Dove right in! Help with RCA 21-D-8628

I ordered 2 replacement vertical output tubes, still cannot get the center bar to sync, and the picture refresh is still too slow. Moved the electrolytics to safer spots and added in new solder/junction spots.

I tried to start testing using a signal gen, oscope, bias, etc.; no golddurn clue what I am doing!! And never have enough probes, or a diode tester, or proper attenuator pads, etc. I need to make some testing pads, get some raw coax, proper connection points, etc.

Is there a way to just 'reset' or reverse/speed up the refresh rate ? Is that what sweep means? There are some things I sort of understand, but no where near what I would prefer!!