VTS1134. Try turning down the horizontal drive control and see if the arcing goes away or calms down. If it is a tuning cap that would be counter clockwise but try turning it in both directions. The sides of the screen should cave in and the picture will loose brightness. I thought I saw a drive control in the schematic. Also do you have a signal going into the set? Is the picture normal and has vertical and horizontal sync? If you are going to keep working on vintage TV a HV probe is a good idea. At some point you may want to restore a color set and a probe is a must.
