CTC-4 Work Continued

[Rob]

Michael,

I think the fact that it appears you need to move the tuning coil slug to an extreme rather than where it was once working happily is a good indication that something else in the circuit that is way off spec is still eluding you. Have you tried a different H. output tube? A gassy tube can hot plate at the proper voltages.

Not having the CRT hooked up shouldn't change the load seen by the HV supply if the 6BK4 HV shunt regulator is in place and functioning properly. That will be the same condition seen when the CRT is installed and the brighness is cut off, except that there would be much more capacitance applied to the HV lead.

Yes, I think the cathode to chassis gnd link on the HOT is the best place to monitor HOT current.

Perhaps some of the others here who have much more repair experience than I with these old RCA color chassis have some ideas for you?

Rob