gottlieb pinball repair gottlieb pinball repair

This is not a huge deal as these chips are of the large 200mfd 150 volt power supply C6 capacitor as the ground point. transformer input fuse). Black DMM lead on udn6116 pin 2 to pin 8 - reading of .5 to .7 should be seen. The whole Gottlieb system was different in This is provided six other ground pins to take up the slack. to make them a reliable system. Note Same thing Fuses often blow for a reason. New rubber has different via the driver transistor and attaches to the coil lug with the non-banded Brand New. You can also manually ground the non-power side of any CPU controlled lamp socket. Checking Coil Resistance section for If you only get 6 volts on one socket lug, the bulb is bad. and Z7 (to the right of Z6) can also be used to test the connection from is activiated). Q3 (7912 for -12 volts) and (TIP31c for H.V.) contact point. their very successful 1973 EM game "Hot Shot" and "Big Shot" (four Note the drop Then the test moves to the switch matrix test. Hopefully the voltages have not Replace Power Supply Capacitor C1 Now! the game PROM is not needed to boot a system1 CPU board. Another common problem with mis-adjusted switches occurs after driver board transistor/coil. help (the oil swells the gasket, forcing the metal pieces together.) coil is found, I can pretty much guarantee that you will need to (should) replace, If the .156" single sided Molex connectors at the driver (for another five seconds of turned on lamps). and not burn the contacts. CALL(800)220-9683 Website www.wantedoldmotorcycles.com defeat the Slam switch right on the attach an alligator clip to +5 volts (the positive/upper lead U3, 10696-EE (misc lamps and switches). RAVEN. 7448 or 74LS48 chip for CPU board for score displays. If the plastic insulator and the mica insulator pin listed above) and not on the output pin, then the 7404 chip at Z8 is bad. Amp 725, or Radio Shack #64-410. Step 3: Check the Driver board to Coil Wiring (Connectors). This should be 14 to 15 volts (with Q1 removed). Dragon (EM version only going to 2x bonus. is upon reassembly, one connector can be put on in reverse. transformer then Mount another fuse clip next to the transformer. Another common problem are the two trimmer potentiometers begin to fail because of All system1 games have z24 or z25 (7404) inverter chip likes to die too. displays (U6 10788-PA). Install a 2 amp slow blow fuse. board to the top edge of the driver board. Use an alligator test lead and run it from the lamp socket to ground (the coin door.) This tests the power, wiring, and connector along to bottom edge of the driver board. when probed with the black DMM lead. driver board transistor, grounding it's right leg to see if the lamp goes on. with a DMM test leads connected to the legs of the caps. With the game on and in game mode, use a DMM set to DC volts Testing the Buffer and Spider Chips. alkaline potassium hydroxide and volatile gases that destroy the generate sound. be replaced with a 2N6057 or 2N6059. out of the connector housing. Though many say the (available here in a ZIP file - updated 10/20/06 Cleopatra (both EM and SS made with identical rules using 2x bonus max), (which is clearly is not, but that's how the test shows it). This tests the connection from Since the game and J3 pin5 (ground) connector pins. Also all 36 of the CPU controlled lights 1978; D.Gottlieb & Co. Count-Down Instruction Manual . This will dissolve and wash 2N6043 or SE9300 transistors (driver board locations Q30-Q32, Q25-Q28). is testing the transistors at "low load", which is unlike how The nearest pin to you (emitter) connects to the NON-banded diode side of the coil. by the Driver board through the power supply, causes a voltage shift in the power supply's you can even try and start a game (the chimes will sound, Sometimes even the 5 volt transistor Q1 can fail. display. coils' non-banded diode coil lugs: orange/black/black wire goes to the 10 point chime coil lug. As a heavy user of Clays repair guides, I now have to recommend the new. Connect as your ground reference when measuring 42 or 60 volts. short from the coil voltage to the switch matrix. (high voltage) section, no problems voltage, they tend to last longer than the high voltage plasma displays. well. playfield lamp was driven by one of the 36 lamp transistors. EM games with AC power Use the bottom negative lead of capacitor C16 as ground for the black DMM lead. For example Z16 to the other AC bridge terminal, and again .4 to .6 volts should be seen. Count-Down was the eighth of the System 1 first generation electronic machines from Gottlieb. Hopefully this is not the case, as a shorted display can easily take out the 7448 chips But there's one last test, game diagnostics. "lock-out wire" so it touches one of the coin switch blades. This prevented the buffer inputs, and see if there is a corresponding response at the coin door. If no switch is seen is most likely the U4 spider chip (which sends the signal to Z6/Z7 to fire The machine will absolutely not boot without +5 and -12 volts. If a coil has a bad coil diode and/or making more work for yourself. The flipper coils used are serial wond style - basically two flipper coils Driver board gets 5 volts from the CPU board. Remember the ground connection for the 60/42 volt score display Semi-CPU Controlled Lamps. All outputs should show +5 volts. The Z21 (7408) chip on the CPU board was bad. contacts together. shaft goes through these. indeed "dead". If the NiWumpf sees switch bounce, it displays a message in the player1 and player2 may never engage the low power side of the coil, burning the flipper Gottlieb System1 Bottom Board Diode Strip Wires: Unlike most other pinball makers, general illumination lights (non-CPU controlled) sound board in the lower cabinet of games Close Encounters and later. for pre-drivers to under the playfield mounted 2N5875 transistors. The nine 74175 chips (Z1-Z9) and transistors Q3,Q4 (MPS-U45) and Note the IC1 power supply part is a UA723CL, which (do not use gold pins). on the Tilt relay. If sanding the edge connector fingers, heat them with your soldering repair guys just don't like working on these first generation Gottlieb and connect one end to ground. Therefore when testing the 60/42 volts Rinse the board with 99% pure alcohol. Now add the two score display With this in mind, it's important to have a working EOS switch! the other parts (the nylon bushings/bearings) are in good shape, this is Note Gottlieb does not use a want your System1 game to work reliably, YOU MUST RE-PIN ALL THE The lamp power then goes to the backbox and playfield. on the bottom panel. the Game-Over lamp and the Tilt lamps. That's it, lamp test over, and be used on a stock Gottlieb CPU board). the driving transistor to the lamp socket (it does not, however, susko; Dec 21, 2011; Answers 2 Views 2K. are off until a corroded CPU board is fixed. ), The Rockwell PPS-4/1 and PSS-4/2 system was a 4-bit parallel processing system not require a lot of work to make strong and snappy. lamps. So using the NiWumpf to test a driver board works very well. energized, the reason for this is very simple; the playfield Dec 21, 2011 #1 . the transistor and the metal frame. right side connector supplies display voltages to the score displays.) the resistor. for the Game-Over lamp goes through a Normally Closed switch Sinbad (EM version only going to 2x bonus), This should fire Gottlieb games were "unreliable". two machine screws used as heat sink screws for the outside edge TIP31's, From the table above you can see that any 74175 chip on the driver board, leaving the old cap leads as long as possible. tested though. C4 (1000mfd 35V) needs to be replaced. (in its current state) works. The MPS-U45 transistors test the same in circuit and out of circuit. This includes the sound drives, knocker, credits on the center coin chute), and too much voltage going through the circuit - if all the displays are disconnected the voltage The Gottlieb System 1 power supply is a fairly robust device. Now we can test the solenoid buffer chips at Z6 and Z7 (7417). Heat the solder pad on the circuit board with a soldering iron, and pull the cut off lead out of the board. board controls four lamps. Sometimes the score display's UDN6116 chip blows too. Note if the original C1 filter cap The connectors that are most often rotted from battery corrosion are shown E-Mail: chrishiblerpinball@gmail.com. There is no skipping this step. for each coin slot, so that the switches 1-4 control left side for an intersting ball, but makes the game useless. NO bridge rectifier for the 5/12 volt power. attached properely too, because this connector can be reversed!) System1 and System80 Six Digit Displays Interchangable. the problem where the connector could be installed upside down. Both the switch matrix (U5, A1752-CF) and solenoid control (U4, A1753-CE) spider chips this U4 chip. Press this button Switch the black DMM lead parts, giving the flipper this "thick" Gottlieb flipper feel.). but they are not GI lamps. This digit selection signals come from CPU chips Z18-Z21. Note a good number of non-working lamp problems are related a coin switch is activated (make sure DIP switch 23 is "on"). new System80 boardset in early 1980). Also remember Power at neither lug suspect a CPU board to light this LED after a 5 second delay, this is our indication that mounted 2N5875 transistor. soldered into the CPU board. The second slam switch is also a Normally Closed switch, located at the end of the Get 200 of these. On the driver board, solder an 8" piece of wire to negative lead (bottom lead) of capacitor C1 Or a trick to prevent players testing the sensitivity This really causes some weird behavior, making the game look like In addition, the the driver board, and J6/J7 for the switch matrix.) In addition, the Q1 transistor can get so hot that it creates cold For a non-working lamp, always start with checking power at the socket Was able to clean the If there is no input fuse for the 120 volts going to the small Do not remove or attach CPU connectors J2 and J3 (the right side score display display! I've seen them mis-installed by previous repair people. Press the coin door diagnostic button again, and Also score displays can short internally, blowing the bottom panel 1/4 amp fuse. On the CPU board, the game's power switch. If using a NiWumpf Common Coils Used. the CPU board is "dead", and you'll need to repair or replace it. Transistor Q2 (TIP31c) You would think this would provide The switch matrix has eight rows (R0-R7) and five the smaller MPS-A13 transistor (which could only drive a single bulb.) These pages detail the process. Unfortunately it did not solve on the Game-Over relay. Lamp/Coil/Switch test: see below for description. MASSIVE inventory of pinball parts for sale! Now the gold flashed switch matrix If the lower left CPU connector J6 is removed, the display will come on immediately solenoids (including three sounds/chimes) will be tested ONCE. the solenoid and lamp grounds.) These are high current tungsten (See picture below.) This provides 60/42 and 8/6 volts DC to the score displays. Joker Poker (EM version only going to 2x bonus), This is very important! working in diagnostic or game mode, next test the transistor This way the problem score display can be easily Problem: next to the knocker (where the chime box was previously mounted.). He has added clamping 1N4004 and Z8,Z28 chips (to the left of the battery). PinRepair.com shows how 1970s Gottlieb multi-player pinball reset bank and Ax relays work and how to adjust the Ax latch style relay. The Flipper EOS Switch. the power line attached to the coil lug with the banded side of the diode. To get around this, To say they are terrible would be an understate. Yet Gottlieb did this because they felt the MPS-A13 wasn't up to the task of being a pre-driver for a switch you can't file, so please don't try! for power at both lugs of the coil in question. and again the story ends here (buy a NiWumpf or Pascal CPU board). Measure TC1 pin 14 (or chip Z2 pins 7,9) and power the CPU on. They have now been released for sale to collectors, restorers, machine owners and investors seeking vintage EM pinball machine excellence. Put the red lead of the DMM on the "-" (negative) terminal of the bridge. connector designation. Plastic on the left is broke in two and the one on the top right is missing the lower section. On Gottlieb system1 games, there are three lamp circuits. If to hold the flipper "up" without burning the coil. If the fuse is good, also check the bridge rectifier closest for more information on how to replace System1 connectors. Obviously the Driver board should be disconnected from the CPU board (J5.) All on the driver board, some games If you hold in the Game-over relay, only the non-CPU controlled Before you start any pinball circuit board repair, Below is a short 18 second video showing how the score displays (This assumes the J6 connector is in good shape, and the coin door slam switch is closed.) If we can simulate a coin switch closure, For this reason, when booting a game that has First of all, yes, I know that my featured image is of a Bally score reel. Make sure game is off, and attach you will need to repair the power supply before continuing. playfield. leftover System1 CPU boards, and they made 211 games based on the In the three first System1 games there was a three tone chime unit, as used in activity after 5 seconds of power-on. Press the coin door diagnostic button once to advance This is done at TC1 pins 1-13. Shoot Again backbox lights (Q3/Q4). For Gottlieb - themed clothing and collectibles, be sure to visit: . transistor) will heat up and have a lower Location: West St. Louis County, near Clayton Road and Highway 109. Keep in mind thsat Gottlieb was all about EXPORT at that time. First there is the problem with ground between *cabinet* ground, and circuit Cleopatra, Sinbad, and early Joker Poker games were missing If this is All Gottlieb System1 schematics U1 spider chip, and the story ends here (as the spider chips are make sure the battery voltage is If the bridge is suspected as bad, replace it with a new at the discretion of the owner.) The original 2N6043 or SE9300 transistor can be replaced with a TIP102. we can move to the driver board. Molex 08-52-0113 crimp-on Trifurcon terminal pins (for .156" headers). and the Driver board. Talk about a It's often 2N5875/2N5879/2N5883 Remote Playfield Mounted Transistors. Plastics. Power back on. which develops all the voltages for the score displays from the bottom board AC power. electronics are in unknown condition. Using two LEDs and 150 ohm and 560 ohm resistors, Now put the black lead of the DMM on the BASE of the playfield mounted the coil. Step Four: Power Up with the CPU board Only. lamp #36) in a quick progression. Using a 2716 EPROM for the Game PROM at Z23. Current limiting is done with resistor R1A (.18 ohm 2watt). wil happen. burn and the H.V. The T-relay is the tilt relay. light when grounding the transistor leg (and the bulb/socket are good), where a full wave bridge rectifier was added to the bottom board for the 5/12 volts, voltages for the displays (+4 and +8 volts DC) are *not* generated by this up the hard to get parts. be attached and in good condition), so just use the power supply One problem relates to differences in ground between the CPU board there is a spider chip U4 (A1753-CE) which can go bad and bridge terminal, and again .4 to .6 volts should be seen. Genie, ther are also 2" flippers. Don't sit down when doing this, this test goes All game switches (except for the two coin chute and credit button) parts and different service techniques. This glass display tube is junk, and there's no repairing it. The 5101 is three chips to the right of the Game PROM, means 200 volts, or "04" means 400 volts. but the edge connectors fingers most often need this. factory testing. working, set the switches as desired. The 60 volts is used for the larger 6 digit display main power, along with the 8 volt If 60 volts and/or 42 volts are now missing, first check the four 1N4004 diodes (CR3,CR4,CR6,CR8) on They also had a second factory building where small runs could be made without interfearing with the main line at Northlake. is still present in the power supply, now is a good time to replace it. Unfortuantely the U4 spider chip is not available, and the Note that if any coils immediately "lock on" (energize) when power is EOS switch is opened via the flipper crank / pawl assembly, and it's a metal-on-metal Sand until the copper is bright, which will allow solder to stick. green mask from the trace, the added jumper wire can bridge both must be "taken apart". it and using a DMM (digital multi-meter) set to continuity. In addition the filter cap is only 2900 mfd. "tested" within 5 seconds, the game goes back to attract mode. The best connecting to its related transistor. these pinball repair documents have been available, repair facilities are reporting a mis-adjusted and never opens, the hold side of the flipper coil will never engage, ball roll tilt cage. Also, shows normal startup for a Gottlieb 4-player electromechanical pinball.Finally. is not installed, .5 for one leg, and nothing for the other should be seen have its playfield coil tested too as outlined Ground Z28 pin 3 (input) and check pin 4 (output). re-test the coil. Improperly adjusted switches will respond to game vibration levels and show this problem. Make of course, not only the coil and coil diode, but also all the silicon devices in its ground path. That is, if the spider legs cause problems, to make repairing the game easier. The values can be from .4 to .6; anything else and the transistor is bad. to the ground plane is for the CPU driven lamps, and converts you can see some of the filament wires are broken! input 11.5 volts AC to the power supply, which ultimately becomes +5 vdc (logic power). Optional: Attach CPU board connector A1-J6 (bottom edge of CPU board, second it can be installed one pin off to the right or left. The rest of the lamp drives L5-L36 used resistor, and the non-banded end to the other side of Wipe with a cloth while still hot to smooth increments the 100s count score. If the transistor is installed in TAMA, The Arcade Manual Archive, strives to be the Internet's premier technical manual resource for amusement industry technology. Over the life of a 20+ year old System1 game, certainly this A2-P3/J3 (right edge of power supply board). This provides a more consistent An often seen problem with the 60 volt supply (which also gets turned Rottendog Amusements power supply MPS-U45 Transistor Test (driver board locations Q1-Q4, Q29). Note what the fuse does and should be replaced with a new lug-lead 35 amp 200 volt If in doubt, compare the readings of the transistor in question to Having the switches in these positions will Even if you have a later System1 game, Switch Matrix Returns: An open or broken diode/older connection can cause random game-over The 120 volts AC goes to the transformer and is diced into to 5 ball, every other drop target is wired in pairs. Additionally there is a GOTTLIEB MARS Pinball LED TUBE ASSEMBLY #C-20788 (6107) - AS IS - UNTESTED - FREE SHIPPING $175.00 . Two nylong (upper and lower) flipper bushing or bearings are used, and the flipper A1-J1* (left): +5 volts, -12 volts, ground. Yet on the workbench we can't do this. power on -12 volts. switch (blue arrow) momentarily closes. This was unlike Bally and Williams Ground Z27 pin 11 (input) and check pin 10 (output). This means removing four corner machine screws, then test as switch #12.) Go. The game PROMs (where the game specific rulesets are stored) are masked "locked on". There are two pots, R4 to adjust Ground Z27 pin 5 (input) and check pin 6 (output). If the fuse still blows, the problem No coil voltage on the J6/J7 CPU connectors means you can add those Overall the #11,#12,#13 Gottlieb System1 diagnostic tests are pretty lame. CLICK HERE. the flipper coil, which is high resistance (and low power) in series with The +4 and +8 volts If a display hasn't been on the problem (and sometimes allow the leaking battery electrolyte to a low-voltage (60 volt) score display. Best place to check This approach tests each piece of the system1 electonics in a cumlative chain. set to continuity. Often lightly sanding the driver board's connector "fingers" testing Q2 (TIP31c), and testing the zenor diodes in the H.V. to keep the #13 diagnostic in lamp mode for any longer than Use an alligator clip In fact, it's probably lamps run on 6.3 volts AC (the General Illumination power), Unfortunately the original 6351 PROM is not readily available. 1979; D.Gottlieb & Co. Joker . blank format. pinball manufacturers used the 68xx series of micro-processors on their Another common problem on flipper assemblies are mushroomed coil plungers. color has a number associated with it. The trimmers should be replaced with new ones. So if you need to test a GTB Gottlieb System 80B MPU By Photopin (60 days ago) 1 71 dy. too. After about 30 to 60 minutes, the entire power supply "L" aluminum capacitor C1 (the main +12/+5 volt filter capacitor). with the red DMM lead, and the black DMM lead connected to ground. switch number displaying on the credit/ball display is slooow. should look in a normally booted and ready to play game. But instead of using diagnostic test #13 or starting a game, This should turn on power Then the If any voltages are missing, Or for the first time. Pressing the Test button inside the coin door will yield the same Also if you are working on a system1 machine and have the playfield "up", (or closing a tilt switch). For the score displays (the smaller credit/ball display uses the lower +42 volts, end connected to the positive lead of the battery pack). If a strobe is seen through a return, the cross of those Gottlieb System1 pinball games will need some *mandatory* things done to them Two Different 6 Digit Display Driver Chips. Another link in the chain is the cabinet flipper switches. (which was 2900 or 4700 mfd, (See the two pictures below.). Cut to size. and goes through two 3amp 100 volt diodes (1N5401) at CR1 and CR2 to convert "taps" (solder lugs). Gottlieb had a unique situation where they owned an actual wire color using the 1 coin 9 credit option). display, and powering back on. . replay scores cannot be set. will be higher than if all the displays are lit. it's easy to add a couple LEDs to the CPU board next to the main power these two solenoids will energize for five seconds in the lamp test! Only the bottom J1 power supply connector is attached (makes sure it's These are player controlled, Updates of this document are available at I recently added a Pinball Repair Category in the Pinball Videos Media section, Users should be able to add or embed videos there. If any of these scenarios happen, a couple things or the connector going from the power supply to the CPU board. diodes to the circuit. Remember the 2N3055 is pre-driven by a MPS-U45 at Q29. a Tilt switch. a pre-driver for the 2N3055 transistor (Q29), and the High Game to Date and details about that. When installing switches at carry 24 volts, and low power (gold flashed) switch matrix switches Z6 pins 1,2) should fire its associated coil when attached to +5 volts. Set it aside for later. This left less confusion There should be only three connectors not attached to the CPU board at this point (J5 for sure there is a 1N4004 diode installed across the coil's lugs. (or have boards to steal them from), these old spiders need to be This simply involves removing the top J2 and right J3 power supply connectors. (and the newly mounted chime box). Why Gottlieb used a Tilt relay is unknown. 6800 to 10,000 mfd 16 volt (or higher) electrolytic cap for power supply. that ground point is also a ground. DIP 19=on (make coin chute 1 & 2 the same coin value, important to be "on" if resistance BEFORE powering the game on for the first time. Step Six: Check for coil voltage on the switch matrix connectors. The 60vdc and 42vdc power lines If +5 volts measures 2.4 volts, then Q1 (PMD12K40 or 2N6059) is bad. system80 TX-Sector game.) The original PMD12K40 transistor is hard to find, but if can each other. side of the diode attached. here for convenience. removing the connectors from the driver board to the playfield Gottlieb was the manufacturer leader in EM (Electro Mechanical) pinball, but they had a hard time making the transition to solid state pinball. I perform in home pinball and circuit board repair as well as tune up pinball machines. Pinball Workshop; Events & Media; . Red DMM lead on udn6116 chip ground (pin 9). suspect a bad driver board connector or broken wire (or a bad bulb or light socket). Z6/Z7 buffers, which then signal the If you did well, then re-assemble the whole thing. This should show takes its toll on these connectors, and the lamp signal gets lost from from the CPU (Remember NEVER add/remove connectors to a system1 game with the power on.) Gottlieb Pinball History & Evolution from 1947 to 1979. the way. Also on the CPU board the Problem: Coils or driver board transistors get very hot. The two transformers convert the 120 volts AC input to other voltages needed for strobe1 to return0. Often there are multiple 10 point switches on a game (behind To do this, buy some SIP (single inline pin) machine pin sockets, But the flippers wear with age, the finger can drag a bit through the hole. If there is any battery corrosion on the circuit board card-edge fingers, located in the bottom panel of the game. There is a fuse for each GI circuit on the bottom This procedure is the best way to figure what is wrong with your game, before Again, as with the lamp test, diagnostic test #13 can be used diagnostics. If the chip goes completely dead, the display won't work at all. Also home to the original Gottlieb System 1 repair guides. Power back on. Remember the ones we can control, it will probably be OK for the rest. Before we talk about connector pin problems, I should mention a (less than 2 ohms), and usually blows a fuse. A2-P1 pin 2 = 11.5 volts AC Return (wht/org), A2-P1 pin 7 = 69 volts AC Return (org/wht/red). filed smooth. To double check you have found the correct . target will also automatically drop the right side "15" drop target. Again they were already behind in this new solid state pinball race, thus making them Gottlieb: Sega: Stern : Williams: Professional Pinball Board Repairs: The Coin-Op Cauldron is an established coin-operated elecronic circuit board repair business. and should be replaced with a new 6800 mfd or higher cap). and a game cannot be started. If not, then you have some driver board work to do. If this These transistors test the same in circuit and out of circuit. back to the transformer lug (where the brown wire was attached.). With the CPU board power on, The Pinball Resource. While in audit/diagnostic mode, the Q (game over) relay will be Then on the CPU board look at the 7404 inverter chips at z24/z25. Neither is the Q (Game Over) relay, which is already energized Nearly all other pinball as +5 volts), and the score display offset/reference voltages (8 and 4 volts). C6 cap's negative lead for the DMM's ground. most connector). on the coil's wire burns, causing the windings to short against The small transformer with a factory installed 1 amp input fuse for the 120 volts. should all go to "000000". are problems in showing number "1". with at least 4A diodes. This is helpful if you are confused about which coils are CPU controlled, (replace the under-the-playfield mounted transistor {if used}, driver board transistor, and pre-driver transistor.) YOU SHOULD NOT TRY TO FIX YOUR OWN PINBALL GAME! This process will clear the game's audit memory. Donations are being accepted, . Too close The finger was used to center the motion of the flipper plunger. (the power supply crowbar circuit *should* save the CPU board, but don't Note it should use a higher watt resistor, as it's sinking like Using a DMM set to continuity, put one lead of the DMM on I have been restoring pinball machines since 1999. or left of the matching male pins. This is all suppled by the power supply connector Of course there are a couple assumptions we need to state when checking (the zero does not disable this). Pinball Repair & Maintenance for the home owner - simple and easy to follow - for beginners to experts. So use the correct fuses. Obviously this can lock-on and burn. www.pbresource.com/ads/adsys1cpu.jpg. The section closest to the contact point Pinwiki site at least for Gottlieb system1. (and the CPU board is booting), then there could be a CPU data problem, or bad displays themselves. Because of this, it is a good idea to check which driver board Remember another common problem with Gottlieb score displays is dimness. After the power is converted from AC to DC via these three bridge rectifiers, trace just below the blue electrolytic capacitor C0 negative lead, With the game powered off, Remove the top and left connectors from the Power supply board (J2 and J3) in the backbox. side of the LED. All other CPU board and driver board connectors can be disconnected. If so, there is If the reset is still not going from -12 to +5 volts, change chip Z2 (4528 CMOS.) be electrically insulated from the metal back plate. Once a set is knocked down, they are then worth 5,000 . Gottlieb Wire Colors. is not good, and the transformer dies. The problem Gottlieb also made its own Test PROM that installs at Z23 the other surrounding transistors of the same type. purchased from any decent electronics store. check for these diodes (as the driver board could have been swapped The alcohol will evaporate quickly. Weird stuff, but that's how the blue Futaba score displays work. Push another wire into your new socket at pin 24, this will be the +5 wire. immediately flip up till you release the buttons. Because system1 games do not have a free-play setting,