PVM suddenly turned too bright while running, G2

[SpiderWaffle]

So I turned on a new PVM to calibrate it, had it running fine for about 10 minutes, nothing unusual, everything looked good as you would expect. Then, in a matter of about 1-2s, the image turned exceedingly bright. Soon later I turned it off and noticed some arcs between the tube and the metal shielding just behind it that were both visually and audibly larger than you would ever normally observe. Hours later turning it back on, I hear a larger than normal electric arcing sound first thing, screen is still far too bright just as it last was, lowering the brightness and contrast knobs considerably can bring it to "normal" brightness levels and everything looks normal as it should. Same things happens every time it is turned off and on now.

So likely something has gone awry with the G2 circuit. I could try lowering the G2 screen knob on the flyback, but that seems like that would just be a temporary hackish fix. Nevertheless, I tried to lower the knob just to see if that could in fact correct all the problems for the time being, but noticed the knob is turned ALL THE WAY COUNTER-CLOCKWISE. Now does anyone know, is that the lowest position, or the highest?

Has anyone observed this before? What course of action towards fixing this makes most sense?

Otherwise I was thinking of bringing an ESR meter to the caps in that circuit next, but the sudden shift in which this occurred doesn't sound like a cap, or just cap, has gone off spec here.

Thanks for any words of wisdom!