Restore 21CT55 to schematic or as built?

[miniman82]

That's right, Wayne. IMO if the HV cap failed, it was probably due to internal breakdown and arcing all on it's own, but that's also likely what took out the flyback. Looking at the schematics, it appears RCA might have realized their mistake. On the CTC-4, the HV tower incorporates it's own set of resistors between the output of the HV rectifier and the shunt reg/CRT. This way even if the shunt or CRT shorts, the resistors end up sinking all the current so presumably the flyback could live. Same principle as the resistor used on sets that used the 21CYP22 CRT- shorting protection. It's probably possible to mod the 21CT55 to include this type of protection; it would not be original so purists might object, but it's cheap insurance against a failure that would destroy an irreplaceable flyback transformer. Just my 2 cents.