here is another, still getting better, you can see all the color guns seem to be working fine. oh and the linearity adj got rid of the odd lines on the bottom

I had to drag her out to look at it :P:

I think I am getting the hang of the fine art of fine tuning and color adj :)

Rockford comes on in 20 min, can't wait, gonna pop some corn.

:yes:

Oh yeah, you're getting there. You'll likely find that you'll be tweaking that thing for some time as each day passes.

well next up will be the filter caps. but you know they seem be working fine, but I know they should go. I figure the inline fuse would protect against a short, and if they open no harm will be done, just problems. I will prob do them just to be safe.

I am getting excited about building a box for it. May have to invest in a table saw next. She is gonna love that idea :no:

I am gonna be out in the garage till late tonight, after rockford hitcock, then night gallery.

I can't see that focus diode tube light up, granted its 2v but it does not seem to be getting very warm I did not check the filaments yet, have to check the schematic to see what feeds the heaters

ok after an hour or rockford I see how the convergence is acting up.

it seems to be out of alignment on the lower part of the screen by vertically (on vertical lines you see red green blue side by side. on the top part of the screen the vertical looks good but the colors are displaced horz (colors are separated and stacked on top of each other on horz lines).

sorry if I am not using the right terminology.

So I guess convergence can be out both directions on different parts of the screen? in my case the upper and the lower.

I am going to spend some time tomorrow with the service manual. Looks like you could need to go to school to learn this stuff, or at least apprentice for a long while.

Wow, You done good and the picture looks great.
Try cleaning all the controls on the convergence board. Check and re solder the pins and ground connections. Also you may need to replace the selenium diodes. It is not as hard as it looks. {See picture}
Ed

This was the first color roundie I saw with the swivel base so I had to buy it and rebuild it. The one side of the cabinet was facing a patio door so the finish is not so great but a good cleaning and some old English fixed it. Most of the tme I do not mess with the cabinets on the old tv's other than cleaning and polish. I would make the problem much worse if I got out the sand paper and such. :scratch2:
Ed

I will check it out. Are those replacement signal diodes I see for the Se?

ah I see it, on mine, do you have a 1NXXXX recommedation? I have some 1N60s germanium if you think they would be a better match that silcon signal diodes.

great looking picture.the linearity could be the resistor on the control.it goes bad all the time causing a vertical problem.if you were closer,i have 3 cabinets that i need to move out.there are in reasonable condition.i think the 15 and 16s produce the best roundie picture.those crts are really spot on.congrats on this.you couldnt have gotten a better one for a first time.

I took the diodes from a early solid state 70's xl 100 convergence board. Found out some of the ss parts in the 70's sets work quit well in the older tube type chassis so I have been on the look out for them. Last weekend I bought two xl 100 chassis for parts. I think I read that the 1n60's will work but never used them.
Ed

messed about with the convergence, got it all pretty good except for the blue horz on the bottom, I just cant get it up (pls no pun) the pot is turned all the way and it just runs out of adjustment.

Vert looks good from sides to center, and horz is fine from center up, just the blue begining about 2/3s down.

I did check the sams the replacement diode are 1N536's

could those effect the max range of adjustment?

50v .75mA silicon, so looks like any of the 1n4 family should be ok,

Ah, that convergence board brings back foul memories. I nearly lost my mind fussing with the board on my first CTC-11. Replaced selenium rectifer with diodes, replaced caps, replaced a couple of pots. Those controls are laughably cheap and not easy to find. Some kind soul donated one, or I'd still be cussing over bad convergence.

I spent hours playing with convergence on that set. On my second CTC-11, convergence took about six minutes, and it looks better than the first ever will. Go figure.

Phil

DAve, some guys have replaced those with diodes and got great results, while others (like Phil) wanted to shoot the set after all the work that was put into it. I've only changed them on one set, and while it did indeed make a difference, it wasn't quite enough for me to be satisfied completely.

Roundie convergence isn't always easy. Some have commented that you're never going to get it perfect... just to do the best you can focusing mainly on the middle of the screen. Anything better than that is icing on the cake.

If the blue is off 2/3 of the way down the screen, I'd try changing those diodes and possibly the caps (especially if they're old tubular caps). It's certainly an easy job to change that stuff out... it's not like you have to tear the whole set apart again.

But, before you do that, just for shits & giggles, try taking that blue magnet out, spin it around 180 degrees, and re-insert it into the assembly. Then start over with all your adjustments as per the instructions and see if that makes it any better. Sometimes spinning those magnets around is all it takes.

roger that Charlie.

the only other thing is I did swap the two vert out transformer wires on pin 4 and 5 on the convergence socket. This was against the color code but the color code for the thordarson was not given (all the other replacement trannys were, and they all used the same color red for red, red blk for red blk etc...). When I installed the thordarson I 1st check the resistance of the old tranny to the wires of the replacement. They all checked for resistance for the same colors except for those two which were swapped. So I installed it with the wiring intact except those two.

I was thinking of swapping them just to see. I think the diff was .75 ohms to center vs 1.5 ohms to center which is a pretty big diff in DC resistance in a tranny.

I don't want to do too many changes at a time so I will try the magnet 1st

then the diodes, then the wire swap.

on the grid its all pretty good but the blue is about 3/8 in off on the horz line on the bottom all the way across, and that is with the pot pegged (its working just not enough range).

try sliding the convergence assembly forward on the neck.also the blue lateral.move it up or down the neck to get that blue to line up.i have had the same problem with my ctc15.moving the parts on the neck changes the geometry.can get it really close and hopefully right on.you have to experiment a little.convergence is an art!it can never be perfect,but we all painstakingly try for it.

just curious to modern TVs have all these adjustments? sorry for my ignorance I only recently got interested in TV's and have not even opened the back of a modern TV.

If I'm not mistaken, modern sets go thru the menus to get to convergence. Seems that big screen sets have a menu that the user can get to and perform convergence, and from what I've seen, it's quite easy and just about anyone can do it as long as they have decent vision. I made some convergence adjustments on my neighbor's big screen a few years ago... it was rather easy. Certainly came out better than a roundie! :)

I believe smaller sets have a secret menu that is not available to the set's owner. If you bring the set in for repair, the repair man knows a certain sequence of buttons to push to bring up the service menu... and I would think convergence would be in there.

We've had discussions here before about the secret service menu... they were pretty interesting.

oh I get it sorta like Easter eggs...

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In my limited experience, if the pot moves but is pegged all the way, it's probably OK and there is some other problem. You can check the pot in place to get some idea of its value. Cleaning them can't hurt, but may not be a miracle cure.

If you want a laugh, you can read about my convergence fun at http://antiqueradio.org/RCACTC-11Television.htm .

I discovered about halfway through that my convergence board & assembly were for a later model than mine. I finally solved the worst problem when I found a hidden break in a wire to the green coil. It still isn't perfect, though, and probably never will be.

You are right to change only one thing at a time. Make sure there is a way to get back to Kansas if you change something and it gets worse.

Maybe it is the nature of this design that you can get the central area good, but may have to accept some kind of compromise at the farthest edges. It sounds like you're already very close, if you have only one problem at the bottom.

Phil

I've read similar comments in a couple of old color TV books. If you can get good convergence over most of the screen, then you did good. With some sets, there will always be areas that you might not be 100% satisfied with. I guess you can say it's just the nature of the beast.

good read Phil. I think if I read enough it will become clear. Funny its like I am slowly coming up to speed on all this, must be my limited intellect, the fact that I need to read it over and over and over for all these concepts to stick.

what would be good is a VIDEO tutorial on the proper setup a set, from lineariy thru convergence.



:yes:

I learn faster by doing something hands-on rather than just reading. One book I've found useful is the RCA Color Television Pict-O-Guide by John Meagher, published by RCA. I have the 1957 edition. It has great explanations of adjusting purity, convergence, etc. -- with lots of pictures! Many used copies are floating around.

Phil

I will keep an eye out for it Phil thx.

ok another session of convergence. I did tweek the blue center magnet, helped some. The picture is very good, I just need to stop looking at the grid, normal tv showing its very nice.

I am going to give it a break now, not sure if I want to mess with the diodes at this point. have to think about that. I still run out of bottom blue horz, but its closer after pulling up that magnet some. My color bars look funky colorwize but the flesh tones and normal viewing seems fine. Not sure what is going on there. I think I will start the filter cap restuffing next.

more pics, note the fuzziness is the cataract on the edge of the screen where the PVA has brokendown.

interesting how the old shows from the 70's (thats the hulk i think) seem to have faded in color.

Geez I want to watch Rockford but its so darn hot out in the garage, must be 90+ and its 10pm...

Hey, that's looking quite impressive, Dave!

Loooking at that crosshatch and then looking at a normal picture... there's a big difference. You may not notice certain things as quickly just watching normal video.

We try very hard to get things just right on these sets. Most other people wouldn't even notice if something was off a little.

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I still have not tried the purity setup, I know that is suppose to be the 1st thing, guess I am just a bit nervous about pulling back the yoke.

I am still wondering if those diodes could be part of the issue. I have not studied the schematic, but if they are there to rectify the currend from the secondary of the vert output, and if they are weak, then maybe the magnetic field is not as strong as it should be. Again just guessing I reall dont have a clue as to what is going on in the convergence circuit.

Also have a real tough time with linearity, both vert and horz are way off.

I did not see a horz linearity adj, so figured I would start with checking the horz osc/damper/HOT for starters.

The vert is tough also cant get it to fill out the screen unless I mis adjust the vert linearity. I think maybe its a vert centering adj that needs to be done, to bring it all down 1st. Need to look over the set instructions again.

Stop. Take a deep breath. Be patient. It will be good.

Convergence depends on multiple things being right. You should not (without lots of experience) try to do it out of order. Each adjustment interacts with the others. You must get purity first. That will put the yoke in the proper position as well. A slight movement either way may be just what you need to get the proper range on the convergence controls.

Then you do the static center convergence. This is what Phil was refering to by turning the blue magnet. You adjusted it and that helped, but you should pull the bar completely out of the assembly and turn it around 180 degres and reinsert it. That may help it bring blue back in range. When the center convergence is right none of the magnets should be at either end of their range. If they are you will have a hard time with dynamic convergence.
At this time go back and check purity. If it is still good move on. If it is off a little start over. Center convergence can impact purity, but not as much as purity affects center convergence.

When you do the dynamic convergence sometimes the lines will converge in the center, but not at the edges, or they will converge at the edges and center will be off. When this happens adjust the controls to make the lines straight. Then start over. Purity, then center convergence, then dynamic convergence. This sounds like a lot, but as you gain experience it will get easier. When you reach the point that it is as good as it will get and you still have issue with control range then start changing componants. The diodes first and any bad caps. Then start all over. Isn't this fun yet.

Now after saying all this, you said you are still having linerarity problems.
Linerarity, both vertical and horizontal, must be right before you do any dynamic convergence.

To adjust vertical you center the raster first using the vert center control, then use vert height and vert lin to adjust the top and bottom of the picture. I do not remember which control the top and which the bottom, I think the height adjument affects the bottom and the lin adjustment affects the top but it could be the other way around. You will need a crosshatch to do this. When it is correct all the squares will be the same size vertically. You may get the squares all the same size then notice that it doesn't fill the screen at the bottom. This indicates you still have a problem in the vertical output circuit. Usually a bad cap or out of spec resistor. If you do not have enough vertical sweep you will never get good convergence.

Horizontal linerarity is a function of the Horiz output and flyback circuits. Horiz efficency affects the width of the raster as well as the flyback current. The idea is to get sufficent width with the least Horizontal cathode current. If you have an acceptable HO cathode current, but the raster does not fill the screen you need to look for weak tubes, bad caps, and out of spec resistors in the Horizontal drive and output circuits. Try a new Horizontal output tube, since a tired tube may work but not fill the screen.

What you have is looking good. Be patient and good luck.

Bill R

Thanks Bill for the encouragement. Taking a deep breath.... ahhhh

fortunitly we have a swap meet to divert me for a bit tomorrow.

What do you think about the Se rectifier on the conv board? I know those can break down over time (Se that is I have no idea about on the conv board).

The blue centering magnet on the top needs to be at the extreme range, it just gets worse as it goes in on the bottom. So that says something is out of whack.

I will give it a break and revisit the purity, guess I as just scared of losing ground.

good news is the pots on the convergence board turn smoothly.

oh and got out the wizard of oz disk, that was fun... rubby slippers are fantastic as was the green witch..

ok I pulled out the top magnet (blue) and turned it 180 and reinserted, that gave me much better horz blue control on the board. Got the best all white grid pattern yet (and the over the air stuff looks great)


Now I just have to deal with the vert height. if I adj for correct lineairity I come up about 1" short on both the bottom and the top. I if I increase the height adj, then I cant adj the linearity. its like I cant make the circle wide enough to fill out the screen without it becoming a tall oval.

the raster fills out the screen horz, just the image does not get wide enough to match the height, if that make since.

I am using a indian head to do this. Mostly I get a tall skinny circle, again unless I back down the vert, then I can adj lineairity for a nice round circle.

I am going to pickup some new tubes tomorrow vert and horz sweep.

I still have not recapped the filter caps...

Isn't there a 50@150 electrolytic on the deflection board? Seems I remember changing this particular lytic would always stretch the picture back out to normal.

that was the only one I did (since the vert output tranny was smoked I did repalce that one, it was leaky, IIRC the resistance measurement was correct as well), that was the cathode bypass cap I think, it was on the board. I have not touched any of the big can caps yet.

I would adjust for correct linearity and look for the problem in the vertical sweep circuit. Probably a bad cap. Check B+ in the vert circuit as well. You just do not have enough vertical sweep. This will also effect convergence.
With their age the Selenium rectifiers on the convergance board should probably be replaced. I don't recall changing many in the day, but they are much older now. I think those are more reliable than ones used in the power supply. I would change them. If for no other reason to make the set more reliable.

Bill R

By the way if you haven't done it yet check the Horizontal output cathode current. It should be under 210ma I think. Also check things like regulator current, HV, and Boost voltage. I am not looking at the schematics, but some sets use a boost voltage from the HV in some sweep circuits, as well as B+. I don't remember on the 16. I think it would be about 800 volts.

Also a 150k resistore between the vert lin and hold controls like to open up in resistance causing issues too! Had this happen on my CTC-16 and one of my CTC-17's. Dave you have done an awesome job at this set!! Beautiful !

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