21-CT-55 power supply failure

[Penthode]

Originally Posted by miniman82

Since it's not a vertical blanking issue, how exactly does this chassis blank horizontally? I don't see a blanking tube.

There is not blanking circuit as such. Blanking is done by the video waveform. Hence if the if there is a bad VIF response or misadjusted fine tuning, high video frequencies will overshoot producing a white line.

Try adjusting the fine tuning and reduce the RGB CRT screen adjustments.