Looks like the tube may be bad? You said you tried rejuvenating with your BK480 and it didn't work, and the guns are fried.
Just an FYI if you are or would look for a used 1492 tube/chassis - The Brunswick 1492 units used in the bowling alleys DO NOT work in the slot/video poker machines from everything I have read. Don't know anything else about those or messed with one.
If the CRT boards and caps are good and the MPU is putting out the video - maybe building the circuit/mod to get a standard LCD monitor to work would be a relatively inexpensive way to get it working.
There may be someone near you that would be willing to test your (Ceronix) board on their slant machine, not too bad to swap out for a test to be sure tube is toast. Maybe they would even be willing to put your chassis/MPU in their machine or theirs in your machine to verify. (Upright would be a little tougher, but doable)
You can send it to me and I will test it in my machine. Shipping could get crazy...
I'm with you on getting the machine cheap and trying to get it up and running without putting a ton of money in it. I won't be doing any more slants when I get rid of this one LOL.
If I see any uprights to get a hold of I make sure the CRT is working - else pass. Hindsight I know.
Tony
EDIT - You can look into an upright, the CRT is inverted/upside down from the slant, just a couple wires to swap to get it to work. And the chassis plugs in different but you could use the board and swap the wires maybe easier.