Pinball Games from 1978 to 1985.
by firstname.lastname@example.org (Clay Harrell), 07/22/15.
Copyright 2005-2015, all rights reserved.
All pictures and text are by Clay Harrell, except where noted.
Internet Availability of this Document.
IMPORTANT: Before Starting!
If you aren't up to repairing pinball circuit boards yourself or need pinball parts or just want to buy a restored game, I recommend seeing the suggested parts & repair sources web page.
Table of Contents
Bibliography and Credit Where Credit is Due.
I can't thank the above people enough. Especially those that provided wiring harness and boards. The guide would be impossible to put together without this! Testing procedures, researching boards and fixes, it just would not happen if the above people did not step up and send me the stuff to experiment. Thanks again guys!
Some people question whether I wrote all this material myself. I did, but of course like everyone, my repair techniques and ideas are gathered not only from my own experience, but from work that others in this hobby do and share at shows, on the internet, etc. So if you're the originator of some cool trick or tip in this document, and I'm not giving due credit, just let me know and I'll add you to the list of contributors above.
1a. Getting Started: Experience, Schematics, Manuals.
Little experience in fixing pinballs is assumed. Basic electrical knowledge is helpful, but not necessary. I do assume you can solder and use the basic features of a Digital Multi-Meter (DMM) such as measuring voltage and resistance. Please see http://pinrepair.com/begin for details on the basic electronics skills and tools needed. This document should help repair a first (or second, or third) Bally pinball.
Schematics and Manuals.
Some Game Plan schematics and manuals are available online too. These are all in PDF format, which means Adobe Acrobat is needed to view them.
Board Layouts and Part Lists:
1b. Getting Started: Necessary Tools
Non-Specialized Tools Required:
Specialized Tools Required:
Cleaning "Tools" Required:
1c. Getting Started: Parts to Have On-Hand
When fixing electronic pinballs, I would highly recommend having some parts on-hand to make things easier and cheaper. All these parts are available from a pinball retailer.
Parts to have:
Transistors, diodes, bridge rectifiers and other electronic parts are available from many sources. Please check out the parts and repair sources web page for details.
1d. Getting Started: Game List
1e. Getting Started: Lubrication Notes
The only parts that will require any lubrication are metal-to-metal moving parts. There aren't very many in a game. Only ball eject and slingshot hinges. 3-in-1 oil also works on these if needed. But try and keep that lubrication in the tool box and away from the game.
If some prior person did lubricate the game, the lubrication has probably now congealed with the infamous "black pinball dust" to form a thick, black mess. This is unrepairable on coil sleeves, and new parts will need to be installed.
1f. Getting Started: The Circuit Boards
Here are the boards that live in the backbox (head) of the electronic Game Plan pinball games.
PSU (Power Supply).
There are three 25 amp 200 volt bridge rectifiers:
There is no HV (High Voltage) circuit because Gameplan uses LED score displays that operate at 5 volts. This makes the Gameplan power supply much easier to repair. Really the only thing that can fail is the 12 volt filter capacitor (11,000 mfd at 16 volts), the LM323K voltage regulator for the 5 volts, or one of the bridge rectifiers. There is a 6.3 volt AC general illumination circuit on the power supply, but it only consists of a fuse and several connectors.
There were two styles of MPU board used in Gameplan machines: MPU-1 and MPU-2. The MPU-1 came first and was used in the Gameplan Cocktail models #110 (Black Velvet, Real, Rio, Camel Lights, Chuck-a-Luck, and Foxy Lady), Family Fun, Star Trip and Vegas. There are only *two* 2k bit ROM sockets at U12/U13 on the MPU-1 board, so it has limited ROM space. Also the MPU-1 was designed to run the DDU-1 score display units only (it can not run the BDU-1 score displays that were used in upright Gameplan pinballs. Used a rechargable (and often leaking) battery to maintain audits and high scores.
The MPU-2 came next starting with Sharpshooter, and had *three* 2k bit ROM sockets at U12/U13/U26. Because of this a MPU-1 can not be used in a game designed for a MPU-2. Other than the ROM space differences between MPU-1 and MPU-2, the boards pretty much operate the same. The MPU-2 is downward compatible to games using the MPU-1. The MPU-2 has both style of edge connectors on the top side of the MPU board; it can run either the BDU-1 display or the DDU-1 display. The MPU-1 ROM software can be used in a MPU-2 (ROM socket U26 will be empty), and it works fine. Because of this the MPU-2 is much more versatile as it can be used in any Gameplan game. The MPU-1 board though can not be used in games calling for a MPU-2, because of the limited ROM space and the inability to power the BDU-1 score display. The MPU-2 also used a rechargable (and often leaking) battery to maintain audits and high scores.
The MPU board is the part to fail most often in the Gameplan board system. This is due mostly to the recharagable battery used on the MPU board. Unfortunately when GP copied Bally, they also copied the idea of using a rechargable battery on the MPU board. Like Bally MPU boards, battery corrosion is the number one cause of GamePlan death. The battery is completely unnecessary for the game to run. All it keeps is high scores and game audits. So any Gameplan MPU board should have the battery removed ASAP. Gameplan even has a free-play option (set by DIP switch #8=on), so there is no need for a battery to keep credits. The only downside to not using the battery is sometimes at power-on wacky high-scores will be seen as the memory has 'garage'.
The GamePlan MPU basically operates much like a Bally -17/-35 MPU board. The main difference between the two is the processor family. Bally used a 6800 CPU and 6821 PIA family of chips, where Gameplan used a Z80 CPU and Z80CTC and 8522 PIA family. Gameplan also used a 6810 RAM, as did Bally. Other similarities between the two pingame systems are a maximum of 40 switches (8 rows by 5 columns), and the MPU board's PIA drives the sounds board with four data lines (four bits) as did Bally (this is unlike Williams and Gottlieb which used driver board transistors to trigger sounds).
Gameplan also used the familar power-on LED flash system (much like Bally) for MPU board diagnostics. Where Bally had (usually) 7 LED flashes at power-on, Gameplan used 6 LED flashes to signal any MPU board problems (or lack of problems) at power-on. The Gameplan LED flashes are discussed elsewhere in this document in depth.
The SDU (Solenoid Driver Unit) uses the same priniciples as the Bally Solenoid Driver board. That is there are nineteen SE9301 (TIP102) transistors driven by four CA3081 pre-driver chips and one 74LS154 decoder chip. This is basically the same solenoid driving circuit as Bally, with some slight changes. For example, two of the 19 driver transistors are for relays - Gameplan has two relay sockets on the solenoid driver board. One SE9301 transistor (#19) drives one relay which engages the flippers during play. Another SE9301 transistor (#9) drives another relay socket which is usually not used (but certainly could be used as a GI relay or some other type of drive relay). Gameplan was thinking ahead, and only used the second relay socket on Andromeda (additonal playfield GI lights) and Super Nova (for the roulette wheel). Since Gameplan games do not use high voltage for the score displays, the SDU has no high voltage circuit. Likewise there is no regulated 5 volt circuit on the SDU either (it is on the power supply board).
There are two versions of the lamp driver board: LDU-1 and LDU-2. The LDU-1 was used in cocktail games, and support only 47 CPU controlled lamps, where the LDU-2 controls up to 63 CPU controlled lamps. Because of this the LDU-2 is more versatile and will work in any Gameplan game. The LDU-2 is plug compatible with the LDU-1. In a pinch the LDU-1 can be used in place of the LDU-2, but if the game uses those sixteen additional CPU controlled lights, the LDU-1 will not be able to light them. The LDU-1 and LDU-2 boards are essentially laid out the same too, just there are two more columns of SCRs and two more connectors on the LDU-2 to support the 16 additional lamps.
The LDU (Lamp Driver Unit) also uses the same principles as Bally's lamp driver board. There is a single SCR for each CPU controlled light. The SCRs used are 2N5060 and MCR106-1 just like Bally, driven through a 74LS154 decoder chip. There are a total of 63 (yes 63 not 64!) SCRs on the LDU-2 lamp driver board allowing the game to have up to 63 CPU controlled lamps. This is three more CPU controlled lamps than Bally had. The larger MCR-106 can also power two #44 lamps in unison, where the 2N5060 can only power one #44 lamp.
The sound board on upright pins is mounted at in the lower cabinet. There are several styles of sound boards: SSU-1 Sound Simulator Unit, SSU-2 (Sharpshooter), SSU-3, SSU-4 (Super Nova), and MSU-1/MSU-2/MSU-3 Micro Sound Units. The SSU boards were sound boards without a micro-processor, and did basic mono and dual tone sounds. The MSU-1, MSU-2 and MSU-3 (Micro Sound Unit) sound boards were the last sound board design by Gameplan. Used on the later games, the MSU board have the best sound because it used a 6802 or 6808 micro-processor. The MSU-3 could produce speech (though I don't know what Gameplan games did have speech).
The score displays use LED displays which run at 5 volts DC. Though not as bright as 190 volt displays, the life on the low-voltage 5 volt GamePlan LED displays is essentially limitless. Hence there is no need for a special circuit to power just the score displays. Also the display boards can be plugged and unplugged with the game power on without any circuit damage (a risky idea with 190 volt Bally/Williams or 60 volt Gottlieb displays).
Gameplan made three styles of score displays. The BDU-1 and BDU-2 were used on upright pinballs. The BDU-1 (most common) and had six LEDs digit, and the BDU-2 had seven LED digits. There was one BDU board for each player. I believe only one or two late Gameplan pinballs used the seven digit BDU-2 (Attila the Hun for example). The DDU-2 was used on cocktail pinballs and has 14 LEDs and the logic to control it for two players (six digit scoring) and a ball or credit display.
Note the tens digit on many games like the Cocktail 110 and Sharpshooter always displays zero when it is lit. This is done in the software, so even during audits or test mode, the tens digit will always show a "0". The only exception to this is the ball/credit display board (which only has four LEDs instead of six). This is rather bizarre when going through the score display test because the tens display never cycles through numbers 0 to 9 like the other five LEDs - the displays are not faulty, that's just how the software was programmed. Later games did not do this and used the zero display for scoring (this enabled Gameplan to stay with 6 digit score displays).
2a. Before Turning the Game On: The Power Supply - Fuses and Test Points.
Power Supply Introduction.
Note that cocktail pinballs and regular upright pinballs use two different styles of power supplies. Though functionally the same, the layout and look are different.
The Power Train.
All bridge rectifiers are 25 amp 200 volt bridges with lug leads.
There are five fuses on the power supply's rectifier board, as viewed left to right:
The power supply can and should be tested before the whole game is turned on for the first time. This is hightly suggested before trying to power the game up with an unknown condition power supply, which could damage the game.
First Remove all the connectors from the power supply's rectifier board. Then turn the game on and use a DMM to test the power supply's rectifier board's four test points:
If everything tests within the ranges above, the power supply is probably in good condition. Next check for AC ripple on the 5/12 volt filter capacitor (see below). If all this checks out, the connectors can be replaced (power off), and the entire game can be powered on for the first time with relative security.
Before re-attaching all the connectors on the power supply board, check for AC ripple on the large 11,000 mfd power supply capacitor. Using a DMM set to AC volts, put each DMM lead on the two leads of the large power supply capacitor. No more than .200 volts AC should be seen. If more than that, replace the capacitor with a new electrolytic 10,000 mfd to 15,000 mfd (16 volt or higher) cap. Any value in the 10,000 to 15,000 mfd range is fine.
AC voltage in this circuit should be .100 volts AC or less. If it is more than that, the 5 volts DC will have "ripple" above the 5 volts. So say there is .400 volts AC measured with the DMM. That means the 5 volts DC will actually have .400 volts of sine wave AC voltage on top of the 5 volts DC (meaning a flucuation of 5.0 to 5.4 volts). This causes the CPU problems like game resets and strange behavior.
Electrolytic capacitors have an effective life of about 10 years. Since all Gameplan games are older than this, they are due to have their main 5 & 12 volt filter capacitor replaced. Electrolytic caps are like jelly rolls - paper and foil wrapped up with electrolyte between the layers. The electrolyte dries out with heat and time, and the capacitor can not do its job of smoothing out the DC voltage.
Power the Entire Game On.
2b. Before Turning the Game On: The MPU battery and Corrosion.
The stock Gameplan rechargable 3.6 volt Ni-Cad battery often leaks its corrosive fluids onto the MPU board. This of course can ruin the MPU board. The best way to address this is to cut the stock battery off the MPU board as soon as possible with wire cutters. The MPU does NOT require the battery to work. In fact, I highly recommend not using the battery at all. It only retains game audit information, credit, and high scores. If this information is not important (and to 95% of the world its not), run the MPU with NO battery.
If the player does need to maintain high score information, a 1 farad memory backup capacitor works very well as a battery replacement. It will take about 8 hours for the game to be "on" to charge the cap. After that playing the game a couple times a month should keep the battery charged enough to maintain the memory (though your mileage may vary, as charge times and lengths will vary depending on the exact MPU board).
Gameplan has an option on all games for free play (no credits or money required to start a game). On the MPU board there are four packs of DIP switches, numbered 1 to 32 from left to right. Each switch pack contains eight switches, so switches 1 to 8 are in the first switch pack, 9 to 16 in the second, 17 to 24 in the third, and 24 to 32 in the fourth switch pack. Turn switch #8 ON and this sets the game to free play. This option is yet another reason to not use a battery, as there is no need for the game to remember credits.
Garbage on the Score Displays.
Removing Battery Corrosion.
2c. Before Turning the Game On: Setting Free Play and Other DIP Switches.
Gameplan uses DIP switches to set game options, coin amounts and other adjustments. On the MPU board there are four packs of DIP switches, numbered 1 to 32 from left to right. Each switch pack contains eight switches, so switches 1 to 8 are in the first switch pack, 9 to 16 in the second, 17 to 24 in the third, and 24 to 32 in the fourth switch pack. The game's manual should be referenced for exact DIP switch settings, but there are some general things that can be documented about Gameplan DIP switch settings.
Always adjust the DIP switches with the game powered off. Switches are read one time by the software at power on.
This information applies to most Game plan games. See the game's manual for exact settings. The setting below came from the Sharpshooter manual (MPU-2), but should apply to most games. Games that originally used an MPU-1 or MPU-2 have slightly different DIP switch values (though games like Sharpshooter, Sharpshooter 2, and Coney Island came with an MPU-2, but have MPU-1 style DIP switch settings).
2d. Before Turning the Game On: Check the Coil Resistance.
Before powering any game on for the first time, it's not a bad idea to, at minimum, give the playfield coils a visual examination. Look for burned coil wrappers or obvious other issues. Make sure the coil plunger moves inside each coil.
To take this one step further, it's a good idea to check coil resistance too with a DMM (digital multi-meter.) Just put the DMM on low resistance, and check each coil. No need to desolder any wires, just check the resistance. Helow is a general table of common coils used in Gameplan machines.
Another problem could be a shorted coil diode. Clip one end of the coil diode and re-check the resistance. If it goes up to what is "normal" (see list above), the coil diode is shorted and needs to be replaced.
Also if a coil was heat stressed, there may be a problem with a shorted TIP121 (essentially a TIP102) transistor on the Solenoid driver board. Keep that in mind.
3a. When Things Don't Work: Fixing the MPU (LED flashes, etc.)
Six MPU Board Flashes.
Powering the MPU board on the Bench.
Here are the connections I was using, perhaps you may have better luck (if you do please let me know). Note connector J1 is the main MPU board connector at the lower right side of the MPU board. This applies to MPU-1 and MPU-2.
Getting More LED Flashes on the Bench.
Required MPU board Connectors.
Reset Line (First Step in a Non-Booting MPU board).
With the power to the MPU board on, use a DMM and check U11 pin 26. It should be 4.5 to 5.1 volts DC. With the power off and the DMM on and connected to U11 pin 26, turn the power on to the MPU board. The DMM should show 0 volts for just a brief moment, and then jump up to 4.7 to 5.1 volts. if it does this, the reset circuit is working. If U11 pin 26 stays at less than 4 volts, the reset circuit is faulty. Start by replacing the four transistor QA,QB,QC (2N3904) and QD (2N4403). Also it's a good idea to replace the 1N4738 8.2 volt zener diode (the Gameplan parts list calls or a 1N959B diode, but use a 1N4738 instead).
Verifying the Reset Section is Bad.
MPU Reset/Clock Circuit Parts List.
MPU-1 Reset Parts (by row):
If there is too much corrosion or you just don't want to mess with replacing a gang of resistors, the whole reset section can be replaced with a single Dallas DS1811-10 or MCP101-450 reset chip. These chips looks like 3-legged transistors, but they are really a "supervisor reset chip". Here are the instructions for installing one in a MPU-2 board:
Somewhere in the era of Sharpshooter, Gameplan changed the reset section on their boards. They added some more resistors and transistors. This probably made for a more reliable reset.
Then in the Sharpshooter era, the MPU-2 reset section was changed again by adding a small reset daughter board. This board added some resistors and two transistors. This resets the game if 12 volts is not present.
Now that the reset circuit is working, the next thing to look at is the clock circuit. Again if this circuit is not working, the MPU will never start to boot.
The main clock circuit components are the 2.4576 mHz crystal and the 74LS04 chip at U3. One way to test the clock is to check TP5, which is located to the right of the CPU chip U11. With a DMM TP5 should measure about 2.1 volts DC. Another good way to check the clock circuit is with an oscilloscope at TP5, U3 pin 1, and U3 pin 4. Below are pictures of what should be seen on the scope. If the below pictures are not seen or TP5 does not show 2.1 volts on a DMM, try replacing U3 (74LS04).
The MPU board requires 24 volts DC (+/- 6 volts) solenoid voltage to boot. This is used for a zero cross circuit. Even though the 24 volts is DC, it is not filtered with a filter capacitor. The voltage comes from the transformer and goes through a bridge rectifier on the power supply board. The bridge "full wave rectifies" the AC transformer voltage into rough DC. This rough DC is required for the zero cross circuit - if a filter capacitor was used to smooth the 24 volts, the zero cross circuit would not work!
Make sure there is 24 volts DC at the MPU board connector J1 pin 3. Also measure TP6 (located below U3) for about 4.9 volts DC. A bad U2 chip (LM339) or U3 (74LS04) can cause the zero cross circuit to fail.
Check the MPU Board Test Points.
Reset, Clock, Zero Cross Test Points Check Out OK.
This excerpt by Jeremy Fleitz. If the Red LED did not flash at all, check the reset on the Z80 and the Z80-CTC. These are both the same and can be checked with a voltmeter at TP4, it should be 5 volts. The Oscillation at this TP is created by the Flip Flop located at IC2 (LM339). This oscillation drives the resets of each of the Z80 and the Z80 CTC until they synchronize with the fourth clock enable on the displays (actually from the PPI). Once established, the LED can start to flash, as the Z80 and the Z80 CTC establish a good synch with the rest of the system. When this happens the reset should go high and stay high. TP3 (the "anti Reset") should be the reserve (low). It should Oscillate, and then go low and stay low. This all should happen within three seconds maximum. If this is not, then check the following:
The J1 Power Connector.
The Watch-dog Timer (Continually Flashing LED).
On the Gameplan CPU board, the watchdog works like this. U2 operates as an oscillator running at about 5 Hertz. The output (U2 pin 13) is fed into one of the one-shots on U1 pin 1. If the U1 pin 2 is high, the U2 signal gets through & resets the processor. The resistor & cap on the one-shot determine the reset pulse width. To prevent the reset from occurring, pin 12 on U1 has to be kept low. This is done by pulsing pin 10 faster then the pulse width on one-shot, set by a different resistor & cap. On any particular Gameplan board, itís about 70 ms. This signal comes from pin 11 on U14. Problems with the processor, U14, U17, chip selection circuitry, A0 & A1, data bus & probably other things can keep this signal from getting back to U1.
I find it best to stop the resets from occurring while troubleshooting the WDT. If U2 is socketed, pull out U2 pin 13, or if everything is soldered in, you can run a jumper from U3 pin 12 to U1 pin 10 (be sure youíre getting a square wave at 60 Hertz rate from U3 pin 12). Either of these will stop the continuous resets and let you troubleshoot the board. In this state, you can get the board to give up to 6 flashes. Until you can get it to run with the WDT circuitry set normally, the board can't properly work in your machine since anything attached to U14 won't work properly.
Additional Daughter Reset Board.
MPU LED No Flashes.
MPU LED Flash 1.
MPU LED Flash 2.
MPU LED Flash 3.
MPU LED Flash 4.
MPU LED Flash 5.
MPU LED Flash 6.
Power-On Sound Tune.
End of LED Flash Sequence.
Unfortunately Gameplan did not do a great job of labeling their parts or having layout diagrams.
Converting the 6551 RAMs to 5101 RAMs.
Bad MPU Board Disc Capacitors.
Reseting the High Score/Credits and Audits.
MPU Board Connectors.
3b. When Things Don't Work: Game ROMs, EPROMs, and Jumpers.
Using "regular" 2716 EPROMs instead of Masked ROMs or TMS2716 EPROMs.
Note the Gameplan MPU board can be jumpers for other styles of ROMs. This includes 2316 or 2332 black ROMs, 2532 EPROMs, or TMS2716 EPROMs (but these require an auxiliary -5 volt power supply which connects to the MPU board at the otherwise unused J8 connector next to the 6810 RAM at U8). Because none of these three ROM/EPROMs are common, I don't recommend any replacement but using standard 2716 (or TMS2516) EPROMs, which are commonly available and easily programmed.
Modifying a MPU-2 for "standard" 2732 EPROMs at U12, U13 and U26.
Component Side Modifications:
Solder Side Modifications:
Some files use the notation "A" (U12), "B" (U13) or "C" (U26) for the 2716 EPROM files. Also some files have an "AB" (U13) ROM which is A and B combined into a single 2732 EPROM, so the "A" (U12) ROM is not needed (additional some jumper modifications will be needed to use a 2732 at U13). The 2716 files were combined into a 2732 file using the following MS-DOS command:
3c. When Things Don't Work: The Built-In Diagnostics/Bookkeeping.
Press the Red test button inside the coin door will activate the game's audits and diagnostic functions. For this to work though the game *must* be in "game over" (attract) mode, otherwise the test switch does not respond. The number of the audit or test is shown in the ball-in-play display. If an audit, the value of that audit is shown in all four of the player score displays. If the game is left in an audit for more than 30 seconds, the MPU will go back to attract mode automatically (this applies to the audit functions only, not the diagnostic functions). Any audit function can be reset by pressing the red S33 button on the MPU board while that audit is displayed (though some games do have an audit reset button inside the coin door too).
Games With the Ones Digit Permanently Programmed to Zero.
Audit values and orders are MPU software dependent, with games designed originally with a MPU-1 starting audits at button press #5, and MPU-2 designed games starting audits at button press #1. Gameplan does have a general audit scheme that applies to many games. Also be aware that many Gameplan games have the "ones" digit permanently programmed to zero (so don't include that zero in the audit number - this does not apply to replay/high score levels). For example if Total Plays says "006210", that means there were 621 total plays. Note that replay levels are reset by the red MPU switch and can be changed by 10,000 points using the credit button.
MPU-1 Audit numbers:
The display test will put a number "0" to "9" in each and every one of the score LEDs (unless the game was programmed with the ones to be permanently "0", in this case the ones digit will always show "0"). The lamp test will flash ALL lamps on and off (if using a test fixture, all 63 lamps will flash on a LDU-2 and all 47 on a LDU-1). The solenoid test will pulse each CPU controlled coil in the game (does not energize mechanical coin counters). The switch test will show any closed switch, so it's best to have all switches open when this test is started (since the score LEDs can only show one closed switch at a time).
Attila the Hun
Sharpshooter and Sharpshooter 2
Star Trip and Family Fun
Attila the Hun
Sharpshooter and Sharpshooter 2
Star Trip and Family Fun
3d. When Things Don't Work: Locked-on or Not Working Coils (SDU).
The SDU board, or Solenoid Driver Unit board, is consists of a 74154 chip (4 to 16 line decoder/demultiplexer), a pre-driver transistor mounted in a CA3081 chip, and a SE9301 driver transistor. There is a pair of relay sockets on the SDU, but only one relay socket is populated. Gameplan was thinking ahead, and only used the second relay socket on Andromeda (additonal playfield GI lights) and Super Nova (for the roulette wheel). The flipper relay is controlled by driver transistor Q9, and the empty socket to its right is controlled by Q19. The Relay controls the Flippers, with the relay energizing for the duration of a game. Power for the board and the MPU encoded information comes from connector J3 at the bottom of the board. Connections to the playfield solenoids is through connector J1 at the left upper side of the board. And connector J2 on the left lower side is the return ground path for the flippers.
Diagnosing Coil Problems.
If the coil is "locked on" (energized) at power-on, or is not working in the game (but does fire when grounding its corresponding transistor tab), next suspect the SE9301 driver transistor. IMPORTANT: With the game's power off, remove connector J1 (upper left) from the SDU board (otherwise false readings can be seen). Now the transistor can be tested with a DMM's diode function. With the black DDM's lead on the metal tab (or center leg) of the transistor, a value of .4 to .6 volts DC should be seen with the red DMM lead on either outside transistor leg. Any value outside of that range and replace the SE9301 transistor (with a TIP102). This test is accurate about 95% of the time (note on occasion a transistor can test as 'good' with this method, and still in fact be bad). If the coil is still not working or locked-on after replacing the driver transistor, next suspect the corresponding CA3081 pre-driver transistor chip. Still a problem? The only thing left is the 74154 decoder chip.
TIP102 vs SE9301.
Game Fires the Wrong Coil or No Coil.
Regardless if the problem is happening on a Gameplan pinball, check all the connector pins on J1 (bottom right side of the SDU). If just one pin is broken, this is one bit of encoded information the SDU is not getting. This will cause the SDU's 74154 chip to decode the wrong information, and energize the wrong coil (or no coil). If all the J1 connector pins are in good condition, next suspect the 74154 chip itself.
Here's the coils generally used in Gameplan pins. Coils from other manufacturers can be used if the frame size is the same, and of course the same relative windings and wire size. Resistance should be measured from an original coil and compared to the replacement coil too (replacement coil should be within 20% of the original coil). Also remember to attach the coil voltage wire to the lug of the coil with the BANDED side of the 1N4004 diode. The non-banded diode lug of the coil is the wire that goes to the driver board's transistor.
3e. When Things Don't Work: Locked-on or Not Working Feature Lights (LDU).
There are two different SCR's used for lights on the lamp driver board: the larger MCR106-1, and the smaller 2N5060. They serve the same function, just the larger MCR106-1 can handle more current (and sometimes lights two lamps, while the smaller 2N5060 can only light one lamp). There is also a CD4514 CMOS decoder that drives the lamps. Sometimes these go bad too. The 45154 puts out an inverted input, and this drives the SCR (Silicon Controlled Rectifier) for each lamp. There are three (LDU-1) or four (LDU-2) 45154 chip on the lamp driver board. Each has a seperate clock, which is controlled by the MPU. If there are a lot of the lamps not working (16 or less), there may be a bad 45154 or the Enable wire for that 45154 is bad. The SCRs can be tested with a DMM's diode test.
Why No Lamp Matrix?
There are many styles of MCR106 rectifiers. When mounting the style without the metal face, note the ANGLE side and the mounting orientation. The angle sided C106 seems to mount "backwards", compared to the metal faced version of the MCR106 (because the manufacturer writing seem like it is on the back of the angled sided SCR). See the picture below.
If a lamp is permanently stuck on, this procedure won't tell you anything. A lamp that is always on is generally caused because its SCR has internally shorted. Replace the SCR.
Assuming the game powers on, you can test a non-working lamp's SCR's to see if it's working (this assumes you have checked the bulb, the lamp socket, and the wiring to the lamp socket).
Lamp Always On.
Testing the Lamp Driver SCRs POWER OFF.
MCR106-1 Lamp Driver SCR test:
3f. When Things Don't Work: Score Display Problems and Fixes.
Gameplan used three different styles of score displays. Most cocktails used the DDU-1 Dual Display Unit, which had two players worth of score displays on a single board. Upright pinballs used the BDU-1 Display Unit six digits displays. A few later games that used the BDU-2 seven digit displays (like Attila the Hun).
BDU-1 (and BDU-2) General Information.
The BDU-2 board is basically the same board as the BDU-1 except it has seven LED displays instead of six. There is an additional MPU-A13 transistor and 22 ohm resistor to control the 7th display. But other than that, the BDU-2 is exactly the same as a BDU-1 display board. Hence all diagnostics applying to the BDU-1 also apply to the BDU-2.
Garbage on the Score Displays.
Another cause of garbage on the score displays has to do with the +5 volt power supply. If the power supply's filter capacitor or LM323k for the +5/12 volts are failing, it can cause garbage on the score displays.
The most common problem I have seen with Gameplan score displays are locked on digits. One or two digits will burn bright and will be on all the time. This can also affect other (working) score displays and cause them look like they have a similar problem too. I like to test displays with just one BDU-1 display connected at a time because of this problem.
The MPS-A13 transistors can also be tested with a DMM's diode function. Put the red lead on the center leg, and the black lead on each of the outside legs. Again as facing the BDU-1 board, the black lead on the right MPS-A13 leg should show 1.2 to 1.4 volts. Black DMM lead on the left leg sould show .6 to .8 volts. A null reading or anything outside this range and the transistor should be replaced. But be aware I have seen a MPS-A13 test as good, but when replaced it did fix the locked-on digit problem. In this case I just used the list of above and replaced the corresponding MPS-A13 and the problem was fixed.
ULN2003 segment controls:
I have not done any work with the DDU-1, but it is similar in design to the BDU displays. Differences include using MPS-U45 transistors instead of MPS-A13's for the digit control. This was done because the U45 transistor are a more robust version of the A13, and each MPU-U45 controls two LED digits. Here's the break down:
The chips that control the segment are a pair of 74LS379 chips, a pair of 74LS48 chips, and a pair of ULN2003 chips. Again very similar to the BDU unit logic.
Can a BDU-2 be used in place of a BDU-1?
3h. When Things Don't Work: Sound Problems.
One thing I noticed on a lot of Gameplan machines is the boot up sequence causes the game to make a lot of sound board noise! In particular Sharpshooter really likes to squeal and yelp at bootup, until the 6th MPU board LED flash has occured and then the game makes a "ratatattat" machine gun type noise as its boot-up sound. This is typical of Gameplan pinballs (but obviously the boot up sounds vary from game title to game title).
MSU Boot-Up LED Flash Codes.
MSU LED N0 Flash.
MSU LED 1st Flash.
MSU LED 2nd Flash.
MSU LED 3rd Flash.
MSU LED 4rd Flash.
MSU LED 5th Flash.
MSU LED 6th Flash.
MSU LED 7th Flash.
MSU LED 8th Flash.
3i. When Things Don't Work: Miscellaneous Problems and Fixes.
Problem: Strange solenoid and/or lamp and/or souund problems where the game just
does strange and unexplainable things.
Answer: Replace a burned flipper coil with the common Bally AQ 25-500 coil. It works surprisingly well, just like the original coil.
Problem: Can I mix up interconnection plugs when assembling a Gameplan game?
Problem: I have some broken drop targets on my Sharpshooter game. Where can
I get new ones?
* Go to the Pin Fix-It Index