You see red and blue lines curved across the screen when there is a blank screen

You need to turn down the screen voltage for the blue and red CRT. I believe the access is through the front on that model.

1) Remove the front grill
2) There should be access panel you need to remove once you remove the front grill. This is where the screen voltage adjustment is located
3) Look for a small black box with six knobs on it. One row is for "Focus" and one row is for "screen". It will be marked, but probably need a flashlight to see which row it is. There will be a "R", "G" and "B" next to each knob to represent Red, Green Blue respectively.

4) Careful with the access panel removed, you are only inches away from very dangerous voltages.
5) slowly turn the R or B knob counterclockwise until the lines on the screen disappear.
Keep your hands away from everything else and only use one hand near the tv. put the other hand behind your back.

6) Once corrected, replace the panel and put the grill cover back on.