Early sound boards carry 43 V too

The A8 sound boards from Lost World to Dolly Parton use 43 V, and later games may still have the wire. When chasing a 43 V fault, unplug the sound board connectors to rule it out.

Systems

• Bally MPU AS-2518-35

Related tips

• 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
• Sound Plus -56 and vocalizer test points
• Odd 43 V coil faults on games with the early AS-2518-32 sound board
• No sound at all: start with the amplifier hiss
• Which -51/-56 sound ROMs respond to the board test button

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)