This article was originally posted on PinballRehab.com.
Reproduced with permission from terryb.
Written by terry
This is part five of a seven part series intended to provide a basic knowledge of electronics, test equipment, pinball manuals and troubleshooting in order to allow the reader to effectively repair pinball games. With that goal in mind I have simplified the explanations and purposely glossed over some details that add no value, and can easily confuse beginners.
The Operators/Service Manual can either be your best friend or worst nightmare. My purpose in this article is to explain the different types of information available and how to get the most out of them.
The example I will be using, Gilligan’s Island, has two manuals. The Operators Manual covers game specific information and the WPC Service Manual covers generic circuit board information (CPU board, Power Driver Board, etc.). On many machines you will find all information combined into one manual.
Operator Manuals can be found online at ipdb.org, just search for the name of your game. Schematics for many pinball systems (when they’re not included in the Operator’s Manual) are available at arcarc.xmission.com. Manuals can also be purchased from most online pinball parts suppliers.
The Operators Manuals includes a lot of information, like game rules and rubber ring info, that are not pertinent to troubleshooting problems and will be ignored for the purpose of this tutorial.
I have created an excerpted version of the Gilligan’s Island Operators Manual, available here, which will help you get the most out of this tutorial. I suggest you open the manual link and use it as a reference as we proceed.
[Editors note: On many computers, right-click to download the excepted version of the Gilligan’s Island Operators Manual.]
While the names may be slightly different, most manuals have the following three sections: Game Operation and Test Information, Game Parts Information, and Wiring Diagrams and Schematics (as mentioned above this last section may be split across two manuals).
The Game Operation and Test Information section includes general information on the game, including game adjustments and game diagnostics.
The Game Parts Information section typically includes a cabinet parts layout, backbox layout, board layout and parts list, playfield parts layout, sub-assembly diagrams and parts list, and location diagrams for solenoids, flashers, lamps and switches.
The Wiring Diagrams and Schematics section includes interconnect (wiring) diagrams, logic (or block) diagrams and schematics.
I have found very important tables (solenoid table, switch and lamp matrix, etc.) in any or all of these sections.
Depending on the game, the manual may also include information on adjustments, repairs and parts relating to game specific toys. For example, the Dracula manual has information on the magnet and long beam opto which is unique to that game.
Many manuals also provide logic states for test points in some circuits, for example the switch matrix or dedicated solenoid circuit. These are extremely helpful when troubleshooting to component level since identify what the test point should read when the solenoid, for example, is energized or not energized.
Page 2 provides an example of a Solenoid Table. If you’re having a solenoid or flasher problem (this page also provides flasher information since they use the solenoid drivers) this is typically where you’ll start. The table provides several important pieces of information: solenoid/flasher type, board connector and pin number, wire color of the switched circuit, driver transistor and part number of the solenoid/flasher.
In this example the table also includes information for the GI circuits. In some manuals this will be a separate table. Flipper information will also sometimes be included in the solenoid tables.
The solenoid type will be low or high power, and each one uses a different type of driver circuit (see Troubleshooting Driver Circuits). The connector and pin number information are for the relevant circuit board. The wire color is for the switched ground wire that runs from the solenoid to the circuit board. The transistor identifier references the specific driver transistor on the circuit board that controls this solenoid.
The solenoid/flasher number, which is displayed during diagnostic tests and on the Solenoid/Flasher Locations page, is also provided.
Note: Depending on the system you are working on the driver circuit can be on different boards. Use the board layout (typically in the Game Parts section) to quickly find the connector number and identify the circuit board. The backbox layout diagram will then help you identify where each board is located (see page 3).
This page and the appropriate board layout page (discussed later) will often provide all the information you need to troubleshoot a solenoid or flasher problem. If not you would next move on to the solenoid logic diagram and if necessary the board schematic.
Firstly, let’s talk about how a matrix circuit works (see page 4, and ignore the far left column for now). Note: All matrix circuits are pulsed circuits and are best tested with a logic analyzer.
Switches and lamps are controlled in a matrix configuration in order to reduce the number of driver circuits required from 64 to 16. This is achieved in the case of a switch matrix by sending a voltage down the column and monitoring the row. This is why the column is called the strobe, or send, side and the row is the return side.
The driver electronics sends a voltage down column 1 while monitoring the returns. If one, or more, of the switches are closed the corresponding row will read high. The voltage is then sent down column 2, column 3, etc. until all eight columns have been turned on and all rows have been checked eight times.
For example, if the Right Jet switch (column 4, row 2) is the only switch closed the following will happen. A pulse will be sent down column 1 and all of the returns will be monitored. No voltage will be sensed on any of the returns. This will continue until a pulse is sent down column 4. This time a voltage will be sensed on row 2 since the Right Jet switch is closed. The rest of the columns will continue to be pulsed, but with no other switches closed, no returns will be high.
Now that we know how a matrix works, let’s look at the information the table provides. The wire color, board connector and pin and the IC identifier are provided for each row and column. So for any switch we can move left across the row to get the return side info and up the column to get the send side info. The switch number, which is displayed during diagnostic tests and on the Switch Locations page, is also provided. See Switch Matrix Theory and Troubleshooting for more info.
You have probably noticed the far left column is slightly different. Some manuals will also have a column on the right, and neither are part of the matrix. (Yeah I know, they did that just to confuse everyone.) In both cases only the wire color is provided.
Again, this is often enough information, combined with the board layout page, to troubleshoot the problem. If not you would next move on to the switch matrix row and column logic diagram and if necessary the board schematic.
The good news is the lamp matrix is a lot simpler (see page 5) to understand. In this case the quantity of driver circuits is reduced by switching both the voltage and the ground side of the circuit. If row 3 is switched to ground and column 3 is switched high, the Left Bank Right lamp will turn on.
For each row and column the wire color, board connector and pin number, and transistor identifier are provided. The lamp number, which is displayed during diagnostic tests and on the Lamp Locations page, is also provided. Again, these are all pulsed circuits and best tested with a logic probe. See Lamp Matrix Theory and Troubleshooting for more info.
Again, this is often enough information, combined with the board layout page, to troubleshoot the problem. If not you would next move on to the lamp matrix row and column logic diagram and if necessary the board schematic.
The LED list provides information and location of the circuit board mounted LED’s that provide troubleshooting information (see page 6). For more information see the Troubleshooting Tutorial.
The fuse list provides information and location of the system fuses (see page 7). For more info see Troubleshooting Blown Fuses.
For each of the circuit boards there is a board layout page (see page 8). This page will typically be used for one of three purposes. First, as mentioned earlier, to locate board connectors. You can also use this page to physically locate components when troubleshooting (i.e. – U18 or F107 or Q86). The last is to get additional parts information once you have identified the failed component and need to purchase it.
Similar pages provide information on major mechanical assemblies.
There are also playfield layout diagrams displaying solenoid/flasher, switch and lamp locations and their identifier number (see pages 9, 10 and 11). The same number is used on the switch and lamp matrix and in diagnostic test mode.
Wiring diagrams provide interconnect information for specific circuits or in some cases entire areas like the playfield (see page 12 Flipper and Lane Change Circuit). This is a good place to start if you’re having a flipper problem since all of the pieces making up the flipper circuit will be shown. Some manuals do a better job than this example and provide wire color and connector and pin information.
Wiring diagrams are helpful when you suspect wiring problems or when you need to identify which board and circuit controls the component you are having problems with.
The lower half of page 12 is a block diagram of the same circuit. A block diagram is a combined and simplified (only the flipper circuit is displayed) version of the wiring diagram and the appropriate schematics. Again, some manuals do a much better job of providing complete information.
The block diagrams provide the best overview of a circuit (consider it a mile high view as compared to the schematics street level view). This is especially true when multiple boards are involved in a circuit. This is much easier than jumping between two or more schematics and typically getting confused in the process.
For beginners and intermediates the block, or logic, diagrams provide a simpler reference when troubleshooting a circuit, as compared to a schematic that can tend to get overwhelming. When the block diagrams have complete information (see the additional examples below) 90% of the time you can troubleshoot a problem without resorting to the schematics.
The schematics provide complete circuit information for each board and in the case of some boards like the CPU are spread over multiple pages. The schematics are typically used when the block diagram doesn’t provide enough information and you have identified the problem is on a circuit board.
Unfortunately the schematics will not always provide all of the information you need to unerstand some circuits. This is where IC datasheets come in.
For example, in the case of buffers the schematic is just going to show the IC package and pin numbers. This doesn’t help much when troubleshooting, but the datasheet will show the internal circuitry of the component and typically a logic chart showing the correlation between inputs and outputs.
I’ve provided some excerpts from the Dracula Operators Manual (click here to view) that provide better wire, connector and pin information than the Gilligan’s Island example. Page 2 is a Lamp Matrix Driver logic diagram, page 3 a Solenoid Wiring Diagram and page 4 is the Fliptronics II Flipper Circuit (actually a block diagram).
- The following is a great site that provides more in-depth electronic tutorials: All About Circuits.
- Randy Fromm’s YouTube Channel also has some great videos on basic electronics theory.
Comments, including general questions about electronics troubleshooting, suggestions, improvements, errors, etc. are welcome (see below).
If you have a specific question about your game, please see our FAQ section.