Joust still broken: video and sound dead

I got the video assembly out of storage, and it’s dead. I know that CRTs use high voltages, and I’m allergic to kryptonite, so I won’t be messing around with that thing. No jousting today. I’m also concerned that the sound board isn’t doing anything, though it’s getting power. I went through the diagnostics in the Joust owner’s manual, and made it through the flowchart to “yep, your machine is busted” in all cases. It’s a safe assumption there are multiple problems with this 30-year-old machine, aside from the ones I’ve fixed so far.

After a break for dinner, I got to thinking. The video output from the CPU board is R, G, B, HSync, and VSync. That sure looks a lot like VGA. Is VGA the same scheme? Do VGA monitors tolerate only certain sync frequencies? Would it… just work?