Oh. Well in that case, I'm surprised it works at all! :D

You'll surely have a very nice picture on it when you go through the paper caps in the rest of the chassis, don't be afraid to pull the metal cover off the color section underneath and have some fun there as well. There's at least 10 more hiding under that hood. Don't come hollerin' though when you wind up needing a matrix alignment, mine was so far out of whack from previous repairs gone wrong, it took me 2 weeks to figure out what the manual was asking me to do. After I figured it out though, it was a snap and now the set has a nice picture indeed.

Congrats!

Now you know that the unobtainium is all good. :thmbsp:

Isn't that the truth! Congratulations! Glad to see it.

When I stuffed the filters of my CTC-9, replaced the CRT and got a raster, I was happy. But it will have to take its place in the queue!

I finished recapping the horizontal and vertical boards. I didn't have a .001 @ 2KV for the vertical board, so I left that one for now:
http://i1216.photobucket.com/albums/...V/P1020413.jpg
http://i1216.photobucket.com/albums/...V/P1020414.jpg

When I fired it up this time, I was able to get the horizontal and vertical to lock easily, and a pleasant surprise-- color lock!
http://i1216.photobucket.com/albums/...V/P1020421.jpg

http://i1216.photobucket.com/albums/...V/P1020425.jpg

http://i1216.photobucket.com/albums/...V/P1020423.jpg

Not bad considering all the maroon drops that remain. On this chassis, there is no metal cover over the color section and everything seems pretty accessible.

To me it looks like the CRT is badly in need of degaussing (or is it purity)? And of course, I got rid of my degaussing coil years ago. Is there any kluge that I could improvise to degauss the CRT? I think I have a small tape head demagnetizer :D

I'm very pleased at how this is going so far!

-Clark

:DWOW! :banana:

Nice, yes a starndard purity setup will prob take care of the colors, and make them pop even better.

A tape head degausser will do more harm than good.
You could probably scrounge a degaussing coil from a newish CRT type junk set and use that with a variac to degauss the screen.
I got my degaussing coil from an active TV repair shop, and you may be able to do the same. Ebay may also have degaussing coils....

Just throwing some ideas out there...

Thanks for the tips and kudos. I think I may be able to borrow a degaussing coil from a friend next week, so I'm not going to try anything foolish in the mean time. Right now, I'm just happy knowing that all the vital organs (including the oozing power transformer) are good. I've never done purity and convergence before so this will be a real learning experience for me. I'm glad to know that all you experts are out there when I need advice :thmbsp:

The picture just keeps getting better. I adjusted the AGC which really woke up the contrast.

Now, I'm going to take a break and watch the Badgers in the Rose Bowl...

"Now, I'm going to take a break and watch the Badgers in the Rose Bowl... "
I can relate to that...just got a my CTC4 to display video an hour of two ago and had to watch it for an hour no color, poor focus, lousy purity, poor convergence and all. When a rare set comes back to life for the first time in decades ya just got stand there in awe.

Another 4 brought back!! congratulations! :D

Thanks! I got a thread going in this section of the forum if you want to see how it is comeing along.

Very nice. I wish I could just drop everything and work on my "stuff". But my CTC-9 is 737 miles away waiting for me to move to Florida. Can't wait...

I'm continuing to recap the whole chassis in stages. I also finally tested all the tubes and found a bunch that were weak, shorted or gassy and replaced them. I also carefully cleaned the tube sockets and the tuner with DeOxit applied with toothpicks and Q-Tips. The set now produces a very stable picture. (I still need to get my hands on a degaussing coil):
http://i1216.photobucket.com/albums/...V/P1020608.jpg

I decided to try a rough adjustment to the convergence, which was really bad. Things went pretty well until I got to the horizontal dynamic convergence:

http://i1216.photobucket.com/albums/...V/P1020604.jpg

http://i1216.photobucket.com/albums/...V/P1020602.jpg

http://i1216.photobucket.com/albums/...V/P1020603.jpg

None of the horizontal convergence controls seem to have any effect. Clearly, there is something amiss. I haven't begun to trouble shoot yet, as I thought I'd check in here first for advice. Any common failures to check out first? I wouldn't be surprised if the selenium rectifier is bad.

Thanks in advance.

-Clark

Wow, that picture is really shaping up. A bad selenium rectifier on the convergence board would not be unheard of. On my first CTC-11, when I unsoldered the legs on the selenium unit, it fell completely to pieces.

http://antiqueradio.org/art/RCACTC-11RectifierParts.jpg

Before it was replaced, simply touching the old rectifier, or the board nearby, made the picture go nuts.

I installed new fast-response diodes that someone sent me. I don't have the type number at my fingertips. Perhaps it is buried in a past thread.

No guarantee that this will cure your problem, but the parts cost almost nothing, and selenium rectifiers are so sketchy that I routinely replace them in radio restorations, just like electrolytic capacitors.

Phil Nelson

I don't claim to be an expert with convergence, but the first thing that jumped out at me when I saw your picture is that it appears the static convergence is off...most notably the Blue lateral adjustment. This is the control on the neck of the crt closest to the socket that moves the blue beam left and right.

I would guess that you haven't tried to perform a full static convergence yet. Using a Dot/Bar generator and set to dots, the goal is to end up with a pure white dot in the center of the screen, using the three static convergence magnets on the neck of the crt. The Blue lateral is also used to obtain that white dot. Once you've got the center white dot the rest of the screen is converged using the Dynamic convergence controls on your convergence board.

I've never seen a perfectly converged vintage color TV. I think the goal is to get it as good as you can and be happy with it. It most definitely does take some artistic and creative maneuvering to get the picture to look good since many of the controls interact with each other.

I would say if you can sit at a distance of about 6 ft. to 8 ft. from the screen and it looks good...you've succeeded.

Hope that helps......
Bob

You really need to get your hands on a degaussing coil and start the purity process before attempting any serious convergence procedures. Other wise you'll drive yourself nuts and get very frustrated achieving that "perfect" convergence.

-Steve D.

Thanks, Phil, Steve and Bob, those are all good suggestions. I did try static convergence first, and I could get the blue dot to move only so far. The lateral positioning magnet did have a large effect on the static convergence, but it's very loose when I rotate it. Is is possible that I need to reposition the convergence yoke?

I think I'll back off for a while until I get a degaussing coil and can preform the purity adjustments.

-Clark

If you pull the sliding magnet out of it's respective track for whatever particular color is giving you grief, and rotate it 180 degrees and then reinsert it, that might give you the movement that you need to align the beams.

You certainly can move the convergence yoke around to find the most effective position for it. Sometimes just a slight rotation right or left will bring things more into alignment. And as was mentioned by Steve, before you go any further...get your hands on a good degaussing coil and get the purity set up properly.

I finally got a degaussing coil which definitely helped the situation. I tried another stab at a rough convergence and this time I got much better results:
http://i1216.photobucket.com/albums/...V/P1020610.jpg

Here are a few screen shots:
http://i1216.photobucket.com/albums/...V/P1020618.jpg

http://i1216.photobucket.com/albums/...V/P1020615.jpg

http://i1216.photobucket.com/albums/...V/P1020617.jpg

As you can see from Dorothy's purple hand, I still have purity issues to deal with. I have also been experiencing intermittent horizontal jaggies (I don't know how else to describe it). You can see it in the screen shots to varying degrees. It's probably from a bad maroon drop cap from among the 20-30 that I have yet to replace. But overall, I'm very happy with how this set is shaping up. I ran it for over four hours straight last night (watched the Broncos & Patriots) and while the power transformer got pretty warm, it was never too hot for me to keep my hand on it. I still haven't measured the HOT cathode current or the HV. But they are high on my list of tasks left to do.

-Clark

On the crosshatch pattern, see how right after every horizontal line there's a little hump in the vertical line? Your horizontal wave shaping coil needs to be adjusted, that's the step in Sams where you scope the coil and turn the slug till you see equal humps.

Hi Nick,

Thanks, that makes a lot of sense. I'll give that a try.

I think that some of the edge purity hairpin magnets are missing. There is only one hairpin magnet at three of the locations on the right side of the CRT whereas there are two at each location on the left side. Are these things hard to come by?

-Clark

Hairpins should be easy to find, pair them up as best you can and don't leave single ones or they will affect the purity.

Well, I've suffered a bit of a set back. I tried adjusting the horizontal "sine wave" coil per the RCA service manual. I attached my scope to test point "E" as instructed, but the waveform appears to be the horizontal drive output, and not the the other waveform. In any case, turning the slug in the sine wave coil did not affect the waveform or the picture. Here's a shot of the waveform that I got:
http://i1216.photobucket.com/albums/...V/P1020619.jpg

I don't know whether the RCA service manual misidentified the test point or if there's another problem. As time went on, I was having more and more trouble keeping horizontal lock. I also found that the horizontal hold control (which is actually the horizontal oscillator frequency control) had to be maxed out in one direction to achieve lock. I tried readjusting the sine wave coil, but it again seemed to have no effect.

Eventually, I was unable to get horizontal lock at all. I powered the set down for a while, and when I powered it up again, I got no raster and the HOT started to red plate. I knew that I still had a bunch of maroon drop caps left which I thought might be the problem, so I pulled the chassis and changed out about 10 more, including those on the video amp/AGC board. When I powered up again, nothing had improved, the HOT red plated and no raster. I'm assuming that I must have lost horizontal drive, or that the horizontal frequency is way out of whack. I tried subbing tubes, and when I put in a NOS 6AU4 damper (even the the old one tests good) the HOT no longer red plated, but I still had no HV or raster (I also tried subbing a NOS 6DQ5). I'm not sure what that means. I inspected the fly, and I don't believe that it's the problem. The only caps left on the horizontal board are two mica caps which I didn't have replacements for. I am still pretty much a novice at this stuff and I'm not sure what to do next. I'm afraid of screwing something up. Incidentally, I never let it red plate for more than a few seconds.

I'd like to be able to power up just the chassis on the bench, but I assume that that would not work without the deflection and convergence yokes attached. I may see if I can power up the chassis with everything connected but the chassis propped up behind the cabinet. That would allow me to finally measure the HOT cathode current. Anyone know if that's possible? I'm feeling a bit frustrated at the moment.

Thanks for any advice,

Clark

looks like you have a .1 not a .01 on the sine wave cap. Better make sure you are reading your cap values on the replacement correctly

did you check under the IF cover for any bumble bee caps? there is a .01 in there that couples the noise invert to the sync sep, seems like it could cause issues with sync.

I am going thru a CTC-9 now. What I do for what its worth is lift one leg of a cap, and use an old school cap tester. If the cap test bad, then I replace it, but before doing that I take the new cap and put it back on the cap tester.

Most of the time the old caps leak but you can get some indication of the value on the cap tester. By leaving all the settings alone, and trying the replacement cap on the tester, you can do two things, verify the value of the replacement and verify the replacement it good.

This step avoids 10x order of magnitude errors and finds the bad new caps. I have had a few of those yellow caps shorted when brand new.

Hi Dave,

Thanks for the feedback. I'm pretty sure that I installed all the correct cap values, but I'll double check. The troubles I'm having now started after I recapped the horizontal and vertical boards and everything was cool for a while. But I didn't check the new caps before installing them, so I could have installed a bad one. They do seem kind of cheaply made. I also have not checked the caps underneath the IF shield, so I will definitely do that.

-Clark

looks like a 104 cap on the horz board, that should be a 103

Good call, Dave. I'm not at home now, but I compared the photo of my recapped horizontal board with Phil Nelson's and I did indeed install a .1 instead of a .01. And I thought I was being so careful:sigh: I'm surprised that it worked as well as it did. That probably explains the horizontal jaggies I was getting. I'll change it out and see what happens.

I hope to have some time this weekend to get back at it.

Thanks again,

Clark

yea been there done that, that's why I always use my cap tester to verifiy what goes in matches what came out.

That is an excellent idea. I will incorporate it in the future. I have gotten somewhat accustomed to the "new" way that they mark capacitors. But when I have been away from it for a while, I have to think. Very easy to make a mistake like that.

One nice thing about the "new" way is that bumblebee caps are marked the same way only instead of digits they have resistor color coded stripes.

Yes, I made a similar flub on a B/W Philco just a few days ago. The comforting thing about finding those errors is that you realize you're not crazy after all -- merely human.

Phil Nelson

My cap tester is one of my must used pieces of equipment.

I just replaced a couple caps in the 9, the .01 that couples the horz osc to the horz out and a .056 on the vert. One was a orange drop, very leaky, the other was a maroon, not as bad but still leaked well below rated voltage. Others tested just fine.

The wave shape coil will have the drive signal coming out one side of it, and the double humped one on the other. You probably just had your probe on the wrong end of the coil, poke around till you find the humped one so you can tune it correctly or horizontal lock will have issues.

Success! I replaced the cap on the horizontal board with the correct value, but the HOT was still red plating. I pulled the 6DQ5 and found that I had a dead horizontal oscillator. After futzing with it for a while, I discovered that the NOS 6CG7 that I had installed was the culprit. It still tests fine but was no longer working in the circuit. I put the old, weak tube in place and the oscillator fired right up. This time, I was able to easily adjust the sine wave coil for the proper waveform:
http://i1216.photobucket.com/albums/...V/P1020621.jpg

Now the horizontal lock is nice and stable with the control in the middle of its range. the horizontal jaggies seem to have disappeared. There are now just a few "maroon drops" remaining and things are looking pretty good:
http://i1216.photobucket.com/albums/...V/P1020630.jpg

I still need to go through the entire purity/convergence set up. I discovered that none of the hairpin purity magnets are missing after all. A couple had been moved to normally unoccupied positions. I think they need to be remagnatized, too.

Thanks again for the help!

-Clark

Lookin good!

I finally had time to attempt a complete purity, convergence and gray scale set up. The picture has dramatically improved. I still need to work on the convergence:
http://i1216.photobucket.com/albums/...V/P1020670.jpg

http://i1216.photobucket.com/albums/...V/P1020674.jpg

http://i1216.photobucket.com/albums/...V/P1020676.jpg

I need to track down the source of intermittent brightness and contrast fluctuations which go away after the set has been on an hour or so. I suspect a tube socket or dirty ground connections.

Also, the image tends to smear a bit (if that's the right term for it), particularly with text. Does this point to an IF problem?
http://i1216.photobucket.com/albums/...V/P1020680.jpg

I managed to remove the safety class for cleaning. Of course, I found the VK thread on this AFTER I struggled with mine:sigh: Fortunately, I didn't damage anything.

I still need to get after the seller about looking for the missing back, but I'm not optimistic that he'll find it so I'll probably be in the market for one. What do they look like? Are they metal, like the rest of the cabinet, or fiber? If someone has a photo of one that they could post, I'd really appreciate it.

That's the update for now. I'm typing this for the second time, since my first attempt mysteriously vanished:dammit:

-Clark

CTC7 Flyback?
 

Really nice job!!!!

One thing I either noticed, or missed, :D is no discussion of the wax ooze from the fly. Have you checked the HOT cathode current yet? If it's OK, do you have any plans to deal with that?

Is it a problem to have that much wax outside the fly?

Nice pictures on that set.

A CTC-7 back is fiberboard with a cardboard squarish box for the CRT neck. If you have seen a CTC-5 back, the CTC-7 seems similar to me. Mine would be hard to get into a picture, but if no one else posts one for you, I could do so.

The back on mine happened to be off, so I snapped a photo. It's perforated metal with a cardboard box for the CRT neck.

http://antiqueradio.org/art/RCACTC-7BackCover.jpg

Other cabinets might have different backs, for all I know. This is the Pensbury cabinet.

http://antiqueradio.org/art/RCACTC-7...AtPurchase.jpg

Regarding the oscillator tube that tested OK but didn't oscillate, I've had the same experience. An emission type tube tester like mine can't check whether a tube oscillates correctly. I don't know if any tester can. I have seen service books that tell you to keep swapping oscillator tubes until you find one that works.

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