[Penthode]

Originally Posted by old_tv_nut

I recommend modifying the CTC-5 video output stage to the CTC-7 configuration.

http://www.videokarma.org/showthread...ication&page=2

I remember the post. Boy the five years swiftly passed.

I ended up modifying the cathode circuit on the 12BY7 because of the blooming problem. But the green cast at high brightness remained.

I think there is more to do because to drive the CRT to conduct, the 12BY7 current remains too high. If I recall correctly, the 12BY7 control grid bias needs to increase (greater minus). Comparing the CTC5 to the CTC7 or CTC9 should reveal the difference.