CTC-9 tint control oddness

[oldtvman]

I had that problem on the set I just sold and it was nothing more than tweeking the agc control.

[DaveWM]

so adj the AGC fixed a tint issue where tint was limited in range? have never seen that effect before, generally it just goes from too much contrast and loss of sync to washed out looking when i adjust agc on other sets.

[DaveWM]

tweeked AGC no change.

pulled chassis checked tint pot with simpson 260 (analog VOM) all good.

checked the 130pf cap connected to tint control, good value, no leakage.

did resistance checks of burst amp, osc tube, phase detector, was a little off of course but mostly within tolerance or just out of. was thrown but the plate load resistor on the reactance control (triode of 6gh8, supposed to be a 6EA8). found a 68k where a 15k was specified, looked factory, check rca field guide, found that resistor changed value on many models, the 68k was on a CTC-11 that used a 6GH8 so I would seem that is an ok sub to be using (the tube chart shows it should be a 6EA8 in the set, but the resistor matches the tube that is installed).

seeing no smoking gun I will proceed with a check out and setup of the color AFC.
my guess is an unbalanced secondary in the burst transformer.

[DaveWM]

https://www.youtube.com/watch?v=CGk2K4NlqTQ

some video of the set in operation on the last few days of analog cable.

[old_coot88]

That looks like it might also have a demod problem. Have you DeOx'ed/reseated the demod tube in its socket and/or subbed the tube?

[DaveWM]

Originally Posted by old_coot88

That looks like it might also have a demod problem. Have you DeOx'ed/reseated the demod tube in its socket and/or subbed the tube?

I presume you mean the 12AZ7 dual triode (ref osc goes to K's chroma info to grids), I have not, but will. Something else that was odd that I did not notice before is I have red screen background (there are RGB bkg pots adj G1 and GB scr pot on G2 which is a little different than I have seen on later models) has to be set to the min for the grey scale to work the G and B are not at min, nvr had a CRT where the red was the strongest gun. So the G2 red runs wide open and you adj the G1 red with a pot.

I prob should check the kine pins for voltages to make sure all is well there.

what makes you think there is a demod problem? seems to me the colors are correct just lacking in phase shift of the ref osc.