Speech call-outs come out distorted or wrong, and the sound sometimes seems to reset, cutting off a call-out until the next switch is hit. Reseating connectors and chips and a new ribbon cable made no difference.

Speech distorted or wrong and sound cuts out: leaked C30 corroded the voice ROM

Cause: Capacitor C30 on the sound board had leaked, and the electrolyte corroded the voice ROM at U21 and its socket.

Checks

• Look closely around the capacitors on the sound board for leaked electrolyte, especially near the voice ROMs.
• Check the voice ROM's pins and socket for corrosion; verifying the ROM images is another early step.

Fix

• Replace C30, clean the corrosion off the ROM and the board, and replace the ROM socket if it is corroded.

Systems

• Data East CPU Version 3

Games

• Batman

Related tips

• Sounds suddenly come out wrong even with new ROMs: bad ribbon cable
• Sound board power input connector CN2
• Check the sound board's regulated -5 V and +5 V
• Sound board versions are not interchangeable
• The 520-5050-00 sound board variant
• Data East and Sega sound boards by game
• No sound at all: check the -5 V regulator
• Loud hum from the speakers

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