My CTC-16XL Project.

[Electronic M]

My guess is the glass was inspected for flaws before phosphor application if one near the edge was found mark it to be bottom or top in the masked off area like that, then apply the phosphor and off to the races of the rest of the build.

I take it you used the heat gun method (which is the least safe)...I'm thinking of trying that today on a couple RCA style cats. Been using the clothespin and sun method on the RCA style and I can't seem to get the finesse right to not crack the glass.

I like the secondary cat a lot better. All you probably need to get that one off the tube is some food and followed by windex and paper towel for the fuzzy residue they leave.

[old_tv_nut]

Originally Posted by Yamamaya42

Cataract repair successful!

...
I did have a slight complication, a secondary CATaract had to be removed before it could be completed.

Now I'm ready for purity and convergence.

Woohoo!

Regarding the new cataract, it may make your convergence off by whisker.

[old_tv_nut]

Regarding the flaw, it definitely is interesting. How exact is the match to the video? Same kind of line of blotches or the exact same pattern of blotches?

[old_tv_nut]

I wonder of the graphics ("30" and the star) were made by taping a transparent negative to the faceplate during exposure, and sometimes resulted in phosphor being pulled off when the negative was removed.

[Yamamaya42]

Originally Posted by old_tv_nut

Regarding the flaw, it definitely is interesting. How exact is the match to the video? Same kind of line of blotches or the exact same pattern of blotches?

exactly the same, in the same place. wired

[Yamamaya42]

all CRT parts in place,
https://imgur.com/p8dy1Am
static went OK , dynamic not so well, may have to rep;ace some stuff on the convergence PCB .

[old_coot88]

Originally Posted by Yamamaya42

all CRT parts in place,
https://imgur.com/p8dy1Am
static went OK , dynamic not so well,...

You might have the convergence yoke positioned too far front-ward. Also, the deflection yoke normally sits approx. 1/4 to 3/8 inch shy of being fully seated against the CRT bell. During purity set-up, you find this 'sweet spot' for best red purity. And yes, this is from factory-sponsered 'RCA school' where field reps actually visited dealers.

On rectangular CRTs, the 'sweet spot' occurs about 3/16 to 1/4 inch shy of the yoke being fully seated.

[old_tv_nut]

Looks like the internal dag hides the convergence pole pieces. Try moving the convergence yoke back and forth a little, looking for the spot with the greatest effect on the convergence.

[Yamamaya42]

Correct, in the newer rectangle ones, you can see where thy go.
I moved it hack some and it helped a bit, cant get it perfect, prob never will.
https://imgur.com/VoHMjmU

as mentioned, I will most likely never get rid of the retrace lines until l find some way to get IF aligned.

it's been so long that I forgot how fun convergence was, you do the static, then start dynamic, then halfway through, you see that Static is off again so you do that over, and keep going round and round, till it's as good as you can get it.

[old_tv_nut]

I'd say that looks good.

Hint on the iterations, if you have to do another one sometime:
Instead of going back to the static adjustments right away when they are knocked off a bit by the dynamics, just keep adjusting the dynamics for parallel lines that are off the same amount all over. Then a single static adjustment will come close to getting the whole screen in, and very minor dynamics will finish the job.

[etype2]

I’d say you summed up the process well. Good results.

[Yamamaya42]

Ironically, while we were waiting for the CRT to heat up in the sun, we watched the moon landing on "Apollo in Real Time" while working on a CRT for a TV that they surely watched it on when it happened.

[Yamamaya42]

I decided to experiment some today.
Wanted to see what I would get if I injected video at the point of the video detector x7, rather than 1st amp.
When I tried, I got the same awful smeared color I saw last time I tried getting color via tuner / IF.
So I decided to try to adjust L7 (4.5mc trap) while in this arrangement, and it made a vast improvement.

So, I hooked everything back up for tuner/ IF mode and tried again.
This is the result
https://imgur.com/IyB3n3Z
https://imgur.com/fDLeg41

much better than it was,
but not perfect :/
the shadow is still there slightly, not sure why, bleeding on strong red, slight diag banding noise .
but it's miles ahead of where it was when i started!

and there is no doubt now that the shmuck who had it before me messed with the coils, IF, and color.

[old_tv_nut]

If you have a video playing through the tuner (not still mode, so the audio is not muted) you should see the 4.5 MHz interference dancing around with the audio, and may be able to tune the trap precisely for minimum interference. If the trap is tuned a bit too low, resetting it may reduce your color ringing (but of course, if the previous idiot fiddled with everything, other mistunings may be contributing the color ringing).

[Yamamaya42]

Originally Posted by old_tv_nut

If you have a video playing through the tuner (not still mode, so the audio is not muted) you should see the 4.5 MHz interference dancing around with the audio, and may be able to tune the trap precisely for minimum interference. If the trap is tuned a bit too low, resetting it may reduce your color ringing (but of course, if the previous idiot fiddled with everything, other mistunings may be contributing the color ringing).

Right now, i am only feeding it video to the tuner, when i adjusted the 4.5 MHz,
and i had to tune it pretty far to get it to this point, I intend to try later with sound hooked up, but I'm not sure how much better it will get.