thought I would start a new thread now that I know the chassis I have.

this is my 1st early color. when I got it I started a slow power up on a variac (metered). when I saw 1 amp at 10v I knew there was a problem so stopped there.

I disconnected the B+ from the bridge rectifier, powered up again, no problem think it was about .7 amp IIRC all filaments (not the crt the chassis is out on the bench at this point). came up.

B+ was about 400v disconnected. The resistance at the 1st 80uf cap was 24 ohms :no:

I started with the easy stuff the filter caps were in pretty good shape (tested with a cap tester for capacity and leakage at rated voltage).

moving a long I started unwrappping various B+ feeds to thinking maybe a shorted bypass (not likely since mostly dipped caps, only a couple of the HV ceramic tube types and the were ok).

last thing I check (prob wishfull thinking it was not the problem) was a transformer behind the HV cage. I assume it is a vert output, but it also drives the convergence board. Being new to color I am just guessing about this.

anyway it has 5 primary and 6 secondary winding. Two of the primary windings are green and green with yellow strip. the GY connects to the 400v B+, I also disconnected the other G on the primary. doing this removed the 24 ohm reading and now I get 8k

At 1st I thought I had a short in the transformer from the primary to the secondary (there is a lead on the secondary that goes to ground).

but I still need to trace the remaing 3 primary leads (blue/red/yellow) to make sure they are not the problem. I hope to pic up a RCA service folder today to aid it the tracing.

primary side blue and red seem ok, the yellow which goes to the yoke has 2 ohms to ground. I am going to have to stop and go get the service manual, just not sure what the internal wiring of the tranny is...

Which CTC-16 do you have? The earlier style or a CTC-16Xx chassis? I'm not sure offhand what all the differences are, but I know there's different Howard Sams for 'em.

Oops, nevermind my chassis question..I noticed your other post. I have a CTC-16 E that I've had since the seventies that still works but I need to refurbish the electronics and deal with a few quirks.

I like the fact that the later versions (like yours) came with the RCA "Hi-Lite" CRT which is an awesome picture tube when in good condition.

got the schematic, not looking good on the vert output. the primary is green,green white,yellow. with all those out of the circuit I still have a low resistance reading to the chassis.

Moyers had it so its on the way :banana:

---

getting ahead of myself, but I would like to make a simple box cabinet with some nice thin legs for it. The old cab is shot.

reading the service manual it says about setting the tuner in the service position, I cant seem to figure out how to bolt the tuner or in some other way to place it on the chassis to make working on it easier. I am guessing there is some way to attach it to the chassis to reduce the awkwardness of the two parts.

Yeah, there are a couple of screws/small bolts near the AC line plug line in. The tuner will fit right into those screws.... knobs facing upwards... and then you tighten the screws. You can leave it there and do all you need to the chassis out of the cabinet.

got it thanks Charlie!

while waiting for the vert out xformer I went ahead and repalced a singe 50uf 150v cap (tested leaky). I am going to give the big can caps a chance to reform I just want to make sure it works and the CRT is ok before going thru the effort to stuff them, They are not shorted, I will monitor the current and see if they come up on the variac when I get the B+ worked out.

Tuner issues, the UHF can be tuned by turning the dial indicator no problem, but not with the tuning knob. If you push down you can fine tune the VHF, but when not pushed down it engages thru a series of gear to the UHF.

It seem that the alum gear is seized to the shaft. What I dont get is how come the UHF can still turn with that alum gear seized? My guess is there is just a friction coupling that normally works when the alum gear is not seized up. It also looks to have some kind of built in gear lash control.

I looks like I may have to remove the lashed gears on the tuner in order to get access to the screws that hold the alum gear assy to the tuner box. then I can work on getting that stuck gear off and re lubed.

Dave,

What are your tuner numbers? KRK... Is there a TMA number on the tuner cluster? I have an RCA guide on almost all of the RCA 60's and 70's tuner assemblies with breakdown of the mechanicals. I can get a copy of the UHF area for you if I have the above info.

Lots of questions, I know - and one last one? Where are you located? Most of us have our location listed in our profile - helps with the local help...

Cheers,

TMA 96A

updated profile.

Got a hickok 533 tube tester today to play with looking for a manual.

TMA 96A

updated profile.

Got a hickok 533 tube tester today to play with looking for a manual.

.....and me just back from Lake Buena Vista!!


I'll look tomorrow for the TMA info.

Check the Boatanchor Manual archive (BAMA) or it's mirror for the 533 manual and tube data. 532, 533, 534 and 600 all share the same tube setup manual.

Cheers,

thats about 15 min from me. hope you had a good time. I get up to VA now and then, near DC (centreville)for work.

fingers crossed should be getting the vert output today....

got it:banana:

now about hooking it up, I guess the smart thing to do would be to make sure I have the exact same wire colors before doing anything.

Make sure the match up to the schematic

cut them off the bad xformer fairly close to the xformr so I can use them for lead dress examples when I replace with the new.

does that seem reasonable? never had to replace a tranny before.

Yeah I'd cut them close to the tranny, too. Sometimes they give you just barely enough to work with.

Keeping our fingers cross!

the plan is to spend some quality time on it tonight, prelim checks show the new one is not shorted so I am pretty sure I have a correct diagnosis.

I wonder if it spontaniously shorted or if there was some defect in the vert circuit thay could have caused a short....

if that was to happen I assume there would have been a spike in current. I think i will double check the vert output tube before firing it up. look for shorts etc...

hmmm looks like that short 9 pin fat tube is the vert output. It is the one with the leaky 50uf cap (replaced it) if that was a cathode bypass, then the leak may have reduced the bias and caused the tube to pull too much current thru the load (primary of the vert trans) of course I dont think I have the right tube tester for THAT tube :no:

yep thats it a 6GF7 dual triode, and that was a cathod bypass cap. Oh well, I can wire it up, but I think I will hold off power up until I can get that tube checked for shorts, prob ok but I jsut would hate to toast the new tranny.

sams and RCA service man both show about -55v bias on the vert osc output grid, of course they show diff voltages for the grid and cathode but both net to about -55.

The sams shows a 38ma current thru the cathode, no way to read that directly but I guess I could determine it based on the V drop across the cathode resistor..


hmmm scratch that not that simple, I was reading something wrong. This would be a nice time to have a test socket that you could jumper each pin on or off.
not a tube extender but a tube extender that you could make/break the pins for current readings. I dont know if such a think exist.

Make sure you check the vertical center control. I have seen them short to chassis ground and burn out transformers and the power supply.
Ed

I will check that thanks.

well it went fine, tranny in, did a slow power up on the variac with the vert and horz tubes pulled. got up to about 250ma I think the sams says about 400ma but of course I did not have the horz/vert operating. The cans stayed cold so hope that is all good.

Will check that vert center pot (did the power up before reading that post).

one odd thing there were two color coded wires that went to the convergence plug that were not "right"

the schematic called for

Grn Red pin 5 .8 ohm
Blk Grn ground
Blk red pin 4 1.5 ohm

blk grn is the center tap of the other two.

the resistance measurements did not jive I had to reverse the pin 5 and pin 4 connections. I confirmed the resistance measurements against the old tranny. on it the color code matched the schematic and the resistance measurements matched.

any way if for some reason I have issues I have enough slack to reconnect per color code (I even left a small tail of the old wire on the socket pin to know which ones were installed different from the code).

there was a single .001 2000v ceramic tube cap off the primary plate side of the tranny to ground, My cap tester only goes to 450v so I could not test for leakage at rated volts. I had a couple .002 3kv disk caps I put in series and used them. I will go ahead and get the proper cap for it.

the plan now is to take it to a local shop with a good tester and check all the tubes out.

checked the vert cent pot, all leads to ground are about 7k which is the same as the B+ load so that looks ok. Thanks for the heads up.

checked the vert cent pot, all leads to ground are about 7k which is the same as the B+ load so that looks ok. Thanks for the heads up.
Your welcome, The ctc 16 chassis is a good chassis and will put out a really good picture when you get her working. Here is a picture of my ctc 16 xl.
I really like the cabinet and it has a swivel base. This set had a shorted vert cent pot and it damaged the power supply. I was lucky that it did not take out the power transformer but had to replace all the can caps, B + Diodes, Power switch and the circuit breaker. The person I bought the set from HAD to plug it in and turn it on. :nono:
Ed

nice cabinet, I am going to have to make a cabinet for my the old one is still wrapped up, termites are contained (i hope) but the damage is severe.

right now I am leaning toward a simple ply box with veneers and maybe some nice thin med long legs (the kind that screw on, nice if I can find some with a brass lower half). I sure would like to reproduce something nice like yours but my wood working is limited.


what do you think about the color code problem on that one section? ever run into something like that?

Here's what my manual has for the TMA96 - hope it helps with the tuner woes.

Cheers,

I'll try this again.

got it thx, it sitting on the variac all tubes out for a slow reform.

Wow, Ed! That's a nice looking 16!

I had one similar a few years back, but the top of the cabinet was in pretty bad shape due to getting wet for a very long time. It was a remote set. I gave it to Rich since he was tinkering with rebuilding cabinets back then.

seems the caps are fine, full voltage quickly, no heat, so I plugged in all the tubes and will hook up the crt/yoke/convergence bd tonight for a full power up. I will monitor the B+ current still.


will do this all later today, will post the results later.
wish me luck...

since I had the sams resistance tables I started check some, on the vert tube I had an odd reading on of the pins, noticed it was the vert hold, no big its just the position of the pot, move the pot and I get wild swings. check the pot and indeed it must be very dirty, so will clean up the pot before powering it up. I am just a bit paranoid about that vertical circuit :yes:

I would think some spray in all of the pots would be in order.

Those resistance tables are sweet when it comes to tracking down resistors that may be out of spec. There are, many times, readings that may seems off and actually only be due to a setting of one of the controls.

copy that charlie, sprayed and looking good. checked about 1/2 the tubes, so far very good. I did spray the 4 pots up front. I was a bit nervous about getting into the pots on the back. guess I could note the position and spray work them and get back to that starting position.

IT WORKS!!

I am going to have to touch up the linearity and there is a slight convergence problem (are they related) on the bottom, but it is coming along. I snapped a couple shots before even playing with the tint/color, so it looks better than this now.

oh and my B+ current looked good 440ma Sams calls for 460 :banana:

gonna knock back a cool soda pop, grab some grub, and see if I can clean up the linearity a bit. Gonna need some one to talk me thru the convergence, I have the manual but would rather talk about it 1st.

Thanks for the encourgement and help, esp Charlie for letting my yack on forever.

Man I want one of those NBC peacocks on DVD soo bad...

looking forward to watching the Rockford tonight, will have to setup a lawn chair out in the garage :yes:

Been following your progress. I hope to work on mine this winter. Nice job!!

I will have to get some more pics, it is looking a LOT better.

I think I will add a .5 amp in line fuse to the B+ just for that extra bit of safety. I had a neighbor over, he is technically inclined, I think I may have set the hook in him.. He remembers this stuff like I do a kids from the 60's

GREAT! :yippy::banana::grnbounce:banana::yippy:


looking forward to watching the Rockford tonight, will have to setup a lawn chair out in the garage :yes:

Yeah, I've spent many hours out in the garage watching TV... and enjoyed it more than in my living room!

I bet your wife will eventually have to come out there and say, "Honey, when are you going to come to bed???" :D

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.

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

Wow, Ed! That's a nice looking 16!

I had one similar a few years back, but the top of the cabinet was in pretty bad shape due to getting wet for a very long time. It was a remote set. I gave it to Rich since he was tinkering with rebuilding cabinets back then.

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 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.

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...

---

with the pot pegged (its working just not enough range).
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

...but may have to accept some kind of compromise at the farthest edges.

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.

---

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.

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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well for grins I picked up some new sweep circuit tubes, I will try them, and then proceed from there. IIRC all the resistance checks in the sweep circuits were GTG based on the sams. freaking HOT was an expensive bugger.

Yeah, 6JE6's and and similar run pretty high. You really wanna treat that baby with kindness! :yes:

ok replaced same issue. so I guess its time I broke down and

1) double check the caps in the sweep circuit, starting with the cat bypass on the horz osc (30uf part of the can cap)

2) check the resistors again (I think I did this based on the sams pin resistance readings already)

3) go thru the full setup routine of the Horz and HV per the service manual
(check HOT current, check HV)

4) get the scope out and look at the waveform on the osc, maybe trace from the plate of the horz to the grid of the HOT to see if any oddness takes place.

I realize I need to get the linearity done 1st before any more messing about with the purity/convergence.

prob should check voltages while I am at it in the sweep circuits.

would a low HV like 21k vs 25k cause horz lineairiy issues?

I was getting ready to set up my horz eff and HV but before pulling the chassis to disconnect the cathode shunts and attach the ma meter I took a reading with the HV prob on the anode, 21k not 25k...

I will also check the horz osc cathod bypass cap, jic its weak and the horz osc is being effected by that.

I think 21k is alright as long as your efficency is low.

well I installed a top side fuse holder right by the HOT, I have a 250ma fuse ready for it. I went ahead and added a 1uf non polar cap across the fuse holder so I can just pop the fuse and attach my meter.

I put the test leads on the 1k resistro on the HV regulater, left them hanging out the back. I actually had just about finished an intall of a term strip right next to the fuse, it was test points for that same resistor, then had a moment of clarity and realized that would put a 390+ term exposed at the back of the chassis :nono:
so I undid that and will live with having to pull the chassis to take the voltage drop reading. After pulling that bone head idea I decided to take a break and go do some DXing on my new Zenith TO.

I will do the current and voltage checks tomorrow when my head is clear.

adj a few degrees the HV adj up to about 23.5 now. HOT current 189, HV reg V drop on 1k resistor 1.2v (shoulda checked the res value 1st).

need to check all the B+ values next.

got the fast acting .2 amp fuse ready to go, more horz sweep checking tomorrow to try and figure the horz linearity issues. Overall looking very very good. Will begin full house recap of all cans soon, will of course recheck the HOT after that.

pic of the hot fuse location. quick easy to check the HOT current just pull the fuse and take a reading, sorry for the blur.

No holes drilled easy to undo if for some reason a future restorer does not like it.

Is the picture not filling the screen horizontally. It looks like it is in the pictures. If not try adjusting the horiz centering control. The low HV will not cause a horiz lin problem, but a lack of horizontal scan will cause a low HV. 23.5KV may be ok. It should be measured with a dark screen.

Bill

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Is the picture not filling the screen horizontally. It looks like it is in the pictures. If not try adjusting the horiz centering control. The low HV will not cause a horiz lin problem, but a lack of horizontal scan will cause a low HV. 23.5KV may be ok. It should be measured with a dark screen.

Bill

No problem with the pic filling the screen, just horz lineairity (circle is compressed on the right side, elongated on the right.

more adjustments more screen shots...

Seems to have ever so slight of a ghost, I wonder if that is some kind of AGC issue, its more noticable on strong high contrast signals. you can see in on the lettering and on the bright shot of the lady (dark hair).

here are some ideas for the cabinet design,

4 side ply box with some oak veneers.

simple splayed legs with a front and rear stretcher, set in a bit, all splays about 15 degrees, all exposed edged rounded over. legs from hardwood, all finished with tung oil.

I will do some full size mockups out out foam to see how the legs work out.

Lacking a table saw will mean some creative jigging for my circlular saw, but the veneers should cover any minor mistakes.

I would not mind getting a router to do the bulk of the rounding over of the legs but then again I could prob do it with hand tools and patience.

pls excuse the rough drawing, just try for the right look.

The color in the second photo is so perfect!

John

Really looking good. Convergence, purity, white balance all look quite good now. I agree with John color on that second picture is great. If there is still some black at the bottom try adjusting the vert centering. You may have enough overscan at the top to move the picture down a bit. The slight ghost could be overloading of agc, it may also be open or shorted peaking coil in the video section.

Bill

adj the vert down a little, better will do some more later still have some to go but its getting late.

Just realized the darn speaker holes are not opened up on the speaker grille (it orig was mounted low, I thought the speaker on the bezel was open, its formed on the inside, there must be a machining process that opens the holes). I still like my design, guees I could go with a side firing speaker, or just do the way it was done, the speaker below the bezel. That would raise up the whole TV about 5". that would really mess up the look.

Gosh, that picture looks nice. You have brought that set a long way since the first photos you posted.

Your cabinet design looks like a lot of fun. Meanwhile, put on a favorite movie and enjoy.

Phil Nelson

Don't twiddle with it anymore. Looks great! :-)

Would it be possible to open the speaker holes. Tedious work, but.... Maybe a dremel tool to carefully cut the slits. Using one that had the speaker mounted there as a guide. The only ones open are the ones right in front of the speaker. You only need enough for the sound to get out.
Other thought would be to cut the speaker grill out and use a piece of grill cloth glued in place. Since you are building a custom cabinet anyway, that might be an option.

Just a thought.

Bill

I could prob open up a few with a dremal and a cut off wheel, of couse if I goofed it would be real ugly. I just wonder how the factory did it. You can see the mold area, even has the guide pins for the speaker.

Biggest problem would be getting good access. Guess the time to do it would coinside with the cataract removal when I have to unbolt the CRT anyway.

given the condition of the PVA I am hoping the cat would just pop off with minimal effort of heat gun or hot wire, which ever method I use.