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Repairing & Upgrading Gottlieb System 80
Pinballs from 1980 to 1989, Part One

by cfh@provide.net, 05/02/09.
Copyright 1998-2009, all rights reserved.

Scope: Includes Gottlieb pinball System 80, 80a, 80b games from Spiderman (1/80) to Bone Busters (8/89). The most popular System 80 games that this information particularly applies to are Black Hole (10/81) and Haunted House (2/82).

Internet Availability of this Document.
Updates of this document are available for no cost at http://marvin3m.com/fix.htm if you have Internet access. This document is part one of three (part two is here and part three is here).

IMPORTANT: Before Starting!
IF YOU HAVE NO EXPERIENCE IN CIRCUIT BOARD REPAIR, YOU SHOULD NOT TRY TO FIX YOUR OWN PINBALL GAME! Before you start any pinball circuit board repair, review the document at http://marvin3m.com/begin, which goes over the basics of circuit board repair. Since these pinball repair documents have been available, repair facilities are reporting a dramatic increase in the number of ruined ("hacked") circuit boards sent in for repair. Most repair facilities will NOT repair your circuit board after it has been unsuccessfully repaired ("hacked") by you. If you aren't up to repairing your circuit boards yourself, I highly recommend checkout out the parts and repair web page at marvin3m.com/parts.htm.

Table of Contents

Bibliography.
In the creation of this document, some information came from the following sources:
  • Gottlieb Service Bullentins, Gottlieb, 1980 to 1990.
  • Gottlieb Star Series 80 Service Manual, 1982. Available from Pinball Resource.
  • John Robertson web articles.
  • Black Hole/Haunted House Gottlieb System 80 Club of America (BHHHC), J. Cook, 1994.
    Section 1a (circuit board defect) of this document from BHHHC page 21.
    Section 1b (power supply fixes) of this document from BHHHC page 40.
    Section 2b (HH upkicker) of this document from BHHHC page 21 and Star Tech Journal.
    Section 3b (transistor subs) of this document from BHHHC page 13.
    Section 3o (Connector/Trans/Coils for HH/BH) of this document from BHHHC page 29&35.

Thanks to all the people that helped with this document. This includes Rob Hayes, John Robertson, Steve Charland, Peter Hall and Pascal Janin.



1a. Introduction, Schematics, Books

    Introduction.
    Gottlieb's System 80 machines had a variety of manufacturer and design problems, which this page will address. Doing the mandatory modifications outlined below will make a Gottlieb System 80 game extremely reliable. Certainly as reliable as any other game made during its time.

    During the early 1980's, many Gottlieb System 80 games were very advanced for their time. For example, Haunted House and Black Hole have some design features that haven't been seen since (large lower playfields, and in Haunted House's case, a three level playfield). These game were a few years ahead of their time. But due to various problems, they received a bad reputation as being undependable. This information corrects these problems.

    To keep a System 80 game running, do all the mandatory *and* recommended fixes. But at the minimum, do the mandatory fixes.

    Tools and Experience Needed.
    Please see http://marvin3m.com/begin for details on the basic electronics skills and tools needed.

    Schematics.
    All Gottlieb System80 schematics and many parts are available from one of the sources on the suggested parts & repair sources web page. Schematics really are required to work on these games. If in a hurry, there are some schematics available for download. These were all scanned from a 1980 Black Hole manual, and should generally be applicable for most System80 games up to Haunted House. After Haunted House, some of the following schematics (like the driver board) should still apply, with only minor changes.

    More System80 Repair Info.
    This site deals mostly with modifications needed to make a system80 game reliable. There is some additional CPU repair information available at the Systematic Gottlieb System 80 Circuit Board Repair web page. For addition repair info, John Kirby has also developed a nice site on system80 repair:

    Gottlieb Technical Seminar Workbook.
    The 1983 System 80/80a technical seminar workbook is also available for download. This is a great overview of the system 80 pinball system, with indepth and easy to understand text. To download this 3.4 meg file, click sy80tech.pdf. Adobe Acrobat is required to view this document.

    Gottlieb Service Bullentins.
    There are some Gottlieb service bullentins posted at http://www.geocities.com/system80pins/sb.html.

    Star Tech Journal Modifications.
    Important Note: It is highly recommended to not do any of the "Star Tech Journal" System 80 modifications outlined in their books and CD rom. Follow the instructions here instead.

    Other System80 Books, Resources and Parts.
    Highly recommended is the J. Cook book, "Black Hole/Haunted House Gottlieb System 80 Club of America". The book is great at identifying problems and provides good solutions (unfortunately, it is poorly organized, and the information is difficult to extract). This web page was inspired by this book, so it is good to have. Unfortunately this book is out of print, but I last saw it for sale from Marco Specialties. Also there is a Gottlieb System 80 Service manual available from Pinball Resource for $12. Pinball Resource is also the only authorized Gottlieb pinball parts dealer in America. John Robertson has some information on Gottlieb problems at www.flippers.com/got-tips.html. Also Pascal Janin sells some NEW system 80 boards (but not the CPU or driver board). A list of his boards can be seen at www.geocities.com/system80pins/pascal.html There is other general System80 information at the "Stork's Nest" (Peter Hall) pinball web site at www.geocities.com/system80pins/.


1b. System 80 Games List, Game Numbers, Board Compatibility

System 80 gen1
Six digit numeric displays, CPU board marked DET PB03-D102-001, uses 512 byte PROM1 and PROM2 game software, U2/U3 not socketed. This CPU board can be modified to use a single 2716 game ROM to run in James Bond and later games.
  • Spiderman #653, 1/80
  • Panthera #652, 5/80
  • Circus #654, 6/80
  • Counterforce #656, 8/80
  • Star Race #657, 10/80

System 80 gen2
Six digit numeric displays, board marked DET PB03-D107-001 or DET PB03-D107-003, uses only one PROM1 2716 game software, U2/U3 not socketed. This "gen2" sys80 CPU board has four times the PROM software capabilities of the earlier "gen1" sys80 CPU board. Hence the sys80 gen2 CPU board will require modified PROM1 software to run in Spiderman to Star race games. This "gen2" CPU board can be used in sys80a games too, but U2 and U3 needs to be changed. Note the only difference between DET PB03-D107-001 and DET PB03-D107-003 CPU board is the placement of the ground trace on the component side of the CPU board.

  • James Bond #658, 10/80
  • Time Line #659, 11/80
  • Force II #661, 1/81
  • Pink Panther #664, 3/81
  • Mars God of War #666, 4/81
  • Volcano #667, 7/81
  • Black Hole #668 (& Eclipse #671 & 671K for kit version), 10/81
  • Haunted House #669, 2/82

System 80a
Seven digit numeric displays. U2 and U3 now use sockets. No DET number but "D20869" is seen. The sys80a CPU board can be used in earlier sys80 games if U2 and U3 is changed.

  • Devil's Dare #670, 8/82
  • Caveman #810PV, 9/82
  • Rocky #672, 9/82
  • Spirit #673, 11/82
  • Punk #674, 12/82
  • Striker #675, 1/83
  • Krull, #676, 2/83
  • Q*bert's Quest #677, 3/83
  • Super Orbit #680, 5/83
  • Royal Flush Dlx #681, 6/83
  • Goin Nuts, #682, 1982
  • Amazon Hunt #684, 9/83
  • Rack 'Em Up #685, 11/83
  • Ready Aim Fire #686, 11/83
  • Jacks to Open #687, 5/84
  • Alien Star #689, 8/84
  • The Games #691, 8/84
  • Touchdown #688, 2/85
  • El Dorado #692, 3/85
  • Ice Fever #695, 5/85
System 80b
Alpha-Numeric displays, U2/U3 chips are replaced with a ROM daughterboard, display decoding TTL chips missing on the right side, only one connector for displays (instead of two), reset board plugged into top CPU socket. The sys80b CPU board can not be used in earlier games.
  • Chicago Cubs Triple Play #696, 7/85
  • Bounty Hunter #694, 9/85
  • Tag Team #698, 10/85
  • Rock #697, 1/86
  • Rock Encore #704, 5/86
  • Raven #702, 6/86
  • Hollywood Heat #703, 9/86
  • Genesis #705, 9/86
  • Gold Wings #707, 10/86
  • Monte Carlo #708, 1/87
  • Spring Break #706, 4/87
  • Amazon Hunt II, #684c, 5/87
  • Arena #709, 6/87
  • Victory #710, 10/87
  • Diamond Lady #711, 12/87
  • TX Sector #712, 2/88
  • Amazon Hunt III (kit only), #684d, 3/88
  • Robo-War #714, 4/88
  • Excalibur #715, 8/88
  • Bad Girls #717, 10/88
  • Hot Shots #718, 2/89
  • Big House #713, 4/89
  • BoneBusters Inc. #719, 8/89

James Bond backbox with a remote battery holder and all the mandatory ground mods.
Upper left: power supply. Upper right: CPU board.
Lower left: sound board. Lower Right: driver board.

Haunted House backbox with a replacement Niwumpf CPU board installed and mandatory
ground mods (no battery need for Niwumpf).
Upper left: power supply. Upper right: CPU board.
Middle left: sound board power supply.
Lower left: sound board. Lower Right: driver board.
Far right: lightning effect board for the backglass.

Alien Star backbox. This is a system80a game. Note the boards are all
mounted "sideways" (compared to the Haunted House above).
Upper left: sound board Upper right: power supply.
Lower left: driver board. Lower Right: CPU board.
Far right: small CPU reset board.

Bounty Hunter backbox. This is a system80b game. Note the boards are also all
mounted "sideways" (like the Alien Star above).
Upper left: sound board Upper right: power supply.
Lower left: driver board. Lower Right: CPU board.
Far right: small CPU reset board.

System80 Board Compatibility.

    CPU Board.
    On the first five System80 games (Panthera, Spiderman, Star Race, Counterforce, Circus), Gottlieb used a *two* game PROM system board (labeled DET PB03-D102-001). These first generation CPU boards used two smaller 512 byte game PROMs at locations PROM1 and PROM2. Starting with James Bond Gottlieb changed modified the sys80 board to use a single 2716 at PROM1 (so nothing plugs into the PROM2 socket), which is four times the amount of potential game ROM software of the original -001 CPU board.

    If the later single game ROM system80 boards ("gen2", DET PB03-D107-001 or PB03-D107-003) is used in one of the first five sys80 games, a modification to the game ROM needs to be made. The game ROM images need to be "double up'ed" into a single 2716 EPROM to make this work. The 512 byte PROM1 and PROM2 images are combined using this DOS command:
    copy /b prom1.512 + prom2.512 + prom1.512 + prom2.512 newrom.716

    Just plugging the two original ROMs into sockets PROM1 and PROM2 won't work on the DET PB03-D107-001 or PB03-D107-003 board. If this ROM modification is not made and the DET PB03-D107-001 or PB03-D107-003 board is used in say a Spiderman, the game won't boot. (A good indication of this problem is the playfield mounted Tilt relay will flicker on and off continually, meaning the game PROM software or socket is bad.)

    The earlier "gen1" two PROM system80 CPU board DET PB03-D102-001 can be modified to use a single 2716 EPROM by following instructions here.

    System80 and System80A CPU boards can be interchanged *if* the appropriate U2 and U3 chips are used. The U2/U3 chips are the "game rules", and are different for System80 and System80A (System80B does not use chips U2/U3). Pascal Jain and www.greatplainselectronics.com both sell an adaptor board for the U2/U3 chips that allow EPROMs to be used. Unfortunately the U2/U3 are masked ROMs, so EPROMs can not be plugged directly in their place without some board modifications (see here for information on this conversion), or this adaptor board.

    Making a System80B CPU board work in System80 or System80A (or vice versa), is a bit of work. The different score displays (and hence driver circuits), and the rules EPROMs are the main problems. The existing System80b display jumpers need to be removed/changed, and chips Z19, Z21, Z22, Z23, Z24, Z25 reinstalled. Also the piggyback board that replaces U2/U3 will need a new EPROM with System80 (or System80a) "game rule" code installed.

    System80b CPU boards also have two PROM1 jumpers which must be configured correctly. Earlier sys80b games used a 2716 at PROM1, and later sys80b games used a 2732. The system80b CPU board must be configured correctly for either EPROM size.

    • E4 installed (and E3 removed) = PROM1 set for 2716 EPROM. A vertical jumper goes from pad E4 to an unlabeled pad just to the left of the resistor above pad E4.
    • E3 installed (and E4 removed) = PROM1 set for 2732 EPROM. Really this is a jumper going between the E3 and E4 pads.

    Niwumpf has also recently introduced a replacement System80 CPU board. Unfortunately it's only available for certain sys80 games Haunted House, Black Hole, Panterra and Spiderman. It has a slightly different boot process too (10 second wait time until the score displays come up, unlike the original system80 CPU which has a 5 second boot-up wait).

A new Niwumpf system80 CPU board with the mandatory ground modification.

    Driver board.
    The driver board used in all System80, System80A and System80B game is the same, and completely interchangable between all games. There are also replacement driver boards available like the Rottendog system80 driver board. This board uses MosFets instead of the stock MPS-U45/MPU-A13 driver transistors.

A new Rottendog replacement system80 driver board, which has a nice ground tab
so the mandatory driver board ground modification can be made easily.

    Power Supply.
    The power supply board on System80 and System80A are interchangable. System80B used a completely different design, and is not interchangable with earlier games. The system80b power supply is the same as the power supply used in later System3 games (except sys80b uses .156" connectors and sys3 uses a square connector), and only provides 5 volts for the boards.

    If you don't want to repair/upgrade your original system80 or system80A power supply, Rottendog makes a nice replacement System80/80a power supply board (with the mandatory ground mods are already implemented into the power supply). In addition, Great Plains Electronics makes a nice replace power supply too (again with the mandatory ground mods already implemented into the power supply).

Left: new Rottendog replacement system80 power supply.
Right: new Great Plains Electronics replacement system80 power supply.

    Sound Board.
    There is a total of four different System80 sound boards (with its own power supply board). Spiderman (#653) to Pink Panther (#664) used the older sound board that was simple sounds only, no speech. Mars-god of war (#666) to Ice Fever (#695) used a sound and speech board with speech as an option. The voices on this board were very crude, but typical 1980s computer voices. All System80B games (#696 to #719) used a new sound and speech board with improved speech. This board has a LED in the center for troubleshooting. The LED on this newer sound board will NOT flash until the CPU board has successfully booted. So if the system80b CPU does not boot, the sound board LED will not light or flash.


3c. System 80 Parts to have on-hand
    Here a list of system80 parts I like to have on hand for repairs.

    • Molex 08-52-0072 crimp-on terminal pins (for single sided connectors).
    • Molex 08-03-0304 crimp-on terminal pins (for double sided connectors).
    • Molex 08-52-0113 crimp-on Trifurcon terminal pins (for .156" headers).
    • Molex 26-48-1121 .156" header pins with no lock. Cut to size.
    • Molex 09-50-3121 .156" white housings. Cut to size.
    • Molex 15-04-0219 .156" polarized pegs.
    • Molex hand crimping tool for above (see here for details).
    • Molex pin removal tool #11-03-0016.
    • 2N6057/2N6059 (NTE247) transistor for pop bumper driver board.
    • TIP102 transistor for pop bumper driver board modification and driver board.
    • 2N5550 transistor for power supply.
    • 2N5879 (or 2N5880 or 2N5883 or 2N5884) power transistor for under-playfield. MJ2955 can also be used.
    • MPU-U45 or CEN-U45 transistors for driver board.
    • MPS-A13 transistors for driver board.
    • 2N3055 (NTE130) transistor for driver board.
    • 2N6043/TIP122/TIP102 (NTE261) transistor for driver board.
    • 2N5550/2N5551 (NTE194) for CPU board.
    • 2N4400/2N4401 (NTE123AP) for CPU board.
    • 2N4403/MPS-A70 (NTE159) for CPU board.
    • TIP31C (NTE291) for power supply
    • UDN6118 chip for score displays.
    • UA723CN or LM723CN chip for power supply.
    • 7400 chip for CPU board.
    • 7404 chip for CPU and driver board.
    • 7448 or 74LS48 chip for CPU board.
    • 7432 or 74LS32 chip for CPU board.
    • 7474 chip for CPU board.
    • 7416 or 74LS16 chip for PBDB.
    • 74121 or 74LS121 chip for PBDB.
    • 74175 or 74LS175 chip for driver board.
    • 6532 RIOT chip for CPU board.
    • 1N4738 zener Diode 8.2V, 1 Watt power supply CR7.
    • 1N4746 zener Diode 18V, 1 Watt power supply CR6.
    • 1N914/1N4148 diodes.
    • 1N4004 diodes for coils.
    • 1N270 diodes for switches (1N4004 can also be used).
    • 330 ohm 1/4 watt resistor for pop bumper driver board mods.
    • 680 ohm 1/2 watt resistor power supply R10.
    • 12k ohm 1/2 watt resistor power supply R3.
    • 4.7k ohm 1/4 watt resistor for under playfield transistor pull-ups.
    • 470 ohm sealed resistor trim pot power supply.
    • 9.1 ohm 1 watt resistor for driver board 2n3055.
    • LEDs for power supply, PBDB, and other uses.
    • 4.7 mfd 16 volt caps for PBDB
    • 47 or 100 mfd 16 volt caps for PBDB
    • 10,000 mfd 20 volt electrolytic cap for power supply.
    • Fiberglass Pencil, good for removing battery corrosion from the CPU board. MCM Electronics, part# SABU10191, $5.50. Also get the fiberglass refills for the pencil, part# SABU1019210, $5.50.

    See the Parts Suppliers section of this web page for places to buy these parts.


1d. Before Turning the Game On: Check the Coil Resistance.
    A very good idea for any unknown game just purchased is to check all the coils' resistance. If the game is new to you, and you have not powered it on, a quick check of coil resistance will tell you a lot about your new game. This takes about one minute and can save you hours of repair and diagnosing work.

    Any coil that has locked on (usually due to a short solenoid driver board transistor) will heat up and have a lower total resistance. This happens because the painted enamel insulation on the coil's wire burns, causing the windings to short against each other. This will lower the coil's resistance, causing the coil to get even hotter. Within a minute or so the coil becomes a dead short (less than 2 ohms), and usually blows a fuse.

    If the solenoid driver board (SDB) or under-playfield mounted transistor is repaired, and the game is powered on with a dead-shorted coil, this will blow the same driver transistor(s) again when the coil is fired by the game for the first time! There is no sense making more work for yourself. So take 60 seconds and check all the coils' resistance BEFORE powering the game on for the first time.

Checking a slingshot coil's resistance with a DMM. The 3.4 ohm reading is fine
for the A-1496 slingshot coil.

    In order to check coil resistance, put your DMM on its lowest resistance setting. Then put the DMM's red and black leads on each coil's lugs. A resistance of 2 ohms or greater should be seen. Anything less than 2 ohms, and the coil and/or driving transistor may be bad. Now remove the wire from one of the lugs of the coil, and test the coil again. If the resistance is still the same (low), the coil or diode is bad (and also perhaps the driving transistor). If the resistance is higher than 2 ohms, the coil is good but the solenoid driver board transistor is shorted and will need to be replaced. Lastly, the coil's 1N4004 diode could be shorted too, giving a false low coil resistance. Cut one diode leg from a coil lug and retest the coil's ohms.

    Remember when reconnecting the wires to the coil that the power wire (usually two wires or thicker wires) goes to the coil's lug with the BANDED side of the diode attached. The thinner wire is the coil's return path to ground via the driver transistor and attaches to the coil lug with the non-banded side of the diode attached.

    If a low resistance coil is found, also suspect the associated driver board or under-playfield mounted transistor as bad. A low resistance coil is a red flag, a warning, that there may be problems on the driver board or with an under-playfield mounted driver transistor. Actually with System80 games, if a low resistance coil is found, I can pretty much guarantee that you will need to (should) replace of course the coil, but also all the silicon devices in its ground path (under-playfield transistor, driver transistor on driver board, and any pre-driver transistor if applicable).


1e. Initial Powering Up (Start Up) for the First Time - Diagnosing Problems
    When ever I get a new System80 game, there is a certain systematic approach I use to power up the game for the first time. I especially do this in cases where the game clearly has not been turned on for a long time, and its electronics are in unknown condition. I use this approach because having a bad power supply can richocette through the circuit boards, causing more damage than you started with (especially with sys80b, because there's no "crowbar" 5 volt protection). This approach tests each piece of the system80 electonics in a cumlative chain.

    Initial Board Identification and Power Chain.

    The general power chain works like this:

    1. Power in through the line cord. This then goes through a RF filter, and then to the main line fuse. This is all on the lower bottom panel.
    2. Transformer, bridge rectifiers, filter caps, fuses in the bottom of the cabinet. The 120 volts AC goes to the transformer and is diced into voltages the game needs. Basically there are several groups of voltages: display (69 volts DC), game logic (12 volts DC), solenoids (25 volts DC), CPU controlled lamps (6 volts DC), general illumination (6 volts AC).
    3. After the transformer creates these distinct AC voltages, they are rectified (converted from AC to DC) on the lower panel using bridge rectifiers. The only exception to this rule is the display voltages which are rectified by the power supply board on sys80 and sys80a using discrete 1n4004 diodes. There is a fuse associated with each of these voltages on the bottom panel.
    4. CPU power (12 volts) and display power (69 volts) is routed to the Power supply board in backbox for CPU, displays, etc.
    5. Power for soleniods and CPU controlled lights and General illumination is routed to the playfield.
    6. CPU board gets 5 volts (only) from the power supply.
    7. Driver board gets 5 volts (only) from the CPU board.
    8. Sound board gets raw power from it's own power supply (Mars and later). With Mars God of War and later games, there is a separate sound power supply in the backbox (except is Mars and Volcano where the sound board power supply is in the lower cabinet).

System80 boards from a Black Hole.

    Step One: Power off, Check the Lower Board Fuses.
    With the game off remove each of the fuses one at a time and test with a Multimeter (DMM) set to continuity. If a fuse is blown, just don't replace it (just yet). Fuses often blow for a reason. Note what the fuse does (there should be labels for each of the fuses).

System80/80a: The power supply path starts in the lower cabinet on the "bottom panel".
The fuses and big orange power supply capacitor in the lower right corner can be seen.
This particular bottom panel is from James Bond.

    If for example the fuse for the CPU driven 6 volt lamp power is blown, test its accompanying bridge rectifier (because if the bridge is shorted, its accompanying fuse will blow). There's only three bridge rectifiers in a system80 game (28 volts coil power, 6 volts cpu driven lamp power, 12 volt logic power). More information on testing the bridge can be found below.

    If the 69 volt fuse for the score displays is blown (sys80/80a), this often means one of the power supply's four 1N4004 diodes used for rectifying this voltage is shorted (sys80b handles its score display voltage differently, right on the display board and not on the power supply). If a 6.3 volt general illumination lighting fuse is blown, that can often mean a shorted light socket on the playfield.

    Personally on system80/80a games, while I'm monkeying around on the lower fuse panel, I replace the orange capacitor for the 12 volt logic power. This capacitor is nearly always bad or failing, and definately should be replaced. More info on this dreaded orange capacitor can be found here.

    Now that the lower fuse panel is all checked out, REMOVE the 28volt solenoid fuse before proceeding! Set it aside for later.

    Step Two: Power off, Check Playfield Coil Resistance.
    This was convered above, but it needs repeating! If a driver board transistor shorted or there is a ground issue, a coil can lock-on and burn. If this is the case, either cut the non-banded diode lead going to the coil, or replace the coil. I do this before initial power-up. Because a burned (shorted) low-resistance coil can damage the driver board.

    Step Three: Isolate the Power Supply.
    This simply involves removing the CPU board J1 connector (the small 4 pin connector). The lone CPU connector provides power to both the CPU board and the driver board for all system80,80a,80b games. With this connector removed, the power supply is isolated from the rest of the game. Now turn the game on. On system80/80a, two LEDs should light on the power supply board. If one or both LEDs are off, there are missing voltage(s). More information on what voltages should be seen and how to test them can be found below. If any voltages are missing or either LED is not lit, you will need to repair the power supply before continuing (more information on that can be found in the Power Supply section below).

    For a summary of voltages, here's the system80/80a test points, with your black DMM lead of voltmeter on TP3 (ground). If any voltages are missing, see the Power Supply section below.

    • TP1 (labeled 60V) should read 60 to 67 volts DC
    • TP2* (labeled 42V) should read 42 to 46 volts DC
    • TP3 is ground. All voltages are referenced to this.
    • TP4 (labeled 5V) should read 4.95 to 5.20 volts DC. This can be adjusted with the small adjustment Pot. I like to set it to 5.10 volts.
    • TP5* (labeled 8V) should read around 8.0 to 8.7 volts DC.

    * Note the 42 and 8 volt sources are crude zener diode regulators and may vary with load. Unloaded these voltages read slightly high.

    On system80b games, there is a single large 5 volts DC power supply in the backbox. It only outputs 5 volts, nothing else. There is also an adjustment pot on this too (again set to 5.10 volts). The above test points do not apply to the system80b 5 volt power supply. To test this unit, put your red DMM lead on any pin of the top most connector of the power supply. Put the black DMM lead on ground (there is a large yellow ground strap in the backbox, use that.)

    Step Four: Power Up with the CPU board.
    Now that the power supply checks out, the CPU board can be added to the mix. Note the Driver board should be disconnected from the CPU board. There is a connector on the bottom of the CPU board going to the driver board, make sure this is removed! For safety reasons, I suggest first removing *ALL* cpu board connectors except for J1 (the small 4 pin power plug).

    Power the game up, and test for 5 volts on the CPU board (test for 5 volts at capacitor C1 right next to the J1 connector, with a DMM test leads connected to the legs of C1). The 5 volts should still be 5 volts (that is, the CPU board is not dragging down the 5 volts because of a shorted component). Note that the 5 volts is adjustable on the power supply, so adjust 5 volts to be 5.10 volts.

    If the 5 volts checks out (4.95 to 5.20 volts DC), turn the game off. Now add the two score display connectors J2 and J3 on the right side of the CPU board. Note on sys80b there is only a single J2 connector. (Remember NEVER add/remove connectors to a system80 game with the power on.) Power up and the score displays should be showing zeros and "strobing". The strobing happens because the coin door slam switch is disconnected from the CPU board. On system80b the displays may say, "slam tilt open". If this is the case, the CPU board appears to be "booting" and operating. If nothing appears on the score displays, the CPU board is "dead", and you'll need to repair it. Check out the CPU board repair section for details on that.

    Power down and inspect/add CPU connector J5 (bottom center) to the CPU board. This is the coin door and slam switch connector. Before attaching the connector, look at its pins. They should be shiny. This connector is right in the battery corrosion area, so if they are gray or green, you will need to replace those pins. Do it now. See the Connector Pin section of this document for help with that.

    The J5 cpu board connector is the coin door switches and slam switch. Attach this connector to the CPU board and power up the game. On system80/80a, there should be a five second delay, and then the score displays will come on. On system80b the score displays come on immediately with some attract mode text. If this is the case, you're doing well, as the CPU board is working well. If this isn't the case, there's some short in the coin door wiring. Assuming the score displays are "on", now you can press the red coin door diagnostic button. More information on the book-keeping/self-tests can be found here. If you can get to test 18 (switch test), it should show all switches open with a "99". If not, there is either a problem with a coin door switch or there is a problem with the switch matrix circuit on the CPU board).

    Power down and inspect/add CPU connector J6 (bottom far left) to the CPU board. This is the playfield switch matrix plug. Before attaching the connector, look at its pins. They should be shiny. This connector is right in the battery corrosion area, so if they are gray or green, you will need to replace those pins. Do it now. See the Connector Pin section of this document for help with that.

    The J6 cpu board connector is the playfield switch matrix. Attach this connector to the CPU board and power up the game. Press the coin door red diagnostic test button and again go to test 18 (switch matrix). There may be some playfield switch closed, so you may not get the "99". But you should be able to close some playfield switches and see that reflected in the score displays with their accompanying playfield switch number.

    Step Five: Power Up with the Driver board.
    There should be only one connector not attached to the CPU board at this point (J4). Inspect this connector for gray/green pins, and replace them as needed. See the Connector Pin section of this document for help with that. With the game off, add this connector to the CPU board. It provides data and power to the Driver board. Power up the game. Since you removed the solenoid 28 volt fuse, none of the coils will turn on. But the CPU controlled lights should be doing their attract mode cycling. With the game on, the red coin door diagnostic button can be pressed and test 16 (cpu driven lamps) can be run.

    Everything is good to this point right? Well now is the time to power off the game, and put the 28 volt solenoid fuse back in the bottom panel. Power the game on, and if any coils immediately "lock on" (energize) when power is turned on, turn the game off! This means there's issues with the driver board (or under-playfield mounted transistors), and that will need to be fixed before proceeding. See the Repairing Driver Board section of this document for help with that.

    If none of the coils lock-on when the game is turned on, the red coin door diagnostic button can be pressed and test 17 (solenoids) can be run (see below).

    Step Six: Run Diagnostics - display test.
    Diagnostics are not very good in system80 land, but they are better than nothing. There is a display test, switch test, solenoid test and a crappy lamp matrix test. Use the coin door red button to access the diagnostics. You will have to go thru 11 steps of book keeping first before getting to the diagnostics.

    On Sys80 and 80a,"00" should show in the credit score display window. Press the start button to skip to test "16" press (bypassing the audits/bookeeping). Press the small red button to move to test "19". This is the display test. The CPU will send a zero across all displays, then a one, then two, and so on.

    On Sys80B, the "test mode" should show in the alpha score display. Press the game start button to skip to "lamp test" press the small red button to move to test "display test". The CPU will send various characters across both alpha displays.

    Go through the entire display test to make sure that all digits and segments are working. Continue if all of your displays are working as they should. This is less of an issue with system 80B since all of the display data is handled at the display and not decoded on the CPU board like 80 and 80A.

    Most display problems are related to bad connectors. If displays are partially working, and wiggling a connector fixes or changes a display, then that connector needs to be re-pinned.

    Step Seven: Run Diagnostics - switch test.
    With CPU connnector J6 attached (switches) to the CPU, remove all balls from game and reset all drop targets to UP. Perform this test with playfield glass off to be able to activate all switches. Turn game on and go through the CPU test and check ALL switches as described below. Press inside coin door red test button:

    Sys80 and 80a: "00" should show in the credit window. Press the game start button to skip to test "16" press the small red button to move to test "18". This is the switch test. The CPU should send "99" to the credit display indicating all switches are open. Activate all switches one by one to make sure the computer only "sees" one switch at a time. Check tilt and coin switches too. Use the switch matrix in the manual for ease of checking off all switches.

    Sys80B: "test mode" should show in the display. Press the game start button to skip to "lamp test" press the small red button to move to test "switch test". The CPU should send "all switches open" to the credit display indicating all switches are open. Activate all switches one by one to make sure the computer only "sees" one switch at a time. Check tilt and coin switches too. Use the switch matrix in the manual for ease of checking off all switches.

    Generally if there is a switch problem, it's related to the CPU board connectors on J5 and J6. There can also be CPU board problems, but usually it's the connectors.

    Step Eight: Run Diagnostics - coil test.
    You should now have verified that the the displays, coin door, and switches are good. The hardest part of system 80 games is getting over the CPU startup hurdle. The next tests are for sounds and coils. Turn game off and connect the large double sided CPU to Driver connector (J4). Before turning the game on, note this:

    A power-on "thunk" is normal on most system80 games. The playfield mounted transistors will activate for a moment. This is normal for an unmodified game. Some people have put out board modifications to prevent this, but I see it as a sign that everything is OK so far, so I personally do not do this modification.

    Coils locking on at power-on is NOT normal, so be ready to turn your game off if this happens.

    The game should go through a normal 5 second delay (80 and 80A) and go into attract mode. Attract mode is the game flashing controlled playfield lamps and possibly cycling a coil or relay. Displays should come up and the game should be ready to play. Start this procedure over if you do not get this normal startup sequence.

    Step Nine - More Diagnostics.
    These steps are assuming you have all connectors in place and have made it to the game's attract mode sequence. Turn game on and let sit in attract mode.

    Check the CPU controlled lamps. These lamps should flash on and off in a logical manner. Lights in a row usually go through that row for a standard attract mode sequence. Lights staying on and not flashing in proper order can often be attributed to CPU PROBLEMS.

    Go into test/diagnostic mode. Get to test #16 (80 and 80A) or "lamp test" (80B) This will cycle a few relays twice (game over, tilt, coin lockout) and jump into lamp and relay tests. This mode is not very helpful, but can isolate any type of relay problem. Replace or adjust any lamps not working. A lamp stuck on or not working at all can be as simple as a dead bulb or bad lamp socket. Or it could be a CPU/Driver board issue.

    System 80B lets you stop the test and constantly strobe a lamp or relay. Hold down the left high score button that you would use to enter in high scores and the lamp indicated will constantly flash.

    Note on some system80 games in lamp test a coil or relay may go on and off. This is because Gottlieb ran out of coil drivers and used lamp driver as a coil pre-drive. Unfortunately they didn't update their diagnostic firmware to reflect this, so the lamp test can toggle a coil/relay on some games.

    Now go into test mode #17 (80 and 80A) or "solenoid test" (80B). This will indicate a number in the display. This number will have a coil associated with it (different for every game) and can be found in the manual. Make sure every number fires the proper coil.

    Opening the coin door slam switch will put the game back into attract mode (after delay).



2a. Before Power Up: Power Train & Power Supply Explained and Repairs/Upgrades
    This section will "start at the beginning" and show how power gets from the wall outlet to the game. It will also describe what typically goes wrong in the power train and how to fix it. Please remember that System80 and System80a used different power trains and power supplies than System80b, though the basic theory and mode of operation are the same. Also many of the fixes and upgrades in this section are mandatory for proper long-term operation of a System 80/80A/80B power supply.

Bottom Panel - Where is all Starts.

    The bottom panel (lower cabinet) is where the power all starts. The line cord comes into the game and goes to line filter. Next it goes to a line fuse (an an outlet plug), and then to the pair of transformers. Not Gottlieb does not use a MOV on the line filter (unlike Bally and Williams), so there is no surge protection in system80 games.

    The two transformers convert the 120 volts AC input to other voltages needed for the game. The large transformer (C-19552) outputs power for the solenoids (24 volts and on some games 38 volts), general illumination light power (6.3 volts), and CPU controlled light power (6 volts). The small transformer (B-19548) outputs the main score display voltage (60 volts), the computer board voltage (12 volts which ultimately ends up as +5 volts), and the score display offset/reference voltages (8 and 4 volts).

System80/80a: The power supply path starts in the lower cabinet on the "bottom panel".
The big orange power supply capacitor in the lower right corner can be seen here.
Replace this capacitor IMMEDIATELY (use 10,000 mfd at 20 volts or higher).
This particular bottom panel is from James Bond.

    The transformer outputs only AC voltages, but the game largely uses DC volts. So most voltages (except for the general illumination 6.3 volts AC) go to bridge rectifiers or power supply diodes that convert the AC to DC volts. There are three bridge rectifier on the bottom panel, all being 35 amp 400 volt lug style bridges):
    • 12 volt bridge which is used for the sound board and ultimately ends up as +5 volts for the logic voltage.
    • 6 volt bridge which is used for the CPU controlled lighting.
    • 24 volt bridge which is used for the playfield coil voltage.
    • Some later sys80/sys80a games (like Haunted House) have a fourth bridge for 38 volts DC. This higher voltage was used for some of the coils.

    After the power is converted from AC to DC via these three bridge rectifiers, it goes through bottom panel mounted fuses. Also the voltaged that don't get converted to DC on the bottom panel also go through fuses on the bottom panel:

    • backbox 6.3 volts AC general illumination
    • playfield 6.3 volts AC general illumination
    • CPU controlled 6 volt DC lights
    • Sound board power 12 volts DC
    • Logic power 12 volts DC
    • Coil power 24 volts DC
    • Score display 60 volts AC

    There are other sys80 fuses beside the bottom board fuses, all mounted under the playfield. There is usually a fuse for each of the pop bumpers and other major coil items like upkickers and drop target reset banks. In fact, there can be a whole slew of fuses under the playfield. So many that the novice can be quite over-whelmed by the sheer number of fuses. And as the games got more advanced, there are more fuses (Haunted House/Black Hole for example have a ton of under-playfileld mounted fuses.)

Under the playfield fuses for James Bond. Not too bad really. As the games get more complicated, there can be A LOT more fuses under the playfield than this.

    My advice for this is simple: test EVERY fuse in the game by removing it and using a DMM (digital multi-meter) set to continuity. Don't try and give fuses a visual test! And I highly recommend removing the fuse from the fuse holder for testing, as this will show a fuse that is cracked or a fuse holder that is bad (and there are far less "false reading" testing a fuse out of circuit.) Obviously this is all done with the power off.

    Note many under the playfield fuses will not have their fuse value stated with a label. Many fuses will, but others will not (or the label fell off). For this reason it's a good idea to get a game manual. Do NOT over fuse! If it says "2 amp slow-blow", then that's what you should use. The fuses are there for a reason, to be the "weakest link". If over-fused, much more expensive items become the weakest link (like driver transistors and/or coils). So use the correct fuses.

Blown Fuses and Bridge Rectifiers.

    Fuses are designed as the weakest link in the chain. Fuse tend to blow for a reason, but they can "just die" due to fatique and age. Yet for the most part, if a fuse is blown on the bottom panel there's usually a reason, like a shorted bridge rectifier. This is a common problem especially for the CPU controlled lights' 6 volt bridge, but the solenoid and 5/12 volt bridge can also short (causing its associated fuse to blow). For this reason, it's a good idea to test the bridges to make sure they are not shorted.

Testing a bridge with a DMM set to the diode function, and putting the red DMM
lead on the ground (green) bridge lug. This bridge is testing "good".

    To test a bridge a DMM (digital multi-meter) is needed. Set the DMM to diode test, and put the red lead on the ground lug of the bridge. (On system80 games the ground lug is easy to find, as it's the one with the green wire attached.) Then put the black DMM lead on each of the bridge lugs next to the ground lug. A value of .4 to .6 volts should be seen on the DMM. Anything outside that range indicates a bad bridge rectifier.

Testing a bridge with a DMM set to the diode function, and putting the black DMM
lead on the positive output bridge lug. This bridge is testing "good".

    Now put the black DMM lead on the positive output of the bridge. This is again easy to find as its the bridge lead diagonal to the ground lug. (Also on newer bridges the positive output lug is set 90 degrees off from the other three lugs.) Then put the red DMM lead on each of the bridge lugs adjacent to the positive output lug. A value of .4 to .6 volts should be seen on the DMM. Anything outside that range indicates a bad bridge rectifier.

    If a bad bridge is found, replace it with a new 35 amp 400 volt bridge with lugs. These are inexpensive and easy to get from a variety of electronic parts houses.

Under Playfield Relays.

    Mounted under the playfield are two relays (or sometimes three like on Haunted House/Black Hole). This is much like what Gottlieb did on their earlier system1 games, and is much unlike what other manufacturers did.

    First is the Tilt "T" relay, which pulls in when the game is tilted. When energized at a tilt, this turns on the "tilt" light in the backbox, turns off the GI (general illumination) lights on the playfield, and turns off the power to all the coils on the playfield. If a ball is tilted during play, the ball will immediately drain (since there's no flipper or coil power). Once the ball hits the outhole switch, the CPU board will de-energize the Tilt relay, and the game continues.

The Game Over "Q" relay and Tilt "T" relay under the playfield on James Bond.

    The other relay is the Game Over "Q" relay. This relay energizes when a game is started, and turns on the power to all the coils on the playfield. All other manufacturers mounted their game over (aka flipper relay) to the CPU or driver board, but Gottlieb mounted theirs under the playfield (a leftover from the EM era).

    As a diagnosing feature, with the game on and in "attract" mode (ready to take money and start a game), the Game Over "Q" relay can be manually held in (assuming your careful and don't knock the relay's activation plate off it's mounting pivot point). This will turn all the power on to the flippers, pop bumpers, slingshots without having to start a game. This is handy when adjusting and testing these devices (like adjusting flippers or testing a Pop Bumper Driver Board).

    Note games like Black Hole and Haunted house used a third under-the-playfield mounted relay ("U"). This relay would turn on the special lighting for the lower playfield, turn on the power to the lower playfield flippers, and turn off the power to the upper playfield flippers. Interestingly Gottlieb used coil voltage (24 volts) to power the #313 lamps for illuminating the lower playfield on Black Hole/Haunted House.

Slam Switch (Coin Door) and Tilt Switches.
    Another unusual thing about Gottlieb is their coin door "slam" switch. This normally closed switch MUST be closed or a game won't start (heck the CPU board won't even really "boot" either). Unlike the other pinball manufacturers where their slam switch was normally open, Gottlieb (foolishly) choose to have their slam switch normally closed (like on the prior System1 games). This means if this switch is open, or the connectors/wiring from the CPU board to this switch are broken/corroded/failed (common problem, due to CPU board battery corrosion), the game will NOT work! This is important to know as it's different than other pinball makers. I should also mention it's really a good idea to do the slam switch modification to the CPU board to prevent future slam switch problems related to connectors and wiring.

The coin door on James Bond showing the normally closed Slam switch.

    In addition to the slam switch, there are of course "normal" tilt switches in system80 games. The ball roll tilt (just inside the coin door area) is a Normally Open style tilt (unlike the prior System1 games that used normally closed). And of course the pendulum tilt is typical of all pinball games. Both these switches must be open for the system80 game to function. Finally there's a playfield mounted weighted tilt switch too, which also must be open. These tilt switches are all in parallel, and will show as switch 26 being closed in the self-test if ANY of them are closed.

The ball roll and pendulum tilt switches on a system80 game (James Bond).
Both of these switches must be normally open (not making contact) for the
game to play.

    There are also some weighted tilt switches mounted in other places. Usually one or two under the playfield for example. These get far less mangled than the ball roll and pendulum tilts (mostly because when a game is moved, the ball roll/pendulum can easily get jammed closed.)

The Power Supply Board (in the Backbox).

    The last stop on the system80 power supply train is the power supply board in the backbox. This takes "raw" unregulated voltages from the bottom panel and converts it to regulated voltages. This means if your wall voltage is 110 volts or 125 volts it does not matter, the regulated 5 volts (for example) will be 5 volts (no more, no less). On system80/80a, there are a few modifications that should be preformed to the power supply for reliable long term operation.

    The logic ground on the power supply board also to be tied to the metal heat sink plate of the power supply (which will be eventually wired directly to ground for a good reliable connection). This is part of the infamous Gottlieb grounding problem, which is evident on both System80 and System1 Gottlieb games.

The System 80/80a Power supply, front and back views. Note the huge
metal heat sink plate the board is bolted to.

    Gottlieb also made a mistake when designing the System 80 power supply, causing the diode CR7 to burn. They shouldn't have made this mistake; their System 1 power supply (which is almost identical to the newer System 80 design) did not have this mistake!

    Many System 80 power supplies had the standard Gottlieb manufacturing error of having the component leads cut too short. Gottlieb cut the leads into the solder meniscus (solder mound) that builds up around each component lead. This can cause the solder joint to crack and fail.

Power supply solder defects.
Note the puckered solder pads.

    Lastly, replacing the larger ORANGE power supply capacitor in the bottom of the cabinet is a very good idea! This will ensure the +5 vdc logic power will be nice and smooth. If this capacitor is bad, the game can reset during play. Computer grade 105 degree capacitors work great for extended life. Any value from 6800 mfd to 15000 mfd can be used, as long as the voltage is 16 volts or better. Ideally, 10,000 mfd is a good value to use. Capacitors larger than 10,000 mfd put added strain on the bridge rectifier. The "inrush" current required to initially charge the larger capacitor can prematurely destroy the bridge rectifier.

    System 80B Power Supply Problems.
    The system80b power supply is a small board with a large heat sinked transistor, two .156" six pin Molex connectors, a resistor and cap, and a trim pot. REPLACE THE 500 OHM TRIM POT. Really no joke that pot is junk, and can cause the power supply to jump from 5.0 volts, to 7 volts, down to 4 volts (yes I have seen this happen). This can obviously play havoc with the game, and even ruin the board(s). Or replace the trim pot with a 1/2 watt resistor of about 270 ohms (non-adjustable, but there's no worry about the voltage drifting). You may have to experiment to get the correct resistor value. Measure the +5 volts on the CPU board at the input electrolytic capacitor near the +5 volt power connector, it should be 5.0 to 5.2 volts DC.

    The system80b power supply also has two 6-pin .156" Molex connectors. 12 volts comes into the power supply at the lower Molex connector, and +5 volts goes out at the top Molex connector. One pin of the top 6-pin connector goes to each board in the backbox, supplying +5 volts to the boards. Because of this, the top power-out connector is often burnt. Replace the power supply board's .156" header pins. Then use Molex trifurcon pins in the plastic connector housing (the original connector housing can be reused).

    Another trick is to just replace the system80b power supply with a video game switching power supply! Just hang the switcher from the inside top of the backbox, supplying +5 volts to all the wires previously attached to the top system80b power supply Molex connector. Connect ground to the ground strap in the backbox. Run 120 volt wires to power the switcher. Don't forget to adjust the switcher's +5 volt trim pot to 5.0 to 5.2 volts.

    It is also a good idea to replace the 10,000 mfd 25 volt filter capacitor by the transformers and bridge rectifiers in the bottom cabinet. This cap can also be tested with a DMM set to AC volts and attached to the leads of the 10,000 mfd filter cap. If more than .50 volts AC is seen, this capacitor is worn out and should be replaced.

    Testing the System80 and System80A Power Supply.
    Before doing any modifications, it's good to know if the power supply (in its current state) works. Here is a good way to test a System80 and System80a power supply. Heck, if the system80 game in question has never been turned on (since you bought it!), this is a good generalized way to "bring her up", without smoke and fire.

      Power Supply Test, Step One:
      • Check all fuses in the bottom panel of the game. Make sure all are the proper rating and type!
      • Remove ALL connectors from ALL boards in the backbox.
      • Attach power supply connector J1.
      • Power the game on.
      • Notice the two LEDs DS1 and DS2. One signifies unregulated 12 vdc is coming into the power supply. The other LED signifies +5 volts is coming out of the power supply.
      • Check the output voltages at TP4 (+5), TP5 (8 vdc), TP1 (60 vdc), TP2 (42 vdc), using TP3 (ground) for a reference.
      • Turn the game off.
      Voltages can be higher than expected. For example, seeing 48 volts for the 42 volts test point, 65 volts for the 60 volts, or 8.6 volts for the 8 volt test point are all Ok. But +5 volts should be in the 4.8 volt to 5.2 volt range (there is a trim pot to adjust the +5 volts).

      Power Supply Test, Step Two:
      If all voltages from 'step one' are present, continue with these steps.

      • Attach the connector from power supply J2 to CPU board A1-J1.
      • Power the game on.
      • Check the output voltages at TP4 (+5), using TP3 (ground) for a reference.
      • Turn the game off.
      This step makes sure that the +5 volts is not dragged down by the CPU board. If +5 volts goes down, try adjusting the power supply trim pot. If voltage is still below 4.8 volts, this will need to be fixed.

      Power Supply Test, Step Three:
      Continue with these steps.

      • Attach power supply connector J3. This is the displays and playfield power connector.
      • Optional: Attach the CPU board connectors A1-J2 and A1-J3. These are the connectors going to the displays.
      • Optional: Attach CPU board connector A1-J5. This is the slam switch and test switch connector. Note: this step not required if the "slam switch mod" has been performed on the CPU board.
      • Power the game on.
      • Check the output voltages at TP4 (+5), TP1 (60 vdc), TP2 (42 vdc), TP5 (8 vdc), using TP3 (ground) for a reference.
      • Turn the game off.
      If 60 volts and/or 42 volts are now missing, there is probably a shorted score display! This is fairly common. Replace the 60 volt fuse in the bottom panel (it may or may not blow!), and disconnect all but ONE of the score display connectors (don't forget the score display in the playfield on Black Hole and Haunted House). Power the game on and check for 42 and 60 volts. Repeat this, adding one score display connector at a time, until the offending score display is found. Warning: only attach connectors with the power OFF.

Sys80/Sys80a Power Supply Modifications.
    Mandatory Parts Needed:
    • (1) 680 ohm, 1/2 watt resistor (for R10).
    • (1) 12k ohm, 1/2 watt resistor (for R3).
    • (1) 1N4738 zener Diode 8.2V, 1 Watt (for CR7).
    • (2) Molex .156" square header pins, part# 26-48-1125, cut to size.
    • (2) Molex .156" crimp-on connector housing, part# 09-50-3121, cut to size.
    • (20) Molex .156" Trifurcon terminal pins, part# 08-52-0113 (Digikey part# WM2313-ND).
    • (1) 6800 mfd to 15,000 mfd, 16 volt (or higher) capacitor (10,000 mfd is the ideal size to use). A computer grade 105 degree capacitor is a good replacement.
    • 3 inches of 18 gauge wire.

    Optional (but recommended) Parts Needed:

    • (1) 1N4746 zener Diode 18V, 1 Watt (for CR6).
    • (1) 470 ohm sealed resistor trim pot.
    • (2) LEDs yellow, orange or red.
    • (1) 14 pin socket for regulator chip.
    • (1) UA723CN regulator chip, but can use LM723CN, LM723CD, NTE923D (or something similar since these chips are common, and Radio Shack sells these). This is used with the 14 pin socket, above.

    Power Supply Disassembly Instructions:

    • Remove the power supply board from the head box. The board includes a large black heat sink plate behind the printed circuitry board (PCB).
    • Test the large metal power transistor (PMD10K40, 2N6057 or 2N6059) installed on the back plate of the board. Set the DMM to the "diode" setting. Then put the black lead on either attachment screw of the transistor (which is connected to the metal case of the transistor), and the red lead on each leg. A reading of .4 to .6 for each transistor leg should be seen. Anything else and this transistor is bad.
    • On the heat sink plate side, remove the 2 screws from the large transistor.
    • On the heat sink plate side, remove the 4 screws from the corners of the plate.
    • De-solder the two legs of the large transistor labeled Q3.
    • Gently pull the heat sink plate from the board.

Left: The parts to be replaced: R10, CR7, R3. Note how hot CR7 has gotten.
Right: Using the solder sucker to remove Q3. Then the metal heat sink plate can
be removed, and the back of the board accessed.

      Mandatory Parts Installation:
      • Replace resistor R3 with a new 12k ohm 1/2 resistor. This resistor often fails.
      • Replace resistor R10 with a 680 ohm 1/2 watt resistor. This will decrease the load on diode CR7.
      • Check diode CR7 (the burnt part!). If damaged, replace with a new 1N4738A diode (or to be safe, just replace it).
      • Re-solder all header connector pins (these often crack). If the header pins are corroded or in bad shape, replace then with new .156" (square) header pins. Also replace the plastic connector housing's pins, Molex part number 08-52-0072, crimp-on pins (see the connector chapter of this document for more info).
      • On the solder side of the power supply board, solder a 18 gauge jumper wire from the ground trace to the lower attachment screw hole. See the picture below.
      • Re-solder any leads that look like they were cut too short.
      • Re-solder the large rivet holes that the large transistor leads go through.
      • Solder clipped off resistor leads to the voltage test points (GND, +5v, +8v, +42v, +60v). This will make it easier to test voltages when the board is installed.
      • Check the values of the other resistors on the power supply board to make sure they are in tolerance.
      • Replace the round metal power supply pins at connector J2 with brand new .156" Molex square header pins (Molex part# 26-48-1125, cut to size). In addition, replace the 6 pin plastic housing going to this connector with a new crimp-on variety (Molex part# 09-50-3121, cut to size). Then crimp on new .156" Molex Trifurcon terminal pins (Molex part# 08-52-0113, Digikey part# WM2313-ND) to the connector wires.
      • Replace the round metal power supply pins at connector J3 with brand new .156" Molex square header pins (Molex part# 26-48-1125, cut to size). Also replace the 7 pin plastic housing going to this connector with a new crimp-on variety (Molex part# 09-50-3121, cut to size). Then crimp on new .156" Molex Trifurcon terminal pins (Molex part# 08-52-0113, Digikey part# WM2313-ND) to the connector wires.

The green wire on the power supply board is soldered
from ground to the screw attachment hole.

Left: The transistor rivet holes that need to be re-soldered. Note the
complete lack of solder around part of the circumference.
Right: A test point after soldering a clipped-off resistor lead in place.

transistor rivets  test point loops

    Optional Parts Installation:
    • Highly Recommended: Replace the 500 ohm trim pot on the power supply board. This old pot gets dirty, and the output voltage can jump around because of it. Replace with a high quality, 470 ohm unit.
    • Install a new 1N4746 zener diode (18 volt) for CR6.
    • Replace the old LED's on the power supply board with new ones. With age, the old LED's get dark and can "sink" (consume) far more current than new ones. Also change the colors of the LED's. For example, use orange or yellow LED's (but not green or blue!) so one can tell at a glance if they have been changed.
    • Install a 14 pin socket for the regulator chip. This regulator chip is often bad, causing the +5 volt power section to fail. Just socket the chip so the the whole power supply doesn't have to be torn apart when it goes bad.

    Finishing (re-assembling) the Power Supply.

    • Make sure the large Q3 transistor's plastic insulator is in place. This plastic part ensures the legs of the large transistor do not short to the metal heatsink plate.
    • Make sure there is a mica insulator underneath the large Q3 power transistor.
    • Re-assemble and screw the heat sink plate back onto the PCB. Re-solder the large transistor's leads.
    • Using a DMM, make sure there is *no* continuity between the metal case of the large Q3 transistor and the metal heatsink plate. If there is continuity, please re-verify the above first two steps.
    • In the bottom of the cabinet next to the transformer, replace the ORANGE 6800 mfd 1" diameter by 3" tall power supply capacitor with a new unit. See below for more details.
    • Test the power supply's voltages. After doing the above mods, install the power supply board back into the game. Connect only the lower plug J1. Turn the game on. Note the two LED's on the power supply board should be lit. Using a DMM, check the DC voltages at the connectors points on the board: +60, +42, +8 and +5 volts DC. When all the voltages are present and verified, turn the game off and re-connect all the disconnected plugs. Power the game back on, and measure the +5 volts DC again. Adjust the trim pot to 5.1 volts.

    2N5550 in the High Voltage section.
    In the high voltage section of the Gottlieb sys80/80a power supply, a 2N5550 transistor is used. If this goes bad, it can be replaced with a 2N5551 (more common and more robust). Both parts cross to NTE194.

    Sys80/Sys80a: Replace the ORANGE 6800 mfd filter cap in the bottom of the cabinet!
    There are two large capacitors here; replace the one WITHOUT the resistor across the leads (note on some system 80b games such as Jacks Open, Gottlieb used *two* large orange capacitors with no resistor wired in parallel, instead of just one). No exceptions here, the orange 12 volt filter capacitor(s) need to be replaced. Any value can be used from 6800 mfd to 15,000 mfd at 16 volts or higher (again on system 80b games like Jacks Open with two orange capacitors wired together, these two can be replaced with one single capacitor). Ideally, 10,000 mfd is about right. Capacitors larger than 12,000 mfd put added strain on the bridge rectifier. The "inrush" current required to initially charge the larger capacitor can prematurely destroy the bridge rectifier.

    The original capacitor can be tested (but don't bother, just replace it!) To test the capacitor, turn the game on, and set the DMM to AC volts. Put the leads of the DMM on the leads of the filter cap. If after a few seconds (after the voltages stops fluctuating) there is more than .2 volts of AC, this capacitor is bad. Again, if using the original orange filter cap, I would highly recommend replacing it regardless of its AC reading.

    Remember when hooking up the new capacitor, do *not* mix up the positive and negative wires going to the new capacitor!

    Other Tips (Missing +5 volts).
    There are two LED's on the power supply board. One for +12 volts, and the other for +5 volts. If the +12 volts is not lit, then the +5 volts won't be either! If only missing the +5 volts, I would suspect the voltage regulator UA723CN (NTE923D) chip first, or the PMD10K40 (Q3) transistor. But hopefully Q3 was tested in the previous procedure. Make sure Q3's transistor bolts are tight, and Q3 is soldered well to it's circuit board eyelets. Also make sure there is no continuity between the metal plate and Q3's metal case.

    Still no +5 volts, then check SCR1 (S107Y1). This device's job is to check turn on and short +5 volts to ground, if +5 volts goes above 6 volts (as a protection measure to the circuit boards). The SCR can be tested (with the power supply off, connectors removed) using a DMM set to diode setting. Measure between TP4 and ground (red DMM lead on ground), and .3 to .5 should be seen.

    Also note power supply transistor Q1 (NPN, SW4F013) can be replaced with a TIP31c transistor. More power supply repair information can be found at http://www.geocities.com/kirbseepe/repairpowersupply.html.

    System 1 Power Supply Problems.
    This document gennerally does not cover Gottlieb System1 games. But since the System1 power supply is so close to the System80 design, I thought it prudent to add some System1 info. See marvin3m.com/sys1 for more System1 repair info.

    • Make sure that Q1 is electrically isolated from the metal back plate (there is a thin mica insulator for this purpose).
    • If +5 volts measures 2.4 volts, then Q1 is bad.
    • If no +5 volts, check pin 7 of IC1. This should be 14 to 15 volts (with Q1 removed). In this voltage is not 14 to 15 volts, IC1 is bad.
    • If Q1 gets very hot and there is no +5 volts, then SCR101 is bad.

The four bridge rectifiers and two electrolytic capacitors in the
bottom panel of System 80 games. The original +12 volt filter
electrolytic 6800mfd capacitor is smaller and usually orange.
This needs to be replaced. This replacement is a computer
grade cap.

bridge rectifiers

    Bridge Rectifiers.
    In the bottom panel of the game, there will be four bridge rectifiers and the two large electrolytic capacitors. The capacitor used for the +12 volts (and ultimately for the +5 volts) is the one that should have been replaced in the above steps. This is the capacitor without the resistor across its leads. The other capacitor smoothes the higher voltages for the solenoids, and is far less critical.

The 12 volts bridge rectifier. Notice the near
left lead (orange wire) is oriented different than
the other three leads. This is the DC positive
output lead.

    Sometimes bridge rectifiers die. If turning on your game immediately blows a fuse, this could mean a shorted bridge rectifier. For example, if the F4 fuse blows immediately at power up on Haunted House or Black Hole, this probably means the connecting bridge rectifier in the bottom cabinet has shorted.

    Bridges can be tested easily. But first the leads of the bridge will need to be identified. Each bridge has four leads: two input AC leads, and two output DC leads (positive and negative). One of the legs on the bridge will be in a different orientation than the others; this is the DC positive output lead. The DC negative output lead is directly opposite (diagonal) to it. The remaining two leads are the AC input leads. Also, the two output DC leads should go to the electrolytic capacitor's positive and negative leads.

    Testing a Bridge Rectifier.
    To test a bridge rectifier, do this:

    1. Put the DMM on diode setting.
    2. Put the black lead of the DMM on the "+" (positive) terminal of the bridge.
    3. Put the red lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the red DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen.
    4. Put the red lead of the DMM on the "-" (negative) terminal of the bridge.
    5. Put the black lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the black DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen.

    Replacing a Bridge Rectifier.
    If one of the bridges tests bad, replace it. Get a MB3502 or MB3504 bridge with lug leads. The "MB" specifies the type of case the bridge is in. The "35" is number of amps. The "02" means 200 volts, or "04" means 400 volts. Higher values can be used in either amps or volts. But don't go lower on either value.

System 80B Power Supply Repair/Upgrade Tips.

    The system80B 5vdc power supply is pretty simple. Other than the LM338 voltage regulator and a couple resistors/caps, there's not much to check. But one thing I would HIGHLY recommend is replacing the 500 ohm trim pot on this power supply, which adjusts the +5 volts. The quality of this pot was bad when new. Add 20+ years and things have only gotten worse. I once saw someone adjusting this pot and crash the CPU board because the original pot had a "flat spot", and put up to 12 volts to the CPU board. Don't mess around with this pot, just replace it.

    After the pot is replaced and the power supply installed back in the game, check the +5 volts and adjust it to 5.10 volts DC, with the CPU board disconnected (left most CPU board small power plug removed). After the power supply is adjusted, power off and re-connect the CPU board, and check the +5 volts again for 5.10 volts DC. Be very careful when adjusting this 5 volt trim pot. The big problem with the sys80b power supply is a lack of a "crowbar" safety circuit. That is, if the power supply fails it can send upwards of 12 volts through the 5 volt circuit, ruining everything in its path (there is no zener diode to protect the 5 volt circuit from over-voltage).

The Gottlieb System3 and System80b +5 volt power supply. The one offending
component on this unit is the low quality500 ohm trim pot, which should be
replaced with a quality version.

    While working on the System80B power supply, resolder the connector header pins, as often these will crack. I also suggest to re-pin the .156" female connectors with new Trifurcon Molex connector pins. And lastly, don't forget to do the ground modification to this power supply (adding a ground wire to J1 pins 1,2 on the power supply), while you have it removed from the game.


2b. Circuit Board Defects - Inspect the boards
    Important note: While doing the following mandatory circuit board modifications, please inspect each board to be repaired for these defects, and correct them.

    Many early System 80 boards (Haunted House and prior) had the standard Gottlieb manufacturing error of having the component leads cut too short. Gottlieb cut the leads into the solder meniscus (solder mound) that builds up around each component lead. This can cause the solder joints to crack and fail.

    To correct this problem, resolder component leads where the solder meniscus has been cut. This defect is evident on both single sided and double sided circuit boards.

Look closely at this board: Can you see the plated thru holes
where there's no solder, or the solder is "puckered"? Also note
the solder around the component pins. Some of these pins are puckered
or completely open. All these need to be re-soldered.

      Another manufacturing error was that the boards were waved soldered at too low a temperature. This created problems on double sided circuit boards in the plated-thru holes. These holes let a trace move from one side of the board to the other. If these holes aren't filled with solder, this can cause intermittent connection problems. This is very common especially at holes near the edge connectors.

      To correct this problem, look at the "via" (plated thru holes) and if the solder is puckered or missing (!), resolder these holes and add some new solder. To ensure complete reliability, stitch a piece of wire-wrap wire thru the holes and solder on both sides of the board.


2c. Mandatory: Battery Replacement/Corrosion (CPU board Reset/Clock Circuits)

The Gottlieb DataSentry battery. This battery
has leaked only slightly (note the corrosion to the
crystal). This board was lucky. Also shown below the
battery are the Z3 (7404) and Z2 (7474) chips.
These are often affected by battery leakage.

    This fix is mandatory. All Gottlieb System 80 boards use a recharagable "DataSentry" nicad 3.6 volt battery. When these batteries don't get used regularly, they can leak the alkaline potassium hydroxide and volatile gases that destroy the CPU board components and connectors. Removal of 15+ year old rechargable battery is mandatory!

Remote AA battery pack and 1N4004 blocking diode, connected to a
System80 CPU board (original battery removed).

    New Remote AA Battery Pack.
    To replace the original battery, add a remote three "AA" battery pack and a 1N4001 or 1N4004 diode (banded diode end first connected to the pcb "+" pin, and the non-banded end connected to the positive lead of the battery pack). The diode is used so the recharging circuit doesn't try to charge the AA batteries. Also the game will work fine with no battery. Not having a battery means that the high scores and operating audits won't be saved. Personally, I find this acceptable, but the memory can come up with wacky high scores (digits misformed or missing). Also always remember to check the 5101 chip Z5 pin 22 (ground is the reference) for battery voltage using a DMM after installing the new remote battery pack. This confirms you have the battery connected right.

An installed memory back-up capacitor. After
the battery is removed, the traces are sanded
shiny. The negative lead of the cap is put in the
negative battery hole. The positive lead is bent,
and soldered directly to the trace leading to the
positive battery hole (since the positive battery
hole was too far away).

    Memory Back-Up Capacitors.
    If one insists on having a battery (can't live without those high scores!), a decent alternative is to install a memory back-up capacitor. These capacitors will charge when the game is on, and slowly discharge to keep the memory alive when the game is off. The advantage to these capacitors is they never wear out, and they won't leak corrosive materials. The down side is the game must be on for about one hour every month to maintain their charge. Also, the game must be on for about about 8 hours continuously to initially charge the capacitor. These capacitors are about the size of a stack of nickels. Jameco (800-831-4242) sells 1 Farad memory caps, part# 142957, $3.95 each, $3.49 for ten or more.

    Note that some CPU boards will work better with a memory cap than others. This has to do with the exact memory on the board, its age, and its exact manufacturing specs. Some memory chips have different power consumption rates, hence varying results can be seen with memory backup caps. Some CPU boards will maintain their memory well with a backup cap, and others may not. "Your mileage may vary" is probably a good statement about memory backup capacitors.

    When I installed my back-up capacitors, the minus and positive leads were not labeled on the cap. There was only a black line on the cap to designate the negative lead (the CPU board is labeled; the positive hole has a "+" next to it). Always check the 5101 chip Z5 pin 22 for battery voltage using a DMM. This will confirm you have the new battery or memory cap connected correctly.

    If the installed memory cap/battery doesn't seem to work (and it was installed correctly!), check the issolation diode CR34. Do this using a DMM set to diode test, with the game off. Black DMM lead to the banded side of the diode, red DMM lead to the non-banded side. Should see about .4 to .6 volts on the DMM. Sometimes the CR34 diode will short (showing .002 or the like), and should be replaced with a new 1n914 or 1n4148 diode. Its job is to make sure the cap/battery doesn't try and power the entire CPU board when the game is off (this would drain the cap/battery quickly.) If the CPU batteries or memory cap is dying quickly, the problem is often either a bad CR34 diode (1N4148) or a bad Z1 CMOS chip (4528). Note these parts are included in Ed's battert corrosion kit below.

    Reset Circuit Check.
    The reset circuit is the most vulnurable part of the CPU board in regards to battery corrosion. To determine if the reset circuit is working on a CPU board is pretty easy. Connect the CPU board to +5 volts (the left most CPU board 5 pin connector), and then check the 6502 pin 40 for +5 volts. If this pin is 0 volts, the reset circuit is not working. If 6502 pin 40 is 5 volts, then the reset circuit is working. Remember the purpose of the reset circuit is to hold the 6502 microprocessor's reset line pin 40 LOW (0 volts) for about 100 milliseconds. This allows the +5 volts to stablize at power-on. Then the reset circuit makes 6502 pin 40 go HIGH (to 5 volts), and the 6502 processor starts running and executing game code (and the game "boots"). So if the reset circuit is not working, the CPU board will never boot (never start executing ROM code), even if the rest of the board is fine. After the reset circuit is working, the next thing you should check on a dead CPU board is the clock signal (again, this circuit is right around the battery). See the Sys80 CPU board Repair section for more info.

    Battery Corrosion and the CPU Board's Reset/Clock Circuits.
    Battery corrosion can do nasty things to the left side of the CPU board. This is the "reset" section of the CPU board (and below the crystal Y1 is the "clock" section). Depending on how bad the corrosion is, many parts may be needed in these areas. Instead of ordering all those separately, I suggest just buying a "Gottlieb System80 Battery Corrosion Repair Kit" GTLB80-BA-KIT from greatplainselectronics.com. This kit includes all the resistors, capacitors, transistors, crystal and chips typically ruined by battery corrosion. For a mere $10 (plus $3.50 shipping), this kit is well worth it. If for some reason the $10 is too much money, here are the typical parts needed for a System80 battery corrosion repair (these are the same parts included in Ed's kit):

    • Z1*: CMOS 4528.
    • Z2*: 7474 or 74HCT74 chip.
    • Z3*: 7404 chip.
    • Z4*: CMOS 4081.
    • Z36*: 4069 CMOS chip.
    • (4) 14 pin sockets for Z2,Z3,Z4,Z36 chips.
    • (1) 16 pin sockets for Z1.
    • SW1: 8 position DIP switch
    • C1*: 100 mfd 10 volt electrolytic cap.
    • C2,C5: .01 mfd (103) ceramic cap.
    • C3,C25: .1 mfd (104) ceramic cap.
    • C36*: 10 mfd 10 volt tantalum or electrolytic cap.
    • CR1-CR8,CR33-CR35*: 1N4148 or 1N914 diode.
    • R3,R43,R49: 5.6k ohm 1/4 watt resistor (green, blue, red).
    • R4,R5,R44: 2k ohm 1/4 watt resistor (red, black, red).
    • R6,R45,R46,R48: 3k 1/4 watt resistor (orange, black, red).
    • R7: 62 ohm 1/4 watt resistor (blue, red, black).
    • R8,R50: 180 ohm 1/4 watt resistor (brown, gray, brown).
    • R9: 1k ohm 1/4 watt resistor (brown, black, red).
    • R34-R41, R54: 4.7k ohm 1/4 watt resistor (yellow, purple, red).
    • R47: 24k ohm 1/4 watt resistor (red, yellow, orange).
    • Q1,Q4*: MPS-A70 or 2N4403 transistor.
    • Q2,Q3*: 2N4400 or 2N4401 transistor.
    • VR1*: 1N5225b or 1N5987b zener 3 volt diode.
    • Y1: 3.579545 mHz crystal.
    * Polarized parts: The above components DO require installation in the "correct direction". Failure to do so will kill the part, and maybe some other parts too. And for sure the board will not work. So be careful!

    Using a Dallas/Maxim DS1811 in the Reset Section.
    Thanks to Pascal Janin, there is also another way to fix the reset section with just a four parts (that replaces nearly 25 parts!) This involves using the new Dallas/Maxim Semiconductor D1811 reset chip (TO-92 package). This inexpensive device looks like a transistor, but is really a three leg chip in a TO-92 transistor package. Click here or here (PDF, more info) for the specs on this chip. Cost of this chip is less than $1, and can be ordered directly from Dallas/Maxim Semiconductor at www.dalsemi.com via their phone number 888-629-4642 (but orders must be faxed in at 408-222-7174). Be sure to order the TO-92 package (part number DS1811-10), as this chip also comes in a surface mount SOT23 package.

    The advantage to the Dallas DS1811 is great: if a system80 CPU board has had some battery corrosion and perhaps some circuit board traces are questionable, the new Dallas part will not utilize most of that. So even a board with lots of corrosion can have 25 reset parts cut out, and just the Dallas installed. So most of the questionable traces on the component side of the circuit board are eliminated too, making battery corrosion less of an issue.

    The Dallas DS1811 comes in three TO-92 flavors of "normal reset threshold":

    • DS1811-15 = 4.13v
    • DS1811-10 = 4.35v *
    • DS1811-5 = 4.62v
    * The best one to order is DS1811-10.

    Here are the installation steps for this chip:

    • Remove reset parts: chip Z1, trans Q1-Q4, diodes CR33, CR35, VR1, resistors R8, R9, R43-R50, caps C2, C25, C36.
    • Install a jumper from Z1 pin 5 to Z1 pin 9.
    • Install a jumper from Z1 pin 11 to Z1 pin 13. Be careful not to accidentally connect pin 12 to the jumper, as it will cause the reset modification to not work.
    • Install a jumper where R45 was installed.
    • Install a jumper between the two top holes of Q3 (the Emitter and Base).
    • Install the Dallas DS1811 (TO-92 package) into the top pads of R50, R44, R49 (pin 1=R50, pin 2=R44, pin 3=R49). Note the flat edge of the DS1811 faces downward away from Z1, toward the dip switches.
    • Retain reset parts CR34, R7 and C3.
    • Note R10 and C14 can be remove or left installed. Since Z1 has been removed, R10 and C14 are no longer used, and can be removed (or left installed).

    The DS1811 is installed with pin 1 going to /RESET, pin 2 to +5 volts (thanks to the jumper at R45), and pin 3 to ground (via the jumpered Q3). A picture of all the removed parts and the DS1811 and jumpers installed can be seen below. Also remember using the DS1811 will not replace the often damaged clock circuit chips at Z2 and Z3.

Picture of the Dallas DS1811 installed in the Sys80 CPU board.

The Dallas DS1811 installed in the Sys80 CPU board (picture by Neil Bradley).

Another picture of the Dallas DS1811 installed in the Sys80 CPU board.

    There is a side affect of the changed reset circuit: the "thunk" that is often heard at boot up on System80 games may be louder, because the reset timing is changed. The duration of the reset pulse issued by the DS1811 lasts 150ms, while the original circuitry generates a 50ms reset. This increases the startup time until the coil and lamp outputs are properly initialized, hence the slightly harder "thunk". Personally I don't really think the "thunk" is louder, but it could be different on your game.

    Removing the Old Battery and Fixing Corrosion.
    Here are the battery corrosion repair steps:

    1. Remove the CPU board from the head box.
    2. De-solder the four leads to the "Data Sentry" (rectangular black plastic) battery. Remove the battery and discard.
    3. If any components are damaged by the battery (look for green and/or gray!), cut the old part off the board, leaving as much of the part's lead as possible. Heat the solder pad on the circuit board with a soldering iron, and pull the cut off lead out of the board. If the lead is not coming out easily, add some new solder to the solder pad. This will help distribute the heat. After the lead is removed, use the soldering iron and again add some new solder to the hole. Then use a solder sucker (Soldapulit) and de-solder the hole.
    4. If there is any gray or greening of a part's leads, replace it. If in doubt, replace it. To be completely safe, replace all the parts included in the list above (especially if Ed's kit was purchased). At a minimum, typically transistors Q2, Q3, Q4 and all the resistors around that area are damaged. Also chips Z2 and Z3 and the crystal Y1 are often damaged.
    5. Check the edge connector fingers (pins) for "green". If the metal pins are green, they will need to be replaced!
    6. After removing the damaged components, sand all green/gray areas of the board with 220 grit sandpaper, including edge connector fingers. Sand until the copper is bright, which will allow solder to stick.
    7. Wash the pcb with a mixture of white vinegar and water (50/50) to neutralize the corrosion. Scrub with a toothbrush. This is very important! If this step is skipped, the corrosion will return.
    8. Rinse the washed board with clean water.
    9. Rinse the board with 99% pure alcohol. This will dissolve and wash away the water. Repeat this step. The alcohol will evaporate quickly.
    10. If sanding the edge connector fingers, heat them with your soldering iron and tin them with solder. Wipe with a cloth while still hot to smooth and remove the excess solder. This can also be done to any traces sanded on the board.
    11. Replace all removed components (except the battery!). Any removed chips should be replaced with a good quality socket.
    12. Check the connectors themselves! If the board has corrosion, the connectors may too! Replace the connector pins if any damage is seen (see the connector section below). They can also be cleaned sometimes with scotchbrite and alcohol. But replacement is the ideal solution.

    Again, order the battery corrosion kit from Ed to get all the parts usually ruined by corrosion.

Remote AA battery holder installed in a James Bond (ground mods done too).


2d. Ground Problem Repair & Upgrade
    These fixes are mandatory.

    The Gottlieb Grounding Problem.
    There are multiple problems with ground in System80 games. One problem relates to differences in ground between the CPU board and the Driver board. The other problem relates to differences in ground between the circuit boards and cabinet ground. We address and fix both problems below.

    First there is the problem with ground between *cabinet* ground, and circuit board ground. John Robertson documented this problem back in 1987. There is a single ground connection between the cabinet ground and circuit board ground on the power supply. If this single connection has resistance (which is common on older games), problems occur. This resistance, with the current drawn by the Driver board through the power supply, causes a voltage shift in the power supply's ground line. If the voltage shift get up to .5 volts relative to the cabinet ground, the solenoid driver transistors are no longer biased off, and start to conduct. This can cause playfield coils to "lock on" and burn, damaging the coil and its associated driver transistor. This single problem made many people think Gottlieb system80 games were "unreliable".

    Now let's talk about the Driver board and its multiple grounds. There are several grounds on the Driver board (lamp ground, logic ground, solenoid ground, etc). Only the solenoid ground should be independent (as it was designed), and all other grounds should be tied together. The logic ground levels between the CPU and driver boards also need to be equalized (as little difference as possible between the two). Because ground between the boards are connected via a single edge connector wire, differences in ground levels can occur. If resistance develops in the connector (very common), and the difference between the logic ground on the CPU and driver board is .1 volts or higher, the CPU and/or Driver board can lock up and be damaged. This in turn can cause coils to lock on and burn. Though this is less of a problem than the cabinet and circuit board ground (see above), it is still a problem.

    Prior to 12/1/99, there was a slightly different procedure in this guide for fixing the driver board ground problems. Thanks to Pascal Janin, we now have a better understanding of the problem. He documented the differences in voltages in the following places:

    • Difference in voltage between the negative side of capacitor C1 (100 mfd 10v) and the connector A1J4 pin A, on the CPU board.
    • Difference in voltage between the negative side of capacitor C1 (100 mfd 10v) on the CPU board and chip Z12 pin 8 on the Driver board (the furthest away ground connection).
    • Difference in voltage between the positive side of capacitor C1 (100 mfd 10v) and connector A1J4 pin B, on the CPU board.
    • Difference in voltage between the negative side of capacitor C1 (100 mfd 10v) on the CPU board and chip Z12 pin 16 on the Driver board (the furthest away +5 volt connection).

    Ideally, as little difference in voltage as possible is desired. Pascal tested this with no modifications, the earlier modification (previously described here), and the new modifications (described below). The methods now documented here yielded the least amount of variance in the voltages.

    These modifications also ensures that the solenoid ground is independent from the logic ground. This is important because if the solenoid ground fails, the solenoid high voltage could go through the logic ground, damaging circuit board components. Also, there can be "feedback" interference to the logic ground from the solenoids. This could damage circuit board components.

    What are We Trying to Accomplish?
    In the "mandatory" ground modification, we make sure the cabinet ground and circuit board ground are solidly tied together (the connection to ground between the cabinet, power supply, CPU and Driver board, and other boards will be made more reliable). In the "optional" ground modification, we make sure the solenoid ground is isolated from the logic ground so that all the solenoid transistors on the driver board (except Q57, Q61, Q63) will have their emitters connected together. But in addition, these solenoid transistor grounds will be isolated from the CPU and Driver board logic grounds (a good place to test for logic ground is at pin 8 of any 74175 chip on the driver board).

The Gottlieb System 80 Driver board, with added ground wire.

The Gottlieb System 80b CPU board, with added ground wire and a remote battery pack.

    Driver board parts that are required:
    • (4) Molex connector pins for the A3-J1/A1-J4 connector (mandatory). See the next section for part numbers.
    • (10) feet of 18 gauge wire (mandatory)
    • Wire wrap wire (30 gauge) or zero ohm resistors (optional)

    Other driver board stuff to have around that is often bad:

    • MPS-U45 transistors
    • MPS-A13 transistors
    • 2N3055 transistors (and connecting 9.1 ohm resistor)
    • 2N6043 transistors

Mandatory Ground Modifications Steps.

  1. PRE-WORK: Test all the driver board transistors. This only takes a few minutes since the Driver board is already removed. If any test bad, replace them now to prevent future problems. See the Testing Transistor with the Driver board Removed section for info on how to do this. Do NOT skip this step! If the driver board is out of the game, it only take a moment to test all the transistors.

  2. STEP 1: On the CPU board, find the electrolytic capacitor C1 directly to the right of the main CPU power connector A1-J1. Attach a 12" wire to the TOP lead of this C1 capacitor, and a forked spade connector on the other end of the wire. This wire is the CPU ground.

    On Sys80/Sys80A, run this added CPU board ground wire to the metal frame of the power supply.

    On Sys80B, run this added CPU board ground wire to the ground plane screw (which attaches to the yellow covered ground plane) in the lower right of the backbox.

Step 1. Sys80/80a ground from power supply capacitor C1's negative lead, to the metal
frame of the power supply. And the ground from the CPU board's electrolytic capacitor
C1 negative lead to the metal frame of the power supply. Picture by J.Robertson.

    Note: Remember how we modified the sys80/sys80a power supply to connect ground with a jumper wire to the metal heat sink plate, in the Power Supply modification section? Well here's where that modification ties into the CPU ground. If this power supply modification step was not done, a wire can be connected from the power supply's negative lead of capacitor C1 (large electrolytic cap at the lower left corner of power supply), to the metal heat sink power supply frame connection. If the black part of the power supply frame is used, be sure to SAND the black off the frame where the wire connects to ensure a good connection.

    On system80 and sys80a, connect the ground wire from the CPU board to one of the mounting bolts on the metal power supply board heat sink plate frame (use a "fork" or "bullet" connector so the CPU board can be easily disconnected). Again if the black part of the power supply frame is used, be sure to SAND the black off the frame where the wire connects to ensure a good connection. Then continue this wire to the metal lock plate in the upper left corner of the backbox. This metal lock plate also has a stock green wire (provided by Gottlieb), which continues down to the to the large copper ground bus in the bottom panel of the game (where all the green wires are soldered), next to the transformer. This is the main ground bus for the game. Optionally another wire can be added from the lock plate/metal power supply plate down to the copper ground strap (be sure to sand this copper ground area clean before trying to solder to it). Also note on some System80 games the 6 volt GI (general illumination) line runs dangerously close to the power supply frame. Make sure the bare 6 volt GI wires do *not* touch the power supply frame.

Step 1. On sys80 and sys80a,
if the power supply board ground to the screw attachment hole wire
modification documented above is not done, a ground wire can be soldered to
the negative lead of the power supply capacitor C1. The other end of this wire
and then attached to the metal ground frame of the power supply.

Step 1. This pictures shows the bottom panel of the game,
and the large copper grounding strap (with all the green ground
wires connected). The green ground wire attachs to the CPU
and Power supply boards here.

Picture by J.Robertson.

  1. STEP 2: Replace the power supply to CPU board power connector cable pins (all sys80,a,b games). On the CPU board connector A1-J1 to the power supply connector J2, replace *all* the pins on both connectors! On sys80 and sys80a, it involves replacing the round male power supply header pins at power supply connector J2 with brand new .156" Molex square header pins (Molex part# 26-48-1125, cut to size). Also replace the 6 pin .156" plastic housing with a new crimp-on variety (Molex part# 09-50-3121, cut to size). Then crimp on new .156" Molex *Trifurcon* terminal pins (Molex part# 08-52-0113, Digikey part# WM2313-ND) to the wire. On all sys80,a,b game on the CPU A1-J1 connector, replace the five pins with brand new Molex single sided terminal pins (Molex #08-52-0072). The original plastic connector housing can be re-used.

  2. STEP 3: For sys80/sys80a, on the power supply connector J3 (which supplies the display voltages and display grounds), replace the entire header connector. This involves replacing the round metal power supply pins at connector J3 with brand new .156" Molex square header pins (Molex part# 26-48-1125, cut to size). Also replace the 7 pin plastic housing with a new crimp-on variety. Then crimp on new .156" Molex *Trifurcon* terminal pins (Molex part# 08-52-0113, Digikey part# WM2313-ND) to the wire. If this connector is not rebuilt, a "low-rent" modification can be preformed. Run a wire from pins 4/5 of power supply connector J3 to the metal frame of the power supply (don't forget to sand the black part of the power supply frame where any wire attaches). If this modification is not done, score display "flicker" can result (especially on any displays that are playfield mounted), and sporatic pop bumper problems (either not working at all or working strangely).

    For Sys80B, some ground modifications must be done at the lower cabinet on the metal transformer panel. On one side of this panel are several 9 pin connectors with white wires. These are the ground wires which connect to the metal housing the transformer panel. Often the part of the connector with the male pins bolted to the side of the metal panel crack. At minimum these should be removed, inspected, and resoldered. If one pin's solder joint cracks, the wire that connects to that pin will lose its ground path! This is a very bad thing. To really bullet-proof this design, all the ground wires can be shorted together BEFORE going to this connector. That way if one pin cracks, it's no big deal, as the other pins take the load.

    On Sys80B another thing that must be done is to resolder the .156" J1 and J2 connector male header pins on the power supply board. There are only two connectors on this board, and it is very common for these to have cracked solder joints around the pins (giving intermittent power/ground paths).

    And on Sys80B power supply, while you're resoldering the header pins, attach a ground wire to the bottom J1 pins 1,2 (ground). Run this wire to the yellow ground plane bolt at the bottom right side of the backbox.

Step 3 on Sys80b,
resolder the power supply header pins and add a ground wire to J1 pins 1,2.

Step 3 On sys80B,
find the 9 pin ground plugs on the side of the transformer metal panel.
Remove the connectors, and then remove the two 1/4" hex bolts that hold the
male pins to the side of the transformer panel. On the back side of these
small connector PCBs, resolder the pins as the solder joints like to crack.

Here's the System80b ground PCB removed from the side of the transformer panel.
Cracked solder joints can be seen here (resolder these).

In the future to prevent a single cracked solder joint pin from effecting
a ground, all the ground wires can be tied together before the connector.

Another way of solving the ground problem on a system80B transformer frame.
The original connectors (at bottom) were cut off and replaced with spade connectors.
These these were bolted directly to the transformer frame.pic by j.p.

Another version of the system80B transformer. This version uses .156" molex
connector pins to attact the ground wires to the transformer frame. This version
should be treated like the above version, where all male pins are check for cracked
solder joints (and possibly resoldered).

Yet another version of the system80B transformer. This version is pretty good, just
make sure all those individual ground connectors on the side of the transformer
frame are tight.

And another version of the system80B transformer. This version is really good, as
all those individual ground connections are soldered to a terminal strip on the
side of the transformer frame.

  1. STEP 4: On all sys80,sys80a,sys80b games, on the connector CPU A1-J4 to Driver board A3-J1 (that goes from the Driver board to the CPU board), double-up the Ground and +5 volt lines (note on some system80b games this may have been done by the factory). Order Molex terminal series 4366, part #08-03-0304 (for 18 gauge wire). Crimp and/or solder the new pins to some wire (see the following section on connectors for how to do this).
    • Insert two pins and wires into the A3-J1 Driver board connector at the back side, far right (as facing the installed boards).
    • Insert the other two pins and wires into the A1-J4 CPU board connector at the front side, far right (as facing the installed boards).
    • Splice the two outside wires from A1-J4 and A3-J1 together (ground).
    • Splice the other two inside wires from A1-J4 and A3-J1 together (+5 volts DC).
    Now the pins are doubled up and have reliable +5 volts DC and ground contacts from the CPU board to the Driver board. One can also buy a new connector that already has this modification done. They are gold plated and have two +5 and two ground pins. This is available from Docent Electronics at 937-253-2768, $25.00 plus shipping.

    Note: Double sided connectors (A3-J3 in this case) use numbers for the pins on the front (component) side of the board, and letters for the pins on the back (solder) side of the board. Some letters are not used because they look too much like numbers. These include: G, I, O, Q. If more than 22 pins are used, a "bar" is designated over the repeated letters. For example, pin 23 (where pin 22 = Z) on the back side of the board would be designated as "/A".

Docent Electronic's CPU to Driver board connector for system80 games.
The ground and +5 volt lines are already doubled-up on this brand new connector.

  1. STEP 5: Run a ground wire directly to the Solenoid Driver board. Just below chip Z10 on the solenoid driver board there is a large, thick trace, which connectos to Z10, Z11, Z7, Z5, Z3, Z1 pin 7. Scrape the solder mask from this trace and attach a 18" wire. Be careful not to short the wire to the row of resistors beneath this large trace, or the smaller trace above it (which connects to Z2 pin 11). Alternatively there is a vertically mounted capacitor on the upper right side of the driver board - connect the ground wire to the lower lead of this cap. On the other end of the wire attach a "fork" connector. Connect the fork connector to the metal frame of the power supply. If doing this on a system80b game, connect the ground wire to the ground plane bolt in the upper right corner of the backbox.

Step 5. Attaching a ground wire to the solenoid driver board below Z10. Picture by J.Robertson.

  1. STEP 6: If the game has an Auxiliary Lamp Driver board (Haunted House, Black Hole, Volcano, Mars God of War, etc.), run a ground wire to this lamp board. The Auxiliary Lamp board is used for the marquee lights in the backbox of a handful of system80 games. If the ground is unreliable to this board, the score displays can flicker and act strange. Scrape the green solder mask from the large circuit board trace between the lower left chip and the MPS-U45 transistors at the edge of the board. Solder a wire to this trace, then continue the wire to the metal power supply frame to complete the ground path.

Step 7. Attaching a ground wire to the chaser light board as used on Haunted
House, Black Hole, and some other system80 games. Picture by J.Robertson.

  1. STEP 7: If the game has a sound/speech power supply board, add a ground wire to this. On the back (solder side) of the board there is a large trace running around the edge of the board. Scrape the solder mask from this trace and attach an 18" piece of wire to this trace. Then continue the wire to the metal power supply frame to complete the ground path.

Step 8. Attaching a ground wire to the sound/speech power supply
board as used on some system80 games. Picture by J.Robertson.

  1. STEP 8 (Sys80B only). The ground wire going to the power supply module connector J1 pin 2 (bottom conector, white wire) needs a second wire attached to this pin for an added ground. Remove the J1 pin 2 from the connector housing, and crimp on a new .156" Trifurcon connector pin, adding a second wire to this pin. Then run this wire to the upper right corner of the backbox and attach to the ground plane screw.

    At this point, the mandatory grounding modifications are done.

System80B Raven backbox with the mandatory ground mods and
remote battery pack installed.

Optional Ground Modifications Steps.

    The grounding modifications can be taken one step further. The following will tie all grounds on the driver board together, except for the solenoid ground (which will be isolated to protect the circuit boards from solenoid feedback to the logic ground).

    If you do not have much circuit board repair experence, it may be a good idea to skip these steps. Though the following solves some driver board ground problems, these mods are not nearly as important as the above "manadatory" cabinet ground to circuit board ground modifications.

    IMPORTANT: a note about "Wire Wrap" used in this procedure.
    Through out this procedure, small 30 gauge blue wire can be seen, which is used for all ground modifications. This wire is known as "wire wrap". I used this type of wire in the pictures below because it's easy to work with (and does "clean" modifications), and it shows up great in the pictures. BUT in reality, it is probably too small for these ground modifications! I highly suggest using thicker wire (such as cut off resistor leads), or double/triple up the wire wrap on each of the connections shown below. There is a potential for up to 8 amps to go through these added connections. Wire wrap will vaporize at about 3 amps.

    Note: for the fixes on the driver board I have the board positioned so the "bottom" is the edge with the J4 edge connector. Likewise for the CPU board, the board is positioned as it would be installed in the game with connectors J4, J5, J6 at the "bottom".

  1. Remove the three metal cased power transistors Q58, Q62, and Q64 (2N3055) from the driver board:
    • Each transistor has two screws. Remove these screws.
    • De-solder the two transistor leads for each of the three power transistors.
    • Notice the thin mica insulator for all three transistors. Cut the mica insulator so the bottom screw (the screw the leads are closest to) is not covered by the mica.
    • On the component side of the driver board, tin the bottom screw contacts for all three transistors. Note this is the contact that leads to ground (the upper contact has no traces attached to it).
    • Test the removed transistors (2N3055). Set the DMM to the "diode" setting. Put the black lead on the metal case of the 2N3