1971 GE Portacolor H3 chassis color help

[wabr101]

TV has had some new caps and tubes. Gray scale is great. Color comes and goes. If I turn channel off and back on color usually returns-or if I fine tune to sound in picture-color returns. Voltages normal-if color goes, screen looks green unless color control is turned full counter clockwise? Tubes were subbed-no changed.
Seems like detuning or turning channel to 3 and back to 4 etc shocks color into working temporarily. Any ideas?