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Copied from “no color on CTC-16” thread, almost exactly like mine.
Posted by Old TV Nut.
So, go back to grounding point E. This should defeat the color killer and let the bandpass amp conduct. Turn the color control all the way up and see if you see any color.
As far as using the scope, set the scope sweep rate to horizontal sweep rate (about 10 microseconds per division). For starters, set the vertical sensitivity to 10 volts per division (or 1 volt if you have a 10X probe) and check for presence of all the waveforms shown in the SAMS schematic for the chroma sync phase detector and color killer, plus the chroma bandpass. Set the vertical to higher gain to view the smaller waveforms that are marked about 10 or 12 volts peak to peak.
Do you have a color bar test pattern to use, or are you using some program video? The chroma waveform on pin 3 of coil A14 will generally not be as big and obvious with program material as with a test pattern, but you should be able to see it come and go when the color killer operates.
This is most likely the source of my problems now, As when Point E is grounded, I get absolutely nothing at g1 of u17 ,even at 200mv, I just see noise , nor is there any signals at chroma phase detector,
but the ref Osc is running, I can see that, not sure what freq.
I do see the horz pulse at g1 of the burst amp, but it still never changes with the video on screen, even though that r145 is correct.
What I don't know (or understand yet ) is something so messed up in this circuit that won't allow video into it through c22 (from 1st video amp) for any of the color to work correctly ? Could IF section be so out of wack that it is not letting any color through for the circuit to work with? A combo of both perhaps?
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