Battery orientation on Data East and Sega CPU boards

The middle cell faces the opposite way to the outer two: top cell NEG-POS, middle POS-NEG, bottom NEG-POS. This is the same with either style of holder, and differs from WPC boards.

Systems

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

Related tips

• Repairing battery corrosion on the CPU board
• Repair battery corrosion on the CPU board
• Check that battery power reaches the RAM at 5D
• Change the CPU backup batteries yearly, with the game on
• Data East CPU diagnostic test EPROM
• Leon's Data East CPU test EPROM
• "Memory Error, Open Door" or "open the coin door" at power-on
• New batteries but still a memory error: check D25

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