Today's Mystery Guest (RCA CTC-4)

[old_coot88]

Phil,
Since you've already done the alignment procedure per the manual, presumably the tint ('hue') control shows some evidence of working when you turn it.
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The display looks like possibly one of the two demods is really wonky or maybe not working at all.
Assuming the hue control is working, I would try this.. using a cap of .01 - .047 or thereabouts, short out each of the demods in turn, watching to see what the tint control does while one demod is shorted.
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At the 12BH7 demod tube V125A, short the plate (pin 1) to ground*. This kills the R-Y signal. On a normally working set, the display will show some colors missing, but with the tint control still functional.
Now short the plate of the other (G-Y) channel (pin 6). You should get a different set of colors, and the tint control should still work.
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If either channel shows little or no color, and/or the tint control has little or no effect, I would look further into that channel for the problem.
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Of course if both channels pass the test, then the wonky-color fault lies somewhere else.
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*Or to B+, doesn't matter since it's signal ground.