CTC-4 Director 21

[Electronic M]

You may need to adjust L86 (sams). It sets the relative phase angles of the demodulators...If it is off you will be able to get the red bar red and the blue bar blue but not both at once (and similar problems)... IIRC you have to adjust a slug on top of chassis and a slug under chassis simultaneously with plastic* straight edge alignment screwdrivers (had to do this on my CTC-4). *Metal screw drivers will act like an extension of the slug and your freshly tuned adjustments will de-tune as the metal driver is withdrawn from the transformer can (spoken from experience ).

If the color temp is right with the set operating in B&W mode then it is right, and does not need messing with....If turning on the color circuits throws the greyscale color temp off then there are problems in the color circuits causing that.

EDIT: BTW congrats on getting sync! It seems these sets like to get dirty intermittent tube sockets.

[SwizzyMan]

Originally Posted by Electronic M

You may need to adjust L86 (sams). It sets the relative phase angles of the demodulators...If it is off you will be able to get the red bar red and the blue bar blue but not both at once (and similar problems)... IIRC you have to adjust a slug on top of chassis and a slug under chassis simultaneously with plastic straight edge alignment screwdrivers (had to do this on my CTC-4).

If the color temp is right with the set operating in B&W mode then it is right, and does not need messing with....If turning on the color circuits throws the greyscale color temp off then there are problems in the color circuits causing that.

EDIT: BTW congrats on getting sync! It seems these sets like to get dirty intermittent tube sockets.

Glad it was just a matter of intermittent connection then that of a bad part! I'll give your suggestion a try.

[SwizzyMan]

Either im not adjusting L86 properly or we have a different problem here. After turning both shafts one turn CCW the screen develops a yellowish green tint. And after a turn clockwise it does the same thing. If i turn the slugs individually the top part of the coil seems to have a bigger effect than the bottom portion. What could I be doing wrong?

[Electronic M]

IIRC (it's been ~4 years since I was working on mine) There maybe some interplay with the tint control. I think there may have been some tinting of gray scale when adjusting those slugs on mine. Also on color sets if the color lock is lost with saturated bars the bars will tend to all turn one color.

Put 86 back how it was, adjust the tint so as many of the bars are as close to the correct color as possible, then try 86 together with the tint control and see if you can get it better.

Also you may have the color level up too high. The first bar should be white IIRC. If you overdrive the color level on some (otherwise perfect) sets the tint of some colors will shift abnormally. Reduce color level till the bars are pastel/faintly colored and readjust.

[SwizzyMan]

Originally Posted by Electronic M

IIRC (it's been ~4 years since I was working on mine) There maybe some interplay with the tint control. I think there may have been some tinting of gray scale when adjusting those slugs on mine. Also on color sets if the color lock is lost with saturated bars the bars will tend to all turn one color.

Put 86 back how it was, adjust the tint so as many of the bars are as close to the correct color as possible, then try 86 together with the tint control and see if you can get it better.

Also you may have the color level up too high. The first bar should be white IIRC. If you overdrive the color level on some (otherwise perfect) sets the tint of some colors will shift abnormally. Reduce color level till the bars are pastel/faintly colored and readjust.

I did have the color turned all the way up. But i did adjust the tint for the best match. The only color that is correct seems to be the red bar which is in the right spot.

[Electronic M]

What I mean is if you turn the color all the way up one or more bars may independently change tint in the opposite direction of another bar such that there is no setting where all the bars are right....I've seen it before where once color is over driven there is no longer a setting where all bars are right since one or more have wandered off of correct relation to the others.

[SwizzyMan]

Originally Posted by Electronic M

What I mean is if you turn the color all the way up one or more bars may independently change tint in the opposite direction of another bar such that there is no setting where all the bars are right....I've seen it before where once color is over driven there is no longer a setting where all bars are right since one or more have wandered off of correct relation to the others.

Got it. Ill lower it then try adjusting L86

[SwizzyMan]

After turning down the color a bit and adjusting L86 I finally have pretty much the correct colors! But as you can see there is heavy interference in the picture. What I think Ill do next is inject a video signal from a dvd player directly to the grid of the Audio amp tube and see if that clears up interference so I can narrow down whats causing it. Any thoughts on what could be the cause of the interference? The camera makes the picture look a bit more clear, but in person the interference is heavy.

[old_tv_nut]

I don't have the SAMS, just the schematic that's on earlytv.org (RCA?). If "L86" on SAMS is the output of the 3.58 MC oscillator (T115 on the earlytv schematic), then you may be killing the oscillator when tuning too far. If all the bars suddenly go to the same greenish hue, that can be an indication that the oscillator stopped running on some chassis (I'm not certain about the CTC4).

Edit: we crossed posts - glad you have it working.

[old_tv_nut]

I really don't have a firm idea about the interference, but I see what looks like delay line ringing in the video (multiple trailing ghosts). Maybe there could be a bad ground or something that's making the video circuits oscillate (?). Does the interference change when you adjust the contrast?

[SwizzyMan]

Well I found the source of all the nasty interference. It was my agile modulator! Funny thing is that the interference doesnt really show up in my 7 but does show up a bit in my 5. I hooked the set directly to my cable box and the difference is night and day. Obviously purity and convergence are piss poor, but I'll do convergence later tonight.

[SwizzyMan]

Convergence on this set couldnt be more confusing. Has anyone here done convergence on a 4 and could you guide me in the right direction? I tried to follow the manual, but it is still rather confusing.

[Phil Nelson]

Originally Posted by SwizzyMan

Convergence on this set couldnt be more confusing. Has anyone here done convergence on a 4 and could you guide me in the right direction? I tried to follow the manual, but it is still rather confusing.

Your TV is starting to look pretty good. What manual are you using? The most detailed service book is the 91-page RCA service clinic manual. This article has a link to download it:

https://antiqueradio.org/RCACTC-4ColorTelevision.htm

I believe the color setup procedure starts around page 25. Go through it step by step, in the order given (i.e., purity first, then convergence). It's essential to use a pattern generator. The dot pattern is most useful for convergence.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[SwizzyMan]

Thanks for the kind words guys! The set is really shaping up now. But there is still a lot of work to be done both electrically and on the cabinet. Im having custom decals made for the decals located under the knobs. Im debating on whether to refinish it or not. Oh and Phil, I am using the factory RCA manual to go through the setup. I will take a look at the one on your page too. Convergence needs to be done before I can do purity since poor center convergence will make it hard to get good purity. Ill try and figure out convergence soon, but it sure is confusing!

[BigDavesTV]

Wow, nice to see it at this point, congratulations!