Gottlieb System 80

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1 Introduction

Gottlieb® System 80 Board Set - 1st Generation

Gottlieb's® second generation of solid state pinballs is System 80. Capabilities were increased in terms of controllable lamps, solenoids, gameplay, and sound. No longer tied to an EM-esque platform, Gottlieb® started to introduce games with more unconventional asymmetric playfields. System 80 marked a foray into double and triple level playfields, speech, and multiball. Unfortunately, it also represented a lateral step in reliability, with battery corrosion, connectors, and bad grounding plaguing the design. Nearly all the same issues as were present with the System 1 platform.

Gottlieb® System 80 Board Set - 2nd Generation

Just like the System 1 games, the System 80 / 80A / 80B design relied solely on connectors and daisy-chained wiring to transport the ground lines from board to board. The exception is that the large ground plane used with System 1 games was no longer used behind the boards with the System 80 games. Gottlieb® still opted to use plastic standoffs to elevate and secure the boards to the backbox or the back side of the lamp box insert. 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.

Gottlieb® System 80A Board Set

The System 80 platform was used for a total of nine years from 1980-1989. During this period, there were three main versions of the boardset. These three versions are referred to as: System 80, System 80A, and System 80B. System 80 was used from 1980-1982, System 80A was used from 1982-1985, and System 80B was used from 1985-1989. The easiest way to differentiate between the three versions is by looking at the style of displays which were used. System 80 used 6-digit displays for scoring, and in some instances, for bonus values or timers. System 80A used 7-digit displays for scoring, and 6-digit displays for bonus values or timers too. Both the 6-digit and 7-digit displays were limited to displaying numeric values. System 80B differed the most by using two 20-digit alpha-numeric displays, which were stacked on top of each other.

Gottlieb® System 80B Board Set - Early

Shortly after the onset of using the System 80B boardset, it was evident that the complexity of playfield designs had quickly outgrown the boardset. Remote satellite boards, and transistors littered the underside of the playfield and inside the cabinet, because the driver board was too undersized to handle these extra duties. A new boardset, known as the System 3 platform, was under development, but was not released until nearly 4 years later in 1990.

Gottlieb® System 80B Board Set - Typical

Once a System 80 / 80A / 80B game has been methodically gone through with board design grounding flaws and connectors corrected, they are just as reliable as any of their contemporaries.

2 Games

2.1 System 80 1st Generation

Title	Date of Release	Production#	Model #	Sound	Notes
The Amazing Spiderman	05-1980	7625	653	Sound only
Panthera	06-1980	5220	652	Sound only
Circus	06-1980	1700	654	Sound only	Ultra Widebody
Counterforce	06-1980	3870	656	Sound only
Star Race	08-1980	870	657	Sound only	Ultra Widebody

2.2 System 80 2nd Generation

Title	Date of Release	Production#	Model #	Sound	Notes
James Bond	10-1980	3625	658	Sound only
Time Line	12-1980	3167	659	Sound only
Force II	12-1981	2000	661	Sound only
Pink Panther	03-1981	2840	664	Sound only
Mars God of War	03-1981	5240	666	Sound & Speech	First Gottlieb® with speech, lane change, and multi-ball
Volcano	09-1981	3655	667	Sound & Speech
Black Hole	10-1981	8774	668	Sound & Speech	First Gottlieb® with 2-Level playing area, Export games used sound only board
Haunted House	06-1982	6835	669	Sound only	First game with 3-Level playing area, Sound only, but used sound & speech board w/o the speech chip installed
Eclipse	1982	193	671	Sound only	Production game and available as a kit for James Bond 007

2.3 System 80A

Title	Date of Release	Production#	Model #	Sound	Notes
Devil's Dare	08-1982	3832	670	Sound & Speech	Export games used the sound only board
Caveman	09-1982	1800	PV810	Sound & Speech	Pinball / Video game hybrid
Rocky	09-1982	1504	672	Sound & Speech
Spirit	11-1982	1230	673	Sound only	Sound only, but used sound & speech board
Punk!	12-1982	959	674	Sound only	Sound only, but used sound & speech board
Striker	11-1982	910	675	Sound only	Sound only, but used sound & speech board
Krull	02-1983	10	676	Sound only
Goin' Nuts	02-1983	10	682	Sound only	Sound only, but used sound & speech board
Q*bert's Quest	03-1983	884	677	Sound & Speech
Super Orbit	05-1983	2100	680	Sound Only	Sound only, but uses the less populated sound & speech board
Royal Flush Deluxe	06-1983	2000	681	Sound Only	Sound only, but uses the less populated sound & speech board
Amazon Hunt	09-1983	1515	684	Sound Only or Sound Only	Sound only, but uses the less populated sound & speech board. Later production games used the sound only piggyback sound board
Rack 'Em Up!	11-1983	1762	685	Sound Only
Ready... Aim... Fire!	11-1983	390	686	Sound Only
Jacks to Open	05-1984	2350	687	Sound Only
Alien Star	06-1984	1065	689	Sound Only	689A Denotes a revision in the ROM code
The Games	08-1984	1768	691	Sound Only
Touchdown	10-1984	711	688	Sound Only
El Dorado City of Gold	09-1984	905	692	Sound Only
Ice Fever	02-1985	1585	695	Sound Only

2.4 System 80B

Title	Date of Release	Production#	Model #	Sound	Notes
Chicago Cubs Triple Play	05-1985	~1365	696	Sound Only
Bounty Hunter	07-1985	1220	694	Sound Only
Tag Team Pinball	09-1985	1220	698	Sound Only
Rock	10-1985	1875	697	Sound Only
Raven	03-1986	3550	702	Sound Only
Rock Encore	04-1986	245	704	Sound Only	Production game using same playfield art as Rock, but mainly available as a conversion kit for Rock
Hollywood Heat	06-1986	3400	703	Sound Only
Genesis	09-1986	3500	705	Sound Only
Gold Wings	10-1986	3260	707	Sound Only
Spring Break	04-1987	3550	706	Sound Only
Monte Carlo	02-1987	4315	708	Sound Only
Arena	06-1987	3099	709	Sound Only
Victory	10-1987	3315	710	Sound & Speech
Diamond Lady	02-1988	2700	711	Unknown
TX Sector	03-1988	2336	712	Sound & Speech
Robo-War	04-1988	2130	714	Sound & Speech
Excalibur	11-1988	1710	715	Unknown
Bad Girls	11-1988	2500	717	Sound & Speech
Big House	04-1989	1977	713	Sound & Speech
Hot Shots	04-1989	2342	718	Sound & Speech
Bone Busters Inc.	08-1989	2000	719	Sound & Speech	Used 3 sound boards

Game date of release, production numbers, and model number provided by the Internet Pinball Database - http://www.ipdb.org

3 Technical Info

3.1 System 80 / 80A / 80B Board Set

Clicking the link above will direct to a new page showing all of the System 80/80A/80B boards.

3.2 System 80 / 80A / 80B Satellite Boards

Clicking the link above will direct to a new page showing all of the System 80/80A/80B satellite boards.

3.3 Recommended Documentation

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3.4 The Wiring Color Code

Unlike every other pinball manufacturer, which adopted a two-color wiring code system, Gottlieb® used three colors. 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, or only one color - the white ground wires used in System 80B games with no trace at all. 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 400. 400 would be a white insulated wire with a yellow trace and two black traces, or commonly referred to as a yellow-black-black wire. The ground lines in early System 80 games are code 54. 54 would be a green insulated wire with one yellow trace.

There is one word of caution, which should be pointed out. If the connections on A1J2 and A1J3 are being replaced, there are wire colors on these connections which are very similar. Although each wire is located on a different housing, please proceed with caution, as it can be difficult to see all three traces without spinning the wire around. The wires which come to mind are 344 and 677 on A1J2, and 433 and 766 on A1J3.

3.5 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 A1J5-10. The coin door connection used on Devil's Dare is A15P1 and A15J1 - the connector pin for switch return 7 on the coin door is A15J1-8.

The following boards are assigned the same numbers throughout the System 80 / 80A / 80B platforms.

• CPU Board - A1
• Power Supply - A2
• Driver Board - A3
• Sound Board - A6
• Pop Bumper Driver Boards - A8
• Reset Board - A24

There are several other board designations used, however, they change from game to game.

3.6 Switch Matrix

Gottlieb® System 80 Switch Matrix

The Gottlieb® System 80 / 80A / 80B switch matrix consists of a maximum of 64 switches. There are a total of 8 switch strobes and 8 switch returns. However, not every switch in the matrix is used on every System 80 game.

Just like the System 1 switch numbering system, the System 80 switch numbers have a similar naming convention. Except, the System 80 switch numbering system is the opposite of System 1. If you are accustomed to working on System 1 games, pay close attention. With Gottlieb® System 80 switches the first number of the switch is its strobe number, while the second number is switch's return number. An example would be switch 54. Switch 54 is located on strobe 5 and return 4 of the switch matrix.

	Strobe 0 (A1J6-1 / A1J5-2)	Strobe 1 (A1J6-2 / A1J5-3)	Strobe 2 (A1J6-3 / A1J5-4)	Strobe 3 (A1J6-4 / A1J5-5)	Strobe 4 (A1J6-5 / A1J5-6)	Strobe 5 (A1J6-6 / A1J5-7)	Strobe 6 (A1J6-7)	Strobe 7 (A1J6-8 / A1J5-9)
Return 0 (A1J6-10)	00	10	20	30	40	50	60	70
Return 1 (A1J6-11)	01	11	21	31	41	51	61	71
Return 2 (A1J6-12)	02	12	22	32	42	52	62	72
Return 3 (A1J6-13)	03	13	26	33	43	53	63	73
Return 4 (A1J6-14)	04	14	24	34	44	54	64	74
Return 5 (A1J6-15)	05	15	25	35	45	55	65	75
Return 6 (A1J6-16 / A1J5-8)	06	16	26	36	46	56	66	76
Return 7 (A1J6-17 / A1J5-1)	07	17	27	37	47	57	67	77

3.6.1 The "Missing" Gottlieb® System 80 Switches

With the Gottlieb® System 80 series of games, there are some switch assignments that are designated the same throughout the System 80, 80A, and 80B platforms. These switches are typically not listed in the switch matrix portion of the manual. You have to review the cabinet schematics, and decipher what switches use what return and strobe. However, it appears that Gottlieb® / Premier® changed this section of the schematic starting with Excalibur or Bad Girls by no longer listing the strobes for these switches. So, below are the "missing" switch assignments for any Sys80B. All the info applies for Sys80 and Sys80A, except the two advance buttons, which weren't used prior to Sys80B.
06 - left advance button (Sys80B only)
07 - play / test switch
16 - right advance button (Sys80B only)
17 - left coin switch
27 - right coin switch
37 - center coin switch
47 - replay button
57 - plumb bob and ball roll tilts (these have the same switch assignment as the playfield tilt switch)

Black Hole is one exception. The switch assigned for the tilt on Black Hole is 26.

Note: The coin door slam switch is not part of the switch matrix.

3.6.2 Setting up a Game for Free Play

Early Gottlieb® 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-Yellow-Yellow
Left coin switch wire - Green-Brown-Brown
Center coin switch wire - Green-Orange-Orange
Right coin switch wire - Green-Red-Red

Gottlieb® System 80 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. 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.

Please note that this modification does not apply to Gottlieb® System 80A and System 80B machines. System 80A and 80B machines use diode boards with edge connections, which are typically located on the cabinet wall near the left flipper cabinet switch. In my experience, jumpering the diodes on System 80A and 80B games do not give the intended free play results of jumpered System 80 diodes. I attribute this to the System 80A and 80B software reading the switch matrix differently.

3.7 Power Supply

3.7.1 System 80 / 80A Power Supply

System 80 / 80A Power Supply

The System 80 / 80A power supply is very similar to the System 1 power supply, where as the circuit board is secured to a large "hot plate" heat sink. This style power supply is used for all System 80 and 80A games from Spiderman to Ice Fever, and is the source of the following:

• +5 VDC logic power
• +8 VDC offset voltage needed for the displays
• +60 VDC for the 6 or 7 digit displays
• +42 VDC for the status display
• Ground from earth ground located on the transformer panel
  

Unlike the System 1 power supply, the +5 VDC logic power is no longer rectified and filtered on the power supply itself. This process is now handled by a bridge rectifier and a large filtering capacitor located on the transformer panel. The System 80 power still employs a crowbar circuit [1] for the logic power, which is very beneficial.

System 80 / 80A Power Supply - Showing the Large Heat Sink

Although these power supplies are fairly reliable, there are some drawbacks to the design. By incorporating a large heat sink for the PMD10K40 / 2N6059 TO-3 transistor on the board, a lot of heat is dissipated throughout the whole board. This in turn will limit the life expectancy of the other electronic components on the board. Equally, the heat sink must be removed in order to perform component level repairs to the board.

3.7.2 System 80 / 80A Sound & Speech Power Supply

A sound & speech board (S&S) is used starting with Mars God of War (MGOW). Because of the voltages needed to drive some of the components on the S&S board, this secondary power supply is added to the power train. The voltages generated from this board are:

• +12 VDC used for the analog inverters and voice synthesizer chip
• -12 VDC used for the analog inverters
• +30 VDC used for amplification

System 80 Sound & Speech Power Supply (1st Generation)

There are two different variations of this power supply. The first style is used only with MGOW and Volcano, and is not a printed circuit board (PCB). The electronic components were screwed to a block of wood, which is located on the left wall of the lower cabinet. Conducting tests and repairs to this style power supply can be awkward and difficult.

System 80 / 80A Sound & Speech Power Supply

Starting with Black Hole, the S&S power supply is now on a circuit board, which is located in the head of the game with the other circuit boards. Even though each style of S&S power supply uses different components for the generation of +12 VDC, the end result is the same. The S&S power supply was no longer used when Gottlieb® went a step backwards, and installed the System 80A sounds only board with the piggyback board. This change occurred during the run of Amazon Hunt.

3.7.3 System 80B Power Supplies

Starting with Chicago Cubs, the Gottlieb® power train went through a bit of a face lift. The System 80B platform uses two separate boards to supply power. This design change is mainly due to the single display board, which rectifies the high voltage on the board itself.

System 80B +5 VDC Power Supply

The small power supply with the finned heat sink is only used to generate +5 VDC for logic power. Although, removing the heat sink is not necessary to work on the board, this power supply has its own set of issues. First, it does not have a crow bar circuit. If the LM338K voltage regulator fails, and fails whereas the voltage increases drastically, it can destroy electronic components on the other circuit boards. Secondly, it's not as bad, but heat is still dissipated throughout the board. Third, the adjustable potentiometer (pot) on the power supply is prone to failure, due to dirt, dust, and contaminants. Finally, it is typical for the header pins on the input and output of the board to develop cracked solder joints. The two latter problems can easily be overcome, and will be addressed in the Recommended Repairs for the System 80B Power Supply Board section below.

System 80B Auxiliary Power Supply

Starting with Rock, the second power supply is added, and is referred to as the auxiliary power supply. The primary functions of this board is used to power the sound board, and amplify the audio output. A breakdown of the voltages supplied by the auxiliary power supply are as follows:

• -12 VDC
• +12 VDC

System 3 Auxiliary Power Supply (80B Aux. Board w/ headers needs inserted here)

This board changed with Bad Girls. Edge connections were no longer used. Instead, .156" header pins were added to the board. The pic to the left depicts a System 3 aux. power supply. Although the System 80B and System 3 boards are slightly different, the pic is being used for illustration purposes at the moment.

3.8 CPU Board

Gottlieb® System 80 CPU Board

The System 80 CPU board is a 6502 based microprocessor system. The 6502 microprocessor (the very same one used in the first Apple computer) executes the basic operating system contained in the masked ROMs at U2/U3. The masked ROMs at U2 and U3 have the same code for all of the different generations of the System 80 platform. U2 and U3 code changed with the System 80A platform. The game code "personality" augments the basic operating system PROM(s). Early System 80 games which used ROMs at both the PROM1 and PROM2 positions were masked ROMs. When only the single PROM1 position was used, EPROMs were used instead. Battery-backed memory for audits and adjustable game parameters is added via a 5101 256x4 bit CMOS memory at Z5. "Scratchpad" memory is contained in the three 6532 RIOTs. <br=clear all>

Control of peripheral devices (in this case lamps, solenoids, switches and sound) is accomplished via three 6532 RIOTs (RAM-I/O-Timer) at U4, U5, and U6. Each RIOT in turn controls it's own "subsystem" to drive these devices.

• Reset section
• Switch matrix
• Solenoids and Lamps
• Displays

There are four generations of the System 80 board. All of the CPU boards can be easily identified by their revision numbers notated just below the operator adjustable dip switches.

3.8.1 1st Generation CPU Board

System 80 CPU Board - 1st Generation

The first generation CPU is used in the first 5 System 80 games, and is marked with the following:

• ASSY PB03-D100-001
• DET PB03-D102-001
• REV B ASSY.

This board uses two masked PROM chips for the game code. The chips are typically labeled with the three digit game model number followed by /1 or /2, designating the game PROM position. An example of this naming convention is shown in the pic to the left. 652/1X and 652/2X are game PROM 1 and PROM 2 for Panthera. The "X" in this case designates a code revision. The masked ROMs at position U2 and U3 are not socketed on this board.
With some simple modifications, this board is upward compatible to use a single 2716 EPROM placed in the PROM 1 socket of the board. With the change of U2 and U3, this board can be used in System 80A games. The board could potentially be used in a System 80B game with many modifications, and the addition of a daughter board, however, it is not recommended.

System 80 CPU Board - 1st Generation (Front)

System 80 CPU Board - 1st Generation (Back)

The "skeletal", semi-populated board scans can be very useful when having to replace or follow traces on a CPU board. Although the scans are of the 1st generation CPU board, most areas can be used for other generation CPU boards too.

3.8.2 2nd Generation CPU Board

Placeholder for System 80 CPU Board - 2nd Generation

The second generation CPU is used in some System 80 games, and is marked with the following:

• ASSY PB03-D100-??? - check boards for the suffix
• DETAIL PB03-D107-001

This board uses a single 2716 EPROM chip for the game code located at the PROM 1 socket position. The chips are typically labeled with the three digit game model number. Occasionally, the chip's game number label will be followed by /1, /2, /3, or even /4. In this case, the number following the slash is the code revision number. An example of this naming convention is 658 /2, which is a game PROM for James Bond - code revision 2. The masked ROMs at position U2 and U3 are not socketed on this board either.
With the change of U2 and U3, this board can be used in System 80A games. The board could potentially be used in a System 80B game with many modifications, and the addition of a daughter board, however, it again is not recommended. The second generation CPU is backward compatible, provided a doubled up, single game PROM is used at the PROM 1 position.

3.8.3 3rd Generation CPU Board

System 80 CPU Board - 3rd Generation

The third generation CPU is used in some System 80 games, and is marked with the following:

• ASSY PB03-D100-011
• DETAIL PB03-D107-003

This board is essentially the same as the second generation board, except an eyelet ground trace was placed just above Z33 on the board. This ground trace was never used. All information which applies to the second generation CPU board, applies to this board. The third generation CPU is backward compatible, provided the same is done to it as the 2nd generation board.

3.8.4 4th Generation CPU Board (System 80A)

System 80A CPU Board

The fourth generation CPU is used in all System 80A games, and is marked with the following:

• D 20869

This board is the same as the third generation board, except the U2 and U3 masked ROM chips have different code, and are now socketed. The PROM 2 socket is no longer populated on the board. The fourth generation CPU is backward compatible, provided the System 80 ROM code is installed at U2 and U3. If used on a game with the 1st generation CPU, the game code must be doubled up on a 2716 EPROM, and installed at the PROM 1 position. This board is forward compatible with System 80B, provided all of the above outlined modifications are performed. Out of all the System 80 CPU boards, this is the most compatible with System 80B, due to using the same base circuit board.

3.8.5 5th Generation CPU Board (System 80B)

System 80B CPU Board

The fifth generation CPU is used in all System 80B games, and is marked with the following:

• D 20869

Even though the base circuit board is identical to the fourth generation CPU board, it's being named the fifth generation board, due to all of the major changes. The U2 and U3 masked ROM and sockets have been replaced with a piggyback daughter board soldered via header pins mounted in the U3 position. The daughter board uses a 2764 EPROM. Most of the related display segment and digit chips are no longer populated. This is due to the single display board handling these functions on its own board. The missing chips once used for the displays are Z19, Z21, Z22, Z23, Z24, and Z25. Equally, jumpers have been placed where Z19 and Z21 once resided. The fifth generation CPU is backward compatible, after the daughter board has been removed, and the missing display chips populated.

Any of the Gottlieb® System 80 / 80A / 80B CPU boards are compatible cross platform. It's just matter of how much work must be done to modify each board.

3.9 Driver Board

The System 80A / 80B Driver Board

The System 80 Driver board is responsible for all controlled lamps, relays, and all solenoids in the game. The CPU controls the driver board operation via a simple interface between A1J4 on the CPU and A3J1 on the driver board. Although the driver board went through some minor changes over the years, the same board can be adapted for all of the System 80 platforms.

To control the games' total of 52 lamp circuits, the interface provides "device select" signals for each of the 74175s (Quad-D Flip-Flops) 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 an MPS-A13 or MPS-U45 transistor, (NDS-U45 transistors were used in place of MPS-U45s in some cases). Gottlieb® did not implement a "lamp matrix" as some other manufacturers did.

It is noteworthy that there are some dedicated lamp transistors, which control specific game relays across the System 80 / 80A platforms. Relays such as the game over, tilt, and coin lockout relays are controlled by Q1, Q2, and Q3 respectively. The tilt and game over relays use the same designation for the System 80B platform, however, the use of a coin lockout relay was abandoned by this time. One neat feature of the driver board circuitry is that lamp "n" is driven by transistor Q"n+1". i.e. L12 is driven by Q13.

Driver Board with Coin Counter Transistors Highlighted

To control the games' solenoids circuits, the driver board uses signals directly from the CPU to enable transistors on the driver board which turn on up to 9 solenoids. For solenoid control, the driver board uses MPS-U45, 2N3055, and 2N6043 transistors. Starting and ending with the System 80 platform, (games from Spiderman to Haunted House), three transistors were reserved to drive optional mechanical coin counters. These mechanical coin counter solenoids and associated transistors are: solenoid 3 (Q54), 4 (Q55), and 7 (Q56). Starting with the System 80A platform, (Devil's Dare), these transistors were no longer reserved for coin counters, and were used for other functions. Equally, the 3 diodes associated with these 3 transistors were changed to 3 zero ohm jumpers.

The games' sound signals (S1, S2, S4, S8) also pass through the driver board at Z13, a 7404 Hex Inverter. See below for S16 and S32.

3.9.1 Repurposed Driver Board Circuits

A Typical Remote Transistor Mounted Under the Playfield

Since quite a few System 80 games employ more than 9 solenoids, and since the original driver board design will drive a maximum of 9 solenoids, Gottlieb® repurposed some lamp outputs to drive "under-playfield transistors" which drive additional solenoids.

A Typical Transistor Driver Board

Once playfields became littered with numerous "under-playfield transistors", Gottlieb® opted to merge some of these transistors into a transistor driver board. The transistor driver board started to appear on Gottlieb® games nearly midway through the System 80B platform, with the game Victory.

The sound S16 and S32 signals are also repurposed lamp outputs. For instance, Haunted House and Black Hole both repurpose L9 to S16. Robo-War repurposes lamp 4 to S16. Note that S16 is not consistently implemented across the System 80 family. Note also that references to the usage of S32 are difficult to find.

3.10 Auxiliary Lamp Driver Boards

A Typical Aux. Lamp Driver Board Using MPS-U45 Transistors (Maximum Control of 10 Lamps

A Typical Aux. Lamp Driver Board Using 2N6043 Transistors (Controls a Maximum of 20 Lamps

Starting with Mars: God of war, several System 80/80A/80B platform games use auxiliary lamp driver boards. These boards are commonly referred to as "chaser boards" or "lamp chaser boards". The reason for either of these nicknames is because these boards are used to control lamps for effect. They are either placed in the backbox or under the playfield. With later System 80B games, they were located in the lower cabinet. Location is typically dependent upon what lamps are being controlled. The aux. lamp driver boards are not controlled by the CPU. The only signals needed for an aux. lamp driver board to function is +5V and ground.

There are several different variants of auxiliary lamp driver boards used. The earliest versions use MPS-U45 transistors to control a maximum of three lamps per transistor. Both 15 and 30 lamp versions (5 or 10 transistors) of this board exist. Some later boards use NDS-U45 transistors instead of MPS-U45 transistors. Is assumed this is due to a the cost or lack of MPS-U45 transistors during production. Either of these style of boards are interchangeable with one another. Finally, there are some boards used in later games which use 2N6043 transistors. These are designed to control #67 flashlamps, but this is not always the case. This style board was used to control lamps also. These boards are equally compatible with previous designed boards, when used as a complete, drop-in replacement. However, MPS-U45, NDS-U45, and CEN-U45 transistors are not 1-to-1 compatible with 2N6043 transistors. A viable replacement transistor for the 2N6043 is the TIP102.

The main difference between any of the auxiliary lamp boards is the amount of transistors used to drive lamps, and the resistor (R13) used to control the rate at which the lamps flash or "chase". Boards using 2N6043 transistors have different resistor values for resistors R2-R11 than boards which use MPS-U45s or NDS-U45s. A table of auxiliary lamp driver boards used on most games is shown below.

Game	Total Transistors	Total Lamps Controlled	R13 Resistor Value	Controls	Location	Notes
Mars:God of War	10	28	330K Ohm	Backglass perimeter chaser lamps	In PF	1 of 2
Mars:God of War	5	10 (LEDs)	330K Ohm	LEDs behind tube	Under PF	2 of 2
Volcano	10	20	560K Ohm	Upper backglass perimeter chaser lamps and volcano effect behind backglass	In backbox
Black Hole	10	28	270K Ohm	Backglass perimeter chaser lamps	In backbox
Haunted House	10	21	270K Ohm	Behind backglass lightning effect lamps	In backbox
Rocky	10	19	560K Ohm	Behind backglass	In backbox
Spirit	10	20	Varies	Behind backglass	In backbox
Tag Team Pinball	10	20	820K Ohm	Multiball insert illumination	Under PF
Rock	10	18	680K Ohm	Extra ball insert path	Under PF
Rock Encore	10	18	680K Ohm	Extra ball insert path	Under PF
Raven	10	20	680K Ohm	Inserts leading to ramp	Under PF
Hollywood Heat	10	20	680K Ohm	Ramp insert illumination	Under PF
Genesis	10	10 (#67 Flashers)	680K Ohm	In top of backbox	Under PF	Uses 2N6043
Genesis	10	10 (#67 Flashers)	680K Ohm	Around playfield window	Under PF	Uses 2N6043
Gold Wings	10	8 (#67 Flashers)	680K Ohm	Flashers in topper	Under PF	1 of 3
Gold Wings	10	6 (#67 Flashers)	680K Ohm	Flashers in topper	Under PF	2 of 3
Gold Wings	10	10	680K Ohm	Inserts leading to ramp	Under PF	3 of 3
Monte Carlo	10	5	680K Ohm	Behind $10,000,000 sign	Under PF	1 of 2
Monte Carlo	10	30	680K Ohm	Lamps around perimeter of topper	Under PF	2 of 2
Spring Break	10	30	680K Ohm	In topper	Unknown	1 of 2
Spring Break	10	20	680K Ohm	Special shot and shooter loop	Under PF	2 of 2
Arena	None	10 (LEDs)	560K Ohm	LED strip under shooter lane wireform	Under PF
Victory	10	10 (#86 bulbs)	680K Ohm	Next to left ramp	Under PF	1 of 2
Victory	10	10 (#86 bulbs)	680K Ohm	Next to right ramp	Under PF	2 of 2
Robo-War	10	20	680K Ohm	Inserts in lower portion of playfield	Lower cabinet	(1 of 2) Uses 2N6043
Robo-War	10	10	680K Ohm	Under playfield glass stop	Lower cabinet	(2 of 2) Uses 2N6043
Bad Girls	10	5	680K Ohm	Drop target illumination	Lower cabinet	1 of 2
Bad Girls	10	10	10M Ohm	Under playfield glass stop	Lower cabinet	2 of 2
Bone Busters	10	12	680K Ohm	Playfield inserts	Unknown	1 of 2
Bone Busters	10	20 (#67 flashers)	680K Ohm	Backbox lamp insert	In backbox	(2 of 2) Uses 2N6043

3.11 Sound Boards

Gottlieb® uses different sound boards throughout the course of all System 80 platforms. Several of the sound boards cross platforms too. Out of all of the sound boards used, there is really only about three base units total with variations made to each one.

3.11.1 Sounds Only Board

Gottlieb® System 80 Sound Board (Sounds only)

The first System 80 sound board is capable of sound only. Based on the 6503 CPU architecture, this sound board is very similar to the System 1 Multi-Mode sound board. However, there are a couple of differences between the two boards. First, the +12VDC is no longer rectifed on the sound board. The +12VDC power comes from the power supply. Secondly, the +5VDC is no longer regulated on the sound board. The System 80 sound receives +5VDC from the power supply also. Finally, the pin outs for the System 1 sound board and the System 80 sound board are completely different. Even though either board will plug into either platform, DO NOT PLUG A SYSTEM 1 SOUND BOARD INTO A SYSTEM 80 GAME AND VICE VERSA!!! If you do, bad stuff will happen. Unfortunately, there are two chips (6503 and 6530) on this style of board which are very difficult to source.

3.11.2 Sound & Speech Board

Gottlieb® System 80 / 80A Sound & Speech Board

Starting with Mars God of War, the second System 80 sound board has the the capability of speech. Ironically, this board is commonly referred to as the "sound and speech board", and was brought over from the Gottlieb® video game division at the time. Fortunately, Gottlieb® chose the 6502 CPU architecture just like the CPU board. There is a 6532 RIOT used also. The downside to this board is the now rare LM379S amp and SC-01 phoneme speech chip are both difficult to acquire.

There are approximately three renditions of this board. Each will be marked with B-20887-X. The "X" denotes a suffix of 1, 2, or 3. If the board has wire wrap or resistors added to the solder side of the board, do not assume that it is some sort of diabolical, weird hack. These were recommended upgrades either done by the factory or out in the field. With each higher revision number, less wire wrap and resistors are present on the solder side of the board. However, each board revision typically has some degree of wire wrap added to it.

3.11.3 Sound Only Board

Gottlieb® System 80 / 80A Sound Board w/ MA-483 Piggyback Board (replaces LM379S amp)

To reduce costs, Gottlieb® abandoned the speech option, and went a step backwards with a board generating sounds only. In doing so, they used the same B-20887-3 base board as the most current sound and speech board. The SC-01 speech chip socket in addition to the 74xx TTL chips, one of the LM741 op amps, and discrete components associated with the speech circuit were not installed on the board. By the time this board was first used, the LM379S amp was too costly and difficult to source. The solution was to add a single-side, piggyback board (as shown in the picture) with a TDA2002 amplifier and other necessary components.

If this board is used as a replacement in a game which uses a sound & speech power supply, (Haunted House for example), modifications to the s&s power supply must be made. This is due to the higher voltages necessary to operate the LM379S amp versus the TDA2002. If this board is installed in a game where the sound and speech board power supply was not modified, the guarantee of destroying the TDA2002 amp is inevitable.

3.11.4 Sound Only Board with Piggyback

Gottlieb® System 80A / 80B Sound Board w/ MA-488 Piggyback Board (Sounds only)

Gottlieb® System 80A / 80B Sound Board w/ Factory Trace Wire

To reduce costs even more, Gottlieb® started using a modified sound only board, which was first used with Spiderman in 1980. This "new" sound board was first used during the production of Amazon Hunt, and continued until Tag Team Pinball. The main modification of the board was the addition of a piggyback board. The piggyback board was used to increase the size of the sound ROM by using a 2716 EPROM.

Two other noteworthy modifications are an added factory trace wire on the solder side of the board, and a cut trace between pin 8 of U7 (7404) and a header pin on the component side of the board. The added trace wire runs from pin 3 of U1 (6503 CPU) to pin 18 of U2 (piggyback header pins). Both of these modifications should remain intact for the board to function properly.

It is also worth mentioning that this is one of the few instances where Gottlieb® used a double-sided piggyback board. The benefit of using a double-sided board is the decreased chance of cracked header pins, where the header pins attach to the underside of the piggyback board.

3.11.5 System 80B Sound Board

Gottlieb® System 80B MA-766 Sound Board

And now for something completely different. Well, not really. The MA-766 sound board hit the scene with Rock, but a similar design was already used prior by the Gottlieb® video game division (Mylstar) when it existed. It is based on the 6502 CPU architecture, but uses two 6502s instead of one.

Two momentary push button switches are present on the board - SW1 and SW2. Upon pushing SW1, the sound board should output a single blip (tone). SW2 is used to manually reset the CPU on the sound board. A bank of 4 dipswitches is located adjacent to SW1. Dipswitches 1-3 should always be off, while dipswitch 4 should remain on for proper function.

3.11.6 System 80B Sound Board

Gottlieb® System 80B MA-886 Sound Board

The MA-886 board is essentially the same as the previous sound board, except it uses 2 separate .156" header pin connections instead of edge connectors for inputs / outputs. Some other obvious changes are the omission of momentary test button SW1, the omission of the 4-bank dipswitch, the omission of YROM2 socket, and the addition of a socket at position S4 on some boards. Momentary test button SW2 is still preset, and is still used to manually reset the board's processor. The lack of YROM2 is because the MA-886 board allows for the use of larger EPROMs. The S4 socket has been added on some boards, and is used to transfer data via a ribbon cable to an auxiliary sound board.

3.12 Displays

3.12.1 System 80 - 6 Digit Displays

3.12.2 System 80A - 7 Digit Displays

3.13 Reset Board

Gottlieb® System 80 / 80B Reset Board

Starting with Devil's Dare, the first System 80A game, the reset board became a staple of the Gottlieb® design to automatically reset the CPU board should the CPU lock up. Apparently games locking up on location was an issue with System 80 games. The reset board was created to resolve this issue, should the game lock up, and no one is present to manually reset the game by shutting it off and turning it back on.

The reset board is a small footprint PCB with the board designation of A24, and is located adjacent to the TC1 connector of the CPU board. The connection on the reset board is A24P1, while the connection for TC1 of the CPU board is A24P2. As long as someone can turn the game off, should it lock up, there is no need to keep the reset board connected. In most cases, the aged reset boards are more troublesome if allowed to remain connected.

3.14 Bookkeeping & Diagnostics

Gottlieb® System 80 Coin Door Test Button Highlighted

To enter the bookkeeping / diagnostic mode, open the coin door and press the red momentary switch. (Note this switch has no credit function) Depending on the particular game, the self test button may be mounted on a bracket located on the coin door or just inside the cabinet near the coin door hinge. Upon pressing this button, the 4-digit status display used with System 80 and System 80A games will display "00" in the credit window. Pressing the self test button again will advance to the next step in the bookkeeping.

There is an option to bypass all of the bookkeeping functions, entering diagnostic mode directly. To achieve this, the self test button must first be pressed. "00" will shown on the status display. Then, the credit / start button should be pressed once. The status display should now show "16". "16" is the first test in diagnostic mode.

Bookkeeping (System 80/80A)
1 - Coins thru left chute
2 - Coins thru right chute
3 - Coins thru center chute
4 - Total plays
5 - Total replays
6 - Game percentage
7 - Extra ball
8 - Total tilts
9 - Total slam tilts
10 - Number of times the HSTD has been beaten
11 - First high score level
12 - Second high score level
13 - Third high score level
14 - High score to date score
15 - Average game time

Diagnostics
16 - Lamp test
17 - Coil test (will cycle and display coil number of coils used in the game. Coin counter coils, if installed, are excluded)
18 - Switch test. (99 = no fault) You can check switch numbers by pressing them on the playfield during this step.
19 - Display test. The displays will cycle through each digit
20 - Memory test. (99 = no fault)

Gottlieb® System 80 "7641" Error

An example of a ROM image checksum error (or perhaps a ROM memory access error) displayed during test 20 is pictured at left. During test 20, if a checksum error is detected, the ROM code in U2/U3 will indicate "7641-X" in the player 1 display window, with "X" being "1" to indicate PROM 1 or "2" to indicate PROM 2. If you have followed the procedure to combine the original game ROMs into a single 2716, this error message is an indicator that the checksum of either the 1st half or the 2nd half of that ROM failed. Replace the ROM.

System 80B uses the same process as System 80/80A to enter bookkeeping / diagnostics. The only difference is upon pushing the self test button the first time, the top alphanumeric display will display "TEST MODE". Pressing the self test button again will enter bookkeeping mode, while pressing the credit / start button will enter diagnostics mode. After entering either mode, pressing the self test button will advance through each step in the appropriate mode.

Any of the tests in diagnostics can be repeated by simply pressing the credit / start button. This applies to all versions of System 80 platforms.

The following also applies to all System 80 platforms. To exit bookkeeping or diagnostics, the slam switch or tilt switch can be triggered. Equally, waiting 60 seconds will reset the CPU back to attract mode. This is probably the only benefit in keeping the slam switch functional. However, considering the sometimes strange side effects, which can arise from a maladjusted or malfunctioning slam switch, disabling the slam switch would probably the better approach.

3.14.1 Pausing the Lamp and Solenoid Test (System 80B Only)

The left advance button on a System 80B Game

The following only applies to System 80B lamp and solenoid tests. A little known fact is that the lamp and solenoid tests can be "paused" on a single lamp or single solenoid. To stop whichever item is being tested during lamp or solenoid test, and repeat the test on the particular item, simply push and hold in the left advance button located on the front of the cabinet, as shown in the picture to the left. The left advance button can then be released, pressed, and held in again to step to the next item in the test. This is a particularly nice feature, because the lamps and solenoids or relays tend to be pulsed rather quickly in test, and cannot be observed very well, until the test repeats itself.

3.15 Rubber Ring Chart

Although the Gottlieb® System 80 game manuals do list the location and part numbers for rubber rings used, some 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, connectors, connectors!!! Since the Gottlieb® System 80/80A/80B 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 80/80A/80B 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 80/80A/80B 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.

• System 80 Connector (J6), The Good, The Bad, and The Ugly
• 

  An example of pins in desperate need of rehab.
• 

  Ahhh...Much nicer after repinning.

4.1.1 Replacing (Repinning) System 80 Connectors

Replacing connectors in a pinball machine somehow adopted the term repinning. Repinning a System 80 connector housing isn't too bad overall. On a difficulty scale of 1 to 10 (1 being the easiest to do) compared to all other makes and platforms made, System 80 connector replacement is about a 3. One benefit regarding the System 80 IDC housings is that they are reusable. Below are the steps to remove the connector from its housing.

• First, grasp the housing in one hand. Use a small "pocket" flat blade screwdriver. add pic later---> (http://www.absorbentprinting.com/tools-and-knives/screwdrivers/pocket-screwdrivers/level-rite-regular-blade-options).
• Next, push the connector's ear down, so the connector can be released.
• Finally, pull gently but firmly on the wire.

Sometimes the connector comes out, and sometimes the wire pops out of the connector. If the latter, use a small jeweler's screwdriver to gently pry the very end of the connector against the rectangular opening in the connector housing. You're trying to get the IDC "ears" of the connector to clear the housing. Sometimes the connector will easily come right out. If it doesn't, use some small needle nose pliers, and grab the "ear" of the connector, and pull it out.

File:MolexPinExtractionTool.jpg

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

Some system 80 connector housings are "double sided" edge connectors. All of the connector housings that are double sided are black from the factory (blue colored housings are typically Jamma connectors used as replacements, and do not apply to this section of this guide). 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.

4.2 The CPU / Driver Board Interconnect Harness

The A1-J4 / A3-J1 Interconnect Harness

The A1-J4 / A3-J1 Interconnect Harness

There are 33 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 (two more can be added). The remaining signals are for lamp, solenoid, relay and sound control. It is extremely important to have solid connectors installed in the CPU / driver board interconnect harness. Without decent connections, lamps, coils, relays, and sound can either lock on or not turn on at all.

4.2.1 Adding Ground and 5V Connections to Interconnect Harness

Yet one more power/ground update to make is to "double up" the 5VDC and ground connections between the MPU and the driver board. The OEM harness contains only one connection between the MPU and driver board for 5VDC and one connection for logic ground. This is an easy upgrade since spare connection positions are available in the connectors that lead to the correct edge contacts on each board. Approximately 8 inches of wire and four bifurcated crimp on pins (bifurcated style, Molex 4366 series, Product Family KK, product ID: 08-03-0304 at Great Plains Electronics) are needed.

Crimp a pin to each end of each wire. The connectors at each end should face opposite directions. Doing this will avoid twisting the wire as you insert the pins into the connector housing. In the picture below, the red wire carries 5VDC, blue wire carries logic ground. These colors were chosen for illustrative purposes only. Any color wire will do, of course.

• MPU-to-Driver Board Harness Upgrade
• 

  Pins crimped to extra wires.
• 

  Spare pin positions in harness.
• 

  5VDC and ground upgraded.

4.3 Ground updates

4.3.1 Recommended Ground Improvements for System 80/80A

When the Gottlieb® System 80 board set was designed, for whatever reason, the designers did not physically attach each board to a common ground plane via a conductive back panel, standoffs and screws as Bally and Williams did. Instead, Gottlieb® relied on connectors and wires between each board to create a common ground. A poor connection due to dirty/damaged/fatigued connector pins will sever the ground between system components resulting in all sorts of odd behavior.

To address this problem, it is important to examine each connector to ensure each pin is clean, and making solid contact with the card edge conductor. The ultimate (and recommended) insurance is to add an additional wire from each board's ground to a common ground point. Historically, the recommended location to join separate board grounds is at the power supply. That ground is then connected to the ground strip in the cabinet bottom.

It should be noted that these ground upgrades were initially recommended and published on the Internet by John Robertson of John's Jukes.

• Recommended Board Ground Wire Locations
• 

  System 80/80A Power Supply
• 

  System 80B 5V Power Supply
• 

  System 80B Auxiliary Power Supply
• 

  MPU Board
• 

  Driver Board
• 

  System 80 Sound Only Board
• 

  Sound and Speech Board
• 

  Sound and Speech Power Supply
• 

  System 80A/80B Sound Only Board
• 

  System 80B Sound Board
• 

  System 80B Aux. Power Supply
• 

  Chaser Lamp Board
• 

  Tie to Cabinet Bottom Ground Strip
• 

  Cabinet Bottom Ground Strip

Another design decision was to provide separate ground wires for groups of lamps and coils on the driver board. There are several variations used to tie the driver board lamp and solenoid discrete ground wires to the ground plane. The most common method Gottlieb® used was passing the ground wires through a large, inline Molex connector. If a group of lamps and/or coils are not working, there is a significant probability that a ground is missing.

4.3.1.1 Ground Improvements for System 80 at Ground Strip

This is a stub

4.3.1.2 Grounds Improvements for System 80A at Transformer Panel

This is a stub

Grounds at Transformer Panel (Alien Star)

Gottlieb® did run the grounds correctly on one particular game. As seen in the adjacent pic, the grounds on Alien Star were attached discretely on the transformer panel. These ground lines did not pass through a Molex connector like games before or games after. Why Gottlieb® did not continue this practice is unknown.

4.3.2 Recommended Ground Improvements for System 80B

4.3.2.1 Grounds Improvements for System 80B at Transformer Panel - Rock to Monte Carlo

Ground connections used on System 80B games from Rock to Monte Carlo are probably the most unreliable style of ground connections Gottlieb® ever used. This type of System 80B ground connection consists of two small boards with two gangs of 9-pin male connections. These boards are fastened to the left side of the transformer panel's metal chassis. The problem with this type of ground connection is that the 9-pin female connection becomes loose, and in turn, ground connections become intermittent. One of the common symptoms of poor ground connections is when multiple solenoids are not functioning. If removing the 9-pin Molex plug from the ground board, rotating it 90 degrees, and reconnecting it causes the non-working solenoids to function, the ground connections are bad. Regardless of whether this simple test proves whether or not the ground connections are bad, it is highly recommended to improve the ground connections for future reliability.

The purpose of the ground upgrades is to remove the ground boards, which takes one more potentially failed connection out of the equation. The grounds will then be secured directly to the transformer chassis via solderless eyelet crimp connectors.

It should be noted that these ground upgrades were initially recommended and published on the Internet by John Robertson of John's Jukes. Below are the steps to properly upgrade the grounds.

• Gottlieb® System 80B Ground Upgrades (Rock to Monte Carlo)
• 

  The stock ground connections plugged into the ground connection boards on the left side of the transformer panel. This pic is a view from the left side.
• 

  Remove all connections from the transformer panel. Then, unscrew the four 5/16" hex head screws which secure the transformer panel from the bottom of the cabinet. Turn the transformer panel on its side. This will allow better access to secure the ring terminals to the side of the chassis.
• 

  Cut all of the ground wires as close as possible to the 9-pin connection. Remove the two boards with the 9-pin male wafer connections. As can be seen in the pic, Gottlieb® did actually secure the discrete transformer panel grounds to the panel's chassis with a single, soldered eyelet connector.
• 

  All the ground wires are to have their insulation stripped back longer than usual - approximately 3/4". Solderless ring terminals are crimped onto the ground wires. The connections used in this particular application are Motormite #85443. Motormite brand does not have to be used. This particular brand and part number are mentioned due to the difficulty in finding the correct connectors to use. Most common ring terminals have a #10 or larger screw eyelet, which will not work effectively, if the eyelets are fastened to the side of the transformer panel chassis. The ring terminals shown here are made for #12-#10 gauge wire with an eyelet for a #8 screw.
• 

  The ground Molex plugs and connection boards which were formerly fastened to the transformer panel's metal chassis. The four ground connector plugs (some games only use three total) were cut off from the incoming ground wires.
• 

  Keep wires which were common to one connector together (driver board ground wires, playfield ground wires, and backbox ground wires). In doing this, future disassembly will be possible, should any of the individual wiring harnesses need attention or the playfield removed from the game. The ground wires are then twisted together and crimped. From experience, a maximum of 4 larger gauge wires can be crimped in one connection. Lighter gauge wires can be paired with or without heavier gauge wires. When doing this, the maximum effective grouping of wires increases slightly.
• 

  The screws which were removed from the ground bus board should be reused to secure the eyelets to the transformer panel.
• 

  The transformer is fastened to the bottom of the cabinet with the ground upgrades in place.
• 

  Pay close attention when securing the transformer panel to the cabinet. All four mounting screws typically have flat ground straps with an eyelet. These eyelet connections *must* be secured to the transformer panel. Otherwise, there earth grounds will not be tied together. Two of these ground connections are circled in the pic. There are two more located on the backside of the transformer panel.

4.4 Power Problems

4.4.1 Replacing the Orange Filtering Capacitor

A worn out original 6800uf/25V Gottlieb® filter capacitor

If your System 80 or early System 80A game still has the original, orange 12VDC filtering capacitor in the cabinet bottom, you should replace it. It's nearly 30 years old, has served the game well for a long time, and deserves a rest. Replace it with a new capacitor, valued from 6800uf to 12,000uf and at least 25V. Don't forget to acquire the right sized bracket to secure the cap to the bottom board.

4.4.2 Recommended Updates and Repairs for the System 80/80A Power Supply Board

The System 80 Power Supply board is a pretty tough bugger. Still, after years of steady operation, they do fail, and they require refurbishment.
The test point values are silk screened on the System 80 power supply board. They are +5VDC, +8VDC, +42VDC, and +60VDC. Ground, or "common" is also labeled.
Given that the parts to refurbish the power supply are cheap and readily available, and that taking the power supply apart is a bit of a pain, a good strategy is to replace all failure prone parts, whether the parts have failed or not, to avoid disassembling the power supply more than once.

Parts you will need are:

1. .156 male header pins without friction lock, 9-pin, 7-pin, 6-pin, or break to size.
2. 500 ohm resistor trim pot. A quality sealed one like the one pictured is advised.
3. 3 inches of 18 gauge wire
4. 47uf, 100V axial capacitor
5. 680 ohm, 1/2 watt resistor (replacement for R10)
6. 12K ohm, 1/2 watt resistor (R3)
7. 1N4738 8.2V 1 watt zener diode (CR7)
8. 1N4746 18V 1 watt zener diode (CR6)
9. LM723 voltage regulator and 14-pin socket (optional if the 5V section is operational)
10. 2N6057 or 2N6059 Darlington transistor (Q3, optional if the 5V section is operational)
11. heat sink compound (optional as required)
12. TO-3 mica insulator or heat sink gasket (optional as required)
13. TO-3 transistor spacer (optional as required)
14. 2N5550 or 2N5551 transistor (Q2, optional)
15. Green LEDs (optional...use if you want to identify the board as having been reworked)

Procedure:

1. Remove the 4 screws that fasten the PCB to the cold plate (heat sink).
2. Remove the 2 screws that fasten the back mounted transistor Q3 to the PCB and cold plate.
3. Use your favorite solder removal tool to remove the solder from the legs of Q3 that extend through the PCB. This is the toughest part of the job. If the board had been really hacked, you may need two irons and a friend to accomplish this.
4. Once the cold plate and Q3 have been removed, set those parts to the side.
5. Replace parts on the PCB as recommended and advised by the particular failure.
6. On the solder side of the PCB, solder a 3" wire from the ground trace to the screw mount, as shown in the picture below.
7. When replacing the original round header pins with new square header pins, you may have to enlarge the holes slightly using a pick as shown in the picture below. Key pins must be removed prior to installation as the PCB has no holes at the key pin position.
8. Recheck all of your work.
9. Sand the black insulating coating from the top/right screw hole on the front of the cold plate, as shown in the picture below. The insulating coating is very tough. A drum sander attachment on a Dremel works very well for this. To ensure you've sanded enough, use your meter to "buzz" between screw holes. You will use this screw hole later to tie the ground from each PCB together.
10. Install Q3 (note that it will only install one way) onto the cold plate using the transistor spacer, mica insulator, and heat sink compound.
11. Mate the two halves of the power supply together and reinstall the two screws which secure Q3.
12. Solder the leads of Q3 to it's through-holes.
13. To ensure continuity at each leg's solder joint, "buzz" the connection between the left leg of Q3 and the top leg of R9.
14. Also "buzz" the connection between the right leg of Q3 and the bottom leg of R11.
15. Install the remaining 4 screws around the perimeter of the power supply board.
16. Lastly, ensure there is NO continuity between Q3 and the cold plate, as shown in the picture below. This is an essential step to ensure proper operation.

• System 80/80A Power Supply Repair
• 

  Parts Required
• 

  Front Side, Parts Removed and Board Cleaned Up
• 

  Back Side, Parts Removed
• 

  Enlarging Header Pin Holes
• 

  Parts Replaced, Front Side
• 

  Parts Replaced and Ground Updated, Back Side
• 

  Strain Relief for R10
• 

  All Done
• 

  Ensuring no continuity between Q3 and the cold plate

Once fully assembled, reinstall the power supply into your game. Connect ONLY J1 (the lower 9-pin connector) at this time. Power your game on, looking for the two LEDs to light. If they do not light, you have rework to perform. Assuming that they do light, test each of the voltages that the power supply creates to ensure the correct power is being generated/regulated. Since the power is not "under load", each of the voltages may read 10% or so high. While measuring the 5V test point, adjust the 5V trim pot to about 5.1VDC.

That's it! You're done.
Note: once you connect the other boards to the power supply, the 5V may sag some. Measure the 5V across the electrolytic cap just to the right of the MPU power connector. Using the 5V trim pot, adjust the 5V power to between 5.0 and 5.1VDC.

4.4.3 Recommended Repairs for the System 80B Power Supply Board

Step one to improving power supply reliability is to replace the original 500 ohm 1 watt adjustment pot. This procedure can be done easily without removing the large heat sink. A replacement sealed pot is recommended, but not completely necessary.

Next, remove all the old solder from the all of the .156" header pins, and reflow new solder onto the joints. The top header pins (J2) supply +5VDC to the majority of the associated circuit boards in the back box. Provided that the power supply is delivering acceptable voltages in the +5VDC range, these two relatively simple repairs are the only things needed for this board.

However, if you've adjusted the pot as much as possible in the appropriate direction, and the power supply is still delivering voltages higher or lower than around +5VDC, it's probably time to look at replacing the LM338K voltage regulator. While not a frequent occurrence, the voltage regulator will sometimes fail.

If the voltages measured are less than 1VDC, the grounds for the power supply (located at the transformer panel) will more than likely need attention. Once the grounds at the transformer panel are better secured, recheck the voltage at the power supply.

Note: When measuring the +5VDC provided by the power supply, first disconnect J2 on the power supply. Measure power at the J2 male headers first. Once within an acceptable range, turn power off and reconnect J2. Measure power across C1, the 100uf/10V capacitor that is next to J1 (power connector) on the MPU. The MPU may drag the +5VDC supply down a bit. If you find this to be the case, adjust the trim pot on the power supply until a steady +5VDC is seen at the MPU. Poor connections between the +5VDC power supply and the MPU board may also reduce the voltage measured at the MPU.

4.4.4 OPTIONAL: Adding Power Indicating LED's to Boards

4.4.4.1 CPU Board LED

How to add a "+ 5 volt" indicator for the Gottlieb System 80 Generation 1 CPU board (the D102 board). This will light up when + 5 volts are present on the CPU board.

Materials needed:

1 Red LED, Jameco # 2125309 or Radio Shack # 276-209 or 1 Green LED, Jameco Electronics # 2125296 (9 cents each) or Radio Shack # 276-022 ($1.69 for a 2 pack)

1 Resistor, 330 ohms, quarter watt, Radio Shack # 271-1315

Drill two 1/16" diameter holes spaced about 3mm apart in the spot indicated just below power connector J1. This area has no traces to interfere with drilling.

Install LED into board with flat side facing toward the power connector J1.

Bend the flat side's lead to the negative (ground) point shown in the picture and solder it.

The other lead of the LED will connect to one side of the 330 ohm resistor. The other end of the resistor will be soldered to the positive trace shown in the picture. You're done.

Now whenever the machine is powered on, this LED will indicate that the CPU board is receiving +5 volts from the power supply.

Holes drilled on front of board

Holes drilled on rear of board

Circled areas are where to drill the two holes for the LED. Any color of LED can be used, but red or green are prefered.

Wiring on solder side of board

LED installed on board

Wiring of the resistor and LED. Note the location of the flat side of the LED.

Finished installation of LED

Completed installation with LED lit up indicating the +5 volts is present on the CPU board.

4.4.4.2 Driver Board LED

Adding a "+5 volt" indicator to the System 80 Driver Board.

Materials needed:

1 Red LED, Jameco # 2125309 or Radio Shack # 276-209 or 1 Green LED, Jameco Electronics # 2125296 (9 cents each) or Radio Shack # 276-022 ($1.69 for a 2 pack)

1 Resistor, 330 ohm quarter watt, Radio Shack # 271-1315

Drill two 1/16" holes spaced about 3mm apart in the board at the location shown in the pictures to the left of the electrolytic capacitor near chip Z1. There should be no traces at that area.

Install the red LED with the flat side facing the trace going to the negative side of the electrolytic capacitor. Bend the LED's flat side lead down to that trace and scrape away some of the green paint at the point you will be soldering it. Now solder that lead to the trace.

Solder one end of the 330 ohm resistor to the other lead of the LED.

The other end of the resistor will now get soldered to the trace that goes to the positive side of the electrolytic capacitor. Again, be sure to scrape some of the green paint off of the trace where the resistor lead will be soldered. You are done.

Now whenever the machine is on, the LED will be lit indicating that the driver board is receiving +5 volts from the CPU board.

Drilled holes on front of board

Drilled holes on the rear of board

Views of the holes drilled for the LED looking from the front and rear of the System 80 driver board.

Wiring of the LED and resistor

Finished installation

Wiring of the resistor and LED. Notice the location of the flat side of the LED. Any color of LED can be used, but red or green is prefered.

Finished installation with LED lit

Completed installation showing the LED lit up indicating +5v power is present on the driver board.

4.4.4.3 Auxilliary Lamp Driver Board LED

Adding a "+5v" LED indicator for the MA-234 auxilliary lamp driver board used in Black Hole and Haunted House.

Parts needed:

1 Red or green LED, Jameco Electronics # 2125296 (9 cents each) or Radio Shack # 276-022 ($1.69 for a 2 pack)

1 Resistor, 330 ohms, 1/4 watt

Drill two 1/16" diameter holes about 3mm apart in the locations indicated in the pictures.

Mount LED with the flat side toward the edge of the board.

The lead from the LED's flat side will be soldered to pin 2 (ground) of connector A11P1. Be sure to slide a piece of heat shrink tubing over this lead so it does not accidently short to the other connector pins.

The other lead of the LED will be soldered to one end of the 330 ohm resistor.

The other end of the resistor will be soldered to pin 4 (+5 volts) of connector A11P1.

Whenever the machine is on, the LED should be lit, indicating the auxilliary lamp driver board is receiving power.

Drilled holes on front of board

Drilled holes on rear of board

View of the holes drilled for the LED as viewed from the front and rear of the board.

LED installed on board

Resistor and LED wiring

Wiring of the resistor and LED on the rear of the board. Notice the location of the flat side of the LED.

LED is lit up

Finished installation with LED lit up indicating presence of +5 volts power on the board.

4.4.4.4 Sound/Speech Power Supply Board LED's

The Sound/Speech power supply board will get a total of four LED's! These are to indicate the presence of -12 volts, +12 volts, and +30 volts going out to the actual sound/speech board and also to indicate +24 volts coming in to the power supply board.

Parts needed:

4 Red or green LED's

2 Resistors, 1 k, 1/4 watt

1 Resistor, 2.2k, 1/4 watt

1 Resistor, 3.0 k, 1/4 watt

Mounting the LED's:

Drill a total of eight 1/16" holes at the points shown in the pictures near connector A7P1. Lead spacing per LED is about 3mm. Be sure the LED's are not too close to each other to interfere with sitting flat against the board. The +12 and +30 volt LED's will mount with the flat side facing diagonally (7 o'clock) toward the lower left board mounting hole.

Wiring: The -12 volt LED will have the lead of the round side (anode) soldered to the heavy ground trace of the board. You'll need to scrape some of the green paint off the trace first. The other lead of this LED will be soldered to one end of a 1k resistor. The other end of this resistor will be soldered to the junction point of resistor R2 and the anode of zener diode CR2.

The +24 volt LED will have the lead from the flat side (cathode) of the LED soldered to the heavy ground trace on the board. You'll need to scrape a bit of the green paint off the trace first. The other lead of the LED will be soldered to one end of a 2.2k resistor. The other end of the resistor will be soldered to the trace going to connector A7P1 pin 6 (+24 volts). Again, you'll need to scrape some of the green paint from the trace first.

The +12 volt LED will have the lead from the flat side (cathode) of the LED soldered to the heavy ground trace. You will need to scrape some of the green paint off the trace first. The other lead of the LED will be soldered to one end of a 1k resistor. The other end of this resistor will be soldered to to the trace going to connector A7P1 pin 1 (+12 volts). You will need to scrape some of the green paint off of the trace first.

The +30 volt LED will have the lead of the flat side (cathode) soldered to the heavy ground trace. You will need to scrape off some of the green paint from the trace first. The other lead of the LED will be soldered to one end of a 3 k resistor. The other end of this resistor will be soldered to the trace going to connector A7P1 pin 2 (+30 volts). You will need to scrape some of the green paint from the trace first.

These LED's above are all optional. The board never originally came with anything to indicate presence of voltages. If you only want to install one, that's fine. I chose to install all four so I can see at a glance that all four voltages are present. You don't have to install all four if you don't want to.

In my picture of the finished front of the board the LED's from top to bottom are:

-12v +24v

+12v +30v

In my picture of the wiring on the back (foil) side of the board, the resistors top to bottom are:

1K

2.2K

1K

3K

Drilled holes for the LED's on the front of board

Drilled holes for the LED's on the rear of board

Views of the drilled holes for the LED's looking from the front and rear of the board.

+12 and +30 LED's installed on front

-12 and +24 LED's installed on front

All four LED's installed on the front of the board. Notice the location of the flat sides of all the LED's.

Wiring of the resistors on the rear of board

All four LED's installed on front of board

Wiring of the resistors and LED's on the rear of the board. All four LED's installed on front of board.

Finished and all LED's lit

All four LED's installed and lit up indicating the presence of the four different voltages.

4.5 MPU boot issues

There are a large and varied number of reasons that a System 80 MPU will fail to boot. Unfortunately, as has been said before, "this is not a Bally world". That is, unlike "classic" Bally and Stern MPUs the System 80 MPU provides absolutely no indication as to why it may have failed to boot.

Debugging a non-booting MPU is somewhat of an art.

Under construction...

1. Ensure your game is providing a solid 5VDC power source
2. Replace the orange electrolytic cap in the cabinet bottom if still original
3. Take the board to the bench
4. Examine the board for Alkaline damage. If present, clean up
5. Ensure the reset section of the board is working. Pin 40 of the 6502 should begin "low", then after about 1/2 second, transition to "high"
6. Check the clock signals at the 6502
7. Check the IRQ signal at the 6502
8. Check the R/W (read/write) signal at the 6502
9. Check the address and data lines to see if they are pulsing
10. Feel each of the masked ROM chips at U2 and U3 as well as the 6532 RIOT chips at U4, U5, and U6. If the IC is too hot to touch, it has probably failed and should be replaced.
11. Check each of the 74XX chips using the procedure "here".
12. If original game ROM(s), replacement with 2716 is advised.

4.5.1 Battery Leakage and Corrosion

Like most any other pinball machine manufactured, Gottlieb® uses 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 the reset section, clock section, or possibly more regions on 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.

Typical Battery Found on a System 80 CPU 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 Gottlieb® CPU boards can last longer than others. Probably the worst culprit of board destruction is the Data Sentry pack, and its associated knock-offs. This battery comes in a black rectangular plastic package.

Typical Battery Found on a System 80A / 80B CPU Board

Another battery pack style which looks very similar to the NiCad battery packs found in "old school" cordless phones. It is actually three small NiCad cells wrapped separately in an orange poly material, which is wrapped in a outer white poly material. These don't leak nearly as badly, but they still have the potential to fail.

Typical NiCad Battery Which was Replaced

The final 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. If you find one of these, it means the battery was previously replaced. The good news is that this battery is newer than the original. However, 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.

NiCad Battery Damage to a System 80A CPU Board
(Note: This is considered very mild damage!)

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 causes every board in the head to be affected.

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

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.

4.5.2 Relocating the battery from the MPU board

The first thing you should do to any System 80 MPU is remove the rechargeable NiCad battery from the MPU board. All batteries leak. It's simply a matter of when they will leak. A leaking battery will damaged your (sometimes irreplaceable) board.

There are at least four methods of relocating and/or replacing the battery on your System 80 MPU.

• You can remove the battery completely and not replace it. The 5101 memory will not persist from power-up to power-up and therefore, high scores, replay levels, and credits will be lost.

Remote Battery

• You can mount a remote battery pack that uses standard AA batteries (x3) to protect your board. You must also incorporate a blocking diode (1N4001, although a 1N4004 will work just as well) to prevent the game from attempting to charge the batteries. Install the blocking diode in series with the positive lead of the battery pack, with the band oriented toward the MPU.

Here a 5.5V, 1F Super Cap is used to retain 5101 memory for up to 30 days

• You can replace the battery with a 1F 5.5V "SuperCap". The capacitor will never leak, will charge during power-on cycles, and will retain 5101 memory for about 30 days. If you've sanded traces as was done in the picture, use electrical tape under the cap to ensure that the negative side of the cap doesn't short a trace. Cut the tape in a circular shape and poke the capacitor leads through it so it can't fall off in the future. (Electric tape is notorious for slipping.) An alternate solution would be get a piece of fishpaper insulator, cut that into a circle and poke holes in it for the capacitor leads.

• You may remotely mount a replacement NiCad battery in a location that, should it leak, damage to valuable circuit boards will not occur.
  

4.5.3 Using a Reset Generator for the CPU Reset Section

If you find that the battery has leaked, alkaline damage can be cleaned up, traces repaired, and new components installed with kits available from several sources, including Great Plains Electronics.

An alternative to replacing a great many of the components is to use the Dallis/Maxim DS1811 reset generator. The DS1811-10 has a typical trip point of 4.35VDC. You may also use the Microchip Technology equivalent, part number MCP130-460DI/TO, available from Great Plains Electronics. Remove all reset section components, clean up residual alkaline damage, add four jumpers, and install the reset generator as pictured below.

After jumpers and the reset generator are added, make certain there is continuity between the three legs of the reset generator and the appropriate locations on the circuit board. Below is a list of the reset generator legs and the board locations. Pin 1 of the reset generator is the left leg, when the flat side of the unit is facing towards the user.

• Pin 1 of reset generator to pin 2 of Z4
• Pin 2 of reset generator to +5VDC line (lower leg of C2)
• Pin 3 of reset generator to ground (upper leg of C2)

• Using the Dallas Maxim 1811 Reset Generator
• 

  A System 80 MPU with alkaline damage repaired/cleaned. Reset circuitry replaced with the much simpler Dallas Maxim 1811

• 

  Illustrated picture of components to remove, keep, and jumpers to add.

• 

  The same image, but with indications of jumper locations (yellow dots) and where to install the Dallas Maxim 1811, flat side facing the bottom of the board.
  Note: View at full resolution

4.5.4 Slam Switch Modification

In order to test the CPU board on the test bench, a modification must be made to the CPU board to make the CPU think that the slam switch is closed. If the CPU thinks that the slam switch is not closed, the CPU will not complete the boot process, instead booting into a mode where the displays flicker all zeros at a very rapid rate. See the image here for a depiction of what you'll see.

Gottlieb® designed the slam switch as a normally closed switch. That is, the switch must be closed for the machine to operate normally. When a brute kicks the machine, the slam switch will open from the inertial force on the weight attached to the switch, and the slam switch will open. Since the CPU is on the bench, we need a way to have this switch closed at all times to properly test the board.

Additionally, slam switches themselves fail. It's a good idea to implement this change as a preemptive fix for slam switch failures.

Slam Switch Mod

The slam switch can effectively be permanently closed by making a small solder bridge across two traces to the right of Z26 (which is on the lower right side of the CPU board). To permanently close the switch, remove the solder mask by scraping with a sharp knife or screwdriver. Create the solder bridge between the two now bare traces. This change will connect pin 13 of Z26 to ground, permanently closing the switch.

Alternative Slam Switch Mod

An alternate method of achieving the same results is to solder a clipped resistor leg across the bottom of capacitor (C30) and resistor (R20), both immediately to the left of Z26.

Keep in mind that the last 4 Gottlieb® System 80B games were released with normally open slam switches. Do not perform the slam switch modification on these games. This includes the following games:

• Bad Girls
• Big House
• Hot Shots
• Bonebusters, Inc.
  

4.5.5 Connecting a logic probe to the MPU

A great place to source power for your logic probe while diagnosing the board is across the filter capacitor just to the right of connector J1. Connect the black lead of your logic probe to the negative (bottom) lead of the capacitor. Connect the red lead of your logic probe to the positive (top) lead of the capacitor. Take care to ensure that the clips don't short to adjacent components.

4.5.6 Using a PC Power Supply For Bench Testing

Future Update****This section works for now, but we can generalize bench power supply construction here: Building a flexible power supply for bench testing PCBs

The MPU board is much easier to work on if it is removed from the backbox and placed on the test bench. An AT-style PC power supply can be used to power the MPU board on the bench.

Obtain an old PC power supply. If you don't have an old computer laying around, head on off to the thrift store and pick one up. Remove the power supply from the case by unscrewing the appropriate screws. Be careful not to unscrew the power supply case itself.

Power Supply

Clip one of the connectors from the power supply wire bundle and clearly mark on the power supply box the value of each of the colored wires from the power supply. Typically, the yellow wire is 12V, red is 5V, and the black is ground. Strip insulation from the end of the red wire and the black wire as the System 80 MPU requires only 5V and ground to boot. Use alligator clips to connect 5v and ground to the appropriate J1 connection. I use larger alligator clips to make the connection easier.

J1 Connector

Mark connector J1 where the positive and negative (common) connection is for the five volts from the computer power supply. The ground connection is on the top of the connector, the 5V connection is on the bottom. The image shows A1J1 with the markings. I took the picture with the board still mounted in the machine. Connect the 5v supply with alligator clips to the positive connector on J1 and the black wire (ground) to the negative connector of J1. That's it! you're good to go!

4.6 Game Resets

System 80 games sometimes exhibit "resets", especially when high power coils fire. Assuming you've updated the power supply grounds and reflowed or replaced the header pins on the Power Supply, there are a few typical causes for System 80 resets.

Gottlieb® System 80A Filtering Capacitors

1. The 12VDC filter capacitor in the cabinet bottom which, if still original, should always be replaced. Originally, this was a 6800uf/25V capacitor. Replace with a 6800uf to 12,000uf/25V cap such as this one from Great Plains Electronics. The filtered 12VDC is regulated down to 5VDC on the power supply board. Note that some games have two of these capacitors (as shown). Note: purchase a VR3A capacitor clamp from Great Plains Electronics when replacing the large capacitor for a clean looking job.
2. The bridge rectifier that originates the 12VDC
3. Missing, broken, or failed coil diodes
4. Poor 5VDC power connections between the power supply and the MPU. The female connector on the MPU connects 5VDC to the MPU via molex crimp-on pins and a "double-wide" edge connector pad. Ground is connected in the same way. But you've done the ground mods, right?

4.6.1 System 80A / 80B Resets

A failed or failing reset board can cause spurious resets too. When first trying to get a System 80A or System 80B game to boot properly, it is best to disconnect the reset board. If disconnecting the reset board resolves the issue, the reset board can remain disconnected, provided that someone will always be in the general vicinity of the game to turn it off, should the CPU lock up.

4.7 Updating a dual game PROM MPU (1st generation) to a single game PROM configuration (2nd generation)

As noted earlier, the first five system 80 games used both sockets at PROM1 and PROM2, populating them with 512 byte masked ROMs. Should one of these ROMs fail, you may be able to find a replacement, but they are becoming more pricey, more difficult to find, and are still prone to failure as they age.

A more flexible solution would be to update the MPU to use a single 2716 UVEPROM at the PROM1 socket.

Modifications must be made to both the solder side and the component side of the board. See the pictures below.

Component side modification:

1. Cut the trace that extends from the left of Z10 between pins 6 and 7. A Dremel with a "ball shaped" cutter bit works beautifully for this. In the second picture below, the cut has already been made. I've filled the cut hole with black Sharpie! to better show the location of the cut.

Solder side modifications:

1. Cut the traces leading to PROM1 socket, pins 19 and 21. Again, the cuts have been highlighted with black Sharpie!
2. Jumper from the PROM1 socket, pin 19, to the PROM2 socket, pin 21 (connects A10)
3. Jumper from the PROM1 socket, pin 21, to the PROM2 socket, pin 24 (connects +5V to Vpp)
4. Jumper from the PROM1 socket, pin 22, to the PROM2 socket, pin 18 (connects A9)
5. Jumper from Z10, pin 13 to the via just below and to the right of Z9 (as you view the back of the board)

Your MPU board is now configured for any System 80 game. All that remains is to acquire a 2716 EPROM containing the game's code. If you have the original ROM images, the DOS command to combine them is shown below. Modify as appropriate to match the file names you have.

copy /b prom1.bin + prom2.bin combined.716

The MPU may also be used in a System 80A game if U2/U3 are updated, and in a System 80B game if considerably more mods are made which frankly, just aren't worth it.

• System 80 1st Generation to 2nd Generation Board Updates
• 

  Dremel Tool with "Ball Cutter"
• 

  Trace extending Left from Z10
• 

  PROM2-to-PROM1 Socket Cuts and Jumpers
• 

  Z10, pin 13 to via Jumper

4.8 Using a 2732 at the PROM2 position in a System 80B MPU

As illustrated in the CPU schematics of game manuals, such as "Bad Girls" and "Big House", it is stated that E3 is directly connected to AB15 (address bus 15). However, there is no mention of the factory modification (outlined below) performed on CPU boards stamped MA-1133. Equally, should the user have an MA-774 CPU board, (used in games starting with Chicago Cubs Triple Play and ending with Excalibur), this modification can be performed to use the board in the following games.

• Bad Girls
• Big House
• Hot Shots
• Bone Busters, Inc.

Not to add to the confusion, but PROM2 is actually located at the socket marked "PROM 1" on the PCB. The area on the board marked "PROM 2", which does not have a socket, is a legacy carried over from the first generation System 80 CPU board.

The following information was taken from a service bulletin located in the back of the 1992 Gottlieb® parts catalog. This modification makes AB15 available to PROM2, when using a 2732 EPROM at this position. Should a 2716 EPROM be used for PROM2, do not perform this procedure. Likewise, should a MA-1133 board be used in a game that only uses a 2716 EPROM at PROM2, reverse the following procedure.

Procedure:

1. If jumper E4 is installed, remove it. You will find the top of the E4 jumper located immediately to the right of the socket marked "PROM 1".
2. Install a jumper at E3. This connects the pad marked E3 to the dual pad marked E4.
3. On the solder side of the board, follow the trace from the pad marked E3 Southeast 1/8 inch, then South about 1/2 inch to a via.
4. Find this via on the component side of the board. It will extend to the left to another via.
5. Cut the trace between the two vias.
6. On the solder side of the board, install a jumper from TC1, pin 35 to the right solder pad of the via which was just cut.
7. All other jumpers should remain installed.

• System 80B PROM 2 2732 Update
• 

  E4 removed, E3 installed, and trace cut below E3
• 

  Jumper from TC1 pin 35 to E3

4.9 Driver Board Issues

Nuts / Screws Which Secure the 2N3055s Collector to Drive Line

Make certain to inspect and tighten the screws which secure the 2N3055 TO-3 transistors to the driver board. Specifically, the screws / nuts as marked in the pic. They tie the transistor cases (collector) to the respective solenoid drive lines. If these cases are not secured, the transistors will not function as intended.

4.10 Solenoid problems

4.10.1 Remote Mounted Transistors

Under Playfield Transistor, with Emitter, Base, and Collector Labeled

Under playfield transistors were originally 2N5875s or 2N5879s. The failure rate of the original transistors tends to be rather high. 30 years can be a long time for a transistor of that technology. Should one fail, it can be replaced with it's beefier siblings - 2N5883 or 2N5884. An MJE2955 will work also.

The green/yellow wire (Gottlieb® wire color code 54) is always connected to the tip of the transistor (collector) and leads to ground.
The "emitter" should be connected to the lug of the coil that has the non-banded side of the diode facing it (black-blue-blue in this picture).
The "base" should be connected to the drive wire from the driver board (brown-red-red in this picture).

Solenoids which use a remote mounted transistor are not enabled by temporarily grounding the pre-drive transistor's tab to ground. This test is typically performed to check the integrity of the wiring from the drive transistor to the solenoid. This test however does not confirm if the drive transistor is good or not.

4.10.1.1 Remote Mounted Transistor Upgrade

Gottlieb® Remote Transistor Circuit

During the run of Black Hole, Gottlieb® released a service bulletin recommending that the existing 10Kohm pullup resistor be changed to a 4.7Kohm resistor when changing from a 2N5875 to a 2N5879 or equivalent. Affected Black Hole games were marked serial number 6271 to 9160. However, there were several games prior to and after 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 when the game is powered up. <br=clear all>

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.

4.13 Display Problems

4.13.1 Display Test

Display test is step number 19 for both System 80 and System 80A games. Each display, including the credit/match display participates in "walking" each digit (0 through 9 beginning with 0) across each display. The "walking" begins at the match side of the credit/match display, then moves to players 1 and 3, then to players 2 and 4. After a "9" is walked through all displays, the cycle starts again with "0".

Simulation of System 80B display test

Display test is test number 20 for System 80B. All 40 of the alpha-numeric "digits" (both the top and bottom displays) will light starting with a "0", next a "+", then an "X", and finally a ",". In doing this, all possible segments of all the display digits are lit at one point during display test.

4.13.2 Open Slam Switch

If after turning a System 80 game on, and the scoring displays turn on immediately without a 5 second delay, there is a problem. However, if the displays are showing all of the outer segments (all segments necessary to display a zero) lit, and "strobing" or "rolling" rapidly as simulated in the image below, this isn't a display problem. The cause of this problem is an open slam switch on the coin door. To address this issue, see the PinWiki section Slam Switch Modification.

Simulation of displays indicating an open slam switch. Note the "rolling" perimeter display segments.

4.13.3 Rejuvenating Tired Displays

Rejuvenating tired System 1/80 displays

System 80 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.

4.14 Sound problems

4.14.1 System 80 Sound Only Board

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4.14.2 System 80 / 80A Sound and Speech Board

4.14.2.1 Different Revisions of the Sound and Speech Boards

• Revisions of the Gottlieb Sound and Speech board
• 

  B20887-1
• 

  B20887-2
• 

  B20887-3

4.14.2.2 Sound "Locks Up" after certain switch closures

The long since obsolete, pricey, and hard to find SC-01 speech chip. This one is an SC-01-A, said to be a little beefier.

This problem may be caused by a malfunctioning or missing SC-01 (or SC-01-A) speech chip.

Games such as Black Hole, Mars God of War, and Volcano utilized the SC-01 phoneme speech chip. These games require a working SC-01 to be present, not only for the speech portions of the sound, but for the sound to not "lock up" after the time that a speech call is made. The CPU relies on an interrupt from the 6532 RIOT to restart sound command processing. That interrupt originates from an "all done" signal from the SC-01 speech chip (shown as ~A/R in the schematics, SC-01 pin 8). If the RIOT never receives an "all done" signal (at PB7) then it will not interrupt the processor and no further speech or sound will be created.

It is also possible that the 2N2222 at Q3 has failed, not allowing the interrupt signal to reach the RIOT. Q3 inverts the ~A/R signal and conveys it to the RIOT as A/~R and also to the MPU as a non-maskable interrupt (U3 6502, pin 6).

4.14.3 System 80A Sound Only Board

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4.14.4 System 80A / 80B Sound with Piggyback Board

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4.14.5 System 80B Sound Board (MA-766)

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4.14.6 System 80B Sound Board (MA-886)

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4.16 Pop bumper problems

Corrected/Modified Gottlieb® System 80/80A/80B Pop Bumper Driver Board

The pop bumpers on all System 80 / 80A / 80B games are controlled by an under playfield mounted board known as the pop bumper driver board (PBDB). Remote pop bumper driver boards are unique to Gottlieb® System 80 games. No other manufacturer made this design decision. The reason Gottlieb® did this is probably to supplement the number of coil drive circuits as well as to solve the common problem of pop bumpers locking on with subsequent damage to the games components.

Each pop bumper has its own board. Each board provides a consistent, strong pop regardless of how long the spoon switch is activated, and ensures (when working properly) a single pop per actuation of the spoon switch.

These boards are single-sided construction, where the traces are located only the solder side of the board. Due to this construction, the solder connections crack easily. Reflowing the solder of the header pins on any suspect boards is recommended to ensure a good mechanical and electrical connection. The components should be inspected as well, because they can also have cracked solder connections that will need to be touched up.

If the pop bumper fires but does not score, examine the secondary switch on each pop bumper to see if it needs cleaning or adjustment. This switch is part of the switch matrix, and can be tested by manually pulling the pop bumper rod and ring down to activate it.

4.16.1 Updating the Pop Bumper Driver Board

Gottlieb® issued a service bulletin to correct a design error with the PBDB. A great many of these boards were delivered in games prior to correcting the design at the factory. Examine the PBDBs to ensure that they have been updated. See the pictures below, noting the differences. A dead giveaway would be the lack of a jumper to replace CR1.

• System 80/80A/80B PBDB Before/After Modification
• 

  Unmodifed PBDB
• 

  Modifed PBDB

Gottlieb® System 80/80A/80B PBDB Update

Should your PBDB require update, follow this procedure:

• Acquire the following parts
  
  • Cut to length .156 molex male header pins with locking ramp (you'll need a 6 pin length)
    
  • 100uf/10V electrolytic capacitor (C4)
    
  • 4.7uf/10V capacitor (C3, tantalum or electrolytic, may be axial or radial)
    
  • Jumper material (use the remaining leg cut from C4 when you install it)
    
• Remove CR1, C3, and C4
  
• Replace the molex connector or reflow the solder on each header pin
  
• Install C4 (100uf/10V) with the negative side facing the male header pins
  
• Use the remaining part of the capacitor leg from C4 as a jumper to replace CR1. Any jumper wire will work...the cap leg is convenient, available, and looks professional when installed nice and straight.
  
• Install C3 (4.7uf/10V), reversing the original polarity so that the positive side faces the jumper just installed and the negative side faces the nearest board edge. Note that C3 may be axial (leads from both ends along the components "axis") or radial (leads on one end of the component). The board is designed to accept either style.
  
• Ensure that the large can transistor (2N6057, 2N6059, PMD10K40 or PMD10K60) solder joints are solid and that the bolted end is making good contact with the PCB trace.
  
• Test the large can transistor...
  
  • DMM set to "diode test"
    
  • Black lead on the nut that secures the transistor
    
  • Red lead on each leg of the transistor
    
  • A measurement between .5 and .7 should be seen. Readings significantly outside of these ranges indicate a failed transistor which should be replaced.
    
• Examine the remaining solder joints on the board to ensure good solid joints and no lifted traces. Note that the trace between the jumper that replaces CR1 and R2 is particularly susceptible to damage and if broken, will cause the associated pop bumper to lock on.
• Reinstall the PBDB and test.
  

***Still in work:***
Steve Charland's LED mod for PBDBs
Replacing the 2N6057 with a TIP-102

4.17 Drop Target Problems

4.17.2 Early System 80 / 80A Drop Target Removal

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

4.17.3 Later System 80B Drop Target Removal

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4.18 Vari-Target Problems

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4.19 Roto Target Problems

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5 Game Specific Problems and Fixes

5.1 Replacing Black Hole Lower Playfield Illumination Lamps with #44 Lamps

This modification developed by Steve Charland.

When Gottlieb designed Black Hole and Haunted House, the designers chose to illuminate the lower playfield with 313 lamps, which are 28 volt lamps. Coil power could be used as a power source, and the lamps are slightly brighter than #44 lamps. However, #313 bulbs are triple the price of #44 lamps and are a unique part to stock.

Converting the power circuit that drives these lamps to 6VDC makes sense and allows the use of the more common #44 lamps.

Overview of the mod

The big picture...
Here's what the final "hack" will look like, just to get you oriented.
Note the use of red wire to indicate this is an "aftermarket" implementation. You may use black-slate-slate wire to have that "factory" look.

Modifications at the "L" relay. Desolder the orange/slate/slate wires.

L relay mods...
Remove the orange-slate-slate wires from the switch stack located on the L relay under the lower playfield. Be sure to cap the wires off so they can't short to anything. In the picture at left, heat shrink tubing was used to cap the wires which were twisted together.

Solder a new 16 gauge wire to the vacant solder tab where you removed the orange-slate-slate wires.

Picking up 6VDC to power the #44 lamps from the black/slate/slate wire

Attaching to the power bus...
Solder the other end of the new wire to the black-slate-slate wire that connects to all of the controlled lights on the lower playfield (pictured left).

Use "zip ties" to secure the new wire to the factory wire bundle. You can feed the wire through the factory "tie downs".

All done...

Let there be light...
All finished with the mod. The bulbs now will light on 6VDC instead of 24VDC. Swap out all of those #313s with #44s or #47s and never worry about looking for the correct bulb again.

5.2 Replacing the Black Hole "Spinning Disk" Motor

Black Hole back box spinning disk motors, having run continuously since 1981 while the game is powered on, often fail.

Various replacement motor options have been used over the years including the Radio Shack hobby motor and the Granger heavy duty motor.

Another simple and inexpensive option is the DC motor sold by ServoCity at: http://www.servocity.com/

Parts required:
Quantity 1 - RZ12-3000-1RPM geared motor - $24.99
Quantity 1 - 3472H 6mm (the motor shaft size) bore aluminum hub - $4.99
Quantity 3 - 92005A116 3mm x 6mm pan head phillips screws - $0.15 each, minimum quantity 4 (for mounting the new motor to the original mounting bracket and for attaching the spinning disk plastic to the new hub)

This 3 RPM motor, which is spec'd to run on DC voltages from 3 to 12V, is driven by 6VDC in the game. Since it is not powered at the full 12VDC, it runs slower than the rated 3 RPM at about 1.5 RPM, which looks good and matches the OEM motor speed closely. The shaft of the motor is also the perfect length. When assembled as described below, the spinning disk rides above the #455 flasher bulbs by about 1/4 inch and also about 1/4 inch behind the inner backglass.

Installation:

1. Remove the spinning disk face and the old motor assembly.
2. Remove the 3 screws that attach the OEM motor to the mounting bracket.
3. Use one of the new 3mm x 6mm screws to mount the new motor to the mounting bracket. Optionally, you may "elongate" one of the holes in the mounting bracket so that another screw may be used, but one screw is probably enough since the motor center protrudes through the bracket.
4. Mount the new hub to the motor shaft so that it is flush with the end of the shaft. Tighten the set screw with a 3/32" Allen wrench (hex key).
5. Mount the motor and bracket assembly to the lamp insert board using the two original flat blade screws.
6. Ensure that only #455 blinking lamps are used in the area behind the spinning disk. #44/47 lamps protrude too far and will scratch the back of the spinning disk.
7. Mount the spinning disk to the hub using two of the 3mm x 6mm screws.
8. Solder the power wires to the solder tabs on the motor. Connecting the Green/Yellow wire to the positive side of the motor causes it to spin counter-clockwise. Connecting the Green/Yellow wire to the negative side of the motor causes it to spin clockwise. You be the judge of the age-old debate as to which direction is correct.
9. Optional: but recommended, insert a 2-pin molex connector inline with the power connections (as shown in the picture below) to provide a quick way to disconnect the motor.
10. Optional: paint the two screws used to mount the spinning disk black.

• Black Hole Spinning Disk Motor Replacement
• 

  Front view of the motor assembly. Note the single screw attaching the motor to the bracket.
• 

  Rear view of the motor assembly. Note the inline 2-pin molex connector.
• 

  455 Lamp Clearance. Nice...
• 

  The Completed Job
• 

  The OEM Motor Assembly after detaching the mounting bracket
• 

  Replacement Parts Acquired from ServoCity

'"`UNIQ--youtube-0000000B-QINU`"' YouTube Video of New Motor Operating

5.3 Alien Star Game Start Failure

Alien Star has a major fault when running the original 689 code. For the game to properly start, one ball must be in the trough and one ball in the outhole. If both balls are located in the trough, only the single trough switch will be closed, and not the outhole switch. When only the trough switch is closed, the game *thinks* that only one ball is installed, (2 balls total are needed), and will do absolutely nothing.

It has not been verified, but running 689A code may resolve this issue.

5.4 Haunted House Upkicker Plastic Tube Mounting Bracket

Mounting bracket for the plastic tube.

The metal mounting bracket that secures the longer plastic upkicker tube to the main playfield breaks its tabs (ears) off allowing the tube to flop around loose. This bracket is actually an electrolytic capacitor mounting bracket for computer grade capacitors. If broken, Mouser Electronics sells this item as part number 539-VR4. The OEM part is a VR4, which is manufactured by Cornell-Dublier (Mallory).

6 Repair Logs

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

6.1 Game Displays 000000 On Power Up and It's Not The Slam Switch

If you power the game on and all of the displays immediately display all zeros without strobing the problem is usually with the slam switch. However, if the slam switch modification has been done or the slam switch is working properly there is a problem with the switch matrix.

I had this problem on my Haunted House machine. I finally found that chip Z15 (7432) was bad.

I was fixing a kicker solenoid on the playfield, the playfield was still in the machine and fully in the upright position. While I was soldering the wire to the new solenoid I did not adequately protect the components below from a solder drip. Well, I did have a solder drip that landed right on a pop bumper driver board connector and shorted the connector. The short caused more than just this problem but for this narrative we will restrict to the slam/switch matrix problem.

Reading in other materials I recognized the problem as the slam switch issue. I used a logic probe to test other components and found the CPU board working, mostly as it should except for acting like the machine was slam tilted. There was little written about the problem outside of the slam switch. I decided to check the matrix by doing a diode check on all of the diodes in the switch matrix. When I did this, I found that many of the diodes were testing bad. These were being tested with the board removed from the machine.

Having replacement diodes in my parts drawer I decided that these must have gone bad during the short. I began unsoldering a few of the diodes. Once disconnected from the circuit board I remeasured the removed diodes and found the correct values on my meter, they were not bad. I then noticed that the bad diodes were all in the same row on the switch matrix. They all traced back to the Z15 chip. I replaced the Z15 7432 and the problem was resolved.

6.2 Testing the Q relay

Had a problem with my Black Hole - Q relay didn't activate. Played a bit with wires, did ground mods, .. After a while I noticed it did work but didn't stay enabled - at the start of a game it closed, 1 coil (ball drain) kicked and the Q relay deactivated again. Noticed this with the playfield in up position, no pinballs installed. Finally tested with playfield down - and pinballs installed - suddenly the behaviour was different: ball drain coil kicked and then the next coil also that put a coil in the shooter lane. Seems the Q relay did work all this time, but will only stay enabled when pinballs are installed in the game ?!