Start with all of the pots at 12o'clock slowly adjust each one until you get a proper picture if you can.
Also take a picture of the screen after the adjustment. There could be several issues like the red gun, color pot, cap kit, convergence. Too soon to say without seeing the screen.
Generally when I get a chassis that is iffy and isn't responding to regular adjustments I do a capkit and adjust the B+ if needed.