Hello:
Another fun machine, we have seen a number of these lately.
Regarding the question about the black above the numbers and letters toward the top of the CRT....are you sure that just isn't the monitor bezel? It's the plastic trim piece inside the door that keeps light from the internal fixtures from washing out the picture. It also keeps fingers and such things from poking into a machine. If that isn't perfectly centered it will make the image seem a little
Regarding the question about the alignment, it seems if this was a convergence issue it would be off everywhere. Plus, the convergence rings adjust RGB so for it to impact black wouldn't that mean all 3 colors are off? Meaning, all the black should be off, even the black suits of the cards.
I'm not sure about the alignment of the payout background, it does look off but I'm not sure how you would adjust that, is it possibly a problem with the video circuitry on the MPU? It would be interesting to stick another working 1490 or 1492 and see if anything changes.
I'm leaning toward image source. Let's see what others have to say.
Chris