It is common for the DAC on Raizing boards to develop color issues over time. The 74HCT273 flip flop outputs seem to go bad on these PCBs, possibly from electrical issues with a game cabinet or mis-handling of the board.

You can validate the DAC's output by going to the color test, which outputs 32-step color ramps for each channel, exercising all fifteen bits. If the gradient ramps have irregular steps or are missing sections entirely, first check that the resistors forming the DAC are okay, and following that, replace the 74HCT273s. Please see the note about desoldering from these boards.

If the game plays blind, the failure can be in a number of places. If the color DAC's 74HCT273 chips have failed, then nothing will drive the video DAC. However, if the game is playing correctly, then it means the palette RAM is working, and the '245s controlling palette RAM address mastery haven't failed; the startup test will catch this problem. It is possible that the blanking signal (going to pin 1 of the '273s) is stuck, blanking the whole screen.

It is also possible that the GAL16V8 at position U33 named "TWIN-CAM" has failed, which is responsible for muxing text and GP9001 video output (and generating the blanking signal mentioned above). Check the page on the Raizing "TWIN-CAM" U33 for details.