Pre-DCS sound board A-12738

Games from Funhouse to Twilight Zone use sound board A-12738: a 68B09E CPU, YM2151/YM3012 FM synth, AD-7524 DAC for samples and a 55536 CVSD speech chip, similar to the System 11 D-11581 board but with more ROM space.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics

Related tips

• Pre-DCS sound boards are tuned per game
• Sound board beep codes before DCS
• Pre-DCS sound cuts out after the game warms up
• Volume stuck at full and buttons do nothing (pre-DCS)
• Sound board fuse F501 blows at power-on (A-12738)
• Fitting a manual volume pot to the A-12738
• Pre-DCS speakers pop and get damaged, LM1875 runs hot
• Sound board beep codes at power-on (pre-DCS)

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Three, Clay Harrell (pinrepair.com)