Quote:
Originally Posted by miniman82
Not sure where else the convergence voltage could come from, you need it from the horizontal for the waveforms. Maybe a tap from the flyback would be a better choice, then the cathode could be more normal with just a resistor.
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If you look at the CTC5 circuit diagram for the horizontal output tube, you will see that the cathode is heavily AC bypassed to ground. There is no signal on the Horizontal Output cathode. The voltage drop on the Horizontal output tube cathode resistances (100 ohm pots and the 82 ohm resistor) is purely DC for static convergence only.
I am suggesting tying the cathode to ground. This will in effect copy the later chassis' CTC7 onwards. I am curious if it is not the reactances in the cathode circuit which reduces the flyback pulse amplitude and makes the HV supply soggy?
As for the DC supply for the static convergence, I was was thinking of constructing a separate regulated DC supply. The DC would be derived from the filament supply. A suggested diagram is attached.
Certainly, simply ignoring the static convergence and simply grounding the Horizontal Output Tube cathode right at the socket would test the HV supply and I will be game to try it when next I pull the chassis.