Using the sound board test switch

Steps

• With the game on, press the sound board's own test button.
• It checks the EPROM and then plays most or all sounds in a loop, with no gaps between them. A gap usually means a sound the board cannot reach.
• Early System 3/4 boards may just give a steady tone; on Disco Fever and Phoenix the button may do nothing.
• The only way to stop the test is to switch off. It works even without the CPU and driver boards.

Systems

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

Related tips

• Type 1 and type 2 sound boards and their switches
• Which sound board each game uses
• Sound board jumpers for 2K sound-only games
• Powering a sound board for testing
• How System 3-6 games trigger sounds
• The sound board is its own computer
• Check sound board jumpers after a board swap
• Leon sound board test EPROM

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