Question about demods/drivers

[miniman82]

CTC-7C of course, but really applies to most of the CTC lineup since the X/Z demod scheme is roughly the same for all of them.


I've discovered that the color issue on this set is due to the G-Y amp not doing anything- I 'scoped it's plate. Blue and Red work as advertized when using the raster buttons on the sig gen (I get the waveform I'm supposed to get), but green refuses to work. The voltages on the G-Y amp are all in the normal range (within 2-3v high of the RCA manual, and only due to the 122v AC input), so what are some possible causes? It's a pretty simple amp being the 'difference' color, since it basically just takes it's cues from the other 2.

Only thing I can come up with is maybe the color matrix is still not aligned correctly (too much red/blue phase difference throwing off green?), though it seems to be pretty close. I don't have issues with rolling color bars anymore since replacing the crystal, and the tint and color controls seem to be doing their jobs. Tweaking the burst phase transformer has no effect, neither does the CW driver.

I don't think the demod is to blame, it looks to be working correctly.

It's not the amp tube either, already tried that.