Depending on when your machine was produced, Some Data East games with the same title may have shipped from the factory with two different configurations. The DMD display board may contain the software on either 2 2MB Eprom chips or only 1 4MB Eprom chip.
You can purchase either version for the same machine, however you will need to change a jumper setting if you are not buying the configuration which your machine is already set up for. The jumper setting at R11 is how you set the game to look for 2MB or 4MB roms. If you are not comfortable soldering jumpers on your board, or do not want to modify your machine, I offer both versions available.
DMD Display Boards with part # 520-5055-00:
Shipped with jumper R11 installed, and use 2 2MB ROM chips in locations ROM0 and ROM1.
DMD Display Boards with part # 520-5055-01:
Shipped with jumper R11 removed, and use only 1 4MB ROM chip in location ROM0
The “jumper” from the factory is actually a 0 ohm resistor, so if you do not have one handy, you can simply use a jumper wire.
Here is my board from Jurassic Park without the jumper installed: