blue flashes on roundie

[DaveWM]

this is the late model last of the roundies a philc ford hybrid.

I finally got it off of the bench and put the legs back on it (metal cabinet, screw on legs).

the pic is good but I get flashes of blue some times a lot of the screen some times just a few lines.

I am guessing a flaking out tube in the color circuits, I will check the blue driver, thinking a shorting tube?

Or maybe I just need to let it play for a while and see if it settles down, I had it on for about an hour, did not seem to change.