Other CPU jumpers and what they set

J1 sets the clock speed, J2/J3 and J4/J5 tie address lines 14 and 15 high or to the CPU, J7 sets the IRQ rate and J8 feeds PIA 11B port A7 for display blanking; the use of J6 is not known. Apart from J4/J5, leave these as the factory set them.

Systems

• Data East CPU Version 1/2
• Data East CPU Version 3
• Data East/Sega CPU Version 3b

Related tips

• CPU jumpers J4 and J5 set the EPROM size at 5C
• Bench-testing a CPU board on +5 V
• CPU boards are only downward compatible
• CPU board versions 520-5003-01, -02 and -03
• Where the TIP122 drivers are on the CPU board
• CPU board PIA positions and jobs
• Data East CPU diagnostic test EPROM
• Combining two-chip CPU code into one 27512 for 5C

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