Williams System 8
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1 Introduction
The Williams System 8 boardset was used in 1984 with only two games, the pitch and bat Pennant Fever and Still Crazy, a novelty game. Combining the driver board, sound board, and cpu directly onto one board eliminated several design deficiencies of the earlier System 3-7 boardsets; mainly the 40 pin interconnector, and extra wiring harness interboard connectors.
System 8 is very similar to its successor (System 9), but it is more of a "slimmed down" version. There are a total of 8 controlled solenoids versus the 16 used with the system 9 boardset. Another distinct difference is system 8 hardware does not utilize special solenoids. System 8 also lacks the connector for a speech daughterboard.
Although System 8 is capable of driving four 7-digit displays and one 4 digit display, only two 7-digit displays are used with Pennant Fever and one 7-digit display is used with Still Crazy. Therefore, master display boards are not used on either game. Both the lamp and switch matrices are 8 x 8 in size, but neither Pennant Fever nor Still Crazy use many switches in their matrices.
2 Games
Title | Date of Release | Model # | Other Boards | Notes |
---|---|---|---|---|
Pennant Fever | 05-1984 | 526 | CPU rev A | Pitch and Bat |
Still Crazy | 06-1984 | 534 | CPU rev X1 | Novelty Vertical Pinball |
3 Technical Info
3.1 CPU Driver Board
3.2 Power Supply
The System 8 Power Supply is identical to a System 11 Power Supply.
4 Problems and Solutions
4.1 Power Problems
4.2 MPU boot issues
4.2.1 Relocating the battery from the MPU board
Use the same procedure as detailed in the System 9 section, here.
4.2.2 Repairing Alkaline Corrosion
Use the same procedure as detailed in the System 11 section, here.
4.2.3 Connecting a logic probe to the MPU
The System 8 MPU lacks test points. Argh!
To connect a logic probe, pick up +5V at the top lead of capacitor C6 (a trace extends down from the larger electrolytic cap at C5).
Pick up ground at pin 9 of 1J5.
4.2.4 Using a PC Power Supply For Bench Testing
For full operation a System 8 MPU requires +5V, +12V, -12V DC and ground. However, -12V is only required for the sound amplifier, so that voltage may be omitted for non-sound-related testing.
Connect...
- Ground to pin 1, 2, or 3
- +5VDC to pin 4, 5,or 6
- -12VDC to pin 8
- +12VDC to pin 9
4.3 Game resets
4.4 Solenoid problems
this is a stub
4.5 Lamp problems
4.5.1 Lamp Matrix Row and Column Testing
4.6 Switch problems
4.6.1 Switch Matrix Row and Column Testing
4.7 Display problems
WARNING: This circuit uses high voltages. Don't continue, unless you are confident in your diagnostic abilities.
4.8 Sound problems
The System 8 MPU creates sound on the MPU itself, much like the baseline version of the System 11 MPU.
General System 8 Sound Subsystem Theory of Operation
- The sound subsystem consists of a 6808/2 processor, 6821 PIA, 1408 DAC, and finally a TDA2002 amplifier.
- Sounds are conveyed to the sound subsystem by the main processor via the input ports of the 6821 PIA at IC13.
- The 6808 at IC11 reads the PIA input port then pulls the appropriate sound file from the sound ROM at IC49.
- The 6808 sends the sound data back to the 6821s second set of output ports, which are attached to the 1408 digital-to-analog converter.
- A remotely located volume pot may be used to adjust volume levels.
- The analog audio is then presented to the TDA2002 for final amplification.
- The amplified audio is presented to the single 8 ohm cabinet speaker.
Pennant fever makes only 8 sounds.
- "Charge" bugle theme
- Organ music, "The Lone Ranger" theme
- "You're out!"
- "Boooo!"
- "Strike One"
- "Strike Two"
- "All right!"
Pressing switch 3 on the MPU should cause the sound system to play "FirePower-like" sounds continuously until power to the game is turned off.
Note that the sound subsystem can be configured to use either a 6808 or a 6802 microprocessor.
To use a 6808, jumper W1 should be in, W2 out.
To use a 6802, jumper W1 should be out, W2 in.
5 Repair Logs
Did you do a repair? Log it here as a possible solution for others.