192 x 64 display needs 120 ns or faster EPROMs

The 68000 on the large display controller runs at 12 MHz, so 150 ns EPROMs, which are fine on the older displays, are too slow and the display will not work. Use 120 ns or faster parts.

Systems

• Data East/Sega CPU Version 3b

Games

• Batman Forever
• Baywatch
• Mary Shelley's Frankenstein
• Maverick

Related tips

• 192x64 display EPROMs must be 120 ns or faster
• Setting up a replacement 192 x 64 display
• The 192 x 64 display makes its own high voltage
• 192 x 64 games: separate backbox supply for the display
• Last resort for a flaky 192 x 64 display
• Large 192 x 64 display power connectors by display maker
• 192 x 64 display blanks out or the game resets
• Running the large display on the bench

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