Adding a line out to the A-12738 sound board

Steps

• J509 taps the mixed audio before the volume control: pin 1 is analog ground, pin 3 is audio.
• On the component side, lift the end of R102 that connects to J509 pin 3.
• On the solder side, run a jumper from the negative side of C21 to the plated hole left of R102 (which connects to J509 pin 1).
• The resulting line out is a fixed level, not changed by the volume control.

Systems

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

Related tips

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

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