Data East/Sega
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1 Introduction
Data East/Sega pinball used a board set with minor differences from 1987 to 1995. This boardset, like most hardware of this generation, is very derivative of Bally/Williams System 11 hardware.
The following boards are typical of what you will find in a Data East backbox.
- RED - Power Supply
- BLUE - CPU
- YELLOW - Playfield Power Board
- GREEN - Sound Board
The first two games, Laser War and Secret Service, did not use a PPB board, and were equipped with a flipper power supply (very similar to the Williams System 7, 9, & early 11 flipper power supply). Secret Service used an MRB-1 (Mega Resistor Board) which was mounted to the back of the body of the cabinet.
There can also be two additional boards, not including satellite boards which were used such as a shaker motor driver board, a magnet control board, etc.
- Games with solid state flippers will have a flipper control board name the TY-FFASI board. This board is located on the left side of the lower cabinet. Games which have more than three flippers, Baywatch and others, use two flipper control boards.
- Display controller boards are mounted behind the displays. DMD controller boards have a separate CPU and communicate to the main CPU via a ribbon cable.
2 Games
For an extensive list of games produced by Data East and Sega, see the List of Data East Games.
The following table lists regular production games based on their circuit board (PCB) and system generations.
| Game List and Board Version | |||||||
|---|---|---|---|---|---|---|---|
| Game (Manufacture Date) | CPU | Power Supply | PPB | Display | Sound | Flipper | Notes |
| Laser War (3/87) | 520-5003-01 or 520-5003-02 |
520-5000-00 | Not used | 2x 7 digit A/N, 2x 7 digit N, 1x 4 digit N |
No PCB 3 lug coil and EOS switch |
Uses 520-5001-00 Flipper Power Supply | |
| Secret Service (2/88) | 520-5003-02 | 520-5000-00 | Not used (see notes) | 2x 7 digit A/N, 2x 7 digit N |
No PCB 3 lug coil and EOS switch |
Uses 520-5001-00 Flipper Power Supply and 520-5015-00 MRB-1 (Mega Resistor Board) | |
| Torpedo Alley (8/88) | 520-5003-02 | 520-5000-00 | 520-5021-00 | 2x 7 digit A/N, 2x 7 digit N |
No PCB 3 lug coil and EOS switch |
||
| Time Machine (11/88) | 520-5003-02 | 520-5000-00 | 520-5021-00 | 2x 7 digit A/N, 2x 7 digit N |
No PCB 3 lug coil and EOS switch |
||
| Playboy 35th Anniversary (5/89) |
520-5003-02 | 520-5000-00 | 520-5021-00 | ||||
| ABC Monday Night Football (9/89) |
520-5003-02 | 520-5000-00 | 520-5021-00 | ||||
| Robocop (01/90) | 520-5003-02 | 520-5000-00 | 520-5021-00 | ||||
| Phantom of the Opera (4/90) | 520-5003-02 | 520-5000-00 | 520-5021-00 | ||||
| Back to the Future (6/90) | 520-5003-03 | 520-5000-00 | 520-5021-00 | ||||
| The Simpsons (10/90) | 520-5003-03 | 520-5000-00 | 520-5021-02 | 2x 16 digit A/N 520-5030-00 |
520-5002-03-12 | 520-5033-00 | |
| Checkpoint (2/91) | 520-5003-03 | 520-5047-00 | 520-5021-00 | 128x16 DMD 520-5042-00 |
First pinball machine with a DMD display | ||
| Teenage Mutant Ninja Turtles (6/91) |
520-5003-03 | 520-5047-00 | 520-5021-00 | 128x16 DMD 520-5042-00 |
|||
| Batman (8/91) | 520-5003-03 | 520-5047-00 | 520-5021-00 | 128x16 DMD 520-5042-00 |
|||
| Star Trek 25th Anniversary (9/91) |
520-5003-03 | 520-5047-00 | 520-5021-00 | 128x16 DMD 520-5042-00 |
|||
| Hook (5/92) | 520-5003-03 | 520-5047-00 | 520-5021-00 | 128x16 DMD 520-5042-00 |
|||
| Lethal Weapon 3 (8/92) | 520-5003-03 | 520-5047-01 | 520-5021-00 | 128x32 DMD 520-5052-00 |
First DE usage of 128x32 display | ||
| Star Wars (12/92) | 520-5003-03 | 520-5047-01 | 520-5021-00 | 128x32 DMD 520-5052-00 |
|||
| Rocky & Bullwinkle (2/93) | 520-5003-03 | 520-5047-01 | 520-5021-00 | 128x32 DMD 520-5052-00 |
|||
| Jurassic Park (6/93) | 520-5003-03* | 520-5047-02 | 520-5021-05 | 128x32 DMD 520-5052-00 |
520-5050-02 | 520-5033-02 | Motor Control board mounted under playfield Uses a shaker motor |
| Last Action Hero (10/93) | 520-5003-03* | 520-5047-02 | 128x32 DMD 520-5052-00 |
Uses a 520-5068-00 magnet control board Uses a shaker motor | |||
| Tales from the Crypt (12/93) | 520-5003-03* | 520-5047-02 | 128x32 DMD 520-5052-00 |
520-5033-03 | Uses a shaker motor | ||
| The Who's Tommy (1/94) | 520-5003-03* | 520-5047-02 | 128x32 DMD 520-5052-00 |
520-5076-03 | Uses a servo motor board for the blinders Uses a shaker motor | ||
| WWF Royal Rumble (5/94) | 520-5003-03* | 520-5047-02 | 128x32 DMD 520-5052-00 |
520-5080-00 (2 used) | |||
| Guns N' Roses (7/94) | 520-5003-03* | 520-5047-02 | 128x32 DMD 520-5052-00 |
Uses a 520-5068-00 magnet control board | |||
| Maverick (10/94) | 520-5003-03* | 520-5047-03 | 192x64 DMD 520-5075-00 |
520-5076-00 | First usage of 'super' 192x64 display | ||
| Mary Shelly's Frankenstein (1/95) | 520-5003-03* | 520-5047-03 | 192x64 DMD 520-5075-00 |
||||
| Baywatch (2/95) | 520-5003-03* | 520-5047-03 | 192x64 DMD 520-5075-00 |
520-5080-00 (2 used) | |||
| Batman Forever (7/95) | 520-5003-03* | 520-5047-03 | 192x64 DMD 520-5075-00 |
||||
* Extra pins at CN3 for printer. See the CPU section for more information.
3 Technical Info
3.1 The Data East Board Set
Data East used several different board generations. It is important to be able to identify the different versions when performing diagnosis and testing.
3.2 Recommended Documentation
Although it is not completely necessary to fix a Data East or Sega pinball machine, having a game specific manual can be extremely helpful, and is recommended. The game manual includes detailed information such as:
- Lamp matrix mapping and location
- Switch matrix mapping and location
- Coil and flasher lamp mapping and location
- Game rules
- Unique playfield parts list including a rubber ring list and locator
- Game specific wiring connections, lamp, and coil diagrams
- Circuit board schematics
- CPU, display, and sound ROM locations
- Circuit board jumper settings
- CPU version compatibility amongst current and previous games
- Diagnostic and troubleshooting information
- Theory of operation of some specific boards
In addition to the game's service manual, Stern Pinball keeps an online archive of service bulletins for Data East and Sega. The service bulletins have some great material, and are available here.
3.3 The Wiring Color Code
Data East / Sega never adopted a color coding system. Instead, the wire color was marked accordingly in the associated documentation, (ie. a white wire with a blue trace is referred to as WHT-BLU, yellow with red is YEL-RED, black is just BLK, etc.).
3.4 Connector Designations
Data East / Sega did not use a board numbering system to any of the specific boards used in a game. In other words, documentation referred to boards as the following:
- PS = Power Supply
- CPU = CPU
- PPB = Playfield Power Board
- Sound = Sound Board
The naming convention for the connector on each board is notated as CNxx followed by a consecutive number, starting with "1" (ie. CN1, CN2. . .CN10, etc.).
According to the Data East Star Trek 25th Anniversary Pinball schematics/manual pp44; there are two connectors which do not follow the CNxx designation. These are 2F1 and 2F2 which connect to the main transformer (secondary side) at the bottom of the cabinet.
3.4.1 Burned Connectors
There are several connectors which are known to go bad after 10s of years of repeated thermal cycling of the system. The connectors become fragile; connector resistance goes up and the pins either heat up and/or melt it's housing. These connectors become an intermittant issue which can cause unexpected malfunctions which are difficult to troubleshoot. Author's Star trek machine gave intermittent incorrect sound effects and display resets.
Check the secondary transformer side connector; 2F2 which is located at the bottom of the cabinet and contains 2 sets of 6.3VAC GI illumination circuits. An example of a burned connector:
If this connector looks charred or looks like it got hot; replace it. At this time; a direct replacement for the connector is not known; however, A functional replacement can be purchased from Digikey under the following part numbers:
DigkeyPN MFG MFG PN Description
A1453-ND TE Connectivity 1-480703-0 CONN Cap 4POS 94V-2 UNI-MATE (female)
A1452-ND TE Connectivity 1-480702-0 CONN Plug 4POS 94V-2 UNI-MATE (male)
A25375-ND TE Connectivity 350551-3 CONN Socket 14-20AWG TIN Crimp
A25375-ND TE Connectivity 350551-3 CONN Socket 14-20AWG TIN Crimp
You'll need 1 of each of the first two, and there is a minimum buy of 10ea of the last two of which you'll need 4ea.
Check CN1 on the Power Supply (PS). A bad connector is shown on the right. Remove the connector. Check to ensure the rounded PCB pins are not blackened with oxidation. If the connector feels loose, it's time to replace it. An exact replacement is available. Molex part number 09-18-5121 can be acquired from Mouser.com as 538-09-18-5121 Pin & Socket Connectors PCB MIXTERM 12P.
3.5 Switch Matrix
Data East uses an 8x8 switch matrix to control all switches except the test button switches and the special solenoid switches (only games which use reflexive CPU boards). A general discussion of the switch matrix can be viewed here.
3.6 Power Supply
Data East made several revisions to their power supplies during production to support different display (small, medium, large) and flipper combinations (2, 3, 4).
Part Number 520-5000-00
This power supply was used on games with alphanumeric displays such as The Simpsons. Has +100 and -100 volts to operate the score displays. The general illumination connectors like to burn up. The fuse clips tend to crack. Although not evident with the example in the picture, pins on CN1 tend to overheat / burn too.
Part Number 520-5047-00
This power supply was used on the six games (Checkpoint to Hook) which used the smaller 128 x 16 DMD. One thing which makes it stand out at a glance are two large 10W power resistors installed on the unit. Other things which make it different from the power supply used with a "standard" 128 x 32 DMD are:
- The use of MJE340 and MJE350 high voltage transistors versus MJE15030 and MJE15031 transistors.
Part Number 520-5047-01
Rev A and B High Voltage section:
- Has no resistor R17
- The Zener diode at D10 is a 1N4764 and is tied to ground
- Zener diode D11 is a 1N4743
- Connector CN7 has three pins for unregulated 12 volts
Rev C of the -01 board has the same changes to the high voltage section as the -02 version below.
Part Number 520-5047-02
Differences from the high voltage section of 520-5047-01 Revision A and B:
- Has a resistor at R17
- The Zener diode at D10 is a 1N4743
- The Zener diode at D11 is a 1N4764 tied to ground
- Connector CN7 has five pins for unregulated 12 volts vs. the -01 version having three pins.
The -02 power supply is backwards compatible with games that use the -01 power supply.
Part Number 520-5047-03
This power supply was used for Data East games with the large format DMD display. Since the large DMD displays had their own power supplies, this board did not contain circuitry to create the high voltages DMD displays require. It provides 5, 12, and -12VDC only.
3.7 CPU Board
- 520-5003-01 (Version 1) - Reflexive
- 520-5003-02 (Version 2) - Reflexive
- 520-5003-03 (Version 3) - Non-Reflexive
3.7.1 Reflexive Versus Non-Reflexive CPU Boards
Version 1 and 2 Data East CPU boards are reflexive. Simply stated, reflexive CPU boards are boards where the 6 special coil drive transistors were enabled by a special coil switch input. These coils were typically pop bumpers and slingshots. Each assembly had its own switch, which was not part of the switch matrix, and was responsible for enabling its associated coil when closed. This implementation is almost identical to Williams System 11 Special Solenoids.
Version 3 boards are non-reflexive. Non-reflexive boards use 6 special coil drive transistors, however, the switches responsible for enabling these coils are part of the switch matrix.
Version 3, non-reflexive boards are backwards compatible, and can be used in a game which would typically use a version 2 board. Conversely, version 2 reflexive boards are not forward compatible in games which use a version 3 board.
3.8 Playfield Power Board (PPB-1)
- 50v coil board
- 520-5015-00
- 520-5021-00
- 520-5021-05
3.9 Sound Board
- 520-5002-0x series
- 520-5002-00
- 520-5002-02
- 520-5002-03
- 520-5050-0x series
- 520-5050-01
- 520-5050-02
- 520-5050-00
- 520-5050-03
- 520-5077-00 - This board is similar to the 520-5050-0x series. It was redesigned to allow up to four 27040 EPROMs for voices and sound effects. It has a different pre-amplifier design than the 5050 series, but uses the same MB3730A power amplifiers.
- 520-5126-02 - This board is very similar to the 520-5077-00 design. The power amplifier section was redesigned. It is reported that it is interchangeable with the 520-5077-00. The sound section of the later Whitestar boardset is almost a 1:1 copy of this board. Even the PAL chips are identical
3.10 Solid State Flipper Board
- 520-5033-0x series
- 520-5033-00
- 520-5033-03
- 520-5070-00
- 520-5076-00
- 520-5080-00
This board was re-engineered to use MOSFETs. It is compatible with a great many DE games via DIP settings.
3.11 Display Board
- 520-500x-00 Master Display
- Slave Boards
- 520-5004-00
- 520-5005-00
- 520-5006-00
- 520-5007-00
- 520-5014-01
- 520-5030-00
520-5042-00 - Used for the 128x16 line dot matrix displays on games Checkpoint through Hook (5 games total).
520-5052-00 - Used for the "standard" sized 128x32 line dot matrix displays on games Lethal Weapon 3 through Guns N' Roses.
520-5075-00 - Used for the large 192x64 dot matrix displays on games Maverick through Batman Forever (4 games total).
3.12 DMD Controller Board
520-5055-00 - Used with "standard" sized 128 x 32 dot matrix displays
3.13 Satellite Boards
3.13.1 Shaker Motor Board
Shaker motor board part number 520-5065-00. This single sided board is pretty simple. However, being a single sided board, it is subject to fractured solder joints on the large current limiting cement resistors. If your shaker motor is not shaking, remove this board and check for failed solder joints.
3.13.2 Magnet Control Board
520-5068-00 - Used on games such as Last Action Hero and Guns 'N Roses
3.14 Accessing Bookkeeping, Settings, and Diagnostic Modes
Solid state pinball machines typically have a built in system for audits and adjustments. Data East/Sega used two types of auditing systems. The first system was Ease-A-Just and was used on Laser War through Mary Shelly's Frankenstein. The Portals system was first used in Baywatch and was used for all machines after.
3.14.1 Ease-A-Just
The East-A-Just system is very similar to the menu system in Bally/Williams System 11 machines. The control panel is located in the cabinet just inside the coin door. The forward/reverse (green) button is an up/down positional switch and the step (black) button is a momentary switch. To enter the East-A-Just system press the step button. If the green button is in the down position the game will enter the diagnostics menu. If the green button is in the up position the game will enter the audits and adjustments menu. Diagnostics are game dependent so check your game manual for specifics. All games do have a switch test with the diagnostics section that can be used to diagnose switch problems. To exit the Ease-A-Just system hold down the Step button. This will rapidly send you to the last setting and will put the game in attract mode.
3.14.1.1 Setting Free Play
Data East machines hide many adjustments under a 'Expand Adjustments' section, including the free play adjustment. To set free play enter the adjustments section of Ease-A-Just by pressing the black button while the green button is in the up position. This will put you in 'Audit' mode. Now put the green button in the down position (reverse) and press the black button (step). You are now in the adjustments section. The last adjustment is typically 'Expand Adjustments'. Change this adjustment to 'Yes' to see many more adjustments, including free play. Adjustment values are changed by pressing the game start button. See: Expand Audits and Expand Adjustments, below.
3.14.2 Portals
To be completed. A brief explanation of the Portals system is in each game manual.
3.15 Setting the Level and Pitch of a Data East Game
+++Need to research which game this was first used on+++
4 Problems and Fixes
4.1 Expand Audits and Expand Adjustments
The Data East Audits and Adjustments settings are limited to a subset of the all that can actually be set. The "menu" can be "expanded" to review and/or change additional parameters by selecting the "Expand Adjusts" and "Expand Audits" option. When this option is presented, press the game start button. Additional Audits and Adjustments may then be accessed.
- Data East
The "Expand Adjustments" menu option. 
The "Expand Audits" menu option.
4.2 CPU Jumper Settings
There is a simple rule of thumb for J4 and J5 jumper settings. This rule applies to all games which use either the version 2 or version 3 CPU board. If two game PROM chips are used at position 5B and 5C, jumper J4 must be installed and jumper J5 must be removed. This applies to games from Laser War to Batman.
If a single game PROM chip is used at position 5C, jumper J5 must be installed and jumper J4 must be removed. This applies to games from Star Trek 25th Anniversary to Batman Forever.
The exception to the rule is Laser War. If a version 1 CPU is used in Laser War, only PROM chip 5C is used. The jumper settings should be J4, J6a, and J7a installed, and J5, J6, and J7b removed. If a version 2 CPU is used in Laser War, and PROMs are used at positions 5B and 5C, jumpers J4, J5a, and J6a must be installed. Likewise, jumpers J5, J5b, and J6b must be removed.
4.3 Fuse Clips
Data East used fuse clips on circuit boards as opposed to fuse holders. These clips are prone to cracking and causing intermittent connections. They cannot be repaired, and should be replaced when cracked. The clips do have a correct orientation. When installing them make sure the "tabs" on the portion that grasps the fuse is oriented outwards. Inserting a blown fuse between the clips when installing new ones helps with achieving the required spacing, and ensuring that the clips do not get installed "backwards".
Fuse clips are located on the power supply, playfield power board (PPB), solid state flipper board, and some of the satellite boards.
4.4 Power Driver Issues
Quickly test the TIP102/TIP122 transistors (Q8-Q13, Q23-Q30, Q39-Q46, Q72-Q79) on the MPU:
- Turn the game OFF
- Set your DMM to Ohms/Continuity buzz
- Attach the black lead to one of the metal grounding straps (crocodile clips are helpful here), there should be one in the backbox you can use
- Touch the red lead to the metal tabs of the TIP122/TIP102's
- Any that read 0 Ohms (ie are shorted) are bad and will need replacing.
You may also need to replace the predriver transistor (2n4401) that the bad transistor is connected to. It is also wise to check the wiring and the coil before powering back on, otherwise you may blow the transistor you just replaced.
See Testing a coil
4.5 PPB Board Issues
Common issues include:
- Burnt GI connector #Burned_Connectors
- Dead TIP36C
- Bad / broken fuse clips
4.6 MPU Boot Issues
4.6.1 Relocating the battery from the MPU board
Relocating the 3xAA batteries off the MPU board is always a good idea. Leaky alkaline batteries are the #1 killer of pinball boards.
The best option is to install a remote battery holder, and place the battery holder somewhere below all the other boards. This ensures that even if the remotely located batteries leak, they won't leak onto (or even drip onto) components of the MPU board. Use good quality alkaline batteries, mark the date of replacement with a Sharpie, and replace the batteries annually.
Adding a connector between the battery pack and the MPU board is a good idea. In doing this, the battery pack can easily be removed from the MPU board. Plus, if the batteries are forgotten, and do leak, the MPU board will not have to be removed to add another battery pack. A 3 x AA battery holder is the typical recommended replacement. If only a 4 x AA battery holder is available, a jumper can be soldered in the first battery position. Likewise, a diode can be placed in this position instead. This will prevent the batteries from being charged and 'cooked' by the game if blocking diode D25 on the MPU board fails. Keep in mind that an added secondary diode to this circuit will decrease the voltage passing to the RAM memory, if D25 is still good. Install a 1n4001 or 1N4004 diode in the position closest to the last + terminal (where the Red Wire exits). The banded side of the diode must be pointing in the direction of current flow, which is towards the (+) terminal marking on the MPU board, and away from the battery pack.
On the MPU, solder the battery cables: positive (red wire) to the bottom right pad and ground (black wire) to the middle right pad.
After adding a remote battery pack, and while the board is still out of the game, it is a good practice to measure the battery pack's voltage at the B+ test point on MPU board. All battery packs are pretty cheaply made, and failures "out of the box" are somewhat common. Checking to make certain the battery pack is functioning before reinstalling the MPU board in the game will save some headaches.
Since the MPU board is already out, another good practice is to check the D25 blocking diode. An open blocking diode will not allow the battery pack voltage to pass through to the non-volatile memory, and the newly installed battery pack will be ineffective. Conversely, a shorted blocking diode will allow the board's +5vdc logic power bus to pass through to the battery pack. This in turn, will charge the batteries, while the game is turned on. Alkaline batteries do not like being charged. They will heat up, and fail prematurely, (rather quickly). In worse cases, the new batteries can even leak or explode if charged. Testing the D25 diode is quick and easy, and worth the trouble checking it out. When in doubt, replace the D25 diode with a 1N4148, or add a secondary 1N4004 to the battery pack. Once again, if a secondary diode is added, it will decrease the voltage passing to the RAM memory, if D25 is still good.
Testing the D23 diode is a good idea too. The D23 (1N5817) diode is used to keep the backup batteries from powering the MPU board when the power is off. Evidence of a failed D23 diode are batteries which fail prematurely.
4.6.2 Data East CPU Board LED Flash Sequence
Much like the Williams System 11 CPU, the Data East CPU performs a basic diagnostics procedure and produces a series of LED flashes to indicate potential boot issues. The CPU automatically tests the PIAs, RAM and EPROMs at each boot.
With all tests passed, the LEDs illuminate in the following sequence at power-on:
- The PIA and +5V LEDs illuminate immediately
- Approximately 1/2-second later the PIA led is turned off and the Blanking LED illuminates
- +5V and Blanking LEDs are illuminated until the game is turned off.
- If a failure is detected on major board components, the PIA LED will display a flash code:
When the PIA led stays on do not assume that one of the 6821 PIAs is bad. A boot failure due to a completely unrelated error might just have occured. If you bench test the board you can also use WMS System 11A to 11C roms to check it out. The diagnostic routine is much superior to the one in the DE rom. If you use WMS U26 and U27 roms J4 must be set. You can combine both roms into a 27512 in which case J5 needs to be set on the DE CPU. Everything will work. Some of the special solenoids are connected to different pins but for bench testing who cares? V2 and later DE boards use a 8K ram. The WMS software will not be able to dectect errors in ram space above the 2K limit.
| PIA LED Flash Sequence | ||
|---|---|---|
| PIA LED | Suspect Component | Location |
| Stays On | One of the 6821 PIAs | various |
| Flashes 1 Time | 6064 RAM | D5 |
| Flashes 2 Times | EPROM | B5 |
| Flashes 3 Times | EPROM | C5 |
4.6.3 Stuck Low Blanking Signal
4.6.4 Stuck Low Reset Signal
4.6.5 Connecting a Logic Probe to CPU Board
Data East CPU boards have the +5V and ground test points located just above the battery holder's upper right corner and to the left of connection CN17. Connections can be made to the appropriate pins on CN17, but it is much easier just to use the test points.
4.6.6 Using a PC Power Supply for Bench Testing
The only voltage needed to power a Data East CPU on the bench is +5VDC. Data East CPU boards have the +5V and ground test points located just above the battery holder's upper right corner and to the left of connection CN17. Connections can be made to the appropriate pins on CN17, but it is much easier just to use the test points.
4.7 Power Supply Issues
The Data East Power Supply is very similar to the Williams System 11 Power Supply. It creates (or passes on) all of the voltages necessary for the game to operate, including...
- 5 and 12VDC for the MPU
- 5, 12, 68, -98, and -110VDC for the Dot Matrix Display (for DMD equipped games)
- 18VDC for the lamp matrix
- 34VDC for coils
- 6VAC (or so) for general illumination lamps
- 5, 12, and -12VDC for the sound board
The power supply also contains a 24VDC relay used to turn general illumination on/off.
The 5VDC power circuit explained (in work)
- The board receives about 9VAC at CN1, pins 10 and 11.
- 9VAC is full wave rectified into about 12 and -12VDC by the bridge rectifier at DB1.
- The 9VAC continues to capacitor C2, a 100uf/25V electrolytic cap that is used as part of a voltage doubler circuit that provides operating power for the 723 regulator. D2, D3 and C3 comprise the remaining components of the Greinacher type voltage doubler. Failure of any of these four components will cut power to the LM723 regulator and affect 5VDC operation.
- Unregulated 12VDC is presented to the LM723 5V regulator at pins 11 and 12.
- R6 is used for short circuit detection. Under ideal conditions (output not shorted or overloaded), there should be a very small voltage drop across R6. If the power supply is shorted -- there will be a large voltage drop across R6. Pin 3 of the regulator will detect the difference and turn down the series pass transistor TR5 in the presence of a shorted output.
- R2 and R3 are connected to the LM723 in a voltage dividing configuration. R2 and R3 together with R4 establish the output voltage levels (5VDC)
4.7.1 Missing 5VDC
A common reason for the lack of 5VDC is failure of the capacitor at C2. This 100uf/25V cap sometimes fails and begins to leak it's contents onto the circuit board. After a period of time, the caustic contents of the cap begin to eat into the board's copper traces. Eventually, the 5V generation path is severed.
The picture at left shows the 5VDC trace completely severed by the hungry caustic leakage from C2.
Note C2, circled in the schematics at left, and it's position in the 5V generation path. It's failure interrupts the path.
Another common cause for loss of 5VDC power is failure of the LM723 regulator. Measure and compare the DC voltage at pins 4 and 5 of the regulator relative to board ground. If the voltages differ, the regulator has failed. Socket and replace the regulator.
4.7.2 Burned Connector Pins
The 12 position "wafer" connector (CN1), which provides AC power input from the transformer secondary, often ends up with burned pins. Complete replacement of this connector is recommended should it become burned. The female housing may be reused, but it's good practice to repin both sides of a burned connector.
In a pinch, "male" header pins on the CN1 wafer may be swapped with "male" header pins at CN2, pins 1, 2, 4, or 5, as those pins are never used.
Data East general illumination power connectors, like many other game systems, tend to burn from long hours of continuous use at current levels higher than the connectors can handle. These connectors are caught in a death spiral of heat & tarnish which increases resistance, which increases current draw, which increases heat and tarnish, etc.
The only sure correction for these connectors is complete replacement of both the male and female connectors.
4.7.3 Low 5VDC and game resets
If you have a low +5v, you'll experience game resets, especially when pressing the flippers during multiball. A 'shotgun' repair would be to replace...
- bridge rectifier (DB1, CM3501),
- C2 (100uf 25v),
- C3 (47uf 63V),
- C7 (330uf 25V),
- LM723 voltage regulator,
- TR5 (2N6057) on the power supply board (use 2N6059 or 2N6284 to replace obsolete 2N6057),
- C1 (1000uf 25V) can also be replaced when you have problems with the -12V supply too.
Most times, this will correct problems with the 5VDC power supply
4.7.4 PS 520-5047-01 - High Voltage Missing at the DMD display
4.7.4.1 No +68v is found at the DMD display
Warning Be extremely careful not to touch anything when working on live High Voltage (HV) circuits.
Assuming it's not the transfomer, connectors or fuses then you should be able to measure a +DC High Voltage (HV) at the banded side of D5 with respect to GND.
If no voltage there, suspect fuses and then test D5 on the diode setting and replace D5 with a 1n4004 diode. Also test, and replace D7 with a 1n4004 diode at the same time for good measure as it's a penny part and probably stressed. Same procedure although it rectifies the a -DC HV.
Measurements are with respect to ground. You should now have a HV +DC reading at the banded side of D5. Test for +68v output. You should also have a HV -DC reading at the non-banded side of D7. Test for -100v and -98v DC output.
Do not be concerned if measured voltages are not exact without a DMD connected, they will read lower under load. It can also be that the DMD display itself is faulty and taking down the PSU.
Capacitors C10 / C11 are important, if you can't test then replace them. Especially if it looks to bulge at ends, old capacitors dry out and then fail. C10 and C11 are both 100uF @ 200v. You should be able to use 150uF at a higher voltage for these, so 150uF @250v is fine.
- Observe the polarity of the capacitors you remove and mark with a Sharpie if not already indicated on PCB mask. This is very important for Electrolytic capacitors which have a polarity!
D5 / C10 are for the +68v HV DC to the DMD Display. D7 / C11 are for the -98v and -110v HV DC to the DMD Display.
- The circuit for +68 voltage is comprised of components under CN5 / CN6 of the Power Board (PSU).
| +68v circuit | |||
|---|---|---|---|
| Part | Description | Location | Eqivalent |
| MJE340† | NPN transistor | TR3 | MJE15030 |
| MPSA92 | PNP transistor | TR1 | available |
| 1n4760B | 68v zener diode | D9 | available |
| 1n5228 | 3.9v zener diode | D6 | available |
| 1n4004 | diode 400v @ 1A | D5 | available |
| 47K | resistor 1 Watt | R8 | available |
| 330K | resistor 0.5 (1/2) Watt | R11 | available |
| 1.5K | resistor 0.5 (1/2) Watt | R12 | available |
| 500 ohm | resistor 10 Watt Ceramic | R15 | available |
| 100uF @200v | Capacitor | C10 | e.g. 150uF @250v |
- † The MJE15030 is a heavy duty version of the MJE340 (TR3)
Check values of the above resistors. Any out of spec. (or showing open) will need to be replaced first. Test DMD again. Then replace the 1N4760 68v and 1N5228 3.9v zener diodes and test DMD again. Then work through the transistors, replacing TR1 then TR3 test the DMD.
4.7.4.2 No -100v is found at the DMD display
Follow a similar procedure to the one above. The plus and minus HV circuits are nearly 'mirror images'.
A missing -98v DC output only while reading -100v points to D11 (1n4742 12v zener diode) or R14 (4K @ 10W ceramic resistor) as faulty. Test resistor value R14 and replace if open or out of spec. Then replace D11 observing banded side for polarity.
The Circuit for -100 and -98 HV voltages are comprised of components under CN5 / CN6 of the Power Board (PSU).
| -100v / -98v circuit | |||
|---|---|---|---|
| Part | Description | Location | Eqivalent |
| MJE350† | PNP transistor | TR4 | MJE15031 |
| MPSA42 | PNP transistor | TR2 | available |
| 1n5379b | 110v zener diode | D10 | available |
| 1n5228 | 3.9v zener diode | D8 | available |
| 1n4004 | diode 400v @ 1A | D7 | available |
| 47K | resistor 1 Watt | R9 | available |
| 330K | resistor 0.5 (1/2) Watt | R10 | available |
| 1.5K | resistor 0.5 (1/2) Watt | R13 | available |
| 100uF @200v | Capacitor | C11 | e.g. 150uF @250v |
- † The MJE15031 is a heavy duty version of the MJE350 (TR4)
Check values of the above resistors. Any out of spec. (or showing open) will need to be replaced first. Test DMD again. Then replace the 1N5379B 110v and 1N5228 3.9v zener diodes and test DMD again. Then work through the transistors, replacing TR2 then TR4, test the DMD. Get the -100v output working first, then go after the -98v circuit.
| -98v circuit only | |||
|---|---|---|---|
| Part | Description | Location | Eqivalent |
| 1n4742 | 12v zener diode | D11 | available |
| 4K | resistor 10 Watt Ceramic | R14 | available |
4.8 Lamp Issues
4.8.1 General Illumination Issues
The single largest issue with general illumination lighting in Data East games, like Williams System 11 games, is burned GI connectors at the power supply. Repinning both sides of the connector is the best solution. Be sure to use "trifurcon" crimp pins in the female .156 9-pin connector housing.
| Wire Color at CN8 | |
|---|---|
| Brown | |
| Yellow (yellow) | |
| Green | |
| Violet | |
| Key | |
| White-Brown | |
| White-Yellow (yellow) | |
| White-Green | |
| White-Violet |
General illumination power is sourced at the power supply. AC power comes in via a 4-pin connection at CN9. A GI relay cube on the power supply is used by the game to switch all GI power on/off. GI power is routed through the PPB board to add fuse protection and nothing else. The power enters the board at J5. Each of the 4 separate GI power lanes is fused on the board. GI power then exits the board through the same connector (J5).
The male connector on the PPB board is subject to cracked solder joints since the board is single sided only. If you are experiencing GI issues, in addition to checking for burned connectors, wiggling the GI connection at the PPB board will sometimes identify the source of the problem.
Data East also used "Z connectors" instead of the more typical "cube" molex connectors. The example at left shows an extremely toasty GI connector between the backbox and the backbox lamp insert panel. Correct this by removing the connector completely. Solder each wire directly together, using heat shrink tubing to insulate. This connector facilitated cheap/fast manufacture and serves no purpose now, unless the user wants to remove the lamp board insert, which is highly unlikely.
4.8.2 Controlled Lamp Issues
4.9 Switch Issues
Data East machines have switch testing built into its diagnostics. If a switch has not been activated in a while (typically 50 games) the machine assumes the switch is bad and displays a message when powered on. Sometimes this message can appear because a working switch hasn't been activated during play. You can manually activate the switch to clear this message.
Data East uses a switch matrix to control all switches except the test button switches and the special solenoid switches. A general discussion of the switch matrix is discussed elsewhere in the PinWiki.
4.9.1 Single Switch Issues
- For micro-switches, make sure the switch lever still works. You should hear a faint "click" when the lever is moved and the switch is activated. You can sometimes form (bend) the switch lever to make the switch require less travel to activate a closure. Note that these switches can still be bad even when the click is audible. The best thing to do is put your machine in switch test mode and manually actuate the switch. If the game does not report the switch closure 100% correctly, replace the switch and the diode. The micro-switch (180-5064-00) on the Vertical Up Kicker (VUK) can wear out. A replacement can be sourced from DigiKey as 480-2381-ND from Honeywell Sensing (MFG PN# V7-1C17D8-048).
- You can use a multimeter instead of the machine's built in switch test to test the switch.
- Set your DMM to continuity.
- Place one lead on the common lug (it should have the banded end of the diode)
- Place the other lead on one of the other lugs.
- The continuity setting should change when the switch is activated.
- Move the DMM lead not on the common lug to the remaining lug.
- The continuity should change and work in the opposite manner.
- Note that this test only tests the switch itself, not the circuitry responsible for reacting to a switch closure nor the wiring between the switch and other components.
- For leaf switches, make sure the contacts are adjusted properly. You can clean the contacts with a business card by putting the card between the contacts, closing the switch, and quickly removing the card.
- Check the diodes for correct orientation and that they are connected correctly. Typically the banded end of the diode goes toward the lug farthest from the common lug. Check your game's manual to be sure. Diodes do fail, but rarely. 1N4001 diodes can be replaced with 1N4002 thru 1N4007 diodes.
4.9.2 Complete (or most of a) Column/Row of Switches Not Working
If a complete column or row of switches are not working, determine first if the problem is on the CPU or out on the playfield.
If the problem is on the playfield, then it is likely that the column/row wire is broken or the connector is at fault. Following are several techniques you can use to find the fault.
- If a complete row/column is out, then either the female connector is bad, or the wire is broken prior to the first switch as physically wired in the game. Note that "physical" wiring order will almost certainly differ from the schematics.
- If something less than a complete row/column is out, then a wire is broken between two of the switches. Track the wire color from one switch to another or use your DMM to "buzz" between switch solder lugs of two switches. This can help you narrow the search.
4.9.3 On Board/Off Board Switch Matrix Problem Determination
The first step in diagnosing a switch matrix problem is to determine whether the problem is on the MPU or somewhere in the game wiring. Testing MPU switch matrix operation is simple.
- Remove CN8 and CN10 from the MPU.
- Power the game on.
- Place the game in switch test.
- Using a short length of wire with a clip on at least one end, jumper pin 1 to pin 1, then pin 2 to pin 1, etc.
- Each time you jumper a pin, a single switch closure should be reported.
- If the game reports only a single switch closure each time you jumper two pins, your MPU is working fine.
- If the game reports multiple switch closures when you jumper two pins, then your MPU switch matrix has been damaged, probably by shorting high voltage to either a switch matrix row or column on the playfield. Reminder...never risk shorting high voltage to the switch matrix by working on the game with power on.
4.9.4 Multiple Switches Reported from a Single Switch Closure
If pressing a single switch in switch test causes the game to report multiple switch closures, determine first if the problem is on the CPU or out on the playfield.
If the problem is on the playfield, inspect the likely switches to ensure that none are shorted to themselves. Check to make sure that the leads do not touch or have not been bent together and that the diode is not shorted against the common lead, as shown in the picture at left.
4.9.5 Periodic "Random" Slam Tilts
Thanks to a couple of folks on RGP for posting this one and to Cliffy for the picture.
Games with playfield hangers and elevated ball troughs (ball trough is located above the playfield) similar to Star Wars, Lethal Weapon 3, Hook, etc. may "slam tilt" unexpectedly. The cause of this is a playfield hanger screw that backs out, makes contact with the lower switch lug, and completes the path to ground for the switch. This causes a "sneak circuit path" in the switch matrix and results in slam tilts as well as other switch anomalies.
4.10 Score Display Issues
Early Data East pinball machines used alpha-numeric score displays similar to those in Bally/Williams Machines. Data East was the first pinball manufacturer to use a dot matrix display (DMD) in a pinball machine, and had three different generations of the display. Starting with Checkpoint and running through Hook, Data East used a 128x16 score display. Williams first used the common 128x32 display in Terminator 2, and Data East soon switched to this display size for the majority of their machines, (from Lethal Weapon 3 until Guns N' Roses). Data East then switched to the larger 128x64 display. This display was used in only four Data East / Sega games including: Maverick, Frankenstein, Baywatch, and Batman Forever.
- Outgassing Displays
- DMDs have a lifespan and will eventually fail. It is important to replace an outgassing display because they will strain your power supply, and eventually damage that as well. Signs of outgassing displays are that areas of the display need to 'warm up' before becoming fully bright or that the display will remain completely blank for a few seconds and then appear normal.
- A side note to the display issues taking some time to light. There are cases of import machines having a circuit to delay the DMD appearing after the machine was turned on before diplaying. This was done by some operators so that serial number and location information was not shown when the machine powered on. This circuit will not damage anything but is not standard. More information about this can be found in a rec.games.pinball discussion.
4.10.1 Alphanumeric Issues
To be completed. Please contribute.
4.10.2 Dot Matrix Issues
Although Data East board designs share many similarities between Bally/Williams, the score display CPU is implemented very differently. Data East has a separate board and CPU for controlling the dot matrix display (DMD). This board is mounted behind the DMD on the score panel. The main CPU and this daughterboard communicate through a ribbon cable. Because of this, it is important that your CPU and display roms are the same version, or are in sync with each other. Running different ROM versions can cause some strange display issues. Ribbon cables are known to have faults, so reseating or swapping the cable may fix some issues.
4.10.2.1 128x16 (Small DMD) issues
The 128x16 DMD was the first DMD used in a pinball machine and was used for five games. It was replaced by the much more familiar 128x32 display.
Sometimes this display will light but the display will appear garbled. The display will flicker and move but the output will not be readable. This can be caused by the R95 resistor on the DMD controller board going out of spec. It should be a 33k 1/2 watt resistor.
4.10.2.2 128x32 (Regular DMD) Issues
The 128x32 DMD was used in the majority of Data East machines and was the only size used by Bally/Williams. The display glass is the exact same version for both Data East and Bally/Williams and can be used as a drop in replacement. However, you will still need the DMD controller board used by Data East machines.
Some games such as Lethal Weapon 3 and Star Wars sometimes used two 27020 EPROMs at locations U12 and U14. You can use one EPROM instead if upgrading to newer code. If one EPROM is used, R11 should be open (nothing installed). This part can simply be cut off the board. If two EPROMs are used, R11 should be jumpered with a zero ohm resistor or a jumper wire. Why Data East called this a resistor (R11) vice a jumper, is anyone's guess. This is discussed in service bulletin 38B.
It is worth mentioning that if two 2MB EPROMs are used, and the R11 zero ohm jumper is not installed, the DMD will remain blank.
High voltage for the DMD is located on the PSU board.
Connection CN2 on the DMD controller board can sometimes be problematic. This is a three pin connector, and only two of the header pins are used for the +5vdc and ground. It is always a good practice to upgrade the connector pins in this housing to Trifurcon connectors. Using Trifurcon connector pins will help ensure that a more solid connection is made at CN2. Unfortunately, the existing connector housing is not reusable, and will have to be replaced when the connector pins are upgraded.
4.10.2.3 128x64 (Large DMD) Issues
The large 128x64 DMD was used in the last four Data East pinball machines. The display is a relatively expensive part to replace, costing several times as much as the more standard 128x32 DMD.
One of the most common issues with this display is that it will periodically go blank or reset the CPU. These issues are typically due to the logic power needed to drive the DMD controller board chips dropping below the required +5vdc. As Stern mentions in their service bulletin, the controller board runs at +5vdc, and "'likes' its 5 volts or darn near close". To overcome the issue, Stern offers an optional wiring harness to increase the reliability of the +5vdc logic power by pulling the +5vdc from an otherwise unpopulated connector on the power supply. A detailed discussion of the kit can be found in Stern service bulletin 106.
4.11 Coils
4.11.1 Flipper Issues
Data East was the first company to use solid state flippers. Starting with Playboy 35 Anniversary, Data East flippers began using a single wound coil instead of the high/low windings found in earlier games and Bally/Williams games. This single wound flipper coil design was developed by Kurt Deger, and is commonly referred to as the Deger design. Although it has gone through some transformation over the years, it is found in most of the Data East games. Service Bulletin #62 contains a listing of flipper coil parts for Data East games and shows the evolution.
The patent for the original Deger design can be viewed here.
When a Data East flipper is energized, 50 volts is sent to the coil for the initial flip. The FFASI board then drops the voltage to 9 volts so that the flipper may be held up for a long period of time without burning the coil. This voltage drop occurs after 40 milliseconds, is CPU controlled, and cannot be adjusted. This is similar to the Bally/Williams WPC FlipTronics II design where the flipper hold is controlled by the FlipTronics II board. Still, many note a different feel between Data East and Bally/Williams flippers.
Data East eventually did add an EOS switch to its flipper design beginning with Jurassic Park. This does differ from Bally/Williams in that the switch is normally closed in Data East games. This was done because certain game features fired the ball quickly back to the flippers. If the ball hit the flippers and moved them 1/16 of a inch the EOS switch would open and 50 volts would again be delivered to the flipper. This is discussed along with the general theory of Data East flipper operation in service bulletin #49. With this design if the hold voltage is broken and the EOS is badly adjusted, you may experience 'machine gun flippers'.
These flippers are controlled by the solid state flipper board (TY-FFASI board) which is mounted in the cabinet. The board is prone to a few failures, but it's a fairly simple circuit so fixing it is normally quite easy. You should see a red LED illuminate briefly when the flipper buttons are pressed.
To test the flipper board:
- Remove the board from the cabinet (it's much easier to work on)
- Check all the fuses on the board, 4 in total (2 power, 2 hold). Also check the fuse clips.
- Check all transistors using a DMM
- Check tracks for continuity and corrosion
- Replace board back into cabinet and power on game
- Enter Diagnostics (so power is sent to the flippers)
- Check for 50VDC at the coil lugs (DMM set to DC volts, black lead on game ground, red lead on banded side of coil diode)
- Press flipper button and check for about 8VDC hold voltage
- Check power/hold voltage on flipper board (DMM set to DC volts, black lead on game ground, red lead on CN2 pins 6&7 (8VDC hold), CN2 pins 8&9 (50VDC power stroke)
If you have no voltage on CN2-8 and CN2-9, check the PPB board J7-1 and J7-5.
If you have no hold voltage on CN2-6 of the flipper board, check the Power Supply board CN1-10 and CN1-11. If you have no hold voltage on the coil lugs, check the hold fuses on the TY-FFASI board.
- The newer 520-5080-00 (EOS) flipper board can be modified to work in games requiring the 520-5033-00 (non-EOS) flipper board. Steps to do this can be found in Service Bulletin #103.
4.11.1.1 Flipper Repair and Rebuilding
A major contributor to weak flippers in any game, including Data East, is a damaged or "hogged out" flipper link. The picture at left shows a flipper link with about 1/8" of "slop" in it. When the flipper coil pulls the plunger in, the flipper crank doesn't begin to actuate the flipper until all of the slack caused by this slop is taken in. At the very least, replacing the link is warranted.
A flipper rebuild is one of the easier things you can do to improve the playability of your machine. Over time the parts of a flipper will wear and need replacing. Signs of this include weak or slow flippers, flippers that do not return quickly, or flippers that travel too far. An experienced repairman can just replace the needed parts but it is far easier to buy a flipper rebuild kit from a pinball supplier. These kits will contains all the parts needed for a general flipper rebuild. Flipper coils are not included in rebuild kits but are not typically needed for a repair.
Some parts are interchangeable between Data East and Bally/Williams flippers due to the similarities in design. For example, coil sleeves, links, and plungers are the same. However the flipper bushings and coil stops, although appearing similar, are not compatible. Buying a complete flipper rebuild kit for your machine will ensure you get all the correct parts.
Below are the steps to rebuild an early Data East solid state flipper. This guide does not currently address the additional steps needed for replacing or adjusting EOS switches.
- Remove the coil stop.
- Pull the coil away from the flipper assembly. Typically the coil does not have to be replaced, so desoldering the leads is not necessary. Remove the plastic coil sleeve from the coil. This should slide out somewhat easily, but a nut driver can be used to push it out. If you cannot remove the sleeve it may have warped due to heat issues. If this is the case, replace the coil. Always replace coil sleeves when rebuilding flippers.
- Remove the return spring.
- Loosen the allen screw that holds the flipper shaft in place. The flipper can now be removed from the top of the playfield. Remove the plunger and link assembly.
- Replace the rubber stopper where the link assembly rests.
- Clean the metal parts of the flipper assembly.
- If your existing flipper has one, remove the spring holder and put in on the new link assembly. Attach one side of the new return spring to the spring holder.
- Replace the flipper from the top of the playfield.
- Loosen the flipper bolt and replace the plunger/link assembly. Do not tighten this yet.
- Attach the other end of the return spring.
- Assemble the coil. Be sure to put the end with the lugs away from the coil stop.
- Replace the coil stop and the spring washer.
- Adjust the flippers from the top of the playfield. On Data East machines the guide holes align with the tip of the flippers. Tighten the allen screw on the link assembly to hold the flipper shaft in place.
As mentioned above, some Williams flipper parts can work in Data East games. In the picture at left, a Williams plunger/link/crank assembly and EOS switch have been substituted. To make this work, the EOS "finger" on the crank must be bent straight and the EOS switch position must be adjusted. It works surprisingly well. The feel is very solid.
It is worth noting that Data East games which use a solid state flipper board, and have upper flippers, do not EOS switches on these flippers. If an upper flipper appears to be missing the EOS switch, it actually is not. This is an intended design.
4.11.2 Ball Trough Issues
Starting with Jurassic Park, a different type of ball trough is used. This ball trough is mounted below the plane of the playfield versus the old style, which is mounted above the playfield. The main purpose of this trough is to allow the storage of more pinballs in the trough. However, there are a whole new list of potential problems that come along with this design.
4.12 Memory Issues (Open The Door message)
You may recieve a message when turning on the game to 'Open the Door'. This is because the game sees that the RAM information is invalid. The game should boot normally after opening the coin door. This is most likely due to the dead batteries on the CPU. The first step is to replace the batteries and make sure there is no corrosion. If corrosion is found, fix those issues first before continuing.
The next thing to check is diode D25 just to the right of the batteries. To test this, set your multimeter to DC Volts, but the black lead on the ground test point near the top of the board, and the red lead on the banded side of diode D25. You should read close to 4.2 volts. Now move the read lead to the non-banded side of the diode. You should read close to 4.6 volts. Move your red lead to test point B just to the right of the diode D25. You should also see close to 4.2 volts. If any of these readings are significantly different replace the diode.
Finally, check for 4.2 volts on the bottom right pin for RAM 5D. This chip will be right below the game ROM. Also, make sure this RAM chip is securely seated. The chip can sometimes become loose when the game ROM is changed due to it's proximity on the board. If all these steps are done and you still get the 'Open the Door' message you will need to replace the RAM chip at location 5D.
5 Game Specific Problems and Fixes
Please see the game specific pages for game specific problems.
6 Repair Logs
CPU Board Repair
Data East Power Supply Rebuild
6.1 Delayed or Missing Blanking Signal
Time Machine CPU board - blanking signal would go high approximately after 7 seconds or more, (if it went high at all), after PIA diagnostic signal would go low (PIA LED would go out). For a properly functioning CPU board, the blanking signal should go high immediately after the PIA signal changes its state from high to low.
Resolution: a bad AMI 6808 CPU chip. Beware of failing AMI chips. It is rumored that AMI chips have higher failure rates than most other manufacturers. This ultimately was a simple fix, but after extensive troubleshooting was performed first. This particular fix is more of an exception than the rule. Generally, a missing blanking signal should be isolated to the blanking generator circuitry (555 timer chip, 2N4403, etc.).
6.2 Incorrect Flipper Pawl Screw Installed
Jurassic Park, but applies to other games
This falls under the "not too often category", but it is worth mentioning. The screws used to tighten the flipper pawls have a dual duty. They of course secure the flipper pawls to the flipper bat, but they also open the flipper EOS switch.
There were two problems with flippers on this game, as can be seen in the pic on the left. First, the screws used were Phillips head screws. A Phillips head screw does not allow for enough torque to adequately secure the flipper pawl to the flipper bat shaft. The factory screws used are #10-32 x 3/4" hardened steel socket head hex Allen screws. In using an Allen screw, chances of stripping the head are minimized, and much more torque can be applied when tightening. The second problem was that the replacement flipper pawl screws were too long. By using a longer screw, it messes with the solid state flipper board's timing, because the EOS switch is opened prematurely. The end result was a weak spastic flipper.
Resolution: Installed the proper #10-32 x 3/4" hardened steel socket head hex Allen screw on both flipper assys.