My Brand New CTC-7!

[Phil Nelson]

Originally Posted by SwizzyMan

Do any color adjustments need to be made and should I adjust the dynamic convergence?

You're done. Don't mess with convergence or anything else. The colors are rich and the flesh tones (always a good test) look natural.

You can tell the convergence is good by watching white lettering that appears in the corners. If convergence was bad, the letter edges would have fringes of wrong colors instead of looking clear and sharp as in the center of the picture.

Congratulations on sticking with this project.

Enjoy!

Phil Nelson

[old_coot88]

Great work, young man!
Just a quick tip on leveling the yoke: Don't attempt to slide the yoke forward (or rearward). Its normal position is 1/4 to 3/8 inch shy of being fully seated against the CRT bell. This is the 'sweet spot' for best purity. It is integral to the factory setup procedure on roundies.*
-
*On rectangulars, it was 1/8 to 1/4 inch shy of being fully seated.

[dtvmcdonald]

Originally Posted by old_coot88

I believe you mentioned the h.osc tube (6CG7) is NOS. But it still could be borderline weak, causing the long lag to lock in.
Perhaps one of the kindly souls here could send you a known-good-in-H.osc-service 6CG7.
-
There's a 'quick & dirty' test that old techies used a lot in the field for this kinda problem.
Have the set warmed up and everything locked in. Turn the set off for about 7 seconds, and then back on. It should come on with the horiz fully locked in. If it comes on with lines and there's a delay to lock in, it's a sure sign the osc. tube is borderline.

If I try that on my CT-100, the horizontal comes up back in sync ...
but with horrendous ringing and distortion in the left part of the screen.
It stays that way forever, or at least a long as I dared leave it on
being afraid of some a meltdown in the flyback.

And it won't work right unless the set is left of for at least 10 minutes,
when it comes up perfectly normally.

[Zenith26kc20]

I can't remember if I posted this info here but here it is again. RCA developed a fast warm up 6cg7 for their color and black and white tv's. It is a clear top tube, getters on the side. They are designed to warm up in 11 seconds, making sure horizontal drive and sync are waiting when the output tube starts conducting. The wrong type can result in a jump in cathode current at turn on or horizontal lines until the 6CG7 warms up. They are also very reliable but are getting a bit pricey because of audiophiles. It is very important to use this tube.

[SwizzyMan]

Would I be able to find one at the tube store (6CG7 special one)? And should I check the cathode current on the h out tube? Going to pull the chassis out today to do my final checks and finish anything that needs to be done.

[SwizzyMan]

Well I found a spare 6CG7 lying around (not the special one) and that one really is pretty much ready to go when the HV kicks in. Should I still invest in the fast heat up one?

[old_coot88]

Originally Posted by dtvmcdonald

If I try that on my CT-100, the horizontal comes up back in sync ...
but with horrendous ringing and distortion in the left part of the screen.
It stays that way forever, or at least a long as I dared leave it on

Is the ringing/distortion in the H sweep itself? Or in the video/video IF chain (does it vary with the contrast setting)?

[old_coot88]

Originally Posted by SwizzyMan

Well I found a spare 6CG7 lying around (not the special one) and that one really is pretty much ready to go when the HV kicks in. Should I still invest in the fast heat up one?

No, not if it's working OK and coming on in sync. I have never had occasion to need the 'special' 6CG7, in 30+ years in the trade.

[Zenith26kc20]

I would monitor the cathode current on the horizontal output tube from turn on to raster. If it does not rise high and settle down once high voltage comes up, I would not worry.
My CTC9C is very picky about the 6CG7.
Just a suggestion to prevent possible problems. Newer 6CG7 tubes probably have the rapid warmup feature. I have seen older ones that were very slow to warm up.

[SwizzyMan]

OK how exactly do I do this?

[SwizzyMan]

Ok checked the current and it went well above 210ma and when the HV kicked in it went past 2000ma. I am pretty sure I did this right. Here is what I did http://www.boxcarcabin.com/rcacathode.htm

[Zenith26kc20]

What is the cathode current once the set settles down?

[SwizzyMan]

178ma after the set has sat for about 30 seconds.

[SwizzyMan]

OK cant get any raster because I dont think the 3A3 HV rectifier tube is doing its job. I cant pull an arc off the metal bell surrounding the 3A3 socket. The filaments on the 3A3 are still intact. I know the flyback is working because I can pull a spark off of the flyback cap. What is going on?

[SwizzyMan]

OK for sure it is something in the 3A3 socket causing the problem. Or does cathode current testing cause this?