Gottlieb System 1

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1 Introduction

Gottlieb® System 1 Board Set

Of the big 4 pinball makers, Gottlieb® was slowest converting from EM to Solid State, producing EMs into 1979 while Bally, Stern, and Williams had all abandoned doing so in 1977 / early 1978. The reason why Gottlieb® manufactured EMs so much longer into the solid state era is primarily due to the demand for EMs in their French market.

In the mid-70's, Gottlieb® approached several companies to manufacture their solid state board set, including National Semiconductor and Rockwell International. The bid ultimately went to Rockwell, because they could supply the circuit boards, chips, and provide the equipment necessary to program the games' OS and game code.

The Gottlieb® System 1 boardset was designed to directly replace the EM logic from the earlier machines. The main differences between the solid state and EM version of a Gottlieb® title with the same layout is the resetting of drop targets during a ball in play, the maximum bonus multiplier values, and in some cases, specific scoring values. The EM games would not reset drop target banks during a specific ball in play; the bonus multiplier was limited to a double bonus only; and similar targets or switches had lower values in some instances. All of these differences are attributed to the scoring threshold of an EM. A Gottlieb® EM game was limited to 199,990, while a solid state game could record scores up to 999,990. Consequently, System 1 games play almost exactly like an EM, just with solid state scoring. The exception is Cleopatra, which is identical in all game and scoring aspects between the EM and solid state version.

The playfield layouts were solid EM-esque designs, with rock-solid Gottlieb® mechanical parts. Unfortunately, the electronics were not as robust in terms of longevity. Major problems were exhibited with connectors, battery corrosion issues, and today's unavailability of essential, proprietary system chips.

One of the biggest issues with the System 1 platform was that it had unreliable ground connections. Unlike the other popular manufacturers of the time, Gottlieb® relied solely on connectors and daisy-chained wiring to transport the ground lines from board to board. A large ground plane was used behind the boards, but the circuit boards' grounds were not physically secured to it. Gottlieb® instead opted to use plastic standoffs to elevate and secure the boards to the backbox. Thus, if a single ground connector failed in the chain, the logic ground could fail for one or several of the circuit boards. This could potentially lead to locked on coils, relays, and / or controlled lamps. In turn, transistors and chips would fail.

2 Games

Title	Date of Release	Production#	ROM	Sound	Notes
Cleopatra	11-1977	~7300	A or 409	Chimes	Also produced as a 4-player EM 'Cleopatra' and a 2-player EM 'Pyramid'
Sinbad	05-1978	12950	B	Chimes	Also produced as a 4-player EM 'Sinbad' and a 2-player EM 'Eye of the Tiger'
Joker Poker	08-1978	9280	C	Chimes	Also produced as a 4-player EM 'Joker Poker'
Close Encounters of the Third Kind	10-1978	9950	G	Chime board	Also produced as a 4-player EM 'Close Encounters of the Third Kind'
Dragon	10-1978	6550	D	Chime board	Also produced as a 4-player EM 'Dragon'
Charlie's Angels	11-1978	7950	H	Chime board	Also produced as a 4-player EM 'Charlie's Angels'
Solar Ride	02-1979	8800	E	Chime board	Also produced as a 4-player EM 'Solar Ride'
Count-Down	05-1979	9899	F	Chime board	Also produced as a 2-player EM 'Space Walk'
Pinball Pool	08-1979	7200	I	Chime board
Totem	10-1979	6643	J	Sound board J-SND ROM
The Incredible Hulk	10-1979	6150	K	Sound board K-SND ROM
Genie	11-1979	6800	L	Sound board L-SND ROM
Buck Rogers	01-1980	7410	N	Sound board N-SND ROM
Torch	02-1980	3880	P	Sound board P-SND ROM
Roller Disco	02-1980	2400	R	Sound board R-SND ROM
Asteroid Annie and the Aliens	12-1980	211	S	Sound board S-SND ROM	Only available as a single player game

The information in the above table was provided by www.IPDB.org. Click the link to view more detailed information and pictures on the IPDB of these Gottlieb® System 1 games.

Conversion kits for system 1 from other manufacturers:

• (circa 1982) Movie (Bell Games, 4p)
• (unknown date) Sky Warrior (IDI, 4p)
• (circa 1982) Tiger Woman (IDI, 4p)
• 1984 Sahara Love (Christian Automatic, 4p, production 150) [conversion of Sinbad]
• 1986 L'Heaxagone (Christian Automatic, 4p, production 150) [original playfield design]
• 1985 Jungle Queen (Pinball Shop, 4p) [playfield based on Gottlieb's® Jungle Queen]

Conversion kit info provided by www.IPDB.org. Click the link to view more detailed information and pictures on the IPDB of these System 1 conversion games.

2.1 Physical Dimensions

Below are the physical dimensions of a Gottlieb® System 1 pinball machine. These dimensions apply to all of the System 1 games, excluding Asteroid Annie and the Aliens. The difference between Asteroid Annie and all other System 1 games is the backbox. The backbox used with Asteroid Annie, which does not have a flat top or hinged access door, is the same as the early System 80 games, such as Spider-Man, Panthera, and Counterforce.

• Gottlieb® System 1 Pinball Machine Physical Dimensions
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3 Technical Info

3.1 The System 1 Board Set

Clicking the link above will direct to a new page showing all of the System 1 boards.

3.2 Recommended Documentation

Although it is not completely necessary to fix a System 1 pinball machine, having a game specific manual can be extremely helpful, and is recommended. The game manual includes detailed information such as:

• Lamp assignments and location
• Switch assignments and location
• Coil assignments
• Game rules including 3 / 5 ball game rule differences
• Playfield parts list including a rubber ring list and locator
• Game specific wiring connections, lamp, and coil diagrams

The first three System 1 game manuals, (Cleopatra, Sinbad, and Joker Poker), include all of the above information, plus circuit board schematics for all circuit boards, except the tone board. Starting with Close Encounters, Gottlieb® minimized the amount of information in the game manuals. Game specific material is included, however, circuit board schematics are not. The Solid State Pinball Games Service Manual (red cover) served as a generic, supplemental manual, which complimented the game manuals. The 2nd edition service manual with the black and blue cover shown below is a revised supplemental manual. The information and scope is more extensive than the first edition (red cover) manual.

Please note that game specific connector wiring is not always game specific for the first three game manuals.

Gottlieb® Solid State Pinball Games Service Manual - 2nd Edition

If you intend to work on System 1 games on a consistent basis, a highly recommended manual to possess is the Gottlieb® Solid State Pinball Games Service Manual - 2nd Edition. This manual is full of great information including:

• Circuit board schematics
• Component bill of materials for circuit boards
• Complete wiring color codes for boards and junctions (early and later codes)
• Troubleshooting tips
• Theory of operation
• Detailed explanations of the System 1 components (switch matrix, displays, etc.)

3.3 The Wiring Color Code

Early on, System 1 games up until around Close Encounters used a single-color and two-color wiring code system. Starting around Close Encounters, Gottlieb® adopted a three color system. Most wiring in a Gottlieb® game used a white base color, which is the wire's insulation color, and three "striped" traces on each wire. I state most cases, because there are some wires which only used two colors - the green insulated ground lines which have a single yellow trace. Below is the Gottlieb® color chart.

	0	1	2	3	4	5	6	7	8	9
Color	Black	Brown	Red	Orange	Yellow	Green	Blue	Purple	Gray	White

Does the color chart look familiar? Well, if you have an electronics background, it should. The Gottlieb® wire code system is the same as the resistor color coding system.

Here are some examples of the color coding system. The color wire code for switch strobe line 0 is 011. 011 would be a white insulated wire with a black trace and two brown traces, or commonly referred to as a black-brown-brown wire. The ground lines in later System 1 games are code 54. 54 would be a green insulated wire with one yellow trace.

3.4 Connector Designations

All Gottlieb® machines have a common naming convention for all of the connectors in the game. A specific connection uses two parts - a prefix and a suffix. The prefix is the board number or an inline wire junction, and the suffix is the connection on the board or a sequential wire junction number. When referencing a specific connector pin within a housing, a dash follows the connection number. For example, the connector pin for the slam switch signal on the CPU board is A1J6-2. The exceptions are the scoring displays. For their designation, a single digit prefix is used in front of the display board prefix for the player position of the display (ie. 3A4-J1 is the connection for the player 3 display). All in-line junctions have a common designation too. For example, the large in-line connection for the coin door is A6P1 and A6J1. The connector pin for switch return 0 on the coin door is A6J1-1 / A6P1-1.

The following boards / connections are assigned the same numbers throughout the System 1 games.

• CPU Board - A1
• Power Supply - A2
• Driver Board - A3
• Scoring Displays - A4
• Status Display - A5
• All Five of the "In-Line" Connections - A6
• Sound Board - A7

3.5 Connectors

The most prevalent connector contacts used in Gottlieb® System 1 games are Molex KK .156" 2578 series contacts. Nearly all housings, the three connections on the power supply, the top housing on the driver board (A3J1), and in-line (A6) connections being the exceptions, are Molex KK single-sided card edge connectors.

Typical Gottlieb® System 1 Harness Connection Between CPU Board (A1J5) and Driver Board (A3J1)

Connection A3J1 on the driver board is a Molex KK single-sided card edge connector, however, it has mounting "ears" on either side. This type of housing was used, so that the A1J5 / A3J1 harness between the CPU board and driver board could not be installed upside down. Unfortunately, this particular housing with ears is no longer available. The power supply uses three different Molex KK .156" crimp terminal housings for header pin connections. All A6 in-line connectors use a combination of Molex .093" plug / receptacle housings with appropriate Molex .093" male / female crimp contacts. Please refer to the table below for the type and connector count of each System 1 board connection.

Connection	Location	Preferred contact type	Housing Part #	Housing contact total	Total contacts used
A1J1	CPU Board - left	Molex .156" edge	09-01-6061	6	5
A1J2	CPU Board - right top	Molex .156" edge	09-01-6191	19	16
A1J3	CPU Board - right bottom	Molex .156" edge	09-01-6211	21	18
A1J4	CPU Board - bottom right	Not used	Not used	Not used	0
A1J5	CPU Board - bottom middle	Molex .156" edge	09-01-6241	24	23
A1J6	CPU Board - bottom left	Molex .156" edge	09-01-6091	9	7†
A1J7	CPU Board - bottom left	Molex .156" edge	09-01-7171	17	15†
A2J1	Power supply - bottom	Molex .156" trifurcon	09-50-8071	7	7
A2J2	Power supply - top	Molex .156" trifurcon	09-50-8061	6	5
A2J3	Power supply - right	Molex .156" trifurcon	09-50-8081	8	5
A3J1	Driver board - top	Molex .156" edge	09-01-6241	24	23
A3J2	Driver board - bottom right	Molex .156" edge	09-01-6071	7	5
A3J3	Driver board - bottom middle	Molex .156" edge	09-01-6211	21	21†
A3J4	Driver board - bottom middle	Molex .156" edge	09-01-6083	8	6†
A3J5	Driver board - bottom right	Molex .156" edge	09-01-6191	19	19†
A4J1	Scoring displays - bottom	Molex .156" edge	09-01-6191	19	18
A5J1	Status display - bottom	Molex .156" edge	09-01-6191	19	19
A6J1 / A6P1	In-Line - coin door	Molex .093" male / female	03-09-1157 / 03-09-2159	15	14
A6J2 / A6P2	In-Line - chimes / knocker	Molex .093" male / female	03-09-1064 / 03-09-2062	6	6
A6J3 / A6P3	In-Line - backbox	Molex .093" male / female	03-09-1157 / 03-09-2159	15	15
A6J4 / A6P4	In-Line - playfield / bottom board	Molex .093" male / female	03-09-1094 / 03-09-2092	9	9
A6J5 / A6P5	In-Line - playfield / bottom board	Molex .093" male / female	03-09-1126 / 03-09-2121	12	12
A7J1	Tone board - bottom	Molex .156" edge	09-01-6091	9	6
A7J1	Sound board - left	Molex .156" edge	09-01-6121	12	9

†Note: total amount can differ from game to game

3.6 Switch Matrix

Gottlieb® System 1 Switch Matrix

The Gottlieb® System 1 switch matrix consists of a maximum of 40 switches. There are a total of 5 switch strobes, (starting with 0, ending with 4), and 8 switch returns, (starting with 0, ending with 7). The first number of every switch is its return number, while the second number is the switch's strobe number. An example would be switch 54. Switch 54 is located on return 5 and strobe 4 of the switch matrix. Due to the switch numbering system used, consecutive switch numbers are not used from return to return. In other words, when the last switch numbered in the last strobe of a particular return, the next switch number in the next switch return is not the consecutive number following the last used number. For example, the last switch number in switch return 0 is 04. The first switch number in switch return 1 is not 05. It is switch 10.

Likewise, not every switch in the matrix is used on every System 1 game.

Connections for the switches originate from the two edge connectors located at the lower left bottom of the CPU board. Connector A1J6 is used for all the switches on the coin door, the ball roll tilt (which is the second slam switch), and in some cases, the pendulum tilt. While connector A1J7 is for all of the switches on the playfield.

	Strobe 0 (A1J7-2 / A1J6-8)	Strobe 1 (A1J6-3 / A1J6-4)	Strobe 2 (A1J7-4 / A1J6-5)	Strobe 3 (A1J7-7 / A1J6-6)	Strobe 4 (A1J7-6)
Return 0 (A1J7-12 / A1J6-3)	00	01	02	03	04
Return 1 (A1J7-13)	10	11	12	13	14
Return 2 (A1J7-14)	20	21	22	23	24
Return 3 (A1J7-17)	30	31	32	33	34
Return 4 (A1J7-16)	40	41	42	43	44
Return 5 (A1J7-15)	50	51	52	53	54
Return 6 (A1J7-11)	60	61	62	63	64
Return 7 (A1J7-10)	70	71	72	73	74

Gottlieb® System 1 Diode Board

Unlike most other manufacturers, Gottlieb® isolated each switch with a 1N270 Germanium diode versus a 1N4004 or 1N4148 silicon diode. The use of a silicon diode will cause the switch matrix to function incorrectly. Furthermore, Gottlieb® attached the diodes to central location diode boards for each switch return versus attaching a diode to the switch itself. In some cases, like shown in the pic, the diode boards are stacked on top of one another. This can make testing the diodes on the lower diode board somewhat difficult. Although, it is not too common for the switch diodes to fail.

It should be noted that the switches on return 0 are always the same for every System 1 game. The following switches have the same designations:

• Switch 00 = Test Switch
• Switch 01 = Coin Switch #1
• Switch 02 = Coin Switch #2
• Switch 03 = Credit (Start) Button
• Switch 04 = Tilt Switches (pendulum tilt on the tilt board and the weighted tilt on the playfield)

Even though the switch matrix is being discussed here, it should also be noted that there are three switches used in System 1 games, which are not on the switch matrix. These three switches are the two slam switches and the outhole switch. Each game has two slam switches. The first is a weighted, normally closed switch on the coin door. The second is a normally closed switch, located at the end of the ball roll tilt cage. Neither the slam switches nor the outhole switch have a switch number designation.

3.6.1 Setting up a Game for Free Play

Early Gottileb® solid state pinball machines, prior to 1990, did not have a free play option available within the game settings. With this simple modification, a game can be set up for free play. First, identify the diode strip in the bottom of the cabinet. Once the diode strip is found, locate the credit button and coin switch strobe line wires. The wires will be located on the left of the diode strip - the non-banded side of the diodes. Below is a list of the wires.

Credit button wire - Green-White or Brown-Yellow-Yellow

1st coin switch wire - Orange-White or Brown-Red-Red

2nd coin switch wire - Brown-White or Brown-Orange-Orange

Gottlieb® System 1 Transformer Board

Solder a small lead wire from the credit button wire to any of the coin switch wires. Make certain that the diode, credit button wire, and coin switch wire are still soldered securely to the diode strip terminal when finished. If soldering is not an option, use a small alligator clip test lead instead. Now, when the credit button is pressed, a credit will be incremented and decremented. A game can be easily started without the need to open the coin door to trip the coin switches anymore.

3.7 Transformer Panel

A Typical Gottlieb® System 1 Transformer Panel

3.8 Power Supply

File:Gtb sys1 psu front.JPG

Gottlieb® System 1 Power Supply - Front

Gottlieb® System 1 Power Supply - back

Gottlieb® System 1 Power Supply with heat sink / mounting plate removed - back

3.10 Driver Board

Gottlieb® System 1 Driver Board

The System 1 Driver board is responsible for all CPU controlled lamps, relays, and solenoids in the game. The CPU controls the driver board operation via an interface between A1J5 on the CPU and A3J1 on the driver board.

Gottlieb® did not implement a lamp matrix as some other manufacturers did. Therefore, diodes to isolate each controlled lamp are not necessary. To control the total of 36 lamps, the interface provides device select signals for each of the 9 Quad-D Flip-Flop 74175 chips on the driver board, and 4 bits of data that is loaded (or "clocked") into a particular 74175 via the aforementioned device selects. Each lamp is driven discretely by a particular output of a particular 74175, which in turn drives either an MPS-A13 (32 total) or an MPS-U45 (4 used for lamps) transistor. There are 2 dedicated lamp driven circuits used for the tilt and game over relays on all System 1 games. The transistors for the game over (Q) and tilt (T) relays are always Q1 and Q2 respectively. Equally, there are 2 dedicated lamp circuits for the high game to date and both shoot again lamps,(one in the backbox and one on the playfield). The transistors for these circuits are always Q3 and Q4 respectively.

There is a maximum of 8 solenoids that the driver board can control. Solenoid transistors receive a pulsed signal from the CPU board, which is applied to the associated transistor base. In turn, the solenoid turns on momentarily. 7 of the 8 solenoid transistors used are a 2N6403. TIP102 transistors are a viable, cheaper replacement for the 2N6403. The 8th transistor is a actually a pair of transistors consisting of an MPS-U45 and a 2N3055. There are 5 dedicated controlled solenoids used on all System 1 games. A table of all the solenoids, their associated transistors, and whether or not they are dedicated is listed below.

Sol. #	Sol. Name	Transistor #	Dedicated (Y / N)
1	Outhole	Q32	Y
2	Knocker	Q25	Y
3	10's Chime	Q26	Y
4	100's Chime	Q27	Y
5	1000's Chime	Q28	Y
6	Solenoid 6	Q31	N
7	Solenoid 7	Q30	N
8	Typically drop target reset	Q29 & Q45	N

Remote Transistor Mounted Under Playfield

Starting with Joker Poker, Gottlieb® went beyond the threshold of controlled solenoids with 9 total. To accomplish this, they used an MPS-A13 lamp transistor to "pre-drive" a 2N5875 transistor remotely located under the playfield. This practice continued on other System 1 games. See the Remote Mounted Transistorsection for a complete listing of games.

Early System 1 Driver Board w/o Blocking Diodes

Gottlieb® System 1 Driver Board w/ Blocking Diodes

There are two variations of the driver board used in System 1 games. Either board will work in any of the System games. The main difference between the two versions of driver boards is the addition of isolation / blocking diodes. These blocking diodes were added to the transistor signal lines from the CPU board. The change occurred during the run of Close Encounters machines. Games prior to Close Encounters and early runs of the same game will not have the blocking diodes added. Late runs of Close Encounters, and any game after will have the blocking diodes. Keep in mind, it is very common to find a board in a game, which was not originally from that particular game. So, don't rely on your Totem or Genie having a driver board with blocking diodes without actually physically looking at the boards installed first.

3.11 Sound

Gottlieb® System 1 Chime Box

The first three System 1 games: Cleopatra, Sinbad, and Joker Poker all used EM style chimes. A chime for 10 points, 100 points, and 1000 points scored during a game would sound off accordingly.

Gottlieb® System 1 Chime Board (Tone Board)

Starting with Close Encounters of the Third Kind through Pinball Pool, a first generation sound board is used. This is a very rudimentary sound board, which is only capable of generating a total of three beep and boop tones. The tone board uses the same three solenoid drive transistors for input as the chime units, which extremely limits the amount of output sounds. The tone board and chime units are interchangeable, and the tone board often gets swapped for the better sounding chimes.

Gottlieb® System 1 Multi-Mode Sound Board

Games from Totem to Asteroid Annie used the Multi-Mode sound board, also referred to as the "2nd generation" sound board. This is the first sound board created by Gottlieb®, which has its own on board CPU chip. The same three solenoid drive transistors used by chime units and tone boards is used by the 2nd generation sound board. Two additional input signals, tilt and game over, are used with this board, increasing its input signals from three to five total. Still, the 2nd generation sound board is somewhat limited, mainly due to the minimal amount of input line signals.

3.12 Display Boards

"What's new is blue!", touted the Cleopatra flyer regarding the blue Futaba displays used in Gottlieb's® first solid state venture. Generally speaking, the System 1 displays are a fairly reliable, long-lasting display. These vacuum fluorescent displays (VFD) have a tendency to outlast the plasma gas displays, which were commonly used by Williams, Bally, and Stern.

File:GTB 6 digit display.JPG

Gottlieb® 6 Digit Display

Two different styles of displays were used throughout all System 1 games - four 6 digit displays for the player's score and one 4 digit display for game status. There were two different 6 digit displays used during the System 1 era, however, either style will work in any game, and can be mixed among styles. The display boards and glasses were the same, but the chip sets which were used differed. One style was based on Sprague UDN6118A chips, while the other was based on Dionics DI513 chips.

Gottlieb® 4 Digit Display

Three distinct voltages are needed for either the 6 digit or 4 digit displays to function properly.
6 Digit Display

• +60vdc
• +8vdc
• 5vac

4 Digit Display

• +42vdc
• +4vdc
• 3vac

3.12.1 Display Test

Gottlieb® System 1 display tests are steps 11 and 12 of the diagnostics. Step 11 tests player 1 and 3, cycling 000000, 111111, 222222, etc. on each display. Step 12 tests player 2 and 4 displays in the same way. The credit/match display, unlike System 80 display test, is not tested during either System 1 display test. That is, the digit sequences are not displayed on the credit/match display during test steps 11 and 12.

3.13 Solenoids and Relays

All System 1 solenoids and relays are powered by a +24VDC solenoid bus. Each game has CPU controlled solenoids and "non-controlled" solenoids consisting of the same types of solenoids:

• flippers
• pop bumpers
• kicking rubbers (slingshots)

The CPU controlled solenoids are ultimately driven via the driver board, while the non-controlled solenoids are essentially "live" at the start of a game. The conditions which make them live are a normally closed switch on the tilt relay and a normally open switch on the game over relay. Once the game over relay locks in, all that is necessary for these solenoids to activate is an associated playfield switch to close, or in the case of the flippers, pressing the appropriate flipper button. All of the non-controlled solenoids have switches with tungsten contacts, which supply power to the solenoids. It is safe to file or burnish these types of switches. However, there are secondary "gold flashed" scoring switches on the pop bumpers and slingshots, which should not be filed or burnished.

Gottlieb® System 1 Game Over and Tilt Relays

System 1 games employ the use of "open cage" relays. Relays relevant to every game are the tilt relay, game over relay, and coin lockout relay. There are seldom used extra relays on some games such as the vari-target reset too. The tilt, game over, and var-target relays are all controlled by the driver board. But, the coin lockout relay is energized as soon as the game is turned on.

Whether or not a solenoid or relay is controlled by the CPU board, all solenoids and relays should have 1N4004 diodes installed.

Below is a list of solenoids / coils used in System 1 games.

Sol. #	Common Usage	Wire Gauge	Windings	Resistance
A-1496	Pop bumper	23	635	2.95
A-5194	Kicker (Slingshot), Pop Bumper	24	780	4.5
A-5195	Outhole (early), Knocker, Kickout Hole	26	1305	12.3
A-16570	Outhole (later), Kickout Hole	27	1450	15.5
A-16890	Game over relay, Tilt relay, coin lock out	35	4000	231.0
A-17564	Vari-Target Reset
A-17875	Flipper	24 / 31	560 / 1100	2.8 / 40.0
A-17876	Chimes	28	1750	24
A-18102	3 or 7 (2 used) bank drop target reset	24	1430	9.0
A-18318	4 bank drop target reset	24	1130	6.7
A-17891	5 bank drop target reset, Roto	22	850	3.35

3.13.1 Solenoid and Relay Test

+++describe built in game test diagnostics+++

3.14 Flippers

++++Add more pics of individual parts of the flipper assy. within text and a parts explosion++++

Gottlieb® System 1 Flipper Assy.

The System 1 3" flipper mechanism first appeared in later Gottlieb® electro-mechanical games. Starting with Buccaneer in 1976, this flipper style assembly was used throughout all of the System 1 and System 80/80A/80B games, except for the last System 80B game, Bone Busters, Inc. in 1989. These flippers are referred to as "fat boy" or "brick" flippers, however, there really isn't a distinct nickname for them which stuck.

Where the System 1 flipper mechanism lacks in overall smoothness, it makes up for this in durability and reliability. The System 1 flipper mechanism is incredibly hardy, and if cleaned and assembled correctly, it will work reliably for a relatively long time. Hence, operators who actually operated System 1 games loved this style of flipper, mainly because they rarely break.

The flipper coil used is serial-wound, dual coil with high power and hold winding. Only a single diode is used with the flipper coil, because the windings are wound in series. The only major difference between EM, System 1, and System 80/80A/80B flipper assemblies is the flipper coil used. EM games used A-5141 coils, while System 1 games used the standard A-17875 coil, which is stronger. Some System 80/80A/80B games used A-17875 coils, but starting around Black Hole, games were using the even stronger A-20095 "super flipper" coil. An intermediate strength flipper coil, the A-24161 coil, was occasionally used starting with System 80A games.

Power to the coil's windings is transferred via an EOS switch, and flippers are activated by a cabinet switch which completes the coil's circuit to ground. Operation of these flippers is similar to any other pinball manufacturer. Although, there are several physical attributes which make them different.

1. A bakelite flipper link was no longer used with this style. Instead, a molded one-piece link and plunger were used. The link and plunger are technically two separate pieces held together via a roll pin, but the two pieces are not available as two separate parts.
2. A dual (upper and lower) flipper bushing, (Gottlieb® refers to them as bearings), system was used. This setup is unique to this style of flipper system, because every other manufacturer and Gottlieb® flippers previously and after only used a single flipper bushing.
3. The normally closed flipper EOS switch uses a plastic, triangular actuator to open the EOS switch. This plastic actuator is secured within the EOS switch stack.

The only major weakness to this flipper design is how the EOS switch is actuated. The EOS switch is opened via the flipper crank / pawl assembly, and it's a metal-on-metal contact point. Even though the thicker than normal metal switch leaf where contact is made on the EOS switch, the flipper crank / pawl can potentially wear a hole in this leaf over time. Gottlieb® did rectify this potential issue in the late '80s, (around the production of TX-Sector), by offered a kit to modify the assembly. The new style crank / pawl had an added a plastic roller, which made contact with the EOS switch instead of the pointed edge of the flipper crank / pawl. The EOS switch was attached to a bracket which attached to the flipper plate's old EOS switch bracket. This was done to compensate for the difference in spacing the roller created. The flipper mechanism was now even better, but in home use this modification may be a bit of overkill.

The only design change the flipper mechanism underwent, during the course of the System 1 platform, was a change in the flipper link. The molded plastic flipper link used on earlier System 1 games had a "tail", which protruded through a hole in the bearing bracket. It is assumed that this "tail" was used to center the motion of the flipper plunger and link, and the "tail" does effectively do this. However, there is one drawback. As the flippers wear with age, the tail can start "dragging" through the hole. In turn, this can create weak flipper action. It is suggested that if the flipper mechanism still has a tail present on the flipper link to cut or grind the tail off.

The majority of this discussion has focused on the 3" System 1 flipper assembly. Not to be forgotten, some System 1 games, such as Joker Poker, Count-Down, and Genie, used secondary 2" flippers. The 2" System 1 flipper design is the same mechanism as electro-mechanical Gottlieb® games. The only difference is the coil used. EM games used an A-5141 coil, while System 1 games used an A-17875 coil.

3.15 Pop Bumpers

Anatomy of a System 1 Pop Bumper

System 1 Pop Bumper

View of Pop Bumper Switches

+++Discuss pop bumpers, describe and show parts explosion of assy.+++

3.16 Drop Targets

This is a stub

3.17 Vari-Target

Vari-Target as viewed from Top of Playfield (Totem)

Vari-Target as viewed from Under Playfield (Totem)

3.18 Accessing Bookkeeping and Diagnostics

Placeholder for Sys 1 coin door test button

3.19 Lamps

++describe lack of lamp matrix, driver board / CPU control of lamps, etc.++

3.19.1 Lamp Test

+++describe built in lamp test diagnostics+++

3.20 Rubber Ring Chart

Although the Gottlieb® System 1 game manuals do list the location and part numbers for rubber rings used, they fail to list the actual rubber ring size. Below is a handy chart, which lists the Gottlieb® rubber OEM number and its size.

Gottlieb® #	Description
A-14793	23/64" White Mini-Post
A-15705	27/64" White Mini-Post
A-10217	5/16" White Ring
A-17493	7/16" White Ring
A-10218	3/4" White Ring
A-10219	1" White Ring
A-10220	1-1/2" White Ring
A-10221	2" White Ring
A-10222	2-1/2" White Ring
A-10223	3" White Ring
A-10224	3-1/2" White Ring
A-10225	4" White Ring
A-10226	5" White Ring
A-13151	3/8 x 1-1/2" Standard Red Flipper
A-13149	3/8 x 1" - Small Beaded Red Flipper
A-1344	Rebound Rubber
1872	Shooter Tip

4 Problems and Solutions

4.1 Connectors

Connectors, connectors, connectors!!! Since the Gottlieb® System 1 boardset primarily relies on Molex connectors to pass data and voltages from board to board, the connectors should be addressed first. Before even attempting to turn a Gottlieb® System 1 game on for the first time, worn or corroded edge connector contacts must be replaced. Cleaning or burnishing connector contacts is not a viable option to ensure a game's reliability.

Poor connector contacts are the number one reason why System 1 games do not function properly. Poor or missing connector contacts have a cascading effect too. The end results of bad connector contacts can be, but are not limited to:

• voltages which mysteriously disappear and reappear
• increased resistance
• specific switches not functioning
• lamps locking on
• lamps not turning on
• displays not properly functioning
• coils not turning on
• coils locking on
• CPU boards not booting, booting sporadically, or randomly resetting
• driver boards not functioning or functioning sporadically

So, it is very important that the connector contacts are shiny, have proper spring tension, and are properly crimped for the over all reliability of the game. Random, flaky issues which happen either sporadically or all the time are attributed to poor connector contacts in nearly every case.

• A Typical System 1 Connector
• 

  An example of connector pins which need to be replaced.
• 

  The same housing after repinning.

4.1.1 Replacing (Repinning) System 1 Connectors

Replacing connectors in a pinball machine somehow adopted the term repinning. Repinning a System 1 edge connector housing is probably the most difficult. On a scale of 1 to 10 (1 being the easiest to do, 10 being the most difficult) compared to all other makes and platforms made, System 1 edge connector replacement is about an 8. Provided the ear inside the plastic housing does not get sheared off, System 1 edge connector housings are reusable. Below are the steps to remove the connector from its housing.

File:MolexPinExtractionTool.jpg

A Molex Contact Extraction Tool, Molex part number 11-03-0016

System 1 connector housings are primarily "single-sided" edge connectors. The exceptions are the three connectors used on the power supply. To remove pins from these connector housings, you need a pricey yet effective tool called a Molex contact extraction tool, (commonly referred to as a Molex extractor). The Molex part number for the extractor is 11-03-0016, and can be purchased from Great Plains Electronics or other electronics vendors. Slide the extractor behind the pin to release the "tang" that holds the pin in. Firmly grip the wire and pull the pin out of the connector.

4.1.2 The CPU / Driver Board Interconnect Harness

The A1-J5 / A3-J1 Interconnect Harness

There are 23 discrete signals which pass from the CPU board to the driver board via this connection. Two of the connectors pass ground and +5v logic to the driver board, while the remaining signals are for lamp, relay, and solenoid control. It is extremely important to have solid connectors installed in the CPU / Driver board interconnect harness. Without decent connections, lamps, coils, and relays can either lock on or not turn on at all.

Repinning both sides of the interconnect housings is the solution to reliable game function. If repinning is not an option, several vendors sell replacement new harnesses. When buying a replacement, use some caution. The original factory harness uses single-sided Molex edge connections. There are some replacement harnesses being sold with double-sided edge connection housings. It is easy to identify these housings, as they are black in color versus the "natural" color of all the other housings used in the game. These types of harnesses do work, but there is one caveat. They are not specifically built to fit the System 1 edge connections on the CPU or driver board, and are a fraction larger than the board edges fingers they are installed on. Hence, there is some lateral (side to side) movement in the connections at both A1-J5 and A3-J1. Because of this "slop", the housing connectors can cross signals to adjacent edge fingers. The end result is relays, lamps, or coils which do not turn on at all or never turn off.

4.2 Ground Updates

Gottlieb® System 1 games are notorious for having poor ground connections. As mentioned at the introduction of this System 1 guide, ground problems are one of the biggest issues with the System 1 platform. Poor ground connections are the number two reason for unreliable System 1 games. Unlike the other popular manufacturers of the time, Gottlieb® relied solely on connectors and daisy-chained wiring to transport the ground lines from board to board. A large ground plane was used behind the boards, but the circuit boards' grounds were not physically secured to it. Gottlieb® opted to use plastic standoffs to elevate and secure the boards to the backbox instead. Thus, if a single ground connector failed in the chain, the logic ground could fail for one or several of the circuit boards. This could potentially lead to erratic behavior with locked on coils, relays, and / or controlled lamps. In turn, transistors and chips would fail.

Chiefly due to age and / or alkaline battery damage, the connectors carrying the ground lines would fail. Connectors become fatigued losing their tensile strength against the edge finger surface of the board. Thus, the ground connections would become compromised. Equally, if battery damage was present due to an aged, leaky battery, the connectors would corrode, and either have too much resistance, or completely break. Replacing the failed connectors is always a great start, and highly recommended. However, there are additional procedures to keep from the ground being lost at each board. Once the ground lines are added to the circuit boards, Gottlieb® System 1 games are one step closer to being as reliable or more reliable than the other pinball manufactures' games from the same era.

Ground tie point in backbox for CPU and driver boards

4.2.1 Additional Ground - Power Supply

Ground added to System 1 power supply on 12v filtering cap

If you happen to be one of the lucky few, where the power supply does not have to be disassembled for repair, an additional ground line can be soldered to the negative leg of +12VDC filtering capacitor. The filtering capacitor is the large axial capacitor, which is oriented horizontally on bottom of power supply board.

Ground added to System 1 power supply on back

If component level work has to be performed on the power supply, the circuit board will have to be physically removed from the heat sink / mounting plate. While the board is removed, an additional ground line can be added to the ground on the backside of the power supply board. This line can then be secured to the pinball machine's backbox via one of the three sheet metal screws used to mount the power supply's metal mounting bracket.

For a cleaner look, the additional ground line could be soldered to the ground on the backside of the board, and then soldered to one of the two threaded standoffs used to secure the power supply board to the heat sink / mounting plate. Make certain to solder to one of the outer standoffs which have no traces surrounding them. Do not tie the additional ground line to either standoff used to secure Q1 to the heat sink / board.

Regardless of the method chosen above, the power supply will have a more solid ground connection, once the additional work has been completed.

4.2.2 Additional Ground - CPU Board

Ground added to System 1 CPU board at A1J4-1 - front

Ground added to System 1 CPU board at A1J4-1 - back

Alternate location for added ground at negative leads of capacitors C16 & C17

4.2.3 Additional Ground - Driver Board

Ground Added to System 1 Driver Board

The best place to add an additional ground on the driver board is the negative side of capacitor C1. The capacitor is marked with a "+" on the top side. Using 18ga stranded wire, the new line must be soldered to the bottom of C1, which is the negative side. This coincidentally happens to be the same place the driver board receives ground from the CPU board via the interconnect harness (A1J5 pin 24 to A3J1 pin 22). On the other side of the newly added ground wire, either a solderless crimp eyelet or solderless crimp fork should be added. Once the driver board is reinstalled into the game, mechanically secure the eyelet or fork with one of the screws which hold the metal board rails. Just ensure the screw used to hold the added ground line has continuity to ground.

4.2.4 Additional Ground - Sound Boards

Ground Added to System 1 Multi-Mode Sound Board

There is a fairly large area where an additional ground can be soldered to the Multi-Mode sound board. This area can easily be identified on the back of the board. One of the nuts used to fasten the 5v voltage regulator to the board is secured to the large ground plane on the board.

Once attached to the sound board, run the additional ground lead directly to the ground plate located on the transformer board. It is a good idea to splice a "quick connect" in the added ground line, so the sound board can easily be removed for service if necessary.

4.3 Power Problems

4.3.1 The Upside Down A2J1 Power Supply Connection

Gottlieb® System 1 power supply with connection A2J1 highlighted

The first power problem is more of a word of caution than anything else. The issue stems from the power input to the power supply, which is located at the bottom connection of the power supply. A2J1 is a 7 pin connection, which is fed power directly from the transformer panel. The problem is that the female connector is not keyed. Since the connector is not keyed, there is a slight risk of installing the connector upside down. The connector would have to be installed with brute force though, as there is a ramp on the bottom of the header pins. On most games, Gottlieb® affixed an orange sticker to this connector, stating THIS SIDE DOWN. However, over time due to heat, moisture, and other circumstances, the warning sticker is typically missing.

If you have to exert force to put the the connector on at A1J2, it is being installed upside down.

4.4 MPU Boot Issues

4.4.1 Battery Leakage and Corrosion

Like most any other pinball machine manufactured, Gottlieb® System 1 games use batteries to supply power to the non-volatile RAM memory. Certain game settings, high score thresholds (including high score to date), audit information, and bookkeeping information are all options which are saved when the game is powered off. And unless some kind soul, who worked on your machine before, either removed the battery and mounted it remotely away from circuit boards, or just plain removed the battery, there will be some variety of a 3.6v Nickel Cadmium (NiCad) rechargeable battery soldered onto your CPU board.

So, what's so bad about having a battery on the CPU board? Well, nothing really, unless it becomes forgotten, and most cases it does. While you let your pinball machine sit unplayed for weeks, months, or even years at a time, the battery remains perched on the circuit board like a ticking time bomb. I'm not saying the battery is going to blow up, although some replacement non-rechargeable batteries could overheat and / or explode if not correctly installed. The battery is like a ticking time bomb, because it is a threat to the overall health of the electronic components, traces, and connectors attached to your CPU board.

Now that I have your attention regarding the whole battery thing, let's talk about the battery, and what happens. . .WHEN GOOD BATTERIES GO BAD. It's not that some batteries were born on the wrong side of the tracks or anything. Any good battery can go bad without much warning. It takes time, but eventually you will find out that your battery has stepped over to the "dark side". That particular time is typically when you turn your game on, the lights come on, and that's it. The displays don't light up, the start up sounds don't resonant, and the silver ball stays in its comfy little home. Nada, nothing, no signs of anything resembling a fun game of pinball. UH-OH! So what happened? The pinball machine worked fine the last time you played it.

Well, while you were out having a good time and enjoying life, the poor, aged, neglected battery decided to wreak havoc all over your CPU board. The CPU battery spewing its guts all over the place is akin to the batteries in the flashlight you haven't turned on since the last power outage over a year or two ago. You go to turn on the flashlight when you need it most, and find out there's something wrong. So being the curious type, you open the flashlight's battery compartment only to find some kind of funk leaking all over, or the batteries now look like they need a shave. The resolution to the flashlight scenario is pretty simple. Throw it away, and buy a new one. Your CPU board problem can be resolved the same way, except it will be a lot more costly, and is not recommended to just pitch it in the trash. If the battery damage to the CPU board is not overly extensive, attempt to repair it.

Gottlieb® System 1 CPU with a Data Sentry Ni-Cad Battery still installed NOTE: U5 spider chip was removed from this board.

It's unfortunate, but every battery has a life expectancy. The only silver lining is that some of the Ni-Cad batteries installed on System 1 CPU boards can last longer than others. Probably the worst offender of board destruction is the Data Sentry pack, and its associated knock-offs. This battery comes in a black rectangular plastic package, and is typically found on newer generation CPU boards.

One of the two typical Ni-Cad batteries found on a System 1 CPU board

The other common battery style is a what looks like an AA battery on steroids. This style is a fraction longer and fatter than an AA battery's physical form, and has two soldered leads on either end. These are normally held by two clips, which are screwed to the CPU board. Although these types of batteries are found on early generation CPU boards, there are some cases where this style of battery is the chosen replacement. Even though a newer battery of this type may be installed on the board, the same results of battery seepage can occur. The only benefit of this type of battery is that it can be carefully cut (in most cases) from the board without removing the board from your game. This is a plus if no battery damage has occurred.

So what happens if you don't heed the above warnings, and the battery is allowed to remain on the board? Plain and simple - THE BATTERY WILL LEAK! It's only a matter of time. Equally, the path of destruction is uncertain. Batteries don't just leak - they release caustic, alkaline fumes. These fumes attack wherever there is copper, even tinned or soldered copper. The end results are:

• solder joints which become green or gray and crusty as opposed to a shiny silver
• connectors which are also now green / gray or potentially broken
• solder mask, the green covering the electronic traces, on the circuit board has either flaked off or is partially delaminating (lifting)
• insulated wire becomes less flexible and brittle
• sometimes the alkaline "cloud" in the game's backbox can even effect the upper portion of driver board.

Particular areas of a System 1 CPU which are susceptible to alkaline damage are:

• Edge connector fingers at A1J6 and A1J7, in worse cases, A1J5. The associated edge connectors inside the housings will be effected in part or in whole too.
• Solder vias from A1J7 to the component side of the CPU board
• The following chips: Z28, Z8, possibly Z9 and Z6, and in worst cases, the U5 spider chip located just above and to the left of the battery. The majority of chips involved are associated with the switch matrix with the exception of Z6 used for some solenoids.
• Resistors R33 - R36 and R37 - R39, in worse cases R45 - R50
• Other components above the top of the battery.

If the spider chip U5 took a substantial hit, writing off the CPU board for parts only may be the best approach. Although it can be a tedious repair, any of the other components mentioned above are readily available, and can be acquired for replacement.

• Gottlieb® System 1 CPU Battery Damage
• 

  Illustration of battery damage zones. Green is the mildest damage. Yellow is a little more extensive. Orange is little worse. Red is the most extensive.
• 

  Typical battery damage to the component side of a System 1 CPU
• 

  Back side of same board. Edge connector alkaline damage is more extensive than the norm.

Electronic components, related solder joints, circuit board traces, connectors, and even insulated wire will become unreliable and/or fail. In all cases, the effected components are less conductive.

The only silver lining with System 1 battery alkaline damage is that in most cases the CPU board will still boot. That's not saying there won't be issues with the switches not reacting or solenoids locking on, but the potential for the board to boot is there. So, if you're curious whether the board is worth repairing, first see if the board boots with only A1J1 (power) and A1J2 / A1J3 (displays) connected. This is of course provided that there is no alkaline damage on any of these three connections. The connections may have to be repinned prior to an attempt of booting the board. Likewise, the slam switches will have to be disabled on the CPU board.

If battery damage has occurred, the related parts must now be replaced. Attempting to remove soldered through components on the circuit board is now even more of a task. The green / gray dull solder does not transfer heat well. Battery damaged solder does not flow like clean solder. Also, crimped connectors are more difficult to remove from their housings, and have a tendency to break before they can be successfully pulled out.

After all the effected electronic components are removed, the board must be treated. This process starts by sanding the traces and solder pads until shiny copper is exposed. It is worth mentioning that a battery damaged board can be treated by bead blasting instead of sanding, however, most people do not have access to such a machine. After the copper areas of the board have been either sanded or bead blasted, an acidic bath of 50% vinegar and 50% (preferably distilled) water is applied to the board. A small brush like a toothbrush can be used to scrub the board's area. The purpose of introducing an acid to the effected area is to neutralize what the battery has left behind. The liquid and fumes from the battery are actually a base, not an acid. Next, rinse the area of the board with water. Once the board is clean, isopropyl alcohol (the higher the alcohol percentage the better) is applied to the same area to rinse away the acid bath, and hopefully dissipate any remaining water. Finally, the board is either blown dry or air dried. This may be a given, but DO NOT ATTEMPT TO APPLY POWER TO THE BOARD IF IT IS STILL WET! Most liquids are conductive to some extent. After the previous steps are performed, the task of installing the new components begins. If any traces or solder pads were damaged, see the Repairing Traces portion of this Wiki guide on to to fix them.

The point I'm trying to ultimately make is this. . . regardless of age, shape, or form, remove the battery from the CPU board, as soon as it realized that there is a battery on the board. If not, the board can be damaged, nonfunctional, and become more difficult or even impossible to repair.

4.4.2 Relocating the Battery from the CPU board

Adding a remote battery to a System 1 CPU board

4.4.3 Permanently Disabling the Slam Switches

A jumper used on each side of the C2 capacitor

Replace capacitor C2 with a jumper wire. This permanently holds the slam switch closed on a Gottlieb® system 1 board. Alternately just solder a piece of wire across C2 to accomplish the same thing.

There are only three main drawbacks after disabling the slam switches.

1. If the game is still being operated in an arcade environment, the door could be banged, kicked, etc., and the game will not reset.
2. If the game is still being operated in an arcade environment, the game could be lifted from the front, and the game will not reset.
3. Exiting from the bookkeeping, audits, and tests will not be as easy. However, this still can be accomplished by gently swinging the tilt bob against the tilt bob ring.

Considering the drawbacks, which in most instances the first two don't apply, versus the benefits, (no more sporadic resets due to flaky slam switches), permanently disabling the slam switches is typically a good idea.

4.4.4 Connecting a Logic Probe to the CPU Board

Logic probe connected to a System 1 CPU board

The most convenient place to connect a logic probe to a System 1 board set is at the positive (+5vdc) and negative (ground) legs of axial capacitor C16. The positive lead is on the top, while the negative is on the bottom. By no means should a logic probe be connected to axial capacitor C17, which located just below C16, (there is a yellow "X" over it in the adjacent picture). Capacitor C17 is for the -12vdc line. Connection to C17 could destroy a logic probe in short order, and if it doesn't, odd results will be obtained while probing circuits.

4.6 Driver Board Issues

Nut / Screw Which Secures 2N3055 Collector to Drive Line

Make certain to inspect and tighten the screws which secure the 2N3055 TO-3 transistor to the driver board. Specifically, the screw / nut as marked in the pic. It ties the transistor case (collector) to the solenoid drive line. If the case is not secured, the transistor will not function as intended.

4.7 Solenoid and Relay Problems

When troubleshooting a System 1 solenoid / relay problem, the first thing is to determine whether or not the solenoid is controlled by the CPU. The following solenoids and relays are not controlled by the CPU:

• Pop Bumpers
• Slingshot Kickers
• Flippers
• Coin Lockout Relay

The remaining solenoids and relays are all controlled by the CPU. These solenoids and relays include:

• Outhole
• Drop Target Bank Reset
• Kickout Hole
• Knocker
• Chimes
• Game Over Relay
• Tilt Relay
• Vari-Target Reset Relay

Regardless of the type of solenoid or relay, both types are on the same +24VDC solenoid bus. Therefore, any solenoid or relay used in a System 1 game is fused by the same main solenoid fuse, and receives rectified DC voltage from the same solenoid bridge rectifier located on the transformer board. Equally, all solenoids and relays have a path which goes to ground to complete the power circuit. The paths to ground between controlled and non-controlled are just different. Non-controlled solenoids have a high powered switch between the solenoid and ground, while controlled solenoids use a transistor or group of transistors to complete the path to ground.

4.7.1 Identifying Potentially Bad Solenoids

Before turning a game on for the first time, it's best to determine if there are any solenoids, which have locked on and overheated. There are primarily two methods to approach this.

The first and easiest method to check for bad solenoids is via a visual inspection, and actuating all of the solenoids' assemblies by hand. One typical sign of a potentially bad solenoid is if there is a brown / burnt ring present around the center of the solenoid wrapper. Not all solenoids with a brown / burnt ring are bad though, and some solenoids are completely missing their solenoid wrappers all together. Therefore, it is necessary to push a solenoid's associated plunger into the solenoid. If the plunger moves freely, the solenoid is more than likely good. Don't forget to inspect the chime solenoids, (if they are used in the game), the outhole kicker, and knocker solenoid. Keep in mind that early System 1 games, Close Encounters and earlier, had a outhole kicker solenoid mounted perpendicular to the underside of the playfield. These are just like standard hole kicker assemblies. However, later System 1 games, Dragon and newer, used an outhole kicker solenoid mounted on the top of the playfield, located under the lower apron. For this style of outhole kicker, the lower apron may have to be removed to get a visual of the solenoid and to actuate it. It is very common for System 1 games to have bad knocker solenoids. This is due to the subtle signs when a knocker locks on. It will only make a noise once prior to locking on. Since it is not located on the playfield, a locked on knocker can easily go unnoticed. Chime solenoids are susceptible to this too, except the lack of a chime or a faint vibration of the chime bar may be heard. Although it is rare for a Gottlieb® solid state relay coil to fail, relay solenoids should be inspected too. If a particular solenoid plunger will not move freely, the solenoid is more than likely bad.

When in doubt whether a solenoid is bad or not, check the resistance of the solenoid with an ohmmeter. Use the solenoid resistance chart above to determine if the solenoid is within spec or not. In most cases, solenoids will have a higher or lower resistance reading than specified. An example would be an A-5195 solenoid. Its factory specified resistance is 12.3 ohms. It is not uncommon for an A-5195 to measure as low as 10 ohms. This resistance is acceptable. In general, if a solenoid measures approximately 30% less than its specified resistance, it may be bad. Likewise, if a solenoid's resistance measures approximated 1 - 1.5 ohms, it is probably bad due to a short in the windings. If a solenoid measures 0 ohms, it may be a shorted diode instead of a bad solenoid.

On the subject of diodes, look for the absence of a loose or missing solenoid diode during a visual inspection. All solenoids used in System 1 games must have a 1N4004 or higher rated diode soldered across the solenoid's lugs. Missing or shorted diodes will potentially strain the associated circuitry. Gently tug on the existing solenoid diodes to make certain they have a good mechanical connection to the solenoid lugs. If one leg of the diode is not connected to the solenoid, it is as if the diode is not on the solenoid at all.

The second, better method for identifying potentially bad solenoids is to measure each solenoid's resistance with an ohmmeter. The reason why this method is better is because a shorted coil diode will be identified while checking the solenoid's resistance. When measuring a solenoid's resistance, place the ohmmeter probes on either side of the solenoid's diode instead of on the solenoid lugs. Following this procedure will identify if a diode is connected to the coil or not in addition to measuring the solenoid's resistance

4.7.2 Non-Controlled Solenoids and Relays

Gottlieb® Non-Controlled Solenoid Circuit

Non-controlled solenoid problems are fairly straightforward. The source current for the solenoid is provided through a normally open switch pair on the Game Over ('Q') relay and a normally closed switch pair on the Tilt ('T') relay. If all of the pop bumpers and slings aren't working, take a look at the switch blades on the game over and tilt relays. They are most likely misaligned or fouled.

Non-controlled solenoids consist of the pop bumpers, slingshot(s), and flippers. They are called "non-controlled", as the driver board / CPU board does not control the activation of the solenoid. Instead, a high-current tungsten switch is used. When the switch closes, it ties the circuit directly to ground, which activates the solenoid. It is a good idea to add an inline fuse holder to this type of solenoid, except for the flippers, with a 2 amp fuse installed in case a solenoid locks on. The fuse will open protecting the circuit from overheating. Simply remove one of the wires from the coil, and add the fuse holder nearby, either the inline wire type, or a holder mounted to the bottom of the playfield.

The high current switch in this type of circuit needs filing with a points file for cleaning, and also a slightly larger gap vs. a gold flashed/low voltage switch. Too close of an adjustment gap will cause the arc produced when this switch opens to eventually pit the contacts and / or weld the switch points together. In the case of slingshots, make certain the switch dampener, which should rest on the smaller of the two switch leaves, is not contacting the larger switch leaf. If the switch dampener stays in contact with the larger leaf, the circuit path will complete inadvertently, and the solenoid will remained energized. If the solenoid stays energized for too long, the solenoid can potentially melt the insulated coating on its windings, short out, and fail, provided that the solenoid fuse does not blow.

There will also be a low voltage contact at the full stroke of the solenoid, used to supply a switch closure signal to the CPU board for scoring purposes. These switches are part of the switch matrix. Failure of these switches will not impede the physical operation of the solenoid.

None of the non-controlled solenoids are activated during solenoid test. Although, any of these solenoids can be activated by their associated switches during solenoid test, because the game over relay will be energized.

4.7.3 Controlled Solenoids and Relays

Gottlieb® CPU Controlled Solenoid Circuit

Controlled solenoid problems can be a little more tricky. In comparison to the non-CPU controlled switches, think of the driver transistor as the high current switch. Its job is to switch the coil to ground, completing the circuit and causing the solenoid to fire.

A bad driver transistor (locked on) will cause issues including the coils melting and other burning issues on the driver boards. Earlier driver boards lack protection diodes for this situation, which could lead to failed chips on the CPU board. Because of this risk many large coils on System 1 games already have factory mounted fuses installed under the playfield to protect against this situation. Any coil not protected can always have fuses added to protect the boards against damage.

Problems with driver transistors locking on are directly attributable to the poor grounds on Gottlieb® system 1 machines; all grounding mods should be done to minimize the effects of transistors that seemingly turn themselves on.

All of the 8 controlled solenoids, (if all 8 are used), are activated one by one during solenoid test. However, any controlled solenoid which is driven by am MPS-A13 lamp transistor and a remote mounted under playfield transistor will not activate during solenoid test. See the chart below for games which use lamp drivers and remote transistors to control specific solenoids.

4.7.4 Remote Mounted Transistor

Remote Transistor Mounted Under Playfield

Some System 1 games went beyond the threshold of 8 controlled solenoids total. The first game to do as such was Joker Poker. There are 4 drop target banks on the game, but only 3 solenoid drivers are available. To overcome this issue, a remote mounted 2N5875 transistor was added under the playfield, and an MPS-A13 lamp transistor was used to pre-drive the remote mounted transistor.

In other cases, Gottlieb® didn't run out controlled solenoid transistors. Instead, they chose to "beef up" the solenoid drive by using a 2N6043 as a pre-drive transistor. System 1 games which use remote mounted transistors are listed in the table below.

Game Name	Sol. Name	Solenoid or Lamp Designation	Pre-Driver Transistor #	Transistor Type	Notes
Joker Poker	Kings Drop Target Bank Reset	Lamp 17	Q17	MPS-A13
Close Encounters	Roto Target	Solenoid 7	Q30	2N6043
Count-Down	Yellow Target Bank Reset	Lamp 17	Q17	MPS-A13
Count-Down	Blue Target Bank Reset	Lamp 18	Q18	MPS-A13
Pinball Pool	Left (1-7) Drop Target Bank Reset	Lamp 17	Q17	MPS-A13
Hulk	Left ("A") Shooter	Solenoid 6	Q31	2N6043
Hulk	Right ("B") Shooter	Solenoid 7	Q30	2N6043
Buck Rogers	Vari-Target Reset	Lamp 17	Q17	MPS-A13	Remote mounted TIP-115
Roller Disco	Left Drop Target Bank Reset	Solenoid 7	Q30	2N6043
Torch	Left Drop Target Bank Reset	Solenoid 6	Q31	2N6043
Torch	Right Drop Target Bank Reset	Solenoid 7	Q30	2N6043
Asteroid Annie	Left Drop Target Bank Reset	Solenoid 7	Q30	2N6043

4.7.4.1 Remote Mounted Transistor Upgrade

Gottlieb® Remote Transistor Circuit

Shortly after the release of the System 80 game Black Hole, Gottlieb® realized that it was necessary to add pull up resistors to remote mounted transistors. Otherwise, the transistor could potentially lock its associated solenoid on, and burn the transistor. However, there were several games prior to Black Hole, where a pullup resistor was never installed. It is highly recommended to add this resistor. This upgrade will decrease the chances of particular solenoids, which use a remote mounted transistor, from locking on upon power first applied to the game.

Gottlieb® Remote Transistor Circuit w/ Pull Up Resistor Upgrade

The 4.7K resistor is soldered to the base of the remote mounted transistor, and then tied to the 24vdc solenoid bus.

4.8 Lamp Problems

Lamp problems are common with most any pinball machine, and Gottlieb® System 1 games are no exception. All Gottlieb® System 1 games use either a #44 or #47 lamp. The choice of which lamp to use is the preference of the game owner. An occasional #455 blinker bulb is used in the backbox in a specific socket, and will only be powered when the game is in the game over state. Of course, #455s can be used elsewhere in the backbox for effect purposes.

It is highly recommended not to replace or remove lamps with the power to the game on. There are primarily two reasons for this.

1. Some lamp sockets must have their mounting brackets bent back to access the bulb for replacement. In turn, the potential of inadvertently shorting one lamp socket to another is possible.
2. Lamps are constructed of an equal balance of glass and conductive metal. If a bulb slips out of one's grasp when trying to remove or install with the power on, there are many areas in the bottom of the cabinet, where the metal of the bulb can short across. A short across other circuits could potentially lead to other unplanned or otherwise unnecessary repairs needed to perform.
   

So in short, change or remove bulbs with the game's power off, just to be safe.
All System 1 games have three separate lamp circuits. The circuits are comprised of:

• General illumination for the backbox
• General illumination for the playfield
• Controlled lamps for primarily the playfield, although, there are four controlled lamps located in the backbox (shoot again, high score game to date, tilt, and game over)

Just one note about controlled lamps. It’s unfortunate, but System 1 games do not strobe the lamps, (turn the controlled lamps on / off), during attract mode. Being at the mercy of the game’s lamp test mode, (self test step 13), is not the greatest option for testing lamps either. During lamp test, the lamps are only powered on solidly for 5 seconds. 5 seconds isn’t nearly enough time to troubleshoot a non-functioning lamp. So, it is best to start a game, and figure out what events it takes to turn the lamp on.

Below are several approaches used to determine the source of a lamp problem, and how it can be resolved.

4.8.1 Bad Bulbs

The first thing when troubleshooting lamp problems, and this may seem blatantly obvious, but determine whether the lamp is good or not. Don't rely on the bulb being brand new either. The ratio of brand new, bad bulbs is slim, but there is that chance a new bulb is not good.

Making certain an old 9v battery is putting out an acceptable lower voltage

The bulbs used in a System 1 game are powered by ~6 volts. A great way to quickly test a bulb is to use a dying 9v battery. Don't use a fresh 9v battery, or you will shorten the life of the bulb. Find a battery that is roughly putting out 7v - 8.25v. An old battery from a smoke detector works pretty well.

Testing a 6v bulb with a dying 9v battery

Place the tip of the bulb on one of the battery terminals, and cock the outer metal casing of the bulb to touch the other terminal. Orientation of the bulb with regards to the positive and negative terminals does not make a difference in this case. Do not hold the bulb across the battery terminals for very long. Just long enough to determine if the bulb's filament is lighting or not.

4.8.2 Lamp Power Issues

Secondly, make certain there is power at the lamp socket. The game will have to be turned on for the following procedures.

4.8.2.1 General Illumination Lamp Power Issues

GI lamps are powered by ~6VAC. When testing a GI lamp socket for power, each lead of the DMM (now set in AC mode) will be placed on the two leads of the lamp socket. If there isn't power at the lamp socket, suspect a bad fuse first. Keep in mind that the backbox GI and playfield GI have two separate fuses located on the transformer board in the bottom of the cabinet. These are typically higher amperage rated fast-blo fuses. The backbox GI on a System 1 game is always on when the game is turned on. If the backbox GI fuse is good, and no backbox lights are lit, the connection at A6J3 / A6P3 (pins 12 and 13) which feeds the GI could possibly be bad.

Gottlieb® System 1 Tilt Relay with Make-Break Switch Highlighted

The playfield GI is always powered on too, except when the game is in tilt mode. If the game was not tilted and /or the tilt switches are not stuck closed, check the switch stack on the tilt relay under the right top of the playfield. Specifically focus on the lower two switch leaves of the make-break switch. These switches can sometimes get bent or misaligned due to the nature of the location of the relay and stack, and become inadvertently closed. If the playfield GI fuse is good and the tilt relay switches are good, the connections at A6J5-1 / A6P5-1 and A6J4-7 / A6P4-7 may be suspect.

If the fuse to a particular GI circuit is bad, and continues to blow every time a new fuse is installed, a short is probably causing the issue. A shorted lamp GI circuit is probably the worst and most difficult lamp related issue to resolve. In most cases, the GI power lines are uninsulated wiring, which make them susceptible to shorted circuits. First, determine if the GI short originates on the backbox lamp insert or on the playfield. GI shorts on the playfield are typically more common than lamp insert shorts. Pop bumper lamps are not CPU controlled, and are included in the playfield GI string. Also, depending on the game, star rollover lamps and kickout hole lamps are sometimes part of the playfield GI circuit. Consult the game manual for these particulars.

Although it can be a pain and time consuming, the best approach is to remove all of the bulbs in the associated shorted GI string. In removing all of the bulbs, we are trying to isolate whether the problem is a bad, defective bulb, or one of the GI power lines is shorting to something else.

4.8.2.2 Controlled Lamp Power Issues

Controlled lamps are powered by ~6VDC. When testing a controlled lamp socket, the red lead of the DMM (now set in DC mode) will be placed on the lamp socket mounting bracket. The bare wire soldered to the lamp socket's mounting bracket is the power bus not the ground bus, so be careful. The black lead of the DMM will be placed on ground. If working under the playfield, the ground plate in the bottom of the cabinet is a good place to connect to ground. If working in the backbox, find where one of the green wires with a yellow trace is screwed to the metalwork, and place the lead on it. System 1 game side rails, lockdown bar assemblies, and other associated trim metalwork, except the coin door, were not grounded from the factory like Bally, Williams, and Stern. Therefore, using any of these as a ground reference is not recommended.

If there isn't any power at the lamp socket, suspect a bad fuse first. The controlled lamp circuit has a separate fuse on the transformer board, and is normally a 5 amp slo-blo fuse. If the fuse tests fine, there is a separate set of switch leaves on the tilt relay, which pass the controlled lamp power to the playfield lamps. Inspect and adjust these switches if necessary. If the controlled lamp fuse and the switches on the tilt relay both test good, there may be an issue with the connection at A6J4-6 / A6P4-6.

If the fuse for the controlled lamps is bad, and continues to blow after a new fuse is installed, suspect a bad controlled lamp bridge rectifier. The lamp bridge rectifier is located on the transformer board. Please see the "Testing a Bridge Rectifier" portion of the PinWiki guides.

If all of the above tests good, there may be a short on the controlled lamp bus line. This is not a very common occurrence, but it can happen. Inspect the underside of the playfield for any wires or brackets touching the controlled lamp bus line, which shouldn't be touching.

4.8.3 Bad Lamp Sockets

Third, determine if the lamp socket is good. Some games have been through the wringer, and the sockets didn't hold up too well due to abuse, a damp environment, or other various reasons. Start by turning the power to the game off. If the socket has some corrosion, try using a lamp socket cleaning tool first. If a lamp socket cleaning tool is not available, a small wire brush used for cleaning copper fittings, a rolled up piece of 220 grit sandpaper, or a Dremel tool with a small wire brush attachment can all be used. After the socket has been cleaned, place the bulb in the socket for the following procedures.

If testing a GI lamp socket, use the dying 9v battery trick again. Remove the fuse of the particular GI circuit which the lamp socket being tested is located. Connect the terminals of the 9v battery to the bulb socket with alligator clip leads. Be careful not to short the alligator clips to each other at the battery's terminals. Equally be very careful not to short the clip leads to an adjacent switch on the pinball machine, or anything else for that matter. One clip will connect to one side of the socket, and the other lead will go to the other side of the socket. DO NOT ALLOW THE BATTERY TO STAY CONNECTED VERY LONG. Since this is a GI lamp circuit, other lamps in the string will be powered by the battery. If the battery is connected to the string for too long, the battery will start to get hot. The battery does not have enough power to keep a string of bulbs lit for too long. The lamp may only glow very dimly, but that is enough to determine if the socket is good or not.

If testing a controlled lamp socket, remove the A3-J3 and A3-J5 connector housings from the bottom of the driver board first. Then remove the fuse for the controlled lamp circuit. Clip one lead of the battery to the lamp socket mounting bracket and the other to the solder tab. The orientation of the negative and positive leads of the battery terminals makes no difference. Again, keep the battery connected just long enough to see if the lamps lights to determine whether the lamp socket is good or not.

4.8.4 Controlled Lamp Issues

4.8.4.1 Lamp(s) Will Not Turn On

So, the bulb is good; the socket is good; there's power at the socket; and the lamp still won't light. Well, this occurrence can only really happen if there is a controlled lamp involved. If all three of the above things apply, it can only mean one thing - the bulb is not getting properly grounded, and will not turn on. The source of this problem may be due to several different issues. But, it is best to start at the bulb socket, and work backward towards the CPU board.

Determine if the connector and wiring from the output of the driver board to the lamp socket is good. With the power off, check the continuity between the solder tab of the lamp socket and the collector (right leg) of the associated lamp transistor. If there is continuity, it’s time to test the transistor. See the How to test a transistor portion of the PinWiki guide. If the transistor tests fine, a gate on the 74175 may be bad. The use of a logic probe on the input and output of the associated lamp gate would be a the best test procedure for definitive results.

If more than one controlled lamp is not lighting, check the game’s manual / schematics to see if the bulbs are related in some way. When four lamps are not lighting, it may appear that the 74175 which controls the lamp transistors may be at fault. This can happen, but the more commonly related issue is that the device select signal for a particular 74175 is lost between the CPU and driver board. This can be due to a bad connection at A1J5 or A3J1. See the chart below for the lamp device select signal path. Finally, if the connections, associated 74175, and lamp transistors are all right, the circuitry on the CPU board is probably at fault.

Device Select	CPU Connector	Driver Input	Driver Quad Flip-Flop (74175)	Transistor #s	Lamp #s
DS1	A1J5-21	A3J1-5	Z1	Q1-Q4	L1-L4
DS2	A1J5-20	A3J1-6	Z2	Q5-Q8	L5-L8
DS3	A1J5-19	A3J1-7	Z3	Q9-Q12	L9-L12
DS4	A1J5-18	A3J1-10	Z4	Q13-Q16	L13-L16
DS5	A1J5-17	A3J1-13	Z5	Q17-Q20	L17-L20
DS6	A1J5-16	A3J1-14	Z6	Q21-Q24	L21-L24
DS7	A1J5-14	A3J1-15	Z7	Q33-Q36	L25-L28
DS8	A1J5-15	A3J1-16	Z8	Q37-Q40	L29-L32
DS9	A1J5-13	A3J1-17	Z9	Q41-Q44	L33-L36

4.8.4.2 Lamp(s) Will Not Turn Off

If a single lamp is involved, or only a handful of lamps with different lamp device select signals, suspect the lamps' associated drive transistors. If a group of four lamps will not turn off, and they are all controlled by the same 74175, suspect the associated 74175 or the device select ("DS" on the schematics). If numerous groups of four lamps will not turn off, suspect the associated 7404 on the CPU board, either Z24 for DS1-DS5 device select signals or Z25 for DS6-DS9 device select signals. If the lamps involved originate from both groups of device select signals, suspect the 74154 4-to-16 decoder IC, Z30, on the CPU board, or possibly the U3 10696EE spider chip on the CPU.

4.9 Switch Problems

There are two types of switches used in System 1 games:

• High current switches with tungsten contacts
• Low current switches with gold flashed contacts

And there are two rules to follow regarding switches.

1. DO NOT CLEAN SWITCHES WITH THE POWER ON
2. DO NOT ADJUST SWITCHES WITH THE POWER ON

The first rule is a little obvious with high current switches, but possibly not so evident with low current switches. The potential to short switches to adjacent metal objects or power bus lines is there. To keep from creating worse, more complicated issues beyond the initial issue, please heed the above two rules.

4.9.1 High Current Switch Problems

High current switches are used wherever the +24VDC solenoid bus passes through. These switches have large surface contacts which allow the solenoid power to pass through without prematurely failing. Assemblies such as the pop bumper power switches, (switches closest to the underside if the playfield), slingshot power switches (located above the playfield), flipper end of stroke switches, flipper cabinet switches. and some relay stack switches. All of the high current switches can be burnished with an ignition file or a flexstone.

Common problems related to high current switches are:

• Fouled or pitted switch contacts
• Maladjusted switches
• Missing contacts
• Contacts no longer peened to its switch leaf
• Broken switch leaves

The first two issues can typically be resolved by either filing the switch pairs or readjusting the switch leaves accordingly. However, if switch contacts are severely pitted, or switches are overly bent numerous times that restoring their proper function is not possible, it is best to replace the switch pair. Likewise, if the switch problem falls into the latter three issues, it is best to replace the switch pair.

4.9.2 Low Current (Switch Matrix) Switch Problems

Low current switches are all of the switches used in the switch matrix. A signal is sent from the CPU on one leaf, while the signal is sent back to the CPU via the other leaf, provided that the switch is closed and functioning properly. The amount of current passing through the switches and its contacts is minimal. Each switch on the switch strobe side has a 1N270 Germanium diode. The purpose of this diode is to isolate each switch from one another in the matrix. Without a diode installed, more than one switch closure would be recognized by the CPU.

4.9.2.1 Switches Stuck Closed

Two of the most common problems with switches staying closed are:

1. The switch dampener is shorting to the adjacent switch leaf.
2. Switch closures suddenly appear after new rubber is applied to the playfield.

The switch dampener is a piece of slightly bent metal located between the two switch leaves. The purpose of the switch dampener is twofold. First, it is used to adjust the switch leaf, which is typically furthest away from rubber or a rollover switch actuator. The dampener rests against the shorter adjustable switch leaf of a switch pair. Since thicker, more rigid metal is used than the switch leaves, the dampener is easier to adjust a switch more precisely if bending it alone or while paired with the switch leaf. The downturn is that the dampener can be adjusted so it rests against the longer switch leaf, thus shorting the switch closed.

Often, when you replace the rubber on the playfield, since the rubber is tighter, switches that are behind the rubber will exhibit less gap. This is especially true when you tighten the posts that hold the rubber before installing the new rubber (always check the post tension to the playfield as often the posts become loose). When you put the new rubber on, check the switch(es) behind it to ensure they are not gapped too close, and adjust if so. The blade that touches the rubber should barely touch it, and the blade behind it should be about 1/8"-3/32" away. This way a slight graze of the ball on the rubber will activate the switch, but not so close that multiple closures will occur, nor will vibration from other mechanical devices cause false closures.

4.9.2.2 Multiple Switch Closures From the Same Switch

Two of the most common problems with switches closing more than once are:

1. The switch dampener is not adjusted tightly against the adjustable switch leaf of a switch pair.
2. Switches are gapped too close.

The second purpose of the switch dampener is to decrease the amount of bounce from a switch once it closes. If you inspect the action of a switch closure, there is always some degree of bounce after the two switch leaf contacts make initial contact. Because the switch leaves are very flexible, the amount of bounce without a switch dampener is much more drastic. The end result of more switch bounce is multiply switch closures.

Switches can become gapped too close, especially if new rubber replaced on the playfield. See the above description regarding replaced rubber for a detailed explanation why this occurs.

4.9.2.3 Switches not Showing as Closed When They Should Be

Conversely, switches may not be identified by the CPU board as being closed when the switches are physically closed. There are several reasons why this occurs. The reasons, (listed from most common or simplest to resolve to least common or most difficult to resolve), for this to happen are:

1. The switch is dirty.
2. The gold contacts on the switch have have been burnished or filed at one time.
3. The connector contacts at A1-J7 or A1-J6 are bad.
4. There is a break in the switch strobe or switch return line.
5. A shorted switch diode.
6. The buffer or spider chips in the switch matrix have failed.

• Inside a pinball machine, there are many different contaminants which can foul a switch, and switch contacts do and will get dirty over time. See the section below on how to clean a low current switch.

• If cleaning a switch does not resolve the issue, carefully inspect the switch contacts with high magnification. If the contacts are drastically scored or appear to have been sanded, the only resolution is to replace the switch pair. During the EM era, the common practice was to clean switches with an ignition file or a flexstone. Because only high current switches were used then, these were both acceptable practices to clean a switch. However, some operators or repair people did not initially grasp the concept of not cleaning solid state switches by filing or burnishing.

• The connectors at A1-J7 and A1-J6 handle all of the switch strobes and returns. If the connectors have not been repinned, it is common for the metal connectors to loose tensile strength, become corroded due to alkaline battery damage, or break. If any of these things have happened, the connection to the CPU board is compromised, and switches may work sporadically or not at all. The best recourse is to remove all the existing connectors, and replace the connectors with new ones. Replacing connectors by crimping new ones in place is the proper method. Cleaning connectors with contact cleaner, sanding the connectors, or bending the connectors are all considered only temporary fixes, if they even work at all.

• It's not too common with System 1 games to have switch lines that break or cold solder joints on switch solder tabs, but it can happen. The best method to find a break in the line is to perform a continuity test from the switch solder tab to the appropriate connection on the CPU board, (A1J7 for playfield switches and A1J6 for coin door switches).

• As mentioned above, the switch strobes do have 1N270 Germanium diodes soldered in line. The diodes are located on a centralized diode board. Although it's not too common, but the diodes can fail. It is best to remove the appropriate connector on the CPU board, either A1J7 or A1J6 before testing a switch diode. In doing this, other components on the CPU, if they have failed, will not skew the readings. Using a DMM in diode test mode, the typical readings seen when testing a 1N270 diode are ~.18 - .27, and no reading when the DMM leads are reversed. These numbers are just a gauge, and different DMMs will yield different results. To best identify a failed diode, take sample measurements from several other switch diodes. If a specific diode under test is comparatively out of the range with the other diodes, chances are that particular diode has failed. Replace failed diode with a 1N270 diode only.

• All of chips responsible driving the switch matrix can fail. The return (Z9 or Z28) and strobe (Z8) buffer chips are the first chips to test. The returns use a 7405, while the strobes use a 7404. It is common for a single gate or a couple of gates to fail on these chips. The chips do not necessarily have all gates fail. A logic probe should be used to ensure that the switch strobe and return line inputs and outputs are reacting as they should. (++++add more result detail here+++). If the buffer chips test fine, the next course of action is test the output of U5 with a logic probe. (++++add more result detail here+++)
  

4.9.2.4 Cleaning Low Current Switches

Low current switches SHOULD NOT BE FILED OR BURNISHED. As mentioned above, the low current switches are gold flashed, and filing, using a flexstone, nail file, or sandpaper will remove the thin gold plating. In turn, the switch will become less reliable or not function at all. The best approach to cleaning a gold flashed switch is to place a piece of heavy card stock (a business card, index card, etc.) between the two switch leaves. A 1/2" wide strip of card stock works best for getting into tight locations, but a business card works in a pinch.

1. Insert the card stock between the two switch leaf contacts.
2. Gently close the two switch leaves, applying slight pressure at the switch contact of the outer switch leaf or leaves.
3. With the switch leaves still closed on the card stock, slowly pull the card stock strip from the length of the switch leaf. Do not pull the card stock strip from the side of the switch, because not as much surface area of the strip will be "wiping" the switch contacts. Plus, the potential to bend or twist the leaf switches out of shape is more probable.
4. The end results of cleaning a switch are what looks like light pencil marks on the card stock, if the switch leaf contacts are in fact dirty.
5. Repeat the whole process, until grey streaks on the card stock are no longer seen.
   

4.9.2.5 Testing Switches in the Switch Matrix

Gottlieb® has a switch test option to test any of the switches in the switch matrix. The switch test can be entered via the white test button, which is located inside the coin door. Switch test starts once "13" is notated on the left side of the status display, and after lamp and solenoid tests have completed. For switch test, the ball can remain in the outhole, as the outhole switch is not on the switch matrix, and not tested while in switch test.

During switch test, any of the switches on the switch matrix can be tested by activating a switch closure, and the associated switch number will be notated on the right side of the status display. If multiple switches are activated, all switches will be displayed from the lowest strobe number first, incrementing the switches on the same return, and continuing to the next switch strobe line, until all results have been displayed. An example would be if all of the drop targets are down (all drop target switches closed) on Charlie's Angels. The 3 bank drop targets are switch numbers 10, 11, and 12, (top to bottom), while the 5 bank drop targets are switch numbers are 30, 31, 32, 33, and 34 (left to right). The results during switch test will display the numbers in the following sequence: 10, 30, 11, 31, 12, 32, 33, and 34.

The System 1 switch test is especially beneficial for identifying complete switch strobe or return failures. If none of the switches are closed in the switch matrix upon entering switch test, but multiple switches are identified as being closed, a switch strobe or return failure is more than likely the culprit. An example would be if switches 02, 12, 22, 32, 42, 52, 62, and 72 are reported as closed, there is a switch strobe issue. Likewise, if switches 30, 31, 32, 33, and 34 are reported as closed, there is a switch return issue.

The switch test on a System 1 game is implemented quite well, except it is painstakingly slow. However, there is an alternate, quick and dirty method to test System 1 switches. This test will not display the actual switch number closure, but it will let the tester know that a switch has successfully been closed or not.

1. Put the game in attract mode.
2. Close the switch to be tested. If the displays "flicker" for a brief moment as the switch closes, the game has identified it as a successful switch closure. If the displays do not "flicker", the switch closure was not identified. Note: This test works with the original Gottlieb® and the Ni-Wumpf replacement MPU board - Pascal PI-1 or PI-1X4 replacement boards may not exhibit this behavior.

This test is particularly great for identifying whether or not a parallel wired scoring switch is stuck closed by closing a second scoring switch with the exact same switch number. If the displays do not flicker, the reason is more than likely due to one of the other parallel switches with the same number remaining closed. An example would be the 10 pt. switches used on a System 1 game. Most games have at least four 10 pt. switches. If all of the 10 pt. switches fail to score during game play, the issue is typically one of the parallel switches is closed. Although the attract mode switch test will not identify which of the many 10 pt. switches is closed, it is great for quickly verifying a switch closure.

4.10 Display Problems

The blue Futaba display glasses used by Gottlieb® System 1 machines are a fairly reliable, long-lasting display. Although, they can and do still fail. It's just a matter of diagnosing the symptoms of a failed display.

Display problems can primarily be classified into the following categories:

1. Power problems
2. Display glass failure
3. Data problems
4. Tired displays

4.10.1 Display Power Problems

Before even attempting to work on System 1 displays, there are two caveats to heed. First and foremost, the displays function due to the necessity of several voltages, including high voltage. IF YOU ARE UNCOMFORTABLE WORKING ON HIGH VOLTAGE CIRCUITS, THEN DO NOT WORK ON SYSTEM 1 DISPLAYS! High voltage can hurt or even kill you. If you don't feel comfortable working around this type of scenario, then hire a professional to do the work. Secondly, any time a display connector needs to be disconnected, DO NOT REMOVE ANY DISPLAY RELATED CONNECTOR WITH THE POWER ON! This goes for the connectors located directly at the display, connectors A1J2 and A1J3 on the CPU board, A2J3 on the power supply board, and A6J3 / A6P3 from the transformer. Removing connectors with the power on can damage the display, the CPU board, and / or you. Sorry to "yell", but it is extremely important to stress the above two statements. Now that this is out of the way, let's move on.

As stated above, the displays need several sources of voltage to function properly. The display voltages used are broken down by the type of display: +60VDC, +8VDC offset, and 5VAC are used for the 6-digit displays; +42VDC, +4VDC offset, +5VDC logic (for the 7432 chip - Z1), and 3VAC are used for the 4-digit status display. When using a 6 digit display with DI513 Dionics chips, +5VDC is necessary for RP1 and RP2 8.2K resistor networks. If any of the above voltages are missing, the display will never light.

Prior to plugging in and turning the game on for the very first time, it is a good practice to check all of the fuse values located on the transformer board first. There is a 1/4 amp slo-blo fuse used for the display voltage, which is located on the transformer board in the bottom of the cabinet. With the game unplugged from the wall outlet, remove the fuse from its fuse holder. When checking fuses, never "eyeball" a fuse. Your eyes may tell you that the fuse is good, but your eyes can fool you. Use a digital multi-meter (DMM) or a continuity tester to check fuses. Put each lead of DMM on opposite ends of the fuse. A tone should be heard. If not, the fuse is bad, and should be replaced with the same value. Fuses are used to protect equipment, the surroundings, and you. Installing fuse values with higher ratings is very dangerous. DO NOT USE A FUSE RATED AT A HIGHER RECOMMENDED VALUE! If the existing fuse is blown, it may not necessarily mean there is a problem. Fuses do get stressed, and sometimes just fail. However, there is more than likely a problem somewhere in the display power train.

With the game still unplugged, the next course of action is to place connector A2J1 on the power supply. A2P1 is the bottom connection on the power supply, and receives all voltages directly from the transformers and a single ground from the ground strip. The connector can be plugged in upside down, but it will take a fair amount of effort to do so. Just be careful when plugging this connector in. Once A2J1 is connected, remove any other connections from the power supply (A2J2 and A2J3). All voltages should be tested before any boards or displays are connected to them.

At this point, plug the game in, and turn it on. Using a DMM or volt meter, check all of the voltages at A2P3. For the +60VDC (A2P3-1) and +42VDC (A2P3-3), pin 5 of A2P3 must be used as the ground reference. Using any other point for a ground reference will result in incorrect voltage readings. Pin 5 is marked "COM" on the board. If the +60VDC is a little low, it can be adjusted with the potentiometer located on the right of the board. The +42VDC is derived from the +60VDC. If there is +60VDC, but not +42VDC, The 18v CR12 zener diode or the R18 resistor may have failed.

If the two high voltages test all right, it's time to check the two offset voltages. The offset voltages are +4VDC (A2P3-7) and +8VDC (A2P3-8). This may seem odd, but either A2P2-4 or A2P2-5 must be used as a ground reference to test these voltages.

If all the display voltages are satisfactory, it is time to move onto the next step of visually inspecting the display boards for obvious defects.

4.10.2 Display Glass Failure

Display with a good display glass

The simplest and easiest problem to identify is display glass failure. All of the 6 digit displays used by Gottlieb® System 1 games will have a black "blotch", for lack of a better term, in the upper left and lower right corner of the glass. The 4-digit status display typically has only one black blotch. The evidence of a black blotch or blotches is good.

Display with Broken Nipple on Back

However, if there is a muted white blotch visible at the corners of the display, it means the display's "vacuum" has been compromised, either due to a cracked glass or broken nipple. If this is the case, the display glass can not be repaired and is useless.

Display with Broken Top Filament. Note that this is the Dionics chipset version of the display.

The display filaments within the glass can also break. The end result will be segments with missing sections or "hot spots" when the display is powered. The "hot spots" are caused by the "dangling", broken filament shorting to other good filaments. If a display filament breaks, do not use the display as shorted displays can damage other game components.

Even though the glass itself is bad, the chips on the display board may still be good. So don't necessarily discount the display as being all bad. UDN6118A and 7432, (chip used on status display only), chips are getting more costly, and Dionics DI513s are very scarce. Since the display board is single sided, removal of the chips is quite easy. Plus, the display PCBs are no longer being made. The display board and / or chips may come in handy some time in the future.

4.10.3 Display Data Problems

+++determining if it is a digit or segment problem, what displays are affected (one or pairs), etc.+++

4.10.4 Rejuvenating Tired Displays

Rejuvenating tired System 1/80 displays

System 1 displays, especially those that haven't been turned on for a long time, sometimes fade. These displays can be rejuvenated by applying voltage to the outside pins of the display glass. Note that voltage should be applied to the display glass pins, NOT the card edge pins. This process "burns" the impurities that accumulate on the filaments off.

In the picture at left, general illumination power (7VAC) from the lamp insert panel is being used to rejuvenate a display.

Procedure:
1. Turn the game off
2. Remove the connector from the display
3. Connect jumper clips from a voltage source to each of the outside pins of the display glass. Note that the lower the voltage applied, the longer the display can tolerate this "rejuvenation".
    That is why some techs choose to use the lower GI AC voltage for this purpose.
4. Power the game on for 1 minute.
5. Disconnect the jumper wires and reconnect the display.
6. Power on to test the display.
7. If the display still isn't bright enough, repeat this process for 1 minute each time, until the display is satisfactorily bright.

Note that if the display filaments, which run across the display horizontally begin to glow orange (or worse, white), too much voltage is being applied or the display has been connected too long. This risks burning one or more of the display filaments out and ruining the display. A cautious, 1 minute at a time, process is warranted.

Note also that one particular System 80 tech ("System 80, not just a job, it's an adventure") suggests that merely leaving the game powered on for 24 hours will accomplish the same rejuvenation.

4.10.5 All Other Display Issues (Not Caused by Displays)

There are several issues which appear to be display related, however, they ultimately are not. In these instances, the displays are used instead as a visual identifier of a particular issue.

4.10.5.1 Open Slam Switch

Simulation of a Display Effected by an Open Slam Switch

If after turning a System 1 game on, and the scoring displays turn on immediately without a 5 second delay, there is a problem. However, this is not a display issue, if the displays are showing all outer segments (all zeroes) lit, and "strobing" or "rolling" rapidly. The problem is actually due to an open slam switch on the coin door or the ball roll tilt.

See how to permanently disable the slam switches.

4.10.5.2 Shorted Coin Switch

If after turning a System 1 game on, and the scoring displays turn on immediately without a 5 second delay, there is a problem. This is not a display issue either. In this case, the scoring displays will all solidly show 000000, and not alternate between high score to date. This is typically a symptom of one of the two coin switches shorting to the coin door.

4.11 Sound problems

4.11.1 Chime Box

There is a small rubber strip on the bottom of the chime box that functions as a cushion for the chime plungers. Over time it becomes sticky and prevents the chime plunger from reacting quickly, causing a weak sounding chime. Remove this strip and replace it with some thick foam weatherstripping; you might have to use 2 layers to get a nice thickness. Clean the ends of the plungers of any sticky residue with some isopropyl alcohol. Inspect the nylon tips of the plungers and replace any that are too short.

Each chime bar is held to the chime box by a screw with a rubber grommet enabling the chime bar to 'float' without touching any metal. If this grommet is old, missing or simply worn, the chimes won't ring true, they'll end up sounding like a dull ting instead of a music like tone. You can get new grommets at any hardware store that has a good selection of hardware. (Sears Hardware and Ace are good places to look). Make sure the chime bars are not screwed down all the way to the box; you want the bars to 'float' for aurally pleasing results.

4.11.2 Tone Board

The design of the basic tone sound board used in system 1's produces a tone as long as the 555 timer's input is grounded. If a continuous tone is produced, suspect a bad driver transistor on the lamp/solenoid driver board holding the ground on.

4.11.3 Multi-Mode Sound Board

Ground screw for 5v regulator on back side of sound board

Make certain to inspect and tighten the screws which secure the 5v regulator to the sound board. The screw / nut as marked in the pic ties the regulator case to ground. If the case is not tied to ground, the regulator will not function as intended.

4.11.4 Converting From a Tone Board to Chimes

Converting from a 3 tone sound board to a a mechanical chime box is rather a simple process. There is a 6-pin Molex connector (A6-J2 / A6-P2) located just prior to A7-J1 of the tone board. This connection carries the driver signals for each chime tone, the knocker, and two +24vdc solenoid lines. A factory System 1 chime box conveniently has the exact same connection.

Gottlieb® System 1 Tone Board w/ A6-J2 Connector Highlighted

1. Disconnect A7-J1 from the tone board, and disconnect the 6-pin Molex connector (A6-J2 / A6-P2).
2. Remove the tone board from the side of the cabinet.
3. Find a suitable mounting location for the chime box, and place it on the side of the cabinet.
4. Mark for the 3 holes at the top and a 4th hole at the bottom of the chime bracket.
5. Drill all 4 holes.
6. Place a screw in the lower hole first, and screw it in approximately 3/4 of the way. This screw is used only to support the chime box bracket, and should not be tightened completely.
7. Screw in the remaining 3 screws.
8. Connect the 6-pin connector.

Gottlieb® System 1 Chime Box w/ A6-J2 Connector Highlighted

A chime box can be used from an EM game by modifying some wiring and adding diodes to the coils. Daisy chain the +24vdc solenoid bus wire to one lug on each coil. Put the signal wire for each chime tone on the other lug; the smallest chime is the 10 point chime, middle sized is 100 points, and largest is 1000 points. The wire colors are orange-black (311) for 10, green-red (244) for 100, and purple-red (255) for 1000. Orient an 1N4004 diode with its band towards the power bus (daisy-chained) wire on each solenoid.

Keep in mind that most Gottlieb® EM chime boxes use A-5195 coils versus the A-17876 coils used in System 1 chime boxes. The A-5195 coils are half the resistance of the A-17876 coils, so the chimes will be struck harder.

4.11.5 Converting From Chimes to a Tone Board

Not nearly a common practice as converting from a sound board to chimes, but it is possible.

4.12 Flipper Problems

System 1 Flippers

4.12.1 Flippers Won't Work at All

+++Discuss Q and T relay switches, cabinet switches, spade connectors on cab switches, EOS switches, link to plunger breakage, etc.+++

4.12.2 Flippers are Weak / Sluggish

+++Discuss plunger tail, pawl / crank placement with regards to upper and lower bushing, cab switches, eos switches, spade connections, etc.+++

4.12.2.1 Removing the Flipper Link Extension / Tail

System 1 Flipper w/ Link Extension (tail) Circled

When servicing System 1 flippers, remove the link extension / tail with a pair of dikes or a hacksaw. This "tail" can create drag, in turn, reducing power to the flippers. The tail was removed with later flipper designs and remanufactured links.

4.13 Drop Target Problems

4.13.1 Replacing Drop Target Plastics

4.13.1.1 Early System 1 Drop Target Removal

For now, please review the drop target removal guide available at PAPinball.com.

4.13.1.2 Later System 1 Drop Target Removal

For now, please review the drop target removal guide available at PAPinball.com.

4.14 Vari-Target Problems

This is a stub

System 1 Vari-Target Mechanism (Totem)

System 1 Vari-Target Mechanism with Recommended Lubricant

5 Game Specific Problems

5.1 Joker Poker

If the "kings" drop target reset coil locks on at start up, see the Remote Mounted Transistorsection.

6 Repair Logs

Did you do a repair? Log it here as a possible solution for others.