Background sound disappears after the game has been on a while: sound setting

If the constant background sound plays after power-up but is missing once the game has sat on for a while, check the sound option in the adjustments before suspecting the board. It was set to 01; setting it to 03 made the background sound play every time.

Systems

• Bally MPU AS-2518-35

Games

• Mr. & Mrs. Pac-Man

Related tips

• No background music, only target sounds: set feature adjustment 18 to 03
• Background sound works in test but not in games: check DIPs 29-30, then reseat connectors
• Sound module -32 and -50 test points
• Identifying AS-2518-51 and AS-2518-56 sound boards
• AS-2518-51/-56 sound board jumpers
• Bench-test a -51/-56 sound board with a test EPROM
• Early sound boards carry 43 V too
• Sound Plus -56 and vocalizer test points

Source: Pinball Repair help group!! (Facebook group)