My Brand New CTC-7!

[Phil Nelson]

You have nothing to lose by simply waiting a while. Remember, the TV worked wonderfully just a short time ago. I wouldn't resolder all of the tube sockets at this moment.

Phil Nelson

[DaveWM]

the coils in the tuner should not be touched, you can alter the tuning by collapsing or expanding them. Hopefully you did not change the shapes of the coils. No need to clean the tuner unless its noisy (snowy picture). When cleaning only the contacts need to be cleaned. Spraying is bad as it can get into places it should not be. Best bet is to leave it be for a few days and IF spray got somewhere it should not be it will dry out.

IF the fine tuning ring has no effect then there is prob something wrong with the mechanicals of it. fine tuning def effects the picture, generally it goes from black and white smeary to beat freq sound bars to loss of sync. see my video re fine tuning about how it should look.

https://www.youtube.com/watch?v=RAk9lKv03zA

Note your 7 may not have the range as demo above but you should still have a range that shows change.

[SwizzyMan]

Made sure to be extra delicate with the copper coils in the tuner did not bend them at all. And as for the fine tuning Dave it is all normal just no color it does everything your video says minus the color. Should I open the tuner back up and just wipe the deoxit off the copper coils with a q-tip? Or is waiting the best thing? Also on the bottom right corner there has always been a discoloration it was at first yellow but now is more a green color I tried doing a purity setup and moving the yoke but no luck and I have tried degaussing the set at least 5 or 6 times and still it won't go away.

[DaveWM]

no color at all means the color osc is prob not running that is if your fine tuning is working like in the video. leave it be for a day or two. wiggle the 6GH8 tube (color osc). perfect purity can be hard to obtain. often just turning the set 90 degrees will have a huge effect on the purity. from the early pics of it working I would say you are fine.

[SwizzyMan]

Well in my case the color osc is a 6U8A. Wiggled it, nothing. Replaced with another 6U8A, nothing. will let it sit till Monday evening and try it again.

[SwizzyMan]

OK lost my HV after I wiggled the 6DQ5 tube in its socket. Not sure why that messed it up but I reinserted the 6DQ5 still nothing tried wiggling it still nothing ran it without it nope. Made sure no pin connections were shorting themselves out. What now?

[SwizzyMan]

Fixed my HV loss. Guess I broke the ground wire on the cathode on the horizontal out tube. Gah! Still no color! just black and white! Note on the color bar test pattern I can just barely see the color in the color bars when I adjust the fine tuning. What is going on?

[DaveWM]

a few things..

are you running at reduced voltage? try it back at 120v if you are.

try adj the horz hold a little bit, not enough to lose sync just a little both ways.

is the pic clear or do you have snow?

try a different channel adj fine tune again.

what exactly did you work on AFTER you had the working picture.

wiggle tubes in chroma section.

are you sure you are getting color on the color bar generator or are you seeing rainbow pattern like a loss of sync?

[SwizzyMan]

Wiggled tubes. That didnt help. At first first I had no sign whatsoever of color. Then I replaced the 6U8A color osc and I got the faint color in the color bar pattern. I will go through and adjust the 3.58Mhz and other coils in the chroma section. I know what I am doing with the coils and I know not to adjust too far. Tried everything you said Dave but still nothing. Will report back after I adjusted the coils. No rainbow pattern at all either.

[SwizzyMan]

Eureka! Was able to get my color back! Going to wrap this whole project up hopefully later tonight. All I did was adjust T704 and L704. Will make a video to show it and see if it needs any work on the color.

[SwizzyMan]

Everything looks good except for the bottom right corner of the CRT. There is a green tint over everything in the bottom right corner. I've tried purity setup and deguassed the CRT multiple times and it won't go away. Is the shadow mask bent too much?

[old_tv_nut]

Originally Posted by SwizzyMan

Everything looks good except for the bottom right corner of the CRT. There is a green tint over everything in the bottom right corner. I've tried purity setup and deguassed the CRT multiple times and it won't go away. Is the shadow mask bent too much?

Do you get a pure red field when doing the purity setup, or is it discolored in the bottom right? The early tubes with "positive guard band" (the holes in the shadow mask are smaller than the phosphor dots) could have white field impurity even when the individual color fields were OK. A really precise purity setup would involve viewing the beam landings with a telescopic microscope (RCA WG309A microscope) to see if they were in the center of the phosphor dots.

The later "negative guard band" tubes (Zenith Chromacolor, for example) where the holes are larger than the phosphor dots, would illuminate the phosphor dots evenly even if the purity adjustment was slightly off, eliminating white field impurity problems.

[SwizzyMan]

Yes bottom right discoloration on the pure red screen. So I'm going to need a microscope?

[old_tv_nut]

Originally Posted by SwizzyMan

Yes bottom right discoloration on the pure red screen. So I'm going to need a microscope?

No, no microscope needed if you can see the effect in the pure red screen - only needed if the red was pure and the white was not.

I'm not familiar with the chassis mounting on your set, but I'm wondering if it's near that corner and maybe you aren't getting it fully degaussed? Can you run your degaussing coil into the back of the cabinet and under that corner?

Edit: and you don't have any loudspeaker or such magnetic item sitting near the set?

[Phil Nelson]

The chassis is mounted on the side, so bottom right of the screen (viewed from the front) is nearest the chassis. Under the chassis in that nearest corner is a choke.

Phil Nelson