 6 credits to the wheel.

The drawing below shows this circuit as it is drawn in the default POGSUP state. The 2nd coin chute connector is plugged into the "2" position.

We start by dropping a coin into the 2nd coin chute (or manually moving the switch). This will immediately energize the 2nd Coin relay as shown in the green circuit. This then will immediately change the state of the switches on the 2nd Coin relay which will cause some things to happen as shown by the blue circuit.

First we see that the 2nd Coin relay switch 1/3 locks in the 2nd Coin relay through SCM 5E. So the 2nd Coin relay will stay energized as long as that score motor switch 5E remains closed.

Moving to the right a bit we can see that the switch 2/3 is in the Score Motor circuit. So when it closes it will start up the score motor.

More to the right we see that switch 3/3 is also closed and connects the Credit Unit Step Up Solenoid circuit. This solenoid will step up the Credit Unit (add a credit) every time it is energized. The Credit Unit Limit switch that is shown there will be closed as long as there are less than 25 credits shown on the wheel, which is the maximum. Once the wheel hits 25 that switch that is mounted on the until will open up to disconnect this circuit, as there is no point in energizing the step up solenoid if it is at its maximum position, this will just stress the system.

picture

We can see at the bottom that we also need to close SCM 11A to complete that circuit and get a credit added. This is where our knowledge of how the score motor works benefits us, if you have a solid understanding of the timing of what will happen when the score motor turns, this circuit becomes very easy to understand. In this case since the connection is in the "2" position we expect to see 2 credits added to the credit wheel (which we can confirm happens by observation).

With the addition of the timing diagram, it should be easy to see how this works. The score motor cam 11 is going to be making a lot of clicks, 6 of them in total for the score motor half-rotation. But the Credit Unit step up solenoid will only see two of those closures and thus will only add two credits. That is because the 2nd Coin Chute relay LOCK-IN is controlled through SCM 5E. As soon as that switch opens then it the voltage to the 2nd Coin Chute relay will deenergize. The timing of this is shown with a red line that shows just where cam 5 causes the change of state. It happens after 2 pulses have occurred this allowing 2 credits to be added, but then it prevents any more from happening because switch 3/3 will open back up as soon as the 2nd Coin Chute relay deenergizes, cutting off the step up solenoid.

coin chutes 7 2nd coin chute 2 credits (resized).jpg

With your knowledge of how the score motor cam timings work it should now be easy to see how moving the adjustment plug allows the number of added credits to change from 2 to 3 to 4 to 5 to 6. The timing is controlled by the score motor switches that will deenergize the 2nd coin chute relay. The 3 position uses SCM 6F to cut it off just after 3 credits have been added, the 4 position uses SCM 7D to cut it off after 3, and so on. Here is how the timing looks for the 3 position.

coin chutes 7 2nd coin chute 3 credits (resized).jpg

You can also see that there is another jumper that is connected to the 3rd Coin Chute relay. It can be placed into any of the 2-6 positions as well, although interestingly you can't plug them both into the same count for the credit step ups. The circuitry for what happens when the 3rd Coin Chute switch is activated via a coin drop is all exactly the same as described above. There are parallel switches for that relay to start up the score motor and to allow the Credit Unit step up solenoid to be activated by SCM 11A. This is shown below for the connection to the 6 credit position as shown in the schematic POGSUP state.

This completes the circuit descriptions for the coin chutes and the thumbnail below shows everything in the schematic that we have covered so far.

Monte-Carlo-Schematic highlights 3 coin chutes (resized).jpg

Also it should be noted that everything described in this section can basically be completely ignored in a home use machine, assuming it has been set for free play (how to do that is simple and will be covered later). There is no need to involve the coin mechanisms, the coin chute switches, put coins in, etc. Sometimes these parts become damaged or finicky so if you don't want to deal with it, you don't have to. However be aware that one leg of the score motor wiring passes directly through the coin chute switches. So if those switches or the wires attached to them become hacked or damaged it will prevent the score motor from turning properly. For this reason, it is best to just set the machine on free play rather than always opening the coin door and jamming down the coin chute switches with a finger or tool which can damage the switch and then prevent the machine from working correctly at all.

Of course if you want to be more authentic to the original arcade experience and keep things as original as possible you can put it all into play if desired and set the machines to take up coins.

START NEW GAME PLAYER 1

Starting a game causes more simultaneous action than any other part of playing a pinball machine. Everything needs to be reset and organized for the start of the new game. The credit button is used to start a new game (however, do note that depending on the setup of the coin chutes and their adjustment plugs, sometimes inserting a coin will also directly reset the machine and start a new game instead of adding a credit to the credit wheel).

The circuit that is used to start a game is shown here as it appears in the schematic in POGSUP condition. The front panel credit button is pointed out, this is what is pushed to start a game.

credit switch circuit POGSUP (resized).jpg

However, it is more logical to look at this circuit after the machine has been powered on, since we would only attempt to start a game with the power on, otherwise nothing is going to happen. As we know from before, when the power is turned on the Game Over relay will automatically trip to the opposite position shown in the POGSUP state (that is, it trips to Game Over mode). So that means the game over relay switch #2/5 shown below will now be closed. We also are assuming that some coins have been added so now there are credits on the credit wheel. Once the credit wheel moves from 0 credits to any number of credits, the Credit Unit Zero switch in this circuit will close. Now we have a complete circuit shown in green when the credit button is pressed, passing through the game over relay switch, the credit unit zero switch, the pushed credit button, and score motor switch 1E. This will then start the reset process.

credit switch circuit initial start (resized).jpg

You will notice that there are 3 other switches in parallel with the game over relay switch and that the way these are wired in parallel means that if any of these is closed the game will start when the credit button is pushed. In fact, one of them, the Player Up Unit Zero switch, is shown closed. So why is that game over relay switch needed? It seems superfluous.

Actually, the positions of the other 3 switches will vary randomly when the machine is turned on and until it is reset the first time. That is because these stepper units may be in random positions depending on where the state of the machine is at any given time, and they don't get reset until the game is started for the first time. Here is how these switches behave on their respective stepper units.

Ball Count Unit Zero. This switch is Open if the unit is set on ball #1, it is Closed if it is set on any other number of balls.

Player Up Unit Zero. It is Open in the player 1 position and it is Closed for player 2, 3, or 4 position.

Coin Unit Limit. It is Closed if 1, 2, or 3 players are selected to play, and open if 4 players are selected to play.

There does exist the possibility that all 3 of these switches are open when the machine is turned on, and so the game over relay switch is used as the guarantee that the game can be started, as it will always be closed when the machine is powered up, even if the machine was powered off before the previous game was finished (as described in the Power On section).

We will revisit this circuit path and why these other switches are there later.

Now that we have a path to start the machine by pushing the credit button, we can look at the circuits that will reset the machine, that is, get it ready so that a game can be played. In order to do this, a bunch of things need to happen which will cause the score motor to turn and the clicking of a lot of relays.

Here are the things that need to happen:
1. Reset the Reset Motor (resets all of the trip relays)
2. Lower the pop-up post if it happens to be up
3. Advance the Total Play Meter by one
4. Reset the Coin Unit to position 1
5. Reset the Ball Count Unit to position 1
6. Reset the Player Up Unit to position 1
7. Reset the Credit Unit by 1 (remove 1 credit)
8. Latch any of the four 100,000 point relays if they have been tripped in the previous game by going over 100,000 points
9. Energize the Game Over Latch Relay (take game out of Game Over condition)
10. Reset all 16 of the Score Reels to the 0 position
11. Kick out the ball to the shooter lane

All 11 of these evens happen in a few half-turns of the score motor. It seems complicated, but we can break it down step by step and use our knowledge of how the score motor works to figure out how it all happens.

Previously the Credit relay was energized by the press of the Credit Button as shown in the previous green path. But the person's finger pushing on the credit button will likely only push it for a very short duration of time. This will energize the credit relay only briefly but that would not be long enough for it to do what it needs to do. To rescue this situation the credit relay has its own lock-in switch which is switch 2/3 as shown in the green path below. Now the credit relay will stay energized by its own lock-in switch and this will keep the Credit relay activated through NC score motor switch 7D (which was also used for adding 4 credits via the coin chute as previously described). Therefore, as soon as the Score Motor makes a half- rotation and switch 7D opens, the Credit relay will turn off (deenergize). This is long enough for it to do its job.

credit relay lock-in (resized).jpg

A switch 1/3 on the credit relay will immediately energize the Coin Relay as shown in the left green path below, passing through score motor switch 8E. As soon as the coin relay is energized we can see that it has its own switch 2/7 which will act as its lock in. It will keep the coin relay energized until score motor switch 8E opens when the score motor turns as shown by the blue circuit.

coin relay energized by credit relay (resized).jpg

As soon as the coin relay is energized, its switch 4/7 will immediately energize the Lock Relay as shown in green below, IF the player has not pressed the left button yet. The Lock Relay will then lock itself on via its own lock-in switch as shown in the blue circuit, and the GI lights will now come on if no one ever bothered to press the left mouse button.

coin relay energizes lock relay (resized).jpg

At the same time the coin relay switch 3/7 will now be closed so it will start the score motor going, which is required to get some more action going. This is the green circuit on the far right.

coin relay starts score motor (resized).jpg

Also immediately after the coin relay is energized its switch 7/7 will cause the Reset Motor to turn which will reset all of the trip relays on that bank. This is shown by the green circuit. Similar to the score motor, the reset motor has an index switch which will ensure that it makes just the right amount of turn, this is triggered as soon as the coin switch closes and starts the motor, as shown in blue.

coin relay starts reset motor (resized).jpg

Another coin relay switch 5/7 as shown below will energize the Reset Relay as shown below in the green path. This circuit passes through the game over relay switch 3/5 which is still closed because the game was in Game Over condition when it was started (game over relay tripped). As soon as the reset relay energizes it locks itself on via its lock-in switch 6/8 as shown in the blue circuit.

coin relay energizes reset relay (resized).jpg

The reset relay switch 1/8 will lower the play-more post between the flippers if it happens to be in the up position from a previous power-down. This is shown in green in the circuit below. Note that when the up post relay actually raises the post it will cause the Down Post Solenoid End Of Stroke switch shown here to stay closed as long as the post is in the up position, this is what allows the post to be lowered back down when needed.

down post on startup (resized).jpg

Just after all of these events happen the score motor will start to rotate (it is started by a switch on the coin relay as we just saw). Here is where our knowledge of how the score motor and all of its switches work really makes it much easier to understand the circuits; how they work and what they are doing.

Consider this part of the schematic, which shows how a lot of the start-up tasks are triggered in sequence by score motor switches. There are 4 relays that are closed from their NO positions, one on the credit relay, one on the coin relay, and two on the reset relay as we can see in red. All of these relays have been energized by pressing the credit button as we have seen.

We can see that now there are connections through the score motor switch SCM 3A for the Credit Unit Reset (removes one from the credit wheel), the Total Play Meter (adds one), The Coin Unit Reset Solenoid (sets the coin unit back to start position or player 1), the Ball Count Unit Reset Solenoid (sets the ball count unit to start position or ball 1), and the Player Up Unit Reset Unit (sets the player up unit to start position or player 1). All of these actions happen at once when the score motor switch 3A closes.

Then shortly after SCM 3A has closed and then opened back up (as we recall from our cam motor shapes and the timing diagrams) score motor switch 4C will close. As we can see from the blue circuit, this then will reset any of the four 100,000 point relays that may have been tripped in the previous game.

startup score motor 3 and 4 (resized).jpg

This part of the circuit shows how the score reels are reset. First we see the reset relay which has already been energized by both the coin relay switch 5/7 and the game over relay switch 3/5 as shown in green. and we can see there is a typical lock-in switch for the reset relay # 6/8. This lock-in switch will hold the reset relay energized until score motor switch SCM 8C opens as shown in green, UNLESS any of the score reels is at a position other than zero. If any of the 16 score reels is at any number other than zero then the reset relay will stay energized and the score motor will keep turning.

Also be sure to see that when the score motor gets to position 4 the Game Over relay will be latched (taken out of Game Over mode) by the closing of SCM 4E as highlighted in red.. This will disconnect the right half of the circuit since game over relay switch 3/5 will revert to its NO state, but it won't matter because the reset relay is held on by its lock-in switch 6/8.

score reels reset 1 (resized).jpg

The part showing the 16 Drum Units Zero (these are the score reels) is drawn in shorthand to save space in the schematic. To help understand the circuit it is better to draw all 16 of the switches and show them in parallel as they are wired. Each score reel has a zero switch, this switch will be OPEN when the score reel is at zero and it will be closed if the score reel is any other number than zero. So now we can see that the reset relay will be held energized as long as any score reel is not in the 0 position. For example as shown here, all of the reels are at 0 except player 2 100s and player 4 100s. Since these are still closed, the reset relay will stay energized through the blue circuit even when SCM 8C opens up.

score reels reset 2 (resized).jpg

The resetting of the score reels is triggered by 2 relays, the #1 Score Reset Relay and the #2 Score Reset Relay. These two relays receive multiple pulses from the score motor which are used to rapidly step the score reels towards zero. The #1 score reset relay gets 5 pulses for each score motor half-turn from cam 5 and resets all of the reels for player 1 and 3, and the #2 score reset relay gets 6 pulses from cam 11 and resets all of the reels for players 2 and 4. You can see that these score reset relays will keep going and sending pulses as long as the score motor keeps turning. Actually if all of the score reels happen to be set at 5 or above then they all will go to 0 within a one-half score motor rotation (cam 5 with 5 pulses will pulse 5 to 6-7-8-9-0), but normally some of the reels are randomly on 1, 2, 3 or 4, so this will take a second score motor turn to get some more pulses from cams 5 and 11.

score reels reset 3 (resized).jpg

To make sure the score motor keeps going, reset relay switch 5/8 will keep the score motor going as long as the reset relay stays energized. This ensures there will be enough score motor turns to reset all of the score reels to 0. Normally it should take a maximum of 2 turns, but the score motor could turn more than twice if a reel is sticking for example. If a reel is stuck and refuses to go to 0 OR if the zero position switch is not adjusted properly and won't open even at zero then this circuit will stay alive indefinitely and the score motor will keep turning and turning, a somewhat common problem.

Also note as shown here that the credit and coin relays will both be deenergized within the first score motor rotation, via SCM 7D for the credit relay and via SCM 8E for the coin relay.

score reels reset 4 (resized).jpg

When all of the score wheels get to 0 this circuit looks like this. Now there will be no switch to keep the reset relay energized as soon as the score motor rotates to the #8 cam which will then open, so the reset relay will deenergize at that point.

score reels reset 5 (resized).jpg

If the ball is sitting in the shooter lane instead of the outhole then the startup procedure is complete. This would happen if the machine were reset before the last game was finished. More commonly the ball will be sitting in the outhole where it drained at the end of the last game. In this case, the last step is to pop the ball back into the shooter lane.

This circuits to kick the ball out from the outhole are shown here. On the left side we see the circuit that will become activated by the ball in the outhole. This green circuit passes through a switch in the outhole that detects the ball and then to the outhole relay. But this circuit can't get activated because it has been cut off from the power supply by the reset relay switch 3/8 which is now open from its NC position while the reset relay is energized doing its job as we just discussed above. As soon as that reset relay deenergizes by SCM 8C as we saw in the picture above, then that reset switch 3/8 will go back to its default NC state. This will complete the green path for the outhole relay, energizing it. It then immediately locks itself in via its lock-in switch 2/8 as shown in the blue circuit. Now when the score motor makes one more turn, the circuit on the far right which controls the outhole kicker solenoid will energize when the score motor hits cam #7 via SCM 7C and the ball will be kicked out. Then shortly after that, SCM 8D on cam 8 will open and the lock-in circuit for the outhole relay will be cut off so that relay will deenergize.

outhole kicker startup (resized).jpg

Of course we need another score motor half-rotation to get that action to occur, and this is provided by the outhole relay switch 5/7 which will close as soon as the outhole relay is energized, thus giving the score motor the go command for another turn. This switch will open when the outhole relay deenergizes after the ball has been kicked out.

outhole relay score motor (resized).jpg

At this point everything has stopped and the game is ready to play for Player 1. Everything is quiet, the ball is in the shooter lane ready to go, and we have accomplished all of the startup tasks, repeated here with their timing shown:

1. Reset the Reset Motor (resets all of the trip relays) (happens right away)
2. Lower the pop-up post if it happens to be up (happens right away)
3. Advance the Total Play Meter by one (score motor rotation #1, at #3 cam)
4. Reset the Coin Unit to position 1 (score motor rotation #1, at #3 cam)
5. Reset the Ball Count Unit to position 1 (score motor rotation #1, at #3 cam)
6. Reset the Player Up Unit to position 1 (score motor rotation #1, at #3 cam)
7. Reset the Credit Unit by 1 (remove 1 credit) (score motor rotation #1, at #3 cam)
8. Latch any of the four 100,000 point relays if they have been tripped in the previous game by going over 100,000 points (score motor rotation #1, at #4 cam)
9. Energize the Game Over Latch Relay (take game out of Game Over condition) (score motor rotation #1, at #4 cam)
10. Reset all 16 of the Score Reels to the 0 position (During score motor rotation #1 and #2, ending at cam #6 of rotation #2)
11. Kick out the ball to the shooter lane (score motor rotation #3 at cam #7)

Since the start-up procedure involves so many things happening, all controlled by the timing of the score motor, it is helpful to create a timing diagram help better visualize how it all works. The diagram below shows how all of the start-up actions are triggered by the various score motor cams during 3 rotations of the score motor for start up.

score motor cams startup procedure (resized).jpg

After this start-up is completed, there will be some visible changes for the lights on the backglass and playfield. On the backglass the Game Over and the Match Number will now be off, and the Ball in Play #1 lamp will be lit and the Player Up #1 will be lit (next to the score reels). On the playfield all 10 of the roulette numbers near the top rollover buttons will be lit as well as a random 2 more on the roulette wheel in the middle of the field.

These changes are all caused by the latching of the Game Over relay from its previously tripped position. When the Game Over relay is tripped it is in the game over condition, and when it is latched it is in the live play condition. The Game Over relay was latched during the startup procedure just described. It is also worth repeating the game over relay in the latched position is as it is shown in the POGSUP schematic.

Looking again at this section of the schematic we can see how the game over relay switch 4/5 now completes the circuit to the Ball Count Unit Disc (which is shown lighting up for ball 1 in play) and the Player Up Unit Disc (which is shown lighting up for player 1). The right part of the circuit which controls the Game Over light and the Match lights is now cut off by that same game over relay switch, so they are now off.

player up 1 and ball in play lites 1 (resized).jpg

Another game over relay switch 5/5 controls the circuit below which will now light up the 10 rollover number insert lights and two of the roulette wheel lights which are 1 and 2 as shown here. These two are controlled by the pointer in the 00-90 Unit Disc which will be analyzed later.

lites 1 thru 10 after startup (resized).jpg

START NEW GAME PLAYERS 2-4

After everything that has been described so far which has all happened from pressing on the credit switch the game is now ready to start for a one player game. But since this is a 4 player machine we also need to look at the circuits for setting up 2, 3, or 4 players.

In order to handle the logic necessary to track more than one player there are two additional stepper units compared to a single player machine such as Bon Voyage. These are the Coin Unit and the Player Up Unit. These are both of the "step-up, reset" style, that is they have a solenoid that moves them up from 1 through 4 one step at a time and a reset solenoid that brings them back down to the initialization position which is 1 (all in one step). You should recall that both of these were reset to their #1 initial position as part of the start-up process above.

The Player Up unit doesn't come into play during start-up, only the Coin unit does. The basic idea of Coin Unit is that it will be positioned to indicate the total number of players for the current game. This is done during the start-up process. Once it gets there, it stays in that position and doesn't move at all for the rest of the game. The only time it will move again is when the machine is restarted, then it will reset again as described above.

Another thing to consider before adding more players beyond player 1 is that some things from the startup procedure above will need to happen again, but not others. Let's look at that list from the initial startup again:

1. Reset the Reset Motor (no need, it was already reset)
2. Lower the pop-up post if it happens to be up (no need, it was already reset)
3. Advance the Total Play Meter by one (YES needs to be done)
4. Reset the Coin Unit to position 1 (YES needs to be done, actually step it up to the next position)
5. Reset the Ball Count Unit to position 1 (no need, it was already reset)
6. Reset the Player Up Unit to position 1 (no need, it was already reset)
7. Reset the Credit Unit by 1 (remove 1 credit) (YES needs to be done)
8. Latch any of the four 100,000 point relays if they have been tripped in the previous game by going over 100,000 points (no need, these were already latched)
9. Energize the Game Over Latch Relay (no need, it was already latched)
10. Reset all 16 of the Score Reels to the 0 position (no need, they all were already reset)
11. Kick out the ball to the shooter lane (no need, it is already in the shooter lane)

So we can see that when we want to add the second player we need to just do 3 things: Advance the total play meter, reduce the credit unit by one, and move the coin unit to the #2 position. So let's look at the circuits and see how this is logically performed.

First we will revisit the initial startup circuit which is triggered by manually pushing the credit button. There is a change compared to when we were starting up from the game over condition before. Now the game over relay switch 2/5 is back to its NO position since the game over relay was latched from the player 1 startup process. The ball count unit zero switch will also be open for sure since it is open when the ball count is reset during startup. And the same goes for the player up unit zero, it also is open when the player up unit is reset (to player 1). But the coin unit limit switch will be closed if the coin unit is in the Player 1, Player 2, or player 3 position. It is currently in the Player 1 position so therefore it provides a path to do another startup process when the credit button is pressed as shown in green.

credit switch circuit player 2 and 3 start (resized).jpg

When the credit button is pressed, the credit relay and coin relay will energize the same as before. However this time the reset relay will never get energized because the game over relay is now latched, so its switch 3/5 will be open as shown below by the arrow. This blocks the path that allows the reset relay to energize, so all of its functions are cut off, which is just what we want for the next player startup. Since the reset relay never energizes, the score reset relays never get energized either which is OK because they score reels are all already at 0 from the first startup.

player 2 start reset relay bypassed (resized).jpg

We can return to a familiar circuit we analyzed above and see how not having the reset relay energized controls what will happen. With the reset relay switch 7/8 in the opposite position shown in red, the right side is cut off. This includes the player up unit reset (it stays in position 1 for now because player 1 will be going first), the ball count reset which is already at ball 1, and the coin unit reset. But now, the coin unit STEPUP will be energized, so the coin unit will move from position 1 to position 2, which then sets the memory position for the machine that there will be two players in this game.

Note that the credit unit and the total play meter are reset by the score motor switch 3A just as before. And you will notice that the 100,000 relays will still get a signal to latch, but they all will have already been latched from the first startup, so that part of this circuit basically does nothing.

startup score motor 3 and 4 for player 2 (resized).jpg

Actually because this circuit is still the same as before the coin relay switch 7/7 will cause the reset motor to make a turn, which really is not necessary because it already turned and reset all of the trip relays during the first startup. This is an unnecessary and superfluous action, but hey, it happens. No harm is done.

coin relay starts reset motor (resized).jpg

We can confirm by observing that the reset motor does turn again when player 2 is started. Also we can confirm that the player 2 startup will just take a single half-rotation of the score motor, as all it needs to do is bring into action cams 3 and 4 to get the jobs done for the coin unit step up, credit unit reset by 1, and play meter step up by 1.

Again remember the coin unit will be set into position according to the number of players loaded in the game. The coin unit will have different functions to perform as the machine is played, but for now we will just look at how it controls the Number of Players lights on the backglass. The schematic below shows the effect of the coin unit step up during the player 2 startup which moves a pointer to complete the circuit for number of players 2 light. The number of players 1 light is always lit as we can see. So when 2 players are loaded then both the #1 and #2 number of players lights are lit.

number of player lite control 2 player (resized).jpg

At this point the game is ready to play for two players. However there is still the opportunity to load players 3 and 4 if desired (and if there are enough credits available). Pressing the credit button for the 3rd time and for the 4th time will cause an exact repeat of the reset process for player 2.

Here we can see the complete circuit for the number of players lites and how the coin unit will light them up for 1, 2, 3, or 4 players as it is stepped up.

number of player lite control (resized).jpg

However there is one change that happens once the 4th player is started. When the coin unit steps up to position 4 its zero switch opens. This then means that all of the 4 possible paths to complete the credit circuit when the credit button is pressed are now open, so nothing will happen from this point no matter how many times that button is pushed.

credit switch circuit player 4 loaded (resized).jpg

At this point, all start up processes are done and the game is ready to play. We have analyzed the yellow highlighted part of the schematic so far.

Monte-Carlo-Schematic highlights 4 startup (resized).jpg

GAME PLAY (10, 100, 1000 POINTS)

For the next sections we will describe all of the possible events that can happen from the time the ball is launched onto the playfield until it drains. This will be done is a somewhat organized manner with the understanding that these events happen randomly during game play.

10 Point Scoring Opportunities

There are 7 switches on the playfield that will score 10 points. 5 of these are Rebound Switches behind rubbers and the other switches are connected to the Left and Right Rebound Kickers (also called Sling Shots). Actually there are 2 switches behind the left and the right rebound kicker rubbers (4 total). Each pair is tied to its corresponding Rebound Kicker (or Sling Shot) Solenoid. Even though only one switch is shown in the schematic section below, this is just another shorthand and there are actually 2 in parallel so if either is closed by ball contact they will activate the rebound kicker solenoid. The schematic shows 4 side rebound switches which matches what you can count (one on the left side and three on the right) but there is only one "top" rebound switch so I don't know what it says "Top Rebounds" with an S. These 7 switches are shown here with green arrows.

playfield 1 10 point switches (resized).jpg

Either the top left or the top right pop bumper will also score 10 points when it is hit by the ball. This is determined by score motor switches 12A and 12B. If you refer back to the shape of the score motor cam #12 you will remember that is set up so it is in one position half the time and the other position the other half of the time, in other words every time the score motor makes a half-turn it will sway states. So in this case the 2 top pop bumpers will switch back and forth between 10 points and 100 points as the score motor turns.

The 7 switches rebound switches and the top pop bumper switches shown here all will energize the 10 Point relay whenever they are closed. Again as a shorthand only one switch is shown for the 4 side rebound switches, there are actually 4 switches there wired in parallel. If the ball contact closes any one of these, then the 10 Point relay will energize and perform a variety of steps. For example in the drawing below one of the side rebounds has been closed from its NO position by a ball striking it. This will energize the 10 Point relay via the green circuit path. The action of the ball bouncing off the switch is very fast and we need the 10 point relay to stay energized for a short period of time in order to perform all of its jobs. So for this reason it has a typical lock-in switch 3/6 which locks it in via the blue circuit.

10 point relay energized and locked in (resized).jpg

The 10 point relay switch 1/6 is connected inline with the Ball Index relay. It can be seen here that when that switch closes from its NO position the Ball Index relay will be energized. The ball index relay is then locked in by its own switch 1/3. The function of the Ball Index relay will be discussed later.

ball index relay lock-in 10 point (resized).jpg

Switch 6/6 is connected to the 10-90 Unit Step-Up Solenoid. This will cause this solenoid to activate and it will advance the 10s Score Reel by one position to add 10 points to the score. Note that this circuit is connected to the Player Up Unit Disc which controls which player will get the points. So if player 1 is playing, then the 1st player 10 point score reel will be incremented by one as shown here in green.

10 point relay score reel step up (resized).jpg

If Player 2 is up, then the pointer will move over to the player 2 position on the player up unit and then player 2 will get the 10 points by the circuit in green. The 10 point score for player 3 and player 4 will work the same way.

10 point relay score reel step up player 2 (resized).jpg

Switch 2/6 is connected to the 100 Point relay. It's job is to advance the 100s Score Reel by one when the 10s reel goes from 9 back to 0. This switch will only close when the 10s score reel advances from 9 back to 0. This is the function of the 10-90 Unit 9th Position switch. It is always NO except when the score reel is in position 9, then it will close, allowing this circuit to be completed so that an additional score of 100 will be added when the 10s reel goes from 90 back to 10. We can see here that once again the pointers on the Player Up Unit Disc control this function in relation to the current player that is up. So when player 1 is playing the this circuit is completed as shown in green. It will move over to any other player that happens to be up by the position of the player up unit disc in the same manner as discussed above.

10 point relay 100 point relay (resized).jpg

Switch 5/6 on the 10 point relay is connected to the 10 point Chime Solenoid. This will cause this solenoid to activate which will create the ringing sound of the 10 point chime.

10 point relay chime (resized).jpg

Switch 4/6 is connected inline with the 00-90 Unit Step-Up Solenoid. Each time the 10 Point Relay is activated, the 00-90 Unit Disc will advance one position. This will be used at the end of the game for the match function and also for the "special feature", these will be described later.
10 point relay 00-90 unit step up (resized).jpg

So to review, causing a 10-point action on the playfield will energize the 10 point relay which will lock itself in so that it has enough time to perform 5 functions.
1. Add 10 points to the score by stepping up the 10s score reel.
2. Add 100 points to the score if the 10s reel has gone from 9 back to 0.
3. Energize and lock in the ball index relay.
4. Ring the 10 point chime.
5. Advance the 00-90 unit by one position.
All of these events can happen in the time it takes the 10 point score reel solenoid to activate. So the lock-in timing is controlled by that solenoids EOS (End Of Stroke) switch. When that solenoid plunger reaches the end of its travel as it is moving the 10s score reel, the EOS switch will open as shown in red below for player 1. This will cut off the 10 point relay lock-in switch 3/6 and the 10 point relay will thus be deenergized. Of course this will happen according for whichever player is up, 1, 2, 3 of 4 since all of the EOS are lines up via a serial connection in that circuit.

10 point relay off EOS (resized).jpg

100 Point Scoring Opportunities

100 points are scored by these playfield events:
• One of the rollover button switches on the upper playfield for the numbers 1-10 are closed by the ball rolling over them.
• Hitting the lower pop bumper at all times and on either of the upper pop bumpers depending on which one is lit for 100 points.
• Hitting either of the two mushroom bumpers.

If the ball contact closes any one of these, then the 100 Point relay will energize and perform a variety of steps. For example in the drawing below one the left pop bumper has been hit by the ball quickly closing its switch 2/3 shown in red and SCM 12A is in the 100-point. This will energize the 100 Point relay via the green circuit path. The action of the ball bouncing off the switch is very fast and we need the 100 point relay to stay energized for a short period of time in order to perform all of its jobs. So for this reason it has a typical lock-in switch 2/5 which locks it in via the blue circuit. This is basically the same setup that the 10 point relay used as described previously.

100 point relay energized and locked in (resized).jpg

The circuit below which is to the left of the 100 point relay in the schematic shows how 100 points are scored when the top rollover buttons are run over by the ball. In this example the #8 rollover is activated by the ball. As soon as that happens, the #8 trip replay becomes tripped (where it will stay until the end of the ball in play) and then the 100 point relay is energized as shown by the green path. The #9 rollover will continue to score 100 through that path every time since now the that #8 trip relay switch 3/5 is not always in the red position. All of the other 10 rollover buttons work in the same manner.

Side note: This is an interesting circuit because you can see that the first time one of the 10 rollover buttons is hit by the ball the corresponding trip relay has not yet been tripped as it was previously reset at the end of the last ball player (or via the machine startup). In this case, the rollover button when hit will immediately energize and trip the relay, and this will immediately move the MBB switch to the right position where it will connect with the 100 point relay. It seems that there wouldn't be enough dwell time with the ball rolling over the switch to get the 100 point relay energized by the MBB switch. In fact you can verify this by observing. Sometimes the trip relay will trip (which can be seen by the number light going off) but there will not be a 100 point score. You can also play with it with the playfield glass off and see that a quick press of the button will SOMETIMES trip the relay but not get the 100 point score. Whereas, once the relay is tripped even a very short duration tap on the button will score the 100 points as the MBB switch is now already in the rightmost position (as shown in the schematic. This is a little bit of a weak point in this circuit, but in the end not a huge deal.

100 point relay 1-10 buttons (resized).jpg

A 100 point score will energize and lock in the ball index relay within the same circuit as the 10-point score described above. The 100 point relay switch 1/5 is connected in-line with the Ball Index relay. It can be seen here that when that switch closes from its NO position the Ball Index relay will be energized. The ball index relay is then locked in by its own switch 1/3. The function of the Ball Index relay will be discussed later.

ball index relay lock-in 100 point (resized).jpg

(The following circuit follows the same logic as for the 10 point relay). 5/5 is connected to the 100-900 Unit Step-Up Solenoid. This will cause this solenoid to activate and it will advance the 100s Score Reel by one position to add 100 points to the score. Note that this circuit is connected to the Player Up Unit Disc which controls which player will get the points. So if player 1 is playing, then the 1st player 100 point score reel will be incremented by one as shown here in green.

100 point relay score reel step up (resized).jpg

(The following circuit follows the same logic as for the 10 point relay). If Player 2 is up, then the pointer will move over to the player 2 position on the player up unit and then player 2 will get the 100 points by the circuit in green. The 100 point score for player 3 and player 4 will work the same way.

100 point relay score reel step up player 2 (resized).jpg

(The following circuit follows the same logic as for the 10 point relay). Switch 3/5 is connected to the 1000 Point relay. It's job is to advance the 1000s Score Reel by one when the 100s reel goes from 9 back to 0. This switch will only close when the 100s score reel advances from 9 back to 0. This is the function of the 100-900 Unit 9th Position switch. It is always NO except when the score reel is in position 9, then it will close, allowing this circuit to be completed so that an additional score of 1000 will be added when the 100s reel goes from 900 back to 100. We can see here that once again the pointers on the Player Up Unit Disc control this function in relation to the current player that is up. So when player 1 is playing the this circuit is completed as shown in green. It will move over to any other player that happens to be up by the position of the player up unit disc in the same manner as discussed above.

1000 point relay 10000 point relay (resized).jpg

(The following circuit follows the same logic as for the 10 point relay). Switch 4/5 on the 100 point relay is connected to the 100 point Chime Solenoid. This will cause this solenoid to activate which will create the ringing sound of the 100 point chime.

100 point relay chime (resized).jpg

So to review, causing a 100-point action on the playfield will energize the 100 point relay which will lock itself in so that it has enough time to perform 4 functions (note that it has one less job than the 10 point action as it does not have a stepper unit to advance).
1. Add 100 points to the score by stepping up the 100s score reel.
2. Add 1000 points to the score if the 100s reel has gone from 9 back to 0.
3. Energize and lock in the ball index relay.
4. Ring the 100 point chime.
All of these events can happen in the time it takes the 100 point score reel solenoid to activate. So the lock-in timing is controlled by that solenoids EOS (End Of Stroke) switch. When that solenoid plunger reaches the end of its travel as it is moving the 10s score reel, the EOS switch will open as shown in red below for player 1. This will cut off the 100 point relay lock-in switch 2/5 and the 100 point relay will thus be deenergized. Of course this will happen according for whichever player is up, 1, 2, 3 of 4 since all of the EOS are lines up via a serial connection in that circuit.

100 point relay off EOS (resized).jpg

1000 Point Scoring Opportunities

There are 6 rollover switches on the playfield that will score 1000 points as shown below.

playfield 1 1000 point switches (resized).jpg

(The following circuit follows the same logic as for the 10 point relay and 100 point relay). These 6 switches as shown here all will energize the 1000 Point relay whenever they are closed. If the ball contact closes any one of these, then the 100 Point relay will energize and perform a variety of steps. For example in the drawing below the Bottom Alley Rollover switch has been closed from its NO position by a ball rolling over it. This will energize the 1000 Point relay via the green circuit path. The action of the ball rolling over the switch is very fast and we need the 1000 point relay to stay energized for a short period of time in order to perform all of its jobs. So for this reason it has a typical lock-in switch 2/6 which locks it in via the blue circuit.

1000 point relay energized and locked in (resized).jpg

(The following circuit follows the same logic as for the 10 point relay and 100 point relay). A 1000 point score will energize and lock in the ball index relay within the same circuit as the 10-point and 100 point scores described above. The 1000 point relay switch 1/6 is connected in-line with the Ball Index relay. It can be seen here that when that switch closes from its NO position the Ball Index relay will be energized. The ball index relay is then locked in by its own switch 1/3. The function of the Ball Index relay will be discussed later.

ball index relay lock-in 1000 point (resized).jpg

(The following circuit follows the same logic as for the 10 point relay and 100 point relay). Switch 5/6 is connected to the 1000-9000 Unit Step-Up Solenoid. This will cause this solenoid to activate and it will advance the 1000s Score Reel by one position to add 1000 points to the score. Note that this circuit is connected to the Player Up Unit Disc which controls which player will get the points. So if player 1 is playing, then the 1st player 1000 point score reel will be incremented by one as shown here in green.

1000 point relay score reel step up (resized).jpg

If Player 2 is up, then the pointer will move over to the player 2 position on the player up unit and then player 2 will get the 1000 points by the circuit in green. The 10 point score for player 3 and player 4 will work the same way.

1000 point relay score reel step up player 2 (resized).jpg

The circuit for the 1000 point score to move the 10,000 score reel is slightly different than for the 10s and 100s. There is no 10,000 point relay so this action triggered directly at the 10,000-90,000 score reel solenoid by the 1000 point relay switch 6/6 as shown in green below. If the 1000s score reel is on 9 then its 9th position switch will close to complete this path. We can see here that once again the pointers on the Player Up Unit Disc control this function in relation to the current player that is up. So when player 1 is playing the this circuit is completed as shown in green. It will move over to any other player that happens to be up by the position of the player up unit disc in the same manner as discussed above.

1000 point relay 10000 point relay (resized).jpg

(The following circuit follows the same logic as for the 10 point and 100 point relays). Switch 3/6 on the 1000 point relay is connected to the 1000 point Chime Solenoid. This will cause this solenoid to activate which will create the ringing sound of the 1000 point chime.

1000 point relay chime (resized).jpg

The 1000 point relay has a switch 4/6 which is use to trigger a hi score award if the exact score of the reels matches the hi score setting. The details of how the hi score award circuit works will be discussed later.

1000 point relay hi score switch (resized).jpg

So to review, causing a 1000-point action on the playfield will energize the 1000 point relay which will lock itself in so that it has enough time to perform 5 functions.
1. Add 1000 points to the score by stepping up the 1000s score reel.
2. Add 10,000 points to the score if the 1000s reel has gone from 9 back to 0.
3. Energize and lock in the ball index relay.
4. Ring the 1000 point chime.
5. Complete the hi score award circuit if the overall score matches.

All of these events can happen in the time it takes the 1000 point score reel solenoid to activate. So the lock-in timing is controlled by that solenoids EOS (End Of Stroke) switch. When that solenoid plunger reaches the end of its travel as it is moving the 10s score reel, the EOS switch will open as shown in red below for player 1. This will cut off the 1000 point relay lock-in switch 2/5 and the 1000 point relay will thus be deenergized. Of course this will happen according for whichever player is up, 1, 2, 3 of 4 since all of the EOS are lines up via a serial connection in that circuit.

1000 point relay off EOS (resized).jpg

MUSHROOM BUMPERS AND GATES

Note that in order to access the four 1000 point rollovers on the right side of the playfield, there are two gates that need to be opened. These are called the Lower Gate which will allow the ball access to the 2 lower rollovers and the Top Gate which will allow access to all 4. These gates work by connecting a wire to the armature of a standard G relay. When the relay is energized the armature will pull in and the connecting wire will then open the gate.

These gates are opened by hitting the mushroom bumpers with the ball. The lower mushroom button opens the lower gate and the top mushroom button opens the top gate.

This circuit shows both of the mushroom bumper circuits. Each mushroom bumper has two associated relays, for example the top gate mushroom button involves the Top Gate M-B Relay and the Top Gate Relay. This circuit is shown here.

The "Top Gate M-B" is the switch that is closed from its NO position when the ball strikes the bumper. This will immediately energize the top gate m-b relay. That means its switch 2/3 will then immediately energize the top gate relay. These circuits are shown in green. The top gate relay is the one with the connecting wire that actually opens the gate. The top gate m-b relay has a lock-in circuit that seems to be a bit odd. It has a typical-looking lock-in switch 1/3 which is then connected through NC switch 1/3 of the top gate relay. However, as we just saw, that top gate relay was energized by the top gate m-b relay. As soon as it becomes energized then its switch 1/3 will open from it NC position and will then deenergize the top gate m-b relay as shown in the second picture. So the top gate m-b relay is ready to be activated again if the ball hits the mushroom bumper, but it won't affect the top gate relay because it is now locked in and holding the gate open. It will stay that way until the ball ends which will be controlled by the outhole relay switch 4/8 opening when the ball ejects for the next shooter.

Here is the circuit just after the ball has struck the top gate mushroom bumper.

mushroom bumpers top gate initialize (resized).jpg

Here is the circuit shortly after, now the top gate relay is held in the energized position which in turn is keeping the gate open.

mushroom bumpers top gate lockin (resized).jpg

The circuits for the lower gate mushroom bumper will work in the same manner.

When the top or lower gates have been opened, the corresponding insert lamp will light up. This is activated by switch 3/3 on the top gate relay and lower gate relay. The circuit below shows the insert lights being lit since both gates have been opened.

gatelights (resized).jpg

GET THOSE ROULETTE NUMBERS, PLAYFIELD HOLES, EXTRA BALL

The main goal for scoring for the Monte Carlo is to get the roulette numbers. Of course it is only showing the idea of a roulette wheel as there are just 10 roulette numbers available to the player. For each of the 10 numbers that are collected during a ball in play there will be a 1000 point bonus when the ball drains. There is also an extra bonus of 5000 for getting all of the odds and an extra bonus of 5000 for getting all of the evens.

There are two ways to get the numbers. One is to roll the ball over the 10 rollover buttons at the top of the playfield, one for each number 1-10. The other is to land in the odds hole or the evens hole. Landing in either of these will get the corresponding odd or even number that is lit up in along the roulette wheel in the middle of the playfield. There are 10 more number lights there and they are lit up in odd-even pairs on a random basis, that is 1&2, 3&4, 5&6, 7&8, 9&10. These will rotate as "randomly" as the game plays, moving each time a 10-point score is hit or each time the ball lands in a hole. This is called the "Spot-Number Feature" in the game flyer.

monte carlo flyer back highlights (resized).jpg

As each number is achieved it will light up the panel on the lower part of the playfield, and the upper lights for that number will then go off. That way the player can keep track of the bonus as they go along with their ball in play.

Other game opportunities are:

• Extra ball by getting all evens lit and landing in evens hole
• Special by getting all evens and all odds and shooting through upper gate
• Play-More Post "holds ball a busy, dizzy captive on the score-studded playfield" as it says on the flyer.

We will go through the circuits for all of these features.

The 1-10 numbers are all controlled by trip relays and there are 10 corresponding trip relays, one for each number. A Trip Relay is a specific kind of relay that is different than the standard G type relay. These relays will become mechanically tripped when they receive their initial voltage and energize. This mechanical trip mechanism can only be undone by way of a rotation of the reset motor to which they are all attached. The reset motor has a set of cams that will push against the mechanical trip of each relay and thus reset them. In general once any trip relay in the machine has become tripped it will stay that way until the ball drains, at which point there will be a signal given to the reset motor to turn.

trip relay bank 1 (resized).jpg

We looked at this circuit section for the 1-10 trip relays earlier to see how they initiate a 10-point score. Here we will analyze all the elements of the circuit.

First we can see that we have a connection to the 50V branch that will complete any time any of the rollover buttons is closed. This is shown below in green for the #2 rollover button. When that switch closes the #2 trip relay will trip.

trip relays 1-10 button 2 trip (resized).jpg

Immediately after that relay is tripped, its MBB switch 3/5 will change positions as shown below. This completes a path to the 100 point relay so 100 points will be score each time that button is hit as described before. Also note that this switch also cuts of the #2 trip relay from getting voltage when the #2 button is closed. It doesn't matter once it has been tripped because it will stay in the same position whether it received voltage or not.

All of the other 1-10 buttons work in this same manner.

trip relays 2 tripped (resized).jpg

The game has an adjustment jones plug called the 1-10 Feature Adjustment which can be used to make the game easier for the player by giving 2-combos when a number is tripped. It is shown in the off position in the POGSUP schematic. The drawing below shows the plug moved over, and this connects 3 pairs of trip relays together as shown by the red lines in the plug. As an example, with the plug installed then when the #2 button is closed the circuit will now also energize and trip the #7 button as shown in the green path. You can follow the circuits and see that #4 and #9 are tied together and #6 and #1 are tied together with this adjustment plug.

trip relays 1-10 2-7 tied with plug (resized).jpg

Either the Odds Hole or the Evens Hole will also trip a number if it hasn't already been tripped. This is shown below in the green circuit where the odds hole relay switch 2/8 has closed from its NO position. When the score motor turns and hits cam 5 then the path will be completed through SCM 5C to trip the #1 trip relay in this case. The same would happen for the evens hole on the right side, in this case it would trip the #2 relay. The 00-90 unit disc as shown here will be stepping up and pointing to different pairs of numbers as the game goes on, so whichever pair it is pointing at will be the one tripped when the ball lands in the holes. The 00-90 disc rotates through the pairs like this: 1-2, 3-4, 5-6, 7-8, 9-10.

trip relays 1-10 odds hole (resized).jpg

The 1-10 trip relays each have a MBB switch in the 6V lighting circuit as shown below. When any number relay becomes tripped its MBB switch 5/5 will change position and this will turn off its rollover button light and will turn on the corresponding light in the bonus score section. This is shown below for the #2 trip relay which has changed positions due to being tripped. The circuit works the same for all of the other lights.

trip relays 1-10 lite switch (resized).jpg

Next we will look at the details of the odds and evens playfield holes. Each of these will actually cause a number of different things to happen when the ball lands in them.

ODDS HOLE

When the ball lands in the odds hole, this following will happen:

1. It will trip the odd number relay corresponding to the one that is shown on the roulette wheel if it has not already been tripped.
2. If all 5 odd numbers are not already lit 500 points will be scored; if all 5 odds numbers are already lit it will score 5000.
3. The flipper post will be raised.
4. The ball will be kicked out of the hole.
5. The 00-90 unit will be advanced one step to move those numbers in the middle of the playfield.

First we find the switch in the odds hole that is closed by the ball when it lands in the hole. This will complete a circuit that will energize the Odds Hole Relay as shown here in green. This will immediately close its lock-in switch 7/8 which will hold the odds hole relay energized through the blue path until score motor switch 10C opens. All of the action for the odds hole will occur in a single half-turn of the score motor, all before this lock in switch opens and shuts everything off at cam 10.

odds hole relay lockin (resized).jpg

We are getting smarter about how the score motor works, so we have a pretty good idea that cam 2 will be used to score the 500 points since it has 5 lobes on it. And it follows then that the odds hole relay needs to start the score motor going which it does with its switch 5/8 as shown in green below.

odds hole score motor (resized).jpg

We can find the circuit for the 500 points here in green. The odds hole relay switch 4/8 has closed from its NO position while the odds hole relay is energized as shown above, and this connects the 100 point relay to score motor switch 2B which will give 5 pulses to the 100 point relay thus scoring 500 points.

odds hole 500 (resized).jpg

The path to get 5000 points is fairly simple, in this case there is a MBB switch 4/7 on the All Odds Trip Relay which will change position and send the 5 pulses from score motor 2B over to the 1000 point relay instead of the 100 point relay.

odds hole 5000 (resized).jpg

That All Odds Trip relay is energized and tripped by this circuit which places a switch from all of the odd trip relays into a series line. The all odds relay won't trip until all 5 of the odd number relays have been tripped as shown with the red closed switches. The all odds switch 3/7 will now open from its NC position which basically just cuts off the all odds trip relay from any more voltage pulses until it is reset.

all odds trip (resized).jpg

This circuit shows how the all odds trip relay MBB switch 7 in the light circuit switches position when the all odds relay is tripped. This then lights up 5000 WHEN LIT insert light near the odds hole to tell the player they now will get 5000 points for landing in the hole. It also cuts off the 5 odds lights that are on the roulette wheel so none of these will light up as the 00-90 unit turns since all 5 odd numbers have already been tripped by the player.

all odds trip lite control (resized).jpg

As the score motor rotates to cam 6 switch 6B will energize the post latch coil through the odds hole relay switch 1/8 as shown here.

odds hole post latch coil (resized).jpg

The play-more post has an interesting circuit. When the post latch coil is energized the post will pop up, and in doing so the Down Post Solenoid End Of Stroke switch will close from its NO position. This switch will stay closed as long as the post is up. There are two buttons on the playfield, one on the left and one on the right, that will cause the post to pop back down when the ball rolls over them. In this circuit the left down post rollover button has been closed. This completes the circuit in green through the down post solenoid EOS switch which will then energize the Down Post Relay. This will cause its switch 2/2 to close from its NO position which will then energize the Post Down Solenoid which will then bring the post back down.

The post also has 2 light bulbs (although drawn as one here) that light up when the post is up, this is controlled by the post solenoid EOS switch also has shown on the far right.

down post (resized).jpg

When the score motor gets to cam 7 the Odds Hole Eject Solenoid will be energize by score motor switch 7C via the odds hole relay switch 8/8. This solenoid has an arm mechanism that will push the ball out of the hole.

odds hole ball eject (resized).jpg

When the score motor gets to cam 9 it will step up the 00-90 unit and change the number pair for the roulette wheel through the odds hole relay switch 6/8 as shown here. This particular circuit uses what I call a "leap of faith" diagram to show the circuit. There isn't a clean way to draw this particular circuit and get it to fit neatly into the schematic, so it is "connected" via a big gap with arrows and location instructions to find each end. This drawing shows a green line connecting the arrows to make it easier to visualize.

odds hole 00-90 step up (resized).jpg

EVENS HOLE

When the ball lands in the evens hole, this following will happen:

1. It will trip the even number relay corresponding to the one that is shown on the roulette wheel if it has not already been tripped.
2. If all 5 even numbers are not already lit 500 points will be scored; if all 5 evens numbers are already lit it will score 5000.
3. If all 5 even numbers are become lit then the Extra Ball feature is activated and the next time the ball lands in the evens hole the player will get an extra ball.
4. If all 5 odds are lit AND all 5 evens are lit (all 10 numbers lit) then the Special feature will be activated.
5. The ball will be kicked out of the hole.
6. The 00-90 unit will be advanced one step to move those numbers.

First we find the switch in the evens hole that is closed by the ball when it lands in the hole. This will complete a circuit that will energize the Evens Hole Relay as shown here in green. This will immediately close its lock-in switch 7/8 which will hold the odds hole relay energized through the blue path until score motor switch 10C opens. (same circuit logic as the odds hole)

evens hole relay lockin (resized).jpg

We are getting smarter about how the score motor works, so we have a pretty good idea that cam 2 will be used to score the 500 points since it has 5 lobes on it. And it follows then that the evens hole relay needs to start the score motor going which it does with its switch 5/8 as shown in green below. (same circuit logic as the odds hole)

evens hole 500 (resized).jpg

The path to get 5000 points is fairly simple, in this case there is a MBB switch 5/9 on the All Evens Trip Relay which will change position and send the 5 pulses from score motor 2B over to the 1000 point relay instead of the 100 point relay. (same circuit logic as the odds hole)

evens hole 5000 (resized).jpg

That All Evens Trip relay is energized and tripped by this circuit which places a switch from all of the even trip relays into a series line. The all evens relay won't trip until all 5 of the even number relays have been tripped as shown with the red closed switches. The all evens switch 4/9 will now open from its NC position which basically just cuts off the all evens trip relay from any more voltage pulses until it is reset. (same circuit logic as the odds hole)

all evens trip (resized).jpg

This circuit shows how the all odds trip relay MBB switch 8 in the light circuit switches position when the all evens relay is tripped. This then lights up an insert light near the evens hole to tell the player they now will get 5000 points for landing in the hole. It also cuts off the 5 evens lights that are on the roulette wheel so none of these will light up as the 00-90 unit turns since all 5 even numbers have already been tripped by the player.

all evens trip lite control (resized).jpg

A MBB switch 8/9 on the all evens trip relay will light up the Evens Hole Extra Ball When Lit insert light to tell the player that the next time they land in the evens hole they will when an extra ball. This is the same circuit that is used to switch the evens hole from 500 to 5000 points when the all evens relay is tripped, except you also need the extra ball relay switch 3/4 to be closed as well to complete the circuit here for the extra ball light.

extra ball ready light (resized).jpg

If all of the 5 even numbers have been tripped and the ball lands in the evens hole, as the score motor rotates to cam 3 the SCM 3C will energize the Extra Ball Relay now that the evens hole relay switch 1/8 is closed AND the all evens trip relay 1/9 is closed. The extra ball relay will be locked-in by the Outhole Relay switch 3/8, so it won't release until the end of the ball. The extra ball relay switch 2/4 is used to turn on the Shoot Again (extra ball) lights on both the playfield and the the backglass as shown in the circuit below, to tell the player that they have won an extra ball.

all even extra ball (resized).jpg

extra ball lights (resized).jpg

The details about how the extra ball logic works when the ball is drained will be covered later.

When the score motor gets to cam 7 the Odds Hole Eject Solenoid will be energize by score motor switch 7C via the odds hole relay switch 8/8. This solenoid has an arm mechanism that will push the ball out of the hole. (same circuit logic as the odds hole)

evens hole ball eject (resized).jpg

When the score motor gets to cam 9 it will step up the 00-90 unit and change the number pair for the roulette wheel through the evens hole relay switch 6/8 as shown here. This particular circuit again uses what I call a "leap of faith" diagram to show the circuit. There isn't a clean way to draw this particular circuit and get it to fit neatly into the schematic, so it is "connected" via a big gap with arrows and location instructions to find each end. This drawing shows a green line connecting the arrows to make it easier to visualize.

evens hole 00-90 step up (resized).jpg

SPECIAL, 100,000 POINTS, HIGH SCORE AWARD

If all of the numbers have been tripped, then both the ALL ODDS and ALL EVENS trip relays will be tripped. This will then activate the Special feature.

Revisiting the lighting circuit we can see than both the all evens and all odds trip relays are now tripped because all 10 numbers have been collected. The same as before this will cause their MBB switches to cut off the roulette wheel numbers and show the 5000 When Lit inset lights for the evens and odds holes (shown in yellow). With both trip relays tripped now the all evens trip relay switch 9/9 combines with the all odds MBB switch to complete the green circuit which lights up the top gate Special When Lit red insert light, telling the player they will win the special if they can get the ball into the top gate.

special when lit light (resized).jpg

The special can only be won by shooting the ball through the top gate where it will hit the first 1000 rollover switch. The top gate might be already open if the player previously hit the top mushroom bumper, or it might be still closed if they have not hit that bumper yet. To help the player along the top gate will automatically open once the special is activated. This is done with switch 1/7 on the all odds trip relay combined in series with switch 2/9 of the all evens trip relay as shown below.

special top gate opened (resized).jpg

This circuit shows how both the all odds and all evens trip relay have now-closed NO switch in series with the top right rollover switch, so as soon as the ball rolls over that switch the special will be one as shown by the green path.

In this case the jones plug for the Hi Score Feature has been set to the Credit position, thus this circuit completes a path to the Credit Unit Step-Up Solenoid which will energize and add a credit.

Interestingly this circuit does not have any way to unlock the special offer after it has been achieved. Like all trip relays they do not become untripped until the reset motor turns, and there is nothing in this circuit that will engage the reset motor. It wouldn't make sense to do this anyway because if the reset motor were started it would also untrip all of the 10 numbers the players have achieved and they would lose their bonus countdown at the end of the ball. This means if you can keep shooting the ball into the upper gate before you drain it you can keep winning specials and adding credits.

special add credit (resized).jpg

If the jones plug is set to Extra Ball instead of credit then this circuit will be completed, which will award the player the extra ball the same way as winning it via the evens hole when all 5 evens are tripped. Note that there is not the weak point here as in the credit circuit because the player can only activate the extra ball (or same player shoots again) function one time.

special extra ball (resized).jpg

Like most Ballys of this era the game has a 100,000 light that effectively takes the highest displayed score from 99,990 to 199,990. This is an easy circuit to see below even though it is connected by one of those schematic leaps (yellow arrow). Each player has a 100,000 relay which is actually a Trip/Latch relay the same as the Game Over relay. In the latched position (which it was automatically put into during the startup procedure) the 100,000 is off. The 100,000 relay gets tripped when the 10,000 reels goes from the 9 position (90,000) to the 0 position. This is triggered by a NO switch called the 10,000-90,000 Score Reel Unit 9th position which will close at this point therefore completing the circuit and tripping the 100,000 relay. The circuit is shown tripped for player one and all 4 players get a similar circuit that works the same.

You will notes that each 100,000 relay has a "reverse lock-in" switch 1/4 which will immediately open after the relay is tripped. This cuts of the relay from receiving voltage again if the machine is completely rolled over again. It is common to see this on trip relays although since the relay is already mechanically tripped it is not going to change its condition until it is mechanically untripped (or latched), so applying a voltage again wouldn't do anything anyway.

100000 trip player 1 (resized).jpg

A switch 4/4 on the 100,000 relay will close when tripped and this will turn on the 100,000 light in the backglass as shown here.

100000 lit player 1 (resized).jpg

As is common the Monte Carlo has a high score feature that will award a special if a certain score is reached. It is also possible for the owner/operator of the machine to set this high score where they wish via an adjustment plug in the backbox. This is shown in the circuit below.

In this case we can have a look at the sign for the score adjustment (stapled in the backbox near the plug) to get some clues about how this circuit works. There are 8 different-colored wires with plugs on the end hanging in there to pick from. So you would select the color wire for the 10,000 range you want to work with. For example, pick the black wire to set the high score in the range between 71,000 and 80,000. Then you push that plug into the 1000 point value you want, so put the black wire into the 5000 socket to make the high score 75.000 (as described in the example).

high score adjs plug (resized).jpg

The schematic below shows the black wire plugged into the 5 position so we have the 75,000 points high score setting. When the 1000's relay is closed at the point where 75,000 is achieved then everything in the green circuit will line up to energize the credit unit step-up solenoid and award a credit. There is a Unit Disc on the 10,000 score reel that shows its position as the score reel rotates, so the black wire is connected to the 7th position or 70,000 points. There is a similar unit disc on the 1000 score reel as shown on the right and the black wire is plugged in to connect to position 5 or 5,000 points. When these line up at 7,000 the circuit is completed and the high score is awarded.

It should be easy to see that the player up unit disc will move over for whichever player is up and the same circuit will score. There are also switches from the 100,000 point relays for the Blue wire (101,000 to 110,000) and the Green wire (111,000 to 120,000), these force the score to go over 100,000 before the circuit can be completed.

Also note that if the high score adjustment plug in placed in the Extra Ball position the player will be awarded with an extra ball instead of a credit. This circuit works the same way as previously described for the Special.

high score won (resized).jpg

TILT, POP BUMPERS, FLIPPERS

There are two different Tilt functions for this machine, as is typical, "slam tilts" and "tilts".

Slam Tilt

There are switches mounted in various places on the machine that are set up in such a way that they will close if the machine is heavily mishandled. The number of slam tilt switches can vary from machine to machine at the discretion of the original buyer. This Monte Carlo has 2 slam switches, one mounted on the coin door (labeled "Front Door Slam in schematic") which will activate upon heavy pounding of the coin door and one on the bottom of the cabinet (labeled "Kick Off") which will activate if the machine is heavily manhandled, for example by picking it up and slamming it down it. These switches are wired in parallel so that if either of them closes the Delay Relay will energize. When the Delay Relay energized it will lock itself on through its own switch 1/2. The lock-in also passes through an incandescent bulb. This is a #455 blinker bulb. For a brief time the Delay Relay will stay locked in through this bulb, but as soon as the bulb blinks it will open the circuit, cutting of the lock-in switch and then the Delay Relay will be deenergized again.

The circuit below shows the front door slam switch being closed which energizes the delay relay by the green path, then it locks itself in via the blue path. The 455 bulb will light for about 15 seconds then go off. When it goes off it becomes open to the circuit so the lock-in is broken and the delay relay deenergizes.

delay relay (resized).jpg

There is one other switch 2/2 on the Delay Relay. It is NC so it opens when the Delay Relay is energized. This cuts off the voltage to the entire 50V supply for the machine. The entire machine goes dead and all of the lights are off. The left flipper and credit functions are disabled, and also if a game has been started the power to the Lock Relay will be cut off. This means it's switch 1/4 will go back to its default NC state and the Game Over Relay will be tripped, ending the game.

After the short time of the delay the machine can be restarted but it will require another coin or credit. It doesn't matter if multiple players have been loaded and started, this misuse of the machine will completely end the game for all players.

delay relay 2 (resized).jpg

The Tilt Relay is a trip relay located on the trip reset motor.

There are 3 methods of getting a tilt during game play. There is the Plumb Tilt which will sway as the machine is nudged and eventually make contact and close with excessive nudging, the Ball Tilt which will close if the front of the machine is picked up causing the ball to roll back, and the Panel Tilt which is a switch mounted on the bottom of the playfield to prevent excessive pounding on the playfield. These are wired in parallel so that if any of these switches is closed the Tilt Trip Relay will energize.

tilt trip relay (resized).jpg

The tilt trip relay has 5 switches that will change state when it is tripped.

Switch 1/5 shown here will close and cause the down post relay to energize if it is in the up position through its EOS switch, thus lowering the post back down.

tilt down post (resized).jpg

Switch 2/5 will open and cut off voltage to the extra ball relay just to make sure the player doesn't get an extra ball after they have tilted the machine. Switch 3/5 will open and cut off power to the playfield features, rendering pop bumpers, kickers, etc dead. These are shown below in yellow.

tilt extra ball and playfield (resized).jpg

Switch 4/5 will close and when the ball lands in the outhole after the game has been tilted it will energize the outhole sequence as usual. This switch ensures that the game will step up to the next ball (or the next player), so the penalty for tilting is just loss of the ball for the player who did the tilt.

tilt next ball (resized).jpg

Switch 5/5 is a MBB switch that changes it state in the lighting circuit which lights up the TILT display in the backglass thus notifying the player of their transgression.

tilt light (resized).jpg

After the ball is drained and the next player is brought into play, the reset motor will also have been turned which resets the trip relay back to the untripped position, reversing these 5 switches.

The circuits for the 3 pop bumpers, the 2 sling shot solenoids, and the 2 flippers are shown here. There isn't too much to analyze here as these are simple and straightforward and work the same as in any pinball machine.

The pop bumper solenoids, or thumper bumpers as Bally calls them, are energized by a switch which is close when the ball bumps into the bumper, causing the bumper to activate. We already covered previously how its switches will then cause the correct scoring event.

The sling shots are just energetic solenoids that are energized when the ball hits the lower apron plastics rubbers and closes the switches which are then connected to these sling shots that will give the ball a healthy kick outward.

The flippers work in the same manner as virtually all pinball machines with flippers and there are many good tutorials available that describe how they work. Each flipper has a switch behind the button that energizes the corresponding flipper solenoid. Initially there will be a high power burst of energy to the flipper via the top coil (yellow circuit), then when the flipper extends outward its End Of Stroke (EOS) switch will open, and this will allow the path through the lower-power coil. This allows the player to hold the flipper button down and not burn up the flipper coil.

flippers pops kickers (resized).jpg

Up to this point we have covered the parts in the schematic highlighted in yellow.

Monte-Carlo-Schematic highlights 8 tilt pops flippers (resized).jpg

BALL DRAIN - YOU TOTALLY MISSED EVERYTHING

If the ball is launched onto the playfield and not a single point is scored as it goes all the way down and drains in the middle, then the machine will actually have some mercy. The ball will be kicked back to the shooter and the ball in play will continue, giving the player another chance after their feeble attempt.

When the ball lands in the outhole it will close the outhole switch, and as shown below in the green circuit this will energized the outhole relay which then locks itself in via its switch 2/8 until score motor switch 8D opens. When the outhole relay energizes its NO switch 5/7 will close which will tell the score motor to make a turn as shown on the right part. When the score motor gets to the #8 cam the outhole relay will lose its lock-in and therefore switch 5/7 will open back up, so the score motor will not turn again, it will just make one half-turn.

ball drain no score 1 (resized).jpg

The part that saves the player and lets them shoot again is shown here. The Ball Index Relay is the savior here. Recalling back to our analysis of scoring events, we remember that the ball index relay becomes closed as soon as any scoring event happens, whether it is 10, 100, or 1000 points. Since this attempt did not produce any scoring, then the ball index relay stays unenergized and the switch 3/3 shown below stays in its NO position. This cuts off the circuit that normally moves the machine to the next ball (which we will be studying in detail later), so the machine stays on the same ball and the player gets another chance.

ball drain no score 2 (resized).jpg

BALL DRAIN - BONUS COLLECTION

The first thing that happens when a more typical ball drains is that the bonus is awarded to the player. With this 4-player machine there is no bonus carryover from ball to ball, so after every ball the player receives whatever bonus they have accrued during their ball in play.

To review what we covered before, the bonus is awarded according to the numbers 1-10 the player has hit and lit during the ball in play. The bonus has several scoring possibilities with a total of up to 20,000 points depending on which numbers are lit in the bonus 1-10 lights near the bottom of the playfield:
• 1000 points for each number 1 thru 10
• If all odd numbers are lit, 1-3-5-7-9, then 5000 points more
• If all even numbers are lit, 2-4-6-8-10, then 5000 points more

There is quite a collection of relays that are used to make this circuit work. Besides the All Odds and All Even trip relays we have already seen we have a Odds Super Bonus trip relay, Evens Super Bonus trip relay, Bonus 6-10 Trip relay, End Super Bonus relay, Bonus Control relay, and Bonus Score relay. These 8 relays all work together with the score motor to get all of the bonus countdowns to work just right. This is such a convoluted circuit I don't know how on earth someone sat down and drew the whole thing out to begin with, but it does do the job. It actually makes sense in the end once you figure it all out. Sort of.

This type of analysis benefits from some observations of the machine in action before starting to tackle the schematic. By setting the machine up for different scenarios (most easily done with the glass off) we can observe that there are these different possibilities, and also, we can observe the number of score motor turns for each possibility. For each of these scenarios the ball is kicked into the shooter lane toward the end of the last score motor rotation.

1. None of the 1-10 numbers are lit, no points are scored and there is 1 score motor rotation
2. Any of the numbers 1-5 (or all 5 of them) are lit but none of the 6-10 numbers are lit, 1000 is scored for each lit number; 2 score motor rotations.
3. Any of the numbers 6-10 are lit (or all 5 of them) but none of the 1-5 numbers are lit, 1000 is scored for each lit number; 3 score motor rotations
4. Any numbers in the 1-5 group AND in the 6-10 are lit, but NOT all of the odds or all of the evens, 1000 scored for each lit number; 3 score motor rotations (acts the same as #3).
5. All of the odds numbers are lit, there can be some evens lit as well but not all evens, 1000 scored for each lit number then 5000 more points scored, 4 score motor rotations.
6. All of the even numbers are lit, there can be some odds lit as well but not all odds, 1000 score for each lit number then 5000 more points scored, 5 score motor rotations.
7. All 10 numbers lit, thus all odds and all evens, 1000 scored for each lit number then 10,000 more points score for a total of 20,000, 5 score motor rotations.

We can now start with the simplest scenario and work our way up to the finale of the super bonus.

#1 no 1-10 points relays tripped.

This is not the same as the no-score ball drain previously discussed. In this case the player did score some points by hitting other playfield items like rebounds or bumpers, but none of the numbers 1-10 were lit. This situation is basically a "no-bonus" scenario so there will be no bonus score are all. As soon as the ball drains it will kick out.

When the ball lands in the outhole, it closes the outhole switch which activates this circuit that we have actually seen before already. The Outhole relay becomes energized through a switch on the Bonus Control relay (green circuit on the left), then it locks itself in via its switch 2/8 and NC score motor switch 8D (blue circuit in the middle). Another outhole relay switch will close and start the score motor (not shown here) and the outhole kicker solenoid will kick the ball into the shooter lane when score motor switch 7C closes (green circuit on the right). Shortly after that score motor switch 8D will open back up and this removes the lock-in for the outhole relay, deenergizing it back to its normal position.

This is the standard ball kickout procedure that will occur in the last score motor turn for all of the bonus countdown scenarios. Here, since there is no bonus, there is just one score motor rotation and this is all that happens.

outhole kicker startup (resized).jpg

Here is a score motor timing diagram showing the sequence of events for this scenario.

bonus 1 score motor (resized).jpg

#2 any of 1-5 tripped.

In the green circuit in the middle below only #3 is shown tripped, but the circuit will work the same if any of them or lit, or even all of them 1-5 since they are wired in parallel in this circuit. Any of these will energize the Bonus Control relay through the NC switch 1/8 of the Bonus 6-10 Trip relay as shown in green. Looking back over to the left we can see that this also causes Bonus Control relay MBB switch 2/4 to switch from one side to the other. This cuts off the outhole circuit, so this is why the ball sits in the outhole and is not kicked out until the bonus award is done. Now the circuit is diverted to the Bonus Score relay which is energized as soon as the ball lands in the outhole, and then becomes immediately locked in by its switch 1/4 and also switch 1/4 on the Bonus Control relay in series.

Looking to the right part of the circuit we see that switch 2/4 on the bonus score relay will now be closed so it will energize the Bonus 6-10 Trip Relay, but not until the score motor switch 10A closes towards the end of the score motor rotation.

bonus collect option 2 (resized).jpg

The Bonus Score relay will have the job of keeping the score motor running any time it is closed which is required to get all of the tasks done using the score motor cams. This is shown below in green.

bonus score relay score motor (resized).jpg

The Bonus Score relay now has a switch 3/4 that will close from its NO position and will allow the 1000 point relay to be energized through the #3 trip relay switch in series with a MBB switch on the Bonus 6-10 Trip relay and score motor switch 5D which will close the circuit and score the 1000 points.

bonus 1000 scoring option 2 (resized).jpg

In fact now we can see on this circuit how 1000 points will be scored during the first turn of the score motor for any of the trip relays 1-5 that are tripped. They are score in a nice order of the score motor cams using switches on cams 3, 4, 5, 6, and 7 in succession to score up to 5000 points if all 5 are tripped. This will shown in the score motor timing diagram.

After the score motor has gone through positions 3-7 and added 1000 points for each of the numbers 1-5 that have been tripped it will then reach position 10 which as we saw will energize the Bonus 6-10 relay. Looking back at our circuit we can see that this will immediately open switch 1/8 on the Bonus 6-10 relay which cuts off the 1-5 trip relays. Now there is nothing to keep the Bonus Control relay energized because the only thing that could do that would be if any numbers 6-10 were tripped which they are not in this example. This is shown in red.

This also means that the MBB switch 2/4 on the Bonus Control relay will go back to its normal state which now connects the Outhole relay to the Outhole switch that the ball is sitting on. Now control is back to the Outhole relay for the second score motor turn and it will work the same way as Option #1. This is shown in green. This will then finish the bonus scoring.

bonus collect option 2 finish (resized).jpg

Here is the timing diagram for the 2 score motor turns that control option 2.

bonus 2 score motor (resized).jpg

#3 Any of the numbers 6-10 are tripped, or all of them, but none of 1-5 are tripped

This scenario is similar to the previous scenario in some ways. We do observe that even though there are no numbers in the 1-5 range to account for this time, the score motor does make an extra turn (for 3 turns total) for the numbers 6-10. Let's figure out why.

The start is very similar to the last scenario. In the drawing below there is a similar arrangement, the difference being that here only #8 has been tripped and none of the numbers 1-5 are tripped. The #8 tripped relay also keeps the bonus control relay energized as shown green in the middle, which is necessary to keep the score motor going for the third turn that is required this time. This in turn energizes the bonus score relay which then locks itself in, same as before as shown on the left. So in the first turn of the score motor, there will be an exact repeat of the circuit described above for the #2 scenario. However, since there are no numbers 1-5 tripped, nothing will happen, that is, there will be no points added as the score motor turns.

When the score motor gets to the #10 cam it will switch 10A will close, also the same as before, and this will energize the bonus 6-10 trip relay.

bonus collect option 3 (resized).jpg

In the same way as the option 2 circuit the Bonus Score relay has a switch 3/4 in this circuit. But this time the bonus 6-10 trip relay has been tripped. This causes 5 of its MBB switches, one for each pair of numbers, to switch from one position to the other and shown in red. Now the numbers 6-10 can score 1000 points each if they are tripped, such as shown for #8 here.

bonus 1000 scoring option 3 (resized).jpg

After the score moves through cams 3-4-5-6-7 which are used to score the 1000 points for the even numbers it will then hit cam 9. This time around this will cause the Odds Super Bonus trip relay to trip as shown below, because now the bonus 6-10 trip relay switch 3/8 is closed since it is tripped. So when score motor switch 9A closes and the odds super bonus relay trips its switch 1/4 will open from its NC position. This cuts off the voltage to the bonus control relay which then means the control will pass back to the outhole relay and the ball will eject on the next score motor turn. This is the same ending as described in option 2.

bonus collect option 3 finish (resized).jpg

After analyzing this circuit for option #3 we can now see that the behavior is exactly the same for option #4 where there are some even numbers mixed in with some odd numbers. In fact, this sequence will take place for any combination of odd and even numbers as long as all 5 odds or all 5 evens are NOT tripped. The timing of all of the events is shown below.

bonus 3-4 score motor (resized).jpg

#5 All odds are tripped, and also some evens can be tripped but not all evens.

If all of the odd numbers are tripped that means there needs to be an additional 5000 points bonus awarded. The machine will proceed through 2 score motor turns and do everything the same as described above for options 3&4, scoring 1000 points each for whatever numbers have been tripped. The difference this time is that since all 5 odd numbers tripped, they will trip the All Odds relay as shown on the far right below in green, since they are all in series with each other. This then closes the NO switch 2/7 on the all odds trip relay as shown in the middle. This will "keep alive" the connection to the bonus control relay so that the score motor will give another turn for the next step.

bonus collect option 5 (resized).jpg

Here is what the circuit connected to the 1000 point relay looks like for the 3rd score motor rotation. The 1000 point scores for the tripped numbers have already occurred in the first 2 score motor turns, the same as before. Once the odds super bonus relay is tripped its MBB switch 4/4 switches positions as shown, cutting of the circuit for the individual numbers and connecting the 1000 point relay to score motor switch 2C which will give it 5 pulses for 5000 points. This is done through the now closed switch 5/7 on the all odds trip relay as shown below in green.

bonus 5000 all odds (resized).jpg

After the 5000 points has been scored the score motor will rotate to the #8 cam and this will next cause the Evens Super Bonus trip relay to trip as shown here, this is because the odds super bonus trip relay switch 2/4 is now closed. This is shown in green on the right. This in turn will cause the even super bonus relay switch 1/4 to open from its NC state and therefore once again the circuit to the bonus control relay will be cut off and control will switch to the outhole relay for the 4th and last score motor turn in the same manner as in the previous options.

bonus collect option 5 finish (resized).jpg

Below is the score motor sequence for this option with 4 score motor turns. The same pattern that we reviewed before is repeated and expanded upon for each additional bonus item. The first turn is used to add 1000 for whichever of the numbers 1-5 are tripped, the second turn adds 1000 for 6-10, and the third turn adds the 5000 points if all odd numbers are tripped. The 4th turn stops the bonus countdowns and returns the ball to the shooter lane, this will always happen on the last turn.

bonus 5 score motor (resized).jpg

Option 6 All evens but not all odds are tripped

If all of the even numbers are tripped then there needs to be an additional 5000 points scored for that bonus. In this case the machine will proceed through the first 3 score motor turns and do everything the same as the previous description for the all odds bonus. However this time there will be no bonus points scored during the 3rd score motor turn. This is because the 1000 point relay is cut off from the score motor 2B switch due to the all odds trip relay 5/7 being in its NO position. So there will be an "empty" score motor turn for the 3rd score motor turn.

Then in the 4th score motor turn the 5000 points will be awarded for the all evens bonus.

For this 4th score motor rotation now the all evens trip relay switch 3/9 will keep the bonus control relay energized so it will then trigger the score motor for the 4th term, similar to the previous circuits. This is shown in the circuit below.

bonus collect option 6 (resized).jpg

The 5000 points for the all evens bonus is in the same circuit as the all odds 5000 bonus, the only difference is that this time the evens super bonus MBB switch 4/4 changes position to allow the 5 pulses from score motor 2C to pass to the 1000 point relay as shown below in green.

bonus 5000 all evens (resized).jpg

After the first 4 score rotations have scored the points, then it will proceed to the 5th and last rotation to kick the ball from the outhole in the same manner as before.

Here is the 5-turn score motor timing diagram for option 6, all evens tripped , some odds can be tripped but not all odds.

bonus 6 score motor (resized).jpg

Option 7 all odds and all evens bonus

The final option is the super bonus where all 10 numbers have been tripped so the player will receive 1000 for each of the 10 tripped relays plus 5000 for all odds and 5000 for all evens for a total of 20,000 points.

All of the actions for this scenario work exactly the same as option 6 described above. The only difference is that this time the all odds relay will be tripped along with the all evens relay so the 5000 points for the all odds will happen in the 3rd score motor turn as usual, then the 5000 for the all evens will happen in the 4th score motor the same as above.

In the case of either option 6 or 7, the bonus scoring will finally be stopped by the circuit below. This is the job of the End Super Bonus relay which became locked in via its switch 2/2 by way of the all evens trip relay. After the all evens bonus of 5000 is score by 5 pulses from score motor cam #2 it will be followed by cam 5 which will energize the end super bonus relay via score motor switch 5B. This then will open its NV switch 1/3 which will cut off the bonus control relay and allow the outhole relay to take over for the last score motor turn.

bonus collect option 6 and 7 finish (resized).jpg

And the option 7 grand finale, the full bonus timing diagram with all 10 numbers tripped.

bonus 7 score motor (resized).jpg

For any of these bonus collect scenarios once the last score motor turn has finished and the ball is kicked out, everything is done and the machine is ready for the next ball or the next player.

Up until this point we have now covered everything in the schematic highlighted in yellow. Getting close to the end!

Monte-Carlo-Schematic highlights 9 bonus (resized).jpg

If I get one some day, I'll do it! I'd like to see the differences between Bally and the other brands. Although for now my top interest for Williams is Firepower, and that one is SS not EM. Almost at the end here, I'll have the rest up as soon as I can, its all written.

BALL DRAIN - NEXT BALL OR NEXT PLAYER

The MC is a 4 player machine so this means there is extra circuitry compared to a single-player machine to handle the combination of the ball in play and the player up. In order to handle this logic, there are 2 additional stepper units in comparison to a single player machine.

Coin Unit: This is a 4 position step-up/reset stepper unit. It is used to set the total number of players for the game in play. This is set at the very beginning when the game is started, and then never moves again until it is reset at the start of the next game. So it has built-in circuitry that is used for 1 player, 2 players, 3 players, or 4 players as has been started. It advances to the correct player position each time the credit button is pressed as we covered back toward the beginning.

Player Up Unit. This also a 4 position unit for players 1-4 however this until will step up during game player as each player comes up to play, and reset back to player 1 after each ball has been finished for all registered players.

Also involved in this circuitry is another stepper which operates the same way as in a single player machine:

Ball Count Unit. The MC uses this to keep track of which ball is in play, and is also used to track the last ball so the game can be ended.

1 PLAYER SEQUENCE

Below is the circuit that controls the ball in play/player up combination each time the ball drains. As previously described the first thing that happens when the ball drains is that all of the bonus points are awarded for lighting the numbers 1-10. As soon as that is done the Outhole relay is energized and the ball is kicked into the shooter lane. The outhole relay is also the trigger for the ball in play and player up control functions by way of switch 6/7 in the which will now close from its NO position. We also know that the Ball Index relay is energized and locked-in which happens when any points are scored, so that means NO switch 3/3 is now closed. The circuit below is as shown in the POGSUP condition in the schematic which has the Coin Unit at position 1 (1 player). The Player Up Unit is also at position 1, and well as the Ball Count. This all makes sense as we have a 1 player game and we have just finished the first ball.

The first thing to happen is triggered by score motor switch 3B, early in the score motor rotation. It will close from its NO position, and this will complete a circuit that will energize the Ball Count Step Up Solenoid as shown in green. This means the ball in play will move from 1 to 2 (or up one position).

The Ball Count Unit has an EOS switch mounted on it so when it steps up this EOS will close. This will happen very quickly, almost immediately. Looking to the right at the blue circuit we see that this will energize the Player Reset relay which will the lock itself in via its lock-in switch 2/2 through score motor switch 1A. This will keep the Player Reset relay energized until he score motor rotates all the way to the rest position, at which point SCM 1A will open back to its NO position.

Because the Player Reset relay is energized its MBB switch 1/2 on the left will switch position as shown in the yellow circuit. This will prevent the Player Up Unit step-up solenoid from energizing through score motor switch 4B, which is what we want because we don't want the player up to advance for a one player game.

Also shown in the circuit below is switch 4/4 of the Extra Ball relay and it is pointed out that if this is open then the green circuit will be cut off and the ball count unit step-up solenoid won't be activated. That means it will stay on the same ball and the player can play again if they have won the extra ball award.

ball drain player 1 ball 1 (resized).jpg

The timing diagram is the same familiar one we looked at before in the bonus countdowns, its the last score motor rotation that kicks the ball out. In addition to that task from before, these ball in play and player up actions also take place during that same score motor rotation, so these are added in here to complete the picture.

ball drain player 1 ball 1 timing (resized).jpg

When the second ball drains in a 1 player game, everything will happen in the same way as before. The only difference in the circuit is that the Ball Count Unit has moved up one position from ball one to ball 1 as shown by the red arrow at the bottom of the picture. This same action will continue until the last ball in play (which will be either 3 or 5). The last ball will be covered later.

2 PLAYER SEQUENCE

Now let's suppose the game has been set for 2 players and player 1 has just drained their first ball. The difference from the previous circuit is that the Coin Unit is now set to the 2 position instead of 1. This changes the circuit and now the Ball Count Step-Up Solenoid is cut off from being able to complete its circuit as shown in red. This means the ball count won't advance (it stays on ball 1). It also means that the Player Reset relay won't get energized because the Ball Count Step-Up Solenoids EOS switch never activates. This in turn means that the Player Reset MBB switch 1/2 stays in its normal position. This then allows the green circuit to complete through score motor switch 4B which energizes the Player Up Unit Step-Up Solenoid, and this will move the Player Up unit from player 1 to player 2. This is exactly what is needed when player 1 drains their ball - it should stay on ball 1 but advance to player 2.

ball drain 2p player 1 ball 1 (resized).jpg
ball drain 2p player 1 ball 1 timing (resized).jpg

The circuit below shown the events when player 2 finishes ball 1. Now that the Player Up Unit is sitting on position 2 there the green circuit will be completed through score motor switch 3B and the ball count unit will step up to ball 2. The ball count unit step up EOS will lock in the player reset relay as before and its MBB switch 1/3 will change position. This in turn will complete the orange circuit which will energize the player up reset solenoid. This will drive the player up unit back to its reset position or player 1. That means we are now ready to play player 1, ball 2.

If you are sharp you will observe from the player 1 circuit that the yellow circuit that energizes the player up reset solenoid is activated also in a 1 player game where it really isn't needed since it will always be on player 1.This indeed does happen which can be confirmed by observation. No harm is done and nothing is changed when the player up reset solenoid activates when it is already in the reset (player 1) state. This is done this way for convenience and simplicity, that way another special circuit doesn't need to be designed to stop that action from occurring when it is not really needed.

ball drain 2p player 2 ball 1 (resized).jpg
ball drain 2p player 2 ball 1 timing (resized).jpg

If you observe the circuit above you should be able to see how the system will control the ball in play and player up for a 3 player game as well. It is all the same logic except now the coin disc will be set to position 3.

When a 4 player game is set the circuit changes a bit as the 4 position on the coin unit disc is bypassed and the ball count step-up is connected directly to the player up unit disc where it will work for the player 4 ball advance as shown below. There is no control logic reason to do it this way that I can think of as it would work exactly the same way if there were a connection between the coin unit disc and the player up unit disc similar to players 2 and 3, so i presume it is done to make things simpler. The same idea applies to position1 on the coin unit which is wired directly to score motor switch 3B instead of through the player up unit disc position 1.

This is shown below for the ball advance circuit after player 4 has finished their first ball.

ball drain 4p player 4 ball 1 (resized).jpg

BALL DRAIN LAST BALL 5 BALL

Now we will look at the sequence of events that happens when the last ball drains. This will be the same regardless of how many players have been registered. That is, if it is a one player game then it will be player 1's last ball, if it is a 2 player game it will be player 2's last ball, and so on.

The last ball might be the 3rd or the 5th ball depending on the setting of the balls per game adjustment plug. It is shown in the POGSUP schematic as set up for 5 balls so first we will look at this setting. The jones plug settings are shown in orange below. That is, the 5th ball has just been played by the last player and has drained.

First, the bonus points will be awarded for that player in the same way as usual.

Then, the ball count unit will advance in the same way we have described before. This is shown in green in the circuit below. This should look familiar because it is the same as was reviewed in the last section. So since the current ball is ball #5 when the ball count unit step up solenoid energizes as before through score motor switch 3B the ball count unit disc will actually move to the ball #6 position. This now affects another circuit which is shown to the right in blue. Immediately as the ball count unit moves to the #6 position it completes the blue circuit, and this will trip the game over relay, putting the machine into the Game Over condition. This means that the game over relay switch 1/5 also shown here will open and this will cut off power to the playfield and most of the relays and solenoids. Since this happens immediately at the #3 position of the score motor, that means the outhole relay will become deenergized before the score motor gets to the #8 position and therefore the outhole kicker solenoid will not be energized since it needs a switch from the outhole relay in its path which will now be opened. This is how the ball stays inside the machine rather than being kicked out after the last ball.

As the score motor gets over to the #8 position its switch 8A will close and since the ball count is now set at 6 this will complete a circuit to advance the ball count unit once again, and it will move to the #7 position as shown by the dotted red arrow. This circuit is shown in yellow. So the ball count unit will actually advance 2 times during the last score motor rotation from 5 to 6 and then from 6 to 7, ending in the #7 position. This is done to cut off the match circuit after it has been applied (match circuit description is coming next).

ball drain last ball 5 ball (resized).jpg

The very last thing to happen is that a match credit is awarded if everything is lined up and the match number matches the final number on the 10s score reel. As shown in green below a credit will be added by energizing the credit unit step up solenoid if the credit unit has not been reached and if the numbers match and line up on the 00-90 unit disc (the match disc) and the 10-90 unit disc (the score real). In this case both of these are on 0 so there would be a match and the circuit would be completed. If the 00-90 unit were pointing at any number other than 0 here then it wouldn't line up with the 0 on the score reel and there would be no match. The match is triggered by the closure of score motor switch 4A so it will happen just after the ball count moves from 5 to 6 at the #3 score motor position from the circuit above.

match p1 5 ball (resized).jpg

This circuit is set up so that every registered player gets a chance to match, as determined by the position of the coin unit. You can see the sequence of match signals as the score motor rotates through the 4-7 positions. Switch 4A for player 1, switch 5A for player 2, switch 6A for player 3, and switch 7A for player 4. For example, if the game were set for 4 players then the coin unit would be set as shown below, and all 4 players would get the chance to match. As drawn here all 4 players happen to have ended their game with 0 on the 10s score real so all 4 would get a match credit as these 4 score motor switched close. This is possible, although not very likely.

match p4 5 ball (resized).jpg

BALL DRAIN LAST BALL 3 BALL

If the balls per game adjustment plug is set for 3 balls per game, then everything will happen in the same way, except of course it will happen 2 balls earlier. The circuit below shows how moving the adjustment plug from 5 balls to 3 balls changes the last ball count step-up to be 4 and 5 instead of 6 and 7 as happened for 5 ball.

The right part of the circuit with the connection to the game over relay most certainly has an error in the schematic as it is shown in the POGUSUP position. The wire that is connected to the ball count unit disc would need to be in the #4 position, one past the 3 ball limit, in the same manner that it is on #6 for the 5 ball setting. Otherwise the game would end when the ball count was switched from 2 to 3 after the second ball was changed.

ball drain last ball 3 ball (resized).jpg

The circuit below shows how the path is completed through the #4 position on the ball count unit disc when the game is set for 3 balls, it is the same as above for 4 players except for the position of the ball count unit disc.

It can also be noted here that the operator or owner of the game can set a jones plug for the Match Feature to the off position if desired. This would cut off the entire match circuit and prevent any credits from being added if there were a match.

match p4 3 ball (resized).jpg

This completes the circuit description, thank you for reading along and there will be a quiz on Monday.

Thank you to everyone who PMed me during the building of this thread with corrections and discussions.

I did draw it completely from scratch. For this project I used Adobe Animate, which was formerly known as Flash. Other possibilities to do it in vector format could be Microsoft Visio or LibreOffice Draw. I don't think I would attempt something of that scale in a bitmap format.

I use Flash for a number of reasons. First, I have been using it for many years so I am very familiar with it. It is known as an 2D animation tool which it does very well, but it is also an underrated vector drawing tool. Once you get the hang of it, you can work quickly in the vector environment. A key feature is the ability to draw something once, then save it to a library as an object. This is critical for any situation where you need to use the same object over and over. You can then just pull it from the library any time you need it and place it where you want. So that is great for drawing things like switches that are used over and over in one of these schematics.

All that said, I wouldn't recommend it unless it was something you were really interested in doing and really desire the end result. It is quite a bit of work, even if you are experienced. Once I started this one I couldn't stop of course, but man it took a long time to finish. These pinball schematics are full of quite a bit of information. The Flash file is quite large, and it has more than a dozen layers. You have to be organized and focused on the details to get it done right. I did do it in sections, and I tried to be as careful as could be as I went along, but even then I would come back to it and spot obvious errors I made. You can drive yourself crazy putting in all of those wire colors and switch numbers.

I recommend having a look at the redrawn Bally Wizard schematic which is uploaded at IPDB. That one is particularly nice IMO. I don't know who made that, or how they did it, but it would be interesting to know how that one was made. Particularly notable is that all of the wires are drawn in their actual colors. In theory it should be somewhat easy to do this in Flash/Animate as you should be able to one-click a line and change its color, but I haven't found an easy way to make the 2-color dashed lines and that is the main reason I didn't do it.

PS if anyone does have access to the latest version of Adobe Animate I can send the native FLA file if you want to see it. PM me an email address. The file is 22MB in size.