Hello,
those are fun games and once you get them working they live another long life!
Yes, you can test/replace capacitors.
The fact that the candle is on means the board is doing something.
The monitor is an RGB1401, probably model A. May the force be with you, hopefully it works. I see solid white screen, that doesn’t mean it is working correctly.
As for your board, Alan at K-Lar is an expert on those and has a testing station. They commonly have problems with the pots in the video circuit (3 pots at the back of the board). You might try spraying those with contact cleaner and swiping them back and forth, those control the color of the background.
Chris