CTC-15 Color Sync - Videokarma.org TV - Video

bgadow · #1 09-29-2004, 08:24 AM

This has been my project for the last week, getting this CTC-15 going. I won't go into the whole story right now but its amazing this set works at all and, right now, it makes a very good b/w picture. I'm very happy. But...I just can't get the color to come into sync. I've been following the alignment instructions in the RCA Pict-O-Guide (and another book I have) and they have been very helpful, but I run out of adjustment on the reactance coil before the color bars will go from horizontal to vertical. I've made multiple tube subs throughout the color section (except the demodulators) and have checked/changed numerous caps/resistors. (but not all; I started with the ones that my RCA Color TV book suggested) I plan on pulling the chassis again & checking some more resistors, but are there any hints anyone can give? One of the books hinted at a connection with the horiz. osc. but I wasn't too confident about that.

Could a colorburst crystal cause this problem? And if so, does Radio Shack still carry them?

Chad Hauris · #2 09-30-2004, 06:14 AM

I was able to cure a problem on a Wards CTC-15 clone set by replacing the crystal...I salvaged one from a junk set. This was a case where the 3.58 osc was not running at all.
I remember when Radio shack used to carry the crystal but I don't think they do anymore.

Steve McVoy · #3 09-30-2004, 06:33 AM

There are some crystals on Ebay now:

http://cgi.ebay.com/ws/eBayISAPI.dll...sPageName=WDVW

Jeffhs · #4 09-30-2004, 02:09 PM

Quote:

Originally posted by Chad Hauris
I was able to cure a problem on a Wards CTC-15 clone set by replacing the crystal...I salvaged one from a junk set. This was a case where the 3.58 osc was not running at all.
I remember when Radio shack used to carry the crystal but I don't think they do anymore.

Chad, I would have thought that if the burst oscillator were not running, there would either be no color whatsoever in the picture or else the screen would take on some ghastly tint, such as purple. If the oscillator (color or horizontal, the latter also having a definite bearing on color sync) is way off frequency, I can see how the color sync would be affected, but the colors themselves would still be there, wouldn't they?

bgadow · #5 10-01-2004, 12:35 PM

It was my understanding, from what I'd read, that a bad crystal would pretty much kill color, maybe with some green streaks in the picture, maybe? But I got to thinking about what an off-frequency crystal might do. But I'm not sure if thats how crystals work. But, anyway, I did make good progress last night.

I found a crystal on a module up in the attic so I pulled it, swapped it into the chassis. But what I found was that the last replacement was pretty shoddy, and I'm not even sure the connections were all being made. (lifted traces,etc.) So with that fixed I put it all back together and was able to get the bars where they belonged. Man, that test pattern was beautiful! It wouldn't stay locked so I was tweaking things when-gosh darn it! The slug in the reactance coil froze! I could not get it to turn for love nor money. After trying for nearly an hour I finally pulled the chassis-again! Glad RCA made it so easy! Had to pull the coil loose (it wasn't soldered too good, either) and found the slug was cracked into thirds. How did my little plastic tuning tool do that? Its IRON! Anyway, I got it all fished out and found another one in my 'collection'. Now, guys, this is why you want to go after those closing tv shops. I don't know where I got the matchbook size container of slugs but you sure don't find them at the radio shack! Now I have to put it all together and hope things are no worse for the wear. Then I can go back to diagnosing the lock problem, which I'm thinking won't be too tough. This seems to be a very stable running set, otherwise.

nasadowsk · #6 10-03-2004, 05:30 PM

My Sylvania 580 chassis arrived with no color. When you turned the color control up, you got a weird greenish tint to things. I figured out the 3.58 oscillator wasn't running, and tweaked the coil and it got 'bump started' and ran. Brought the color in pretty good.

I also found on my CTC-16 set, the oscillator's output isn't a true sine wave. I found that peaked, it was distored, and spun it back a little to make it cleaner.

bgadow · #7 10-03-2004, 10:23 PM

Well, gang, this set is "good enough" for now. After about 10 minutes the color locks (and stays locked) and looks great. I'm guessing maybe a resistor that has to heat up, but for now I'll let it slide. As soon as the site is back to 100% I'll post a pic, along with the full story of this old beast!

bgadow · #8 10-26-2004, 10:27 PM

Finally getting some pictures up. First, the full background on this set. In the early 90s I was coming across a lot of old color tube consoles, and 2 of those were roundies. The first one, IIRC, was the Admiral, a blonde set with many problems-terrible cataracts, a broken tuner and a ruined finish. (it was a dump find) The thing did work, though. I remember sitting back in my old workshop watching Desert Storm happen on that set. If I had it today I would, of course, fix it up. Really, the toughest thing would have probably been the cabinet. The cataracts, I now know, aren't that big a deal, and the tuner just needed a gear. Sadly, I left it out at the edge of the woods behind my mother's house to die a slow, pitiful death

Not long after that I found this CTC-15, also at the dump. It was in good condition and worked, the only problem being a short raster. BUT it had cataracts, and I had no idea they could ever be repaired so, while other sets came and went, this one just sat out in the garage, unloved. Finally, this summer I brought it in the house-hooked up the crt tester to see if it was worth fooling with...the filaments glowed very dimly and the voltage seemed to be pulled down for some reason. Soon I discovered why: One by one, the filaments died. The crt had gone to air over the last 10 years or so. But, all is not lost. A few months earlier, after reading about cataract surgery and other amazing feats here on this forum, I got to thinking. I went out to my mother's house and found the remnants of that old Admiral. The cabinet had completely disolved into the landscape. Everything else is long ruined. But the CRT-hmmm...

Brought it home, the sight of that face was gruesome. (will post a pic someday) I came right off when I pulled loose the tape. To shorten the story, it tested fine! I had cleaned it up and left it in the attic. So now it was all ready to be called into duty in this RCA.

I glued the faceplate back on, did the swap-first crt I've ever changed. Did some minor repairs to the chassis, replaced some tubes that had been borrowed over the years-it powered up, much to my surprise, without drama! Still had the same short raster problem. Took some searching but finally found there was an open resistor off of the height control. Then came the color sync issue as described earlier in the thread. Odd, when I turned it on tonight I expected it to act like it did the last few times I've used it, that is, rainbows for about 10 minutes, and then rock-solid sync. But tonight it synced right away and stayed there. I'm not complaining!

Anyway, sorry for the long story. I'm real happy with this set, especially the crt, considering it spent about 12 years face down on the ground! And the purity is fine, another surprise to me. A couple of the center convergence magnets were missing from this set, but I was able to glue some small magnets to pieces of popsicle sticks and it worked fine. The only other thing, and one of you should be able to help here-the tuning/volume knobs are incorrect. (they were missing) If someone could post a closeup I could search my pile for something that is at least closer.

Charlie · #9 10-26-2004, 11:30 PM

Bryan,

Awesome color! Is this a remote set? Sure has a nice cabinet!

I hope my 15 gets that way!