Response from Jonathan: Steven,

If you put the game into cocktail mode and you are still experiencing the color change with the ship at the top of the screen then it sounds more like a board issue. The only way to know for sure, however, would be to swap another board with similar pinouts (such as Zig Zag, a Dig Dug clone) into the cabinet. We’re definitely leaning more towards a board issue at this point.

If you are going to try some of our monitor tricks, you’ll probably have better luck degaussing the monitor rather than adjusting the convergence rings. Adjusting the convergence rings usually solves problems such as color bleeding and shadowing. If you’re not experiencing these problems it’s best to leave the convergence rings alone. Degaussing would be your best bet as a magnetized shadow mask can often lead to wrong colors.

Hope that helps you out. Please let us know if you have any other questions and keep us updated on your progress.