Wiggle your video plug on the chassis to see if you have a crack solder joint. Put your black lead on video ground and red lead from your meter on each color( on video plug) and see if you get around 1 vdc or so and it goes up and down depending what is on the screen. If you have voltages there, then either you should check voltages on the neck board. get a manual. You could check for a green transistor( on neck board) short that is why you have so much green. Switch green drive transistor with blue and see if problem changes color then you know transistor is bad.If your voltages are good on your neck board i would look into rejuving the tube.