Replacing the obsolete 55536 speech chip
The speech chip is a Motorola HC-55536 or HC-55564, now hard to find. The MC3417 (14 pin) or MC3417L (16 pin) can stand in. The 16-pin MC3417L, the easier one to find, fits if pins 8 and 9 hang outside the socket; those pins are not connected and need no wiring.
Systems
Related tips
- The D-11581 sound board: chips and ROMs
- Game-over music missing: reflow the sound board header pins
- Volume suddenly goes to full blast and the volume pot does nothing: shorted pot wiring
- Constant hum instead of sound: shorted capacitor C26 on the sound board
- How System 11 makes sound
- Power-on sound tones and what they mean
- CPU sound diagnostic switch SW1 results
- Which System 11 sound board each game uses
Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Two, Clay Harrell (pinrepair.com)