Williams System 3 - 7

Note: This page is a work in progress. Please help get it to a completed state by adding any useful information to it.

1 Introduction

Williams entered the SS (Solid State) era with a conversion of a 1976 Williams EM (Electro Mechanical] pinball game called Grand Prix.

It is thought that 4-5 games were converted to solid state prototypes using the new WMS System 1 MPU and digital displays.

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Next was a 10 unit run of another 1976 EM game called Aztec. The SS version of Aztec is considered to be WMS System 2 and is also very rare. Both System 1 & 2 happened right at the end of 1976. It was a hybrid machine still retaining the EM chime unit in the cabinet for sound and a credit window and EM reel behind that on the backglass. The player scoring was digital.

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System 3 games were the first Williams SS production games, starting with Hot Tip in Nov. '77 and ending with Disco Fever in Aug '78. There were based on the Motorola 6800 8-bit CPU and using an MC6820 PIA (Peripheral Interface Adaptor) to handle the Display I/O from the MPU board. They also had three other 6820 PIAs (the same type) on the Driver Board for the Switch inputs and the Lamp and Solenoid outputs (Solenoid drives were mainly for the Coils at this point, a few triggered sound calls).

During System 3 (Phoenix, Disco Fever) a memory protect circuit modification was added as to help protect CMOS RAM data during power up and power down of the game. DIP switches were being used to set game settings (such as # of balls per game, high score replays).

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System 4 games ran from Pokerino in Nov '78 through to Stellar Wars in Mar '79. A notable game just before Stellar Wars was Flash (another Steve Ritchie designed game and one that outsold all of the other System 4 games combined with a production run of 19,505. During System 4, Williams moved from using DIP switches to change game settings to having the game settings changed from the coin door switches. The settings were still stored in battery protected CMOS RAM. [ed Note: Citation needed ? - I'm fairly sure this is accurate] A coin door interlock switch enforced that CMOS memory could not be modified unless the coin door had been opened by the operator. Some of the game audits (coins accepted, total number of games played, etc.) still could not be changed without access to the MPU board behind the backglass.

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System 6 games ran from Tri-Zone in Jul '79 to Scorpion in Jul '80. two notable games from this era were from the end of '79 and the beginning of '80 Gorgar and Firepower. Gorgar (14,000 produced) was the first talking pinball, and Firepower (17,410 produced) both talked and introduced the 'Lane Change' and 'Multiball (tm)' features to SS games. Note that there had been muliball play available in EM games, this is a common misunderstanding. The features these games introduced became standards on almost all pinball games produced to right up until today.

System 6a deserves to be mentioned here as it marked a transition to System 7. The game Alien Poker from Oct '80 used the Syatem 6a MPU board (which was not very different from System 6). But it supported 7 digit scoring displays and a redesigned Master Display Driver board, located behind the backglass on the back of the 'Lamp Board'. It also used a special 4 digit "credit/match" display in the approximate position where the System 6 Master Display Driver had been showing the same information (on a 6 digit display, with 2 of the digits unused). This new 7 digit scoring displays with a 4 digit credit/match display were then used in all the System 7 games (and System 9).

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System 7 games ran from Black Knight in Nov '80 through to Star Light in Jun '84. Complete System 7 Game list

Black Knight (13,075 produced) introduced a two level playing field and Magna-Save (tm) where the ball could be stopped from draining down the sides by pressing a cabinet button that activated an electromagnet. Star Light (100 produced) was almost a 'botique' game by Williams' standards as the focus was then on System 9 and prodiction of Space Shuttle. At least one Star Light game was used as a Prototype for System 9.

System 7 was considered a step change. It had a redesigned MPU board, now supporting a single 7-segment display for improved diagnostic information, instead of the original 2 LEDs that system 3-6a had used. It also added commas to the player scoring displays and moved the sound select support to the MPU board. An extra 6821 PIA supported both the sound/speech selects and the display of commas. An extra 12-pin header at 1J8 was added to provide connections for the new Sound and Commas support. This freed up five solenoid drives at positions #9-13 on the Driver board, which had been sound/speech selects. They were then available to drive extra game Coils or Flashlamps.

The MPU used two 2114 Static RAMs, these 1024 x 4 bit RAMs replaced the use of 6810 RAMs mentioned above. There was extended memory addressing, support for 2732 ROMs (or EPROMS) as standard and a huge number of jumper selections available. The jumpers support various memory addressing schemes and ROM sizes, and makes the System 7 board MPU "backwards compatible" to emulate and run any of the previous System 4-6a games.

The sound and speech boards were unchanged for System 7, speech board remained compatible since their introduced for Gorgar.

The separate Driver Board remained almost completely unchanged from System 3 right through to System 7. One small change was made to the Driver Board during System 7. Eight resistors were changed to zero-ohm jumpers in the switch matrix inputs, apparently to increase senstivity.

The Driver Board mates with the MPU board using 40 x 0.156" header pins on the MPU and female sockets on the Driver Board. This is a continual source of repair problems for this era of Williams machines. To solve this, when designing System 9 Williams combined the MPU and Driver Boards (and the Sound Board) on to a single PCB (Printed Circuit Board), and removed the problems associated with the now infamous Williams "40-way" connector. Only the speech "daughter card" remained separate, as digital speech was considered an optional extra.

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System 8 was used on a single game Pennant Fever in May '84. This was a 2 player 'Pitch and Bat' game with men running round bases. It was the first solid state 'Pitch and Bat' that Williams produced. System 8 was never used for pinball games.

2 Games

2.1 System 3

• Contact
• Disco Fever
• Hot Tip
• Lucky Seven
• World Cup

2.2 System 4

• Flash
• Phoenix
• Pokerino
• Stellar Wars

2.3 System 6

• Blackout
• Firepower
• Gorgar
• Laser Ball
• Scorpion
• Time Warp
• Tri Zone

2.3.1 System 6A

• Algar
• Alien Poker

2.4 System 7

• Barracora
• Black Knight
• Cosmic Gunfight
• Defender
• Firepower II
• Hyperball
• Joust
• Jungle Lord
• Laser Cue
• Pharaoh
• Solar Fire
• Star Light
• Time Fantasy
• Varkon
• Warlok

3 Technical Info

3.1 System 3 Architecture

System 3 Technical information goes here.

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3.2 System 4 Architecture

System 4 Technical information goes here.

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3.3 System 6 Architecture

Technically System 6 was not a huge architecture jump from System 4, it did use the 6808 CPU, and more ROM memory could be addressed and this was used to hold increased game code on Firepower. It used a 2716 Game ROM (2K) which was standard plus 3 x Harris Bipolar Proms (512 bytes each) giving a total game code size of 3,584 byles. 3K of code space is hardly anything by today's PC standards.

Williams also moved to using the updated 6821 PIAs and the 6802 CPU later during System 6. [ed note: Need citation here as to exactly when this happened, and verification from an original owner's game board] The 6802 processor was the same architecture and was "backwards compatible" with the 6808, but had internal RAM, instead of the 128 x 8 bit MC6810 which must be used with the 6808 CPU. Pin 36 is usually grounded on the 6808, and you can therefore use a 6802 on older boards and it will work, provided the external 6810 RAM is good. If you set Pin 36 of the 6802 "high" (usually through a 4.7K "pull up" resistor to the +5v logic rail) then the internal RAM is enabled. The 6810 (if not socketed) can usually be left in place.

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3.4 System 7 Architecture

System 7 Technical information goes here.

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4 Problems and Fixes

4.3 Display Driver Board Issues

Possibly doesn't apply to some, can't think of an example.

4.4 Sound / Speech Board Issues

Richard (Firepower) - The sound board is actually a "mini-MPU" board running a 6808 CPU and 6821 PIA. It has it's own PSU and takes 13v AC voltage directly from the Transformer and rectifies it to provide the +5v logic and +12v reset circuits. I believe this design was for ground isolation and noise reduction.

I have a whole section hosted temporarily on this homepage. It is discussing the Sound/Speech architecture and repairs for this era of games. It is my own work, and some of it was copied into the pinrepair manuals, if you see similarities, it is *not* because I copied Clay.

I looked into converting it to wiki with a MS word plugin, but had problems with the conversion crashing. If someone more knowledgeable about the 'ways of the Wiki' wants to take a stab at converting it, I will edit it to fit better in this space. The links to my sites (and diagrams) will need to disappear and be replaced by links to IPDB manuals or other places. I don't mind if the facts and information in tables are presented verbatim as they are my designs and invention. -Cheers.

5 Game Specific Problems and Fixes

Example would be servo controller on Independence Day pinball

6 Repair Logs

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