RCA CTC...Something? poor HV output.

[Findm-Keepm]

Originally Posted by Arcanine

I honestly never thought I would see that TV produce even a half watchable picture. That is as close to perfect as I'd call a set that old.

Looks great! ElectronicM done you right! Great job!

[WISCOJIM]

Originally Posted by Arcanine

And do not buy what the tester says. Jim will chime in and agree, HV Rectifiers never test correctly. They almost always test as bad. Same thing for the Focus 1V2 tube, they test almost bad. You have to remember, the tube usually has 25kW pumping though it, so the tester can't even scratch the surface. Jim and I tested almost 10 of those tubes and they all tested pretty much the same. "Bad"

Affirmative.

.

[Electronic M]

Originally Posted by Arcanine

The 6JE6/6LQ6 that's installed in the CTC16 now (Or rather when I delivered it to you) is actually from the CTC20 originally (It's hat looks more like that of a HV Rectifier). I swapped them around. Go ahead and take it out and keep it, and pop my spare RCA back in. That gives you an HO tube for the CTC20 then.

Last night I tested all lytics in the CTC-16 for capacitance and leakage up to rated voltage with my Heathkit C3. I completely recapped the C2 and C3 (sam's cap number) cans. Can C2 had 2 leaky and one high ESR section out of 4. C3 had one high ESR section out of 2 sections so I decided to replace the whole thing for good measure. C1 tested perfect, no leakage low esr, so it was left alone.

I powered it up with your above suggested H out tube swap and the set came on and ran with H centering jitter for 3-10 min before the width shrank greatly which prompted immediate power down. The new ho tube was drawing more than 5ma more cathode current so swapped back to tube that came in the set when I got it....Cathode current is lower and jitter is not present.

I ran it for 1 hour with h out cathode current metered the whole time (it stayed just below 200mA the whole time) and started to hear HV like sizzling and noticed screen noise/h line jitter (multiple clusters of roughly 1-3 h lines would be off center from the rest). I turned it off and the sizzling stopped with power off, opening the cage revealed very mild wax melt (compared to last time), HV winding rubber tire formed warts between HV rect cap cup and the center. It was hottest beneath wart area. The HV rect tube is a RCA 3A3C the chart calls for a 3A3A....I seem to recall once reading that some variants of that tube caused arcing in the CTC-16, but I can't recall it exactly or find it....Could that be the cause?
The tire was VERY soft and pliable in the wart area. I'm really worried that the flyback might not have long for this world.

Originally Posted by Arcanine

And do not buy what the tester says. Jim will chime in and agree, HV Rectifiers never test correctly. They almost always test as bad. Same thing for the Focus 1V2 tube, they test almost bad. You have to remember, the tube usually has 25kW pumping though it, so the tester can't even scratch the surface. Jim and I tested almost 10 of those tubes and they all tested pretty much the same. "Bad"

I don't put much stock in testers results of sweep tubes, but my tester has notes with the settings HV rects...In the case of the 3A3 it says tube good if reads 40 (in the bad scale range) or more. It read 20, and it's replacement read 90 so that is what went in.

I got the CTC-20 together and was able to get a monochrome picture and sound from it.

I'll post some info/opinions in your CTC-16 fly cooling thread latter I have a certain woman SCREAMING at me to do some remodeling work on the house right now.

[Arcanine]

I wonder if the Tire it self has become conductive? Shango066 on YouTube talks about that a lot on these old RCA sets. And it usually happens in the exact area mine is having major issues with. Right below the hat that the HV Rectifier tube goes in too.

Here is an idea: Carefully see if you can peel the tire off the flyback in the effected area, go to Autozone, or Advance Auto and get Permatex UltraGrey RTV and cover the effected area completely with a layer or two of the RTV to see if that solves the issue it's suffering. It really sounds like the tire has become conductive internally.

Look up Shango066's videos on this. He's repaired much sicker, weaker flybacks this way and it seems to hold up. It's not pretty, but these parts are unobtanium and I cannot afford to source a new fly.

And I don't want to sit with a sick lump of a TV I'm never going to do anything with. I haven't the space to just sit and let it do nothing. I only have room for one single TV this large. If the fly in this set is sick, and you have the patients and time to source a fly, fix the CTC20 and keep the CTC16.

Keep me informed.

Vidoes: https://www.youtube.com/watch?v=BUnPkymnxUw
https://www.youtube.com/watch?v=OHyQo76ySG4

it's not pretty but this might save the CTC16's fly.

[Electronic M]

I'll examine the fly more carefully to see if I can find what is going wrong.

Would you mind if I drilled a couple of holes in the HV cage so I can see in with it assembled?

The 20 has vertical problems and I have yet to address the coils that are snapped off the rear board.....I don't know if I can get the 20 to work as a color set again (those snapped coils are for color IIRC), let alone by the time you want back at (it might be extra cooperative and come together easy, but I don't want to bet on that yet)....The 16 is working fine aside from the fly issue so I want to try and fix that before I give up and focus on the 20...

I've watched the videos and am willing to try the silicone method if that is what the symptoms merit, but I want to see exactly what it is doing first.

As soon as I can look at it more I'll get back to you.

[dieseljeep]

Originally Posted by Electronic M

I'll examine the fly more carefully to see if I can find what is going wrong.

Would you mind if I drilled a couple of holes in the HV cage so I can see in with it assembled?

The 20 has vertical problems and I have yet to address the coils that are snapped off the rear board.....I don't know if I can get the 20 to work as a color set again (those snapped coils are for color IIRC), let alone by the time you want back at (it might be extra cooperative and come together easy, but I don't want to bet on that yet)....The 16 is working fine aside from the fly issue so I want to try and fix that before I give up and focus on the 20...

I've watched the videos and am willing to try the silicone method if that is what the symptoms merit, but I want to see exactly what it is doing first.

As soon as I can look at it more I'll get back to you.

If someone has a junk CTC19 or a CTC24, the color circuits are the same.

[Arcanine]

All bets are off. No time frame now, so don't rush. You don't need to rush your self on the 16 or the 20. I'll wait. I don't want to have to sit and worry that fly is going to melt inside it's cage and or burst in to flames if I don't shut it off after under an hour of use. OR the Fly is just going to go KERPOOF after a couple uses and leave all your hard work moot with a dead set. Unfortunately, I'm not able to, or willing to fork over another possible $250 for a "good" flyback plus your labor on that set if that flyback ends up killing it self. That set's future is hanging on it's flyback.

Take. Your. Time. As much as you need.

Feel free to drill and open the cage anyway you need to look inside and see what the fly is doing or aid in cooling it. I'm willing to bet money on that arcing issue, either internally or externally, silently. It's burning the tire in the same exact spot that the videos on youtube. It seems like a simple thing, it's just a bunch of windings inside there, and look at how his was arcing and melting it self, but still worked and keeps working after. Mine is working decently except getting hot with no real explanation and melting the tire in the exact area he mentions in his two videos. I think it's arcing inside the tire and melting it.

Like I said, if you think my fly is sick and I think it's arcing, peel it's tire off and look inside, then seal it back up with RTV. The stuff is only like 4 bucks for a large enough tube to cover the whole flyback. I use Grey all the time, I just used it last week to replace valve cover gaskets on my Ranger.

[Electronic M]

Looks like it was arcing on the back of the tire.


I wanted to duplicate the arcing behavior so I ran it 20 minutes, and forgot the mirror inside....When the symptoms came back they were fresh ones from the mirror falling between the 11'oclock outer edge of the fly and the cage. Mirror silvering is conductive so all it had to do was melt the plastic edges of the mirror.... After removing the mirror it wanted to arc from the mirror contact point on the tire so I ripped enough off the tire to help, and put a piece of plastic (seen in the last tireless shots) in there to block the spot in the cage it wanted to arc to.


I then ran it for almost 2 and a half hours watching it closely, and periodically putting my ear next to the cage to listen for bad noises in hopes the blackened back top of the tire would arc to prove my theory that it was the cause of yesterday's 1 hour arcing.....Nothing happened in those 2+ hours! It worked fine. The tire was warm at the end and some external wax was on the edge of melting/slightly melty, but the only reason I had to shut it off was because I was summoned by the folks for a menial task.

I pulled off the back charred section, and came to the conclusion the tire was so loose it might as well be removed entirely. I'll get some silicone tomorrow and give it a new coat.



Here is what I got out of the 20 last night, but forgot to post.


Thanks for allowing me time to get it right. I have been pushing to get it done since there is other stuff (my stuff, and others') I want to work on, and honestly I can see why you were/are not a big fan of this set....I'm sort of tired of pouring my energy into it only to find the next thing or get lack luster non-proportional improvements.

It's darn fascinating working on these chassis and seeing what they are all about compared to others I've seen/worked on, but now my curiosity is sated and from this experience I can say I don't think I'll ever actively seek out another CTC-16 or 20....These sets remind me why I'm (mostly) a Zenith man.

[Arcanine]

Looks like my theory and hours of watching Shango's videos paid off.

Remember to peel off that beige silicone stuff that he removed in the second video to make sure there is no carbon tracking on the fly it self behind that gross stuff.

Go to the car parts store and get the Permatex UltraGrey. Automotive RTV lacks the acids, as Shango mentioned in the videos, and it can withstand very high voltage, is completely non-conductive. And it can stand up to very high temperatures.

Yeah. Now you see why I passed it on to you for repair. I bought it thinking it was working well and would be simple to keep going. In reality it was very sick and in very bad shape internally and it needed a lot more work then I knew how to give it...

I'm super excited to see it working again and look forward to seeing it in person once it's complete.

I'm glad to see the CTC20 has life. If you can fix or source those coils, I bet it'll come back to life. It's a fairly nice set honestly, I wish it had better care when it was being stored so it would have survived better. Makes me feel even better that it works, you'll get the cash you asked for. You got a Roundy that works with a good CRT and a lot of potential, and a couple other bonuses I am tossing in for all the time you put in to this thing for me that I think you'll like =)

[Arcanine]

This may be interesting to you, Tom.

http://www.videokarma.org/showthread.php?t=254649

I found the original thread from Colin when he found the CTC20 back in 2012. It looks like the TV worked pretty well. I would try and bring it back to life if I were you. If you can't fix those snapped off coils, I would try and source them.

If down the road you decide to sell the CTC20, I'll be first in line to get it back. I actually find it to be extremely attractive. I'd make the space to have it with the CTC16 =)

[Electronic M]

I got the old silicone off and recoated the fly for the CTC-16 on Saturday. It went well, and aside from the rubber tire being charred/bubbled there were no scorch marks or carbon tracks to be found (the old silicon and fly paper were fine).



I decided not to smooth it since a rough surface has more surface area, and thus should cool better.

I gave it about 1.5-2 hours run time with the silicone still soft (which cured it nicely), and it ran like a champ the whole time.

Then I got sidetracked till last night upgrading my laptop to Windows 10 (long story).

I gave it another hour and 40 minutes on. No, arcing, no wax ooze, but the fly does get rather warm...I want to try and find some time to put 3-6 continuous hours on it to see how it holds up. When I can I'll get some heat sink compound for the fly to chassis (may also squirt some between the windings and core). I'll also try to add some vent holes and a fan to it, but I gotta figure out where and which fan (the best side to put a decent sized fan is against the side of the cabinet, and not usable).


I worked on the 20 today. I resoldered the busted coax to the color level control, and resoldered the snapped off chroma transformers.....It came on, a moment later I hear a snap and the vertical fills out. Then I proceed to adjust what I believe is the chroma osc. transformer and start to get color barber-poling.....Then another snap, raster is lost, and smoke from the area of the chroma osc. transformer. I swap the two leads I guessed the connection points to, and try to reassemble it, but the bottom has melted/warped to the point where I'm not sure that transformer is worth fixing anymore....The vertical relapsed to not filling the screen too. That CTC-20 is a real mess.

I think I'll work on something else for an hour or two to get a break from RCA color work.

[Findm-Keepm]

Originally Posted by Electronic M

I gave it about 1.5-2 hours run time with the silicone still soft (which cured it nicely), and it ran like a champ the whole time.

Heat doesn't cure RTV, only exposure to air and time. Room Temperature Vulcanizing. Heat may open air passages (tunnels) within the RTV, which is why the DoD bans heat application to RTV products. If you are trying to seal up something, why heat it and create tiny tunnels?

Now epoxy, yes - heat that stuff! It shortens the cure time, and makes bubbles trapped within to pop, making for a better cure. But RTV, no.

[Arcanine]

Originally Posted by Electronic M

I got the old silicone off and recoated the fly for the CTC-16 on Saturday. It went well, and aside from the rubber tire being charred/bubbled there were no scorch marks or carbon tracks to be found (the old silicon and fly paper were fine).



I decided not to smooth it since a rough surface has more surface area, and thus should cool better.

I gave it about 1.5-2 hours run time with the silicone still soft (which cured it nicely), and it ran like a champ the whole time.

Then I got sidetracked till last night upgrading my laptop to Windows 10 (long story).

I gave it another hour and 40 minutes on. No, arcing, no wax ooze, but the fly does get rather warm...I want to try and find some time to put 3-6 continuous hours on it to see how it holds up. When I can I'll get some heat sink compound for the fly to chassis (may also squirt some between the windings and core). I'll also try to add some vent holes and a fan to it, but I gotta figure out where and which fan (the best side to put a decent sized fan is against the side of the cabinet, and not usable).


I worked on the 20 today. I resoldered the busted coax to the color level control, and resoldered the snapped off chroma transformers.....It came on, a moment later I hear a snap and the vertical fills out. Then I proceed to adjust what I believe is the chroma osc. transformer and start to get color barber-poling.....Then another snap, raster is lost, and smoke from the area of the chroma osc. transformer. I swap the two leads I guessed the connection points to, and try to reassemble it, but the bottom has melted/warped to the point where I'm not sure that transformer is worth fixing anymore....The vertical relapsed to not filling the screen too. That CTC-20 is a real mess.

I think I'll work on something else for an hour or two to get a break from RCA color work.

I think with the CTC20 it's going to come down to sourcing good replacements for those two transformers... I wish better care had been taken when it was stored disassembled. I like the style, I may wanna buy the set back, so I'd be interested in helping seek the parts.

I'd almost be interested in coming up there and learning from you while you work a little. Learn the basics I'm missing from you, that stumped me so endlessly with the CTC16. How to read and test resistors, check voltages properly, test capacitors.

As for cooling the CTC16's flyback, I was thinking of putting a small, low voltage brushless computer fan on the bottom of the right side of the flybox (Facing it with the back of the set off), blowing in on the transformer, with a vent hole on the top left side to blow the heat out. It would only take a low voltage wall-wart to power a computer fan, which could easily be wired to the TV's cord and switch, so when the set is switched on, the fan powers on. Brushless computer fans are very quiet and move plenty of air. I have several plus several power supplies laying around that'd drive it perfectly.

I'm going out of state in a few days and I'll be gone until December 10th. so while I am gone, feel free to watch and enjoy my CTC16 all you like. Besides the warm flyback, I would certainly call it done.

Windows 10 sucks so far. If you want Windows 7 I have an unlocked installer that I can give you that updates it self and is fully featured. I'm giving you a pretty high end business grade dell laptop as a bonus for all the work you did on the CTC16. it'll have Windows 7 Professional installed on it and I'll include a DVD of the reinstall stuff for you.

[Arcanine]

Originally Posted by Findm-Keepm

Heat doesn't cure RTV, only exposure to air and time. Room Temperature Vulcanizing. Heat may open air passages (tunnels) within the RTV, which is why the DoD bans heat application to RTV products. If you are trying to seal up something, why heat it and create tiny tunnels?

Now epoxy, yes - heat that stuff! It shortens the cure time, and makes bubbles trapped within to pop, making for a better cure. But RTV, no.

Having worked in the Automotive Industry for the last 11 years, and having sold parts for the last 3 years, I feel I can step in.

You're right, heating it will create bubbles, but UltraGrey, UltraBlack, and the more modern RTV's set up with in an hour of being applied, and cure fully with in 24 hours. It can be placed in to service with in an hour.

Also, we're talking about a hot engine block, not a paper & wax flyback transformer in a vintage television. The flyback doesn't get nearly as hot as an engine. It's heat did nothing to aid in making bubbles, or curing it any faster then it would cure anyway.

I requested he used UltraGrey because of that reason, and because I have had amazing personal success sealing up leaky Flybacks with it before. I keep a small tube in my toolbox. Sony Fly's are notorious for splitting in the center of their hard plastic "tire" and leaking out high voltage and arcing. I just slather a little UltraGrey on, let it cure, and the voltage leaks are gone.

Just my two cents. You are 100% right, it will have that issue on a smoking hot engine, but a warm flyback won't effect it in the same manner.

[Findm-Keepm]

Originally Posted by Arcanine

Having worked in the Automotive Industry for the last 11 years, and having sold parts for the last 3 years, I feel I can step in.

You're right, heating it will create bubbles, but UltraGrey, UltraBlack, and the more modern RTV's set up with in an hour of being applied, and cure fully with in 24 hours. It can be placed in to service with in an hour.

Also, we're talking about a hot engine block, not a paper & wax flyback transformer in a vintage television. The flyback doesn't get nearly as hot as an engine. It's heat did nothing to aid in making bubbles, or curing it any faster then it would cure anyway.

I requested he used UltraGrey because of that reason, and because I have had amazing personal success sealing up leaky Flybacks with it before. I keep a small tube in my toolbox. Sony Fly's are notorious for splitting in the center of their hard plastic "tire" and leaking out high voltage and arcing. I just slather a little UltraGrey on, let it cure, and the voltage leaks are gone.

Just my two cents. You are 100% right, it will have that issue on a smoking hot engine, but a warm flyback won't effect it in the same manner.

And I've used RTV many times for corona prevention before - but conductive tracking does occur, and only at high voltages - where the RTV was heat cured and paths for corona were created.

I've serviced TVs since the 70s, dealt with corona and arcing in 55KV AWG-9 radar transmitter power supplies, 16KV Conrac monitor power supplies, and solved many problems with RTV. But in my humble 30+ years in electronics, I've seen RTV'd flys fail just as often as the originals, and mostly due to the carbon tracks - their death certainly created by heat or disturbed curing. RTV has such a strong dielectric strength that 1/20" will seal against corona in a 50KV system, but one tiny (electron wide) hole is all it takes to fail. Patience and curing at room temperatures, with no disturbance for the allotted time is all that is needed for success.

Now with ATS (Activation Temperature Sensitive) silicone (similar to RTV) products, the crap won't cure without heat, and at a prescribed temperature. I've use it as well - aerospace stuff - we can't afford it - but take some good old RTV3145, the good grey stuff, simply apply and let it cure, no heat. No reason to bake out bubbles that leave a tunnel behind as they head for the surface, setting up a corona/burn path....

Remember, we're trying to save flybacks, not guarantee a kill....

But i digress, it's not my flyback.