My Brand New CTC-7!

[DaveWM]

ok on the horz board is a 68k resistor. look at the schematic its the one that is across the coil. You will need to lift one leg of it to check the value. report back, if its way off it can make the adj to crit, I think you should have more of a range than 1/2 turn. It would need to be way high like 2x R605

[DaveWM]

after you check that there is a procedure to set the sine wave adj coil, should not be needed unless its been messed with.

Lastly regarding color, did you check the color killer pot setting? IIRC fully CCW is no killer, fully CW will kill the color.

[SwizzyMan]

Did not mess with that pot. Will pick up on this tomorrow currently going to be out of town till tomorrow afternoon.

[SwizzyMan]

Is the color killer pot on the top side of the chassis or the bottom?

[DaveWM]

look for hollow shaft on contrast pot, thin screwdriver should fit inside.

[SwizzyMan]

Messed with the killer pot was turned all the way ccw turned it clockwise fully and now I have a rolling rainbow and my color bar pattern. I am hearing this is caused by the 3.58mhz color oscillator and it is fixed with a coil adjustment.

[Electronic M]

If you have a standard color bar pattern, but the bars rather than being a solid color are RGB barber poles Color synch is achieved through tuning the chroma osc. transformer/coil.

[DaveWM]

before you start messing with coils, try adj the fine tuning, going past optimum tune just to see if you can get a lock. The best color will be in the wormy mode of the tuning just before losing sync.

[DaveWM]

the color killer should be setup so when there is no programming just snow, start fully CCW should be some color in the snow, advance until the color in the snow just goes away. I have a video on this.

[SwizzyMan]

Fine tuning does nothing at all I spent 30 minutes messing with it.

[SwizzyMan]

So uh, should I adjust that coil?

[old_coot88]

Color sync adjustment (to correct barberpoling) is done with the Reactance coil. Phil Nelson should be able to direct you to it.
Re. the color killer adjustment, for now leave it fully in whichever direction gives color.
The color killer feature is actually moot nowadays. It was useful in the days when lots of broadcasting was still in B&W, to prevent unwanted color confetti in the B&W picture.

[dtvmcdonald]

Its OK to adjust the reactance coil only, L704 in the schematic from RCA.
See instruction on p 27 of manual. It should snap in and stay stuck in if
you don't ground the input as described on p. 27. Its best not to do the
rest of the adjustment described unless it locks, However its a good
idea, if you have the equipment, to check all the waveforms and report back here.

[SwizzyMan]

I did try to adjust the top portion of that coil and I got no response whatsoever.
The rolling rainbow did not visually decrease or anything.

[DaveWM]

L704 does not have a "top" its a single slug coil. I hope you were not adj T704 which is a transformer with a top and bottom.

did you make a video of the adj you were making with the fine tune? Not sure I understand when you say it makes not difference at all. do you mean nothing at all happens when you adj? as in the fine tuning is not working at all?

I hate to keep having to say this but without video of what is happening its hard to give good advise. Your descriptions will mean different things to different people, a picture is worth a 1000 words.

Perhaps the others on this forum are ok giving advise without seeing what is happening, Its just something I prefer not to do.

I will restate the last thing you should be doing is adjusting coils, I would do tube swaps in the color osc circuits 1st, often the osc tube is a problem.