I've never been able to use the VGA input on those boards. You have to use the wire harness that is included with the board and that goes to the video output wires on the game (your yellow wires in the picture).
After you do all that, usually you have to fine adjust the settings on the CGA/...
Hydro Thunder is a medium resolution (EGA) game.
Needs to be hooked up normal and then take the original monitor output and hook that to the CGA/EGA to VGA converter.
Then converter to the new VGA monitor.
Guessing they do not know what they are doing. Plus opening across the street from an another arcade/ food/ bar place was not smart. That place you can actually eat at. And I'm surprised that arcade is still open. It's not that big of town.
I've always wanted to open an arcade in my town. I know it's not profitable without food and such. I never pulled the trigger.
But what the heck is this that just opened? I have way more in my personal collection than what this is.
25" -> 19" & 25" -> 27" is a big difference.
25" < > 24" isn't going to do anything noticeable.
I've used 25K7400 chassis on 24K7400 that were missing the chassis.
Most of the Wells Gardner 24" K7400 came out of a Atomiswave. A 25" will not fit in those. I've used a 25" K7400 chassis on a 24" K7400 tube with no problems.
24" K7400 chassis on a 25" K7400 tube should be no different.