How do you fix a cathode ray tube?
A cathode ray tube typically is not repairable. It is like a light bulb in that the filament may fail. If that happens, you are out of luck. If the picture is dim, a transformer used to be available from Radio Shack and other electronics suppliers, that will boost the filament voltage and increase the brightness of the picture temporarly. That is the only “repair” possible other then replacement. If you are sure the problem is a bad CRT and you have a black screen..you are out of luck for repair…