Sound board 520-5050 EPROM jumpers

520-5050-01 (Batman, Star Trek, Hook, Lethal Weapon 3) has W6 fitted and W7 open, for 27020s at U17 and U21. 520-5050-02 (Star Wars, Rocky and Bullwinkle, Jurassic Park) has W6 open and W7 fitted, so U17 takes a 27040 while U21 keeps a 27020. On both, W1 and W4 are fitted.

Systems

• Data East CPU Version 3
• Data East/Sega CPU Version 3b

Related tips

• The 520-5050-00 sound board variant
• Check the sound board's regulated -5 V and +5 V
• Sound board versions are not interchangeable
• No sound at all: check the -5 V regulator
• Sound board power input connector CN2
• No sound with all voltages present: the PALs

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)