With CRT drivers there are high value resistors in the CRT base side, on the brightness and G1 controls, that tend to drift high in value, and thus you get either a smeared image or flyback lines, depending on the resistor. Suspect any resistor in the high voltage area around the tube base and around the LOPT that is over 47k, and which is discoloured, and check the value of them. Many will have drifted high.
Any electrolytic values 22uF to 220uF, 100V or higher replace on sight, they will be high ESR by now having been run nice and toasty for years. They are on power supply rails, and generally have a high ripple current through them from being part of the LOPT tank circuit. Beware of bipolar electrolytics that are often used to couple the scan coils, they can leak or go bad as well, and are not replaceable with a regular electrolytic, though I have replaced a good number of them with 10uF 160v metal film capacitors mounted up off the board to get the space to fit the few in.