Powering a sound board for testing

Steps

• In the game: pull F2 and F3 and unplug sound board connector J3, leaving J1 (power), J2 (speaker) and J4 (volume) connected.
• On the bench: ground to J1 pin 5 or 6, +12 V DC to J1 pin 1 or 2, -12 V DC to J1 pin 8 or 9 (a PC supply works), a small speaker on J2 pins 2 and 3, and a jumper across J4 pins 1-2 in place of the volume pot.
• On a System 6/7 board with speech, remove the speech board and fit jumper W1 for the test; remove W1 and refit the speech board afterwards.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A
• Williams System 7

Related tips

• Which sound board each game uses
• Sound board jumpers for 2K sound-only games
• Using the sound board test switch
• How System 3-6 games trigger sounds
• The sound board is its own computer
• Type 1 and type 2 sound boards and their switches
• Setting up a sound board for speech
• Sound board completely dead

Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)