Was watching my beautiful CTC-36 portable one day about 2 months ago, and (as seems to happen to me on a regular basis with various sets) heard a loud POP, and the set lost all color sync.....the color went to bars of color rapidly flipping vertically, while the actual picture was still locked in, in black and white.

After my Portacolor debacle over the last few days, I needed to get some vindication, so I opened up the RCA. After replacing a .01 mfd ceramic capacitor on the board where the color drive controls are located, the color locked in nicely, but I'm getting color retrace lines on the screen.

Picture is purposely washed out by the controls to give you a better idea of what I've got. Picture itself is very slightly jittery, but locked in solid. Just a tiny tiny amount of jitter, just enough to make you angry ;)

Ideas?

First thing I would do is run it with the back off and flex the boards with a stick and look for a change. Could be a cracked solder or poor connection somewhere.
Could be a retrace issue or the crt is being overdriven. A ground or component failed in the screen, drive or video circuits.

Does it seem much brighter that before?

Im sure I have the service data on that chassis and can dig it out for a date with the scanner.

Brightness, contrast, etc, are all about the same. There is a remote possibility that I might have flexed something in the convergence board when I pulled the main chassis, as it was a tight squeeze getting the chassis over the top of the board to pull it out. I'll give that a try this evening. Thanks!

Brightness, contrast, etc, are all about the same. There is a remote possibility that I might have flexed something in the convergence board when I pulled the main chassis, as it was a tight squeeze getting the chassis over the top of the board to pull it out. I'll give that a try this evening. Thanks!

That problem is not convergence board related.
In your original post, you stated a CTC38 chassis in the text. I think the set you have is a CTC36, which is simular to the CTC22 design. :boring:

Right, good catch. I had it correct in the thread title.....

Is CTC36 that 19inch tube deal with the low focus voltage crt?

Im blanking out right now on that. If so try moving the tubes around in the sockets. Or maybe you bumped the service switch.

It uses a 19HNP22 picture tube, so I'm not sure if that qualifies as a low focus model :)

Tapped all the tubes, nothing. BUT, I did figure out that the retrace lines have something to do with the vertical sync section. When brought just out of lock, the lines get somewhat brighter, and pulled along with the sync when it was adjusted to freewheel very slowly. I cleaned the pot for the vertical hold, and for a brief while, the issue disappeared.

I may be wrong, but it seemed like it came back when the DeOxit dried up, which would lead me to believe that the cleaner in its wet form added some resistance to the circuit at that point? Normally I'd say no, it's just dirty.....but this wasn't happening before the ceramic cap blew.

For the moment, I tweaked the AGC, contrast, and brightness, so that it's barely visible. I mean after all, I need a television to watch, right? :D

[QUOTE=ctc17;3059430]Is CTC36 that 19inch tube deal with the low focus voltage crt?

Those sets had a great picture on them when they were newer.
After they got a few years old, the focus seemed to be rather poor. Even if the CRT tested good and all three guns equal, the clairity was lacking. I have a CTC51K and a CTC53, same thing. I got used to seeing clear scan lines on a CRT set, but those sets are a disappointment. :sigh:

I have to say, the focus is pretty darn good on the set. These pics were shot before the "incident", but the picture is pretty much the same now, save a hint of retrace.....

I actually have two of these sets. The other has the "use it one day, it's working, turn it on later, and now the set has no sound or picture but has a full raster" issue that I seem to run into with late 60s RCA color sets. That'll be the next one I tear into.

...

If it was better before a bad cap, and now you replaced a cap and it is not a good as it was, it would be logical to look and see if any resistors around that cap may have taken a large surge, and perhaps are now way out of spec. I see a diode in the vert blanking circuit, while I doubt its the problem would not hurt to check.

Decided to put a couple more hours on the set tonight, and the result was the same.....light retrace. The picture started out jittery, but stabilized after about 10 minutes of play.

In the automotive field, there's some points in time where you have to allow the component to fail, to identify the root cause. Since my diagnostic skills leave something to be desired (I can spot the easy stuff), I decided to give that a try. Didn't woik :) .

Since there's only about a half dozen resistors on that board IIRC, I'm just going to go ahead and replace them all. I figure if you're going to take the time to desolder one end to take the resistor out of the circuit, you might as well just do the other end too and replace it......

Meanwhile, I decided to play around with the set's twin brother that I have. It's a newer model, ES415W, which shows to be a CTC-53 chassis, with the 18VDBP22 picture tube. I saw a date inside of 1973 on one of the components, meaning this set must have been one of the last tube sets RCA made. Weird thing is that it's not a Mural set.

Physically, VERY close in appearance to the other set. Makes a nice picture, too....after cleaning dirty pots and just letting it run. Now, I just have to figure out how to adjust the horizontal centering......

My only complaint about these sets is that they take FOREVER to warm up and produce a picture. The sound comes on after about 10 seconds, then it takes so long to see anything on the screen, you'd swear you lost HV :)

I'd forgotten about that trait-I have a pile of CTC-53's but only one inside and cleaned up. It holds my record, by a quite a bit, for longest warmup. I think I timed it at over 60 seconds to get a raster. I do find the picture they make to a have a pleasant quality. Biggest problem with my "good one" is something heat sensitive in the vert circuit that causes a lot of drift until it's good and warmed up. I've replaced the tubes and caps, not sure if I started replacing resistors or not. That set hasn't been turned on in probably 3 years :(

Dont forget to check that diode. I dont know what make it is but to be safe you should heat sink it before removal (you maybe able to check in circuit, did not look too close to know for sure).

I'd forgotten about that trait-I have a pile of CTC-53's but only one inside and cleaned up. It holds my record, by a quite a bit, for longest warmup. I think I timed it at over 60 seconds to get a raster. I do find the picture they make to a have a pleasant quality. Biggest problem with my "good one" is something heat sensitive in the vert circuit that causes a lot of drift until it's good and warmed up. I've replaced the tubes and caps, not sure if I started replacing resistors or not. That set hasn't been turned on in probably 3 years :(

Happen to have any parts sets? I could use a brightness pot for mine....someone at some point installed a pot with a different shaft, probably replacing one that was defective.

Dont forget to check that diode. I dont know what make it is but to be safe you should heat sink it before removal (you maybe able to check in circuit, did not look too close to know for sure).

I will, definitely. I think to go further, I'll need a SAMS on the set. Going to have to order one online.

I'd forgotten about that trait-I have a pile of CTC-53's but only one inside and cleaned up. It holds my record, by a quite a bit, for longest warmup. I think I timed it at over 60 seconds to get a raster. I do find the picture they make to a have a pleasant quality. Biggest problem with my "good one" is something heat sensitive in the vert circuit that causes a lot of drift until it's good and warmed up. I've replaced the tubes and caps, not sure if I started replacing resistors or not. That set hasn't been turned on in probably 3 years :(
I found resistors on the vertical board that changed value really bad.
My CTC51K wouldn't stop rolling and the size and linearity wouldn't adjust properly. Even when I replaced the 13GF7 and the 50MFD 'lytic. :sigh:
My set is a real cheapie. It never came equipped with a degaussing coil. :no:

As long as we're discussing this chassis, what the heck is this lever thing? Is this how horizontal centering is accomplished, or is it something else? I haven't touched it, but it seems like it would rotate in the opposite direction if it was....

prob loosen the yoke

prob loosen the yoke

It's a long screw for the yoke clamp. Actually for the whole yoke and convergence assembly.

Makes sense, thanks. I was hoping deep down that it *was* some type of horizontal centering adjustment, as I can't get the set to fill out about an inch on the right side of the screen.

Linearity was a little out of whack, but it pulled in fine with a little tweaking.....sounds like I may be looking at new resistors there as well, but damned if I can figure out how to adjust the horizontal centering.

Yea my TV has the same yoke clamp.

http://img.photobucket.com/albums/v395/Evilweredragon/tvboard3.jpg

Makes sense, thanks. I was hoping deep down that it *was* some type of horizontal centering adjustment, as I can't get the set to fill out about an inch on the right side of the screen.

Linearity was a little out of whack, but it pulled in fine with a little tweaking.....sounds like I may be looking at new resistors there as well, but damned if I can figure out how to adjust the horizontal centering.

It's been ages, since I did TV repair on a regular basis. Trying to remember if there is a horizontal centering option on that chassis.
Are you sure the damper tube and horizontal output tube is perfect? When you see an image on the screen, such as text, does it seem centered?
If so, your problem is insuffient sweep. Is your B+ Around 255 volts?
BTW, is that the CTC53 or the CTC36, as you seem to be working on two sets.

...

I seem to recall reading somewhere that defects in the dual diodes in the horz AFC circuit can sometimes cause odd shifts in the horz centering.

You need Sams 1342-2. I'm sure somebody on here could set you up with a copy (I have one but not a spare, and I'm trying to keep one full set). The part number for that brightness pot is 126307. It has to come from the CTC53XM chassis; I'll have to check what I have.

I think my local library has some SAMS there. I could perhaps see if I can photo copy the book if it's not too many pages.

It's been ages, since I did TV repair on a regular basis. Trying to remember if there is a horizontal centering option on that chassis.
Are you sure the damper tube and horizontal output tube is perfect? When you see an image on the screen, such as text, does it seem centered?
If so, your problem is insuffient sweep. Is your B+ Around 255 volts?
BTW, is that the CTC53 or the CTC36, as you seem to be working on two sets.

This is the CTC53. I'm sorry, I really should have broken this into two threads. The sets seemed so close in appearance I had no idea until I got the back off that these were two significantly different animals.

Everything seems centered, but it's so damned close to the edge right now I can't tell if it's a sweep issue or a centering issue. I didn't check B+, because I figured there *had* to be a simple adjustment for this. Ain't seeming like it :) . And my tester won't do these particular tubes....again, figuring it was an adjustment.

Pretty sure that something somewhere has drifted in value, because after a couple hours of play, it seems to have just about centered itself somehow. I'm not going to ask HOW, but now there's maybe 5/16" of blank real estate on the right side, and that I can live with for now.

I decided that I'm going to go ahead and replace the resistors on the board of the CTC36, I just have to determine the rating of them. Since I don't have the sams for it, I may wait until I get one, I'll probably order over the weekend. I would assume that 1 watt would do, but I don't want to get any surprises down the road.

I seem to recall reading somewhere that defects in the dual diodes in the horz AFC circuit can sometimes cause odd shifts in the horz centering.
It can also cause very weak H sync.

I have several CTC53s, and they all had a number of out of tolerance resistors on the horizontal and vertical osc board. Replacing them helped solve a lot of deflection/sync problems. I also found that several of the orange/brown/green drops were out of tolerance, or leaky.

That's no surprise. I kind of figure that if I want these two to be perfect, all new mylars would be the ticket, and resistor checks as well. At this point, though, it's an example of the law of diminishing returns.....the sets are both very watchable, and stable as they are. I've run each for several hours, and they're both now pretty solid performers, each having something slightly out of whack that doesn't really bother me.

I'll probably let these be for now and just run them (unless something fails), as I have a CTC-25A console that I absolutely LOVE that is going to need attention next. I have the sams for that one on the way now. I'm not looking forward to that one, as it's going to need cataract surgery as well. But I absolutely love the set, so it'll be worth it :)

There's only 4 sets in my humble collection that don't work at the moment. I'm starting to get scared that I'll be left with nothing to do pretty soon! :)

[QUOTE=dieseljeep;3059475]

Those low focus voltage CRTs can really benefit from a very light rejuvenation, even if they test good. I've found the "cleaning" mode on my Beltron brings back razor sharp focus without being too harsh on the CRT.

I did exactly this yesterday, because the CRT seemed pretty dim. The CRT tested bad, bringing up the heater voltage to 8.8 and letting it cook for 10 minutes yielded a marginal improvement. Since it still has a watchable picture, though not really bright, I really hesitate to do a rejuvenate.....

Tim,
For the CTC36, look for the fold-out factory schematic in the RCA Color TV service manual you got from me. It is better than sams because the component numbers match the PW board labels.
The .01 cap you replaced may have been C608, which filters boost from rectifier CR606 by returning it to +280 volt via R618, a 1K resistor. This resistor also provides the screen voltage Check that 1K resisitor and try replacing CR606 - Im not sure you can really check the boost rectifiers but theyre all similar. See page 141 for text on the blanking circuit. As DaveWM said, the blanking diode CR605 needs checking. "Pops" tend to fry diodes.

The CTC53 IS a different animal alright, so a few items need checked to eliminate the easy stuff for the width issue.
The 31LZ6 Horiz output has a cathode protection via auxiliary thermal element in the set's circuit breaker, make sure the cathode voltage on this tube is less than 1 volt. Then check the 280v supply at pins 1 or 8 of the yoke plug.
next, see if the 130 volts at terminal T on PW400, where the tube is located, also check terminal BB (boosted boost) WTF that means, with a meter set on 1000 volt, you should see around 700 volts there. If this is OK, that clears your horizontal output stage. Last stop is the yoke...pull the plg and measure resisitance between pins 4+5, it measures the 4700 ohm 2 watt resistor in there.

I saw many of these as motel sets, no complaints since they kept us busy.

PS Nothing is better to do on bitter cold nights than this troubleshooting stuff...

Amen to that!

I've put probably another 3 or 4 hours use on the set, and at the moment, it's about the same. Thing is, with the picture tube being pretty dim, and the possibility of finding one sort of remote, I'm wondering if trying to improve things as they are at the moment is worthwhile....especially since this works as is, and I have other sets to pay attention to ;).

This set is in my home office at the moment, where brightness isn't really needed. What do you think? If I'm going to risk other serious damage, then I might as well have at it.

Meanwhile, I have my 9T246 apart again, trying to bring it a few steps closer to perfection. After that, it's my '47 DeWald, then the RCA CTC-25 console.

Thanks to bgadow, my CTC-36 has new life! :thmbsp:

A friend of mine from MD brought up a bunch of TVs, including a pair of CTC-36 parts sets. Since one of the parts sets was totally rusted but had an excellent picture tube, I pulled the 19HNP22, and put it in my set.

Took me just under 3 hours, with coffee breaks and a lot of cleaning, about 45 minutes of alignment included in that figure. How the heck I ever did alignment without a cross hatch pattern I'll never know. Prolly why they never turned out that good :D

Anyway, here's a shot of the set with the new tube in, just before the cross hatch alignment. Thanks Bryan!!!!

yes,bryan and kim are the salt of the earth!handier than a pocket on a shirt.set looks good!more screen shots,please

Here's a couple more screen shots.....hard as hell to get a good screen shot with a camera, as we all know ;)

Came out pretty good, I'd say. Still having the picture jitters until she warms up for about 15 minutes.....I just have to get in there and start checking some tubes.....

For some reason the convergence in these pics looks wayyyyy off. It's really not, it's darn close, except for a very little but of red shadow in the far upper right.

We'll blame the camera ;)

I was truly surprised when I tested that crt and saw how strong it was. I got that set working but with a real bad vert fold that I just couldn't get rid of. You saved me from having to chase it any more! Now I just need to find a home for those 3 CTC-53's out in the shed.

The damper and horizontal output tubes in that set tested stone dead, but the 5GH8s were really good, so I transferred those over to the Mural set. I took the good caps out of the vertical section that you installed, and am saving those for another set. I'm saving as much of that set as humanly possible, but rust got to a lot of it. In fact, I had to hacksaw the clamp on the back of the picture tube to get it off.....which was kinda scary!

Funny, on the black case set, I saw that someone at some point replaced that same .047 ceramic cap on the bottom board that on mine, went off like a firecracker. Musta been a common thing :)

I ended up using the remains of the broken clamp from my CTC-36 to put back on the tube, but when I had the back off the Mural set, I saw that someone had used zip ties in its place. I thought, wow, why didn't I think of that! So, I'm gonna pop the back off the set again, test tubes, and get rid of that rusty broken clamp.

We had a temporary roommate for about 6 weeks that ended up using my CTC-53. Much to my shock, she ended up falling asleep to it every night, and it ran nearly every night all night for at least a month :eek: . But the thing never faltered.

When I first started tinkering with old TV sets (c.1990) I found a CTC-53 at a junk store that worked but no color. I paid the local repair shop to fix it and the first night I fell asleep to David Letterman in color-and woke up to Today in black/white. Repair didn't hold. (I think all they did was change a 5GH8, but I wasn't that smart then) I paid another repair shop to do the repair and they fixed it right (changing the 5GH8 plus a resistor that had gone bad.)

...

Replaced some weak tubes in the CTC-36 today, and it seemed like the convergence drifted a bit when I decided to put up a crosshatch pattern.

Whoever at RCA that decided to put those convergence boards right underneath the top vents for the set should be shot dead, if he's still alive :mad: . Right where all the crap can fall right into it and screw up everything. BAH.

Half the controls do nothing, and I couldn't bring it back in to convergence perfectly. Vertical convergence is spot on, but horizontal, especially the right lower where you need to use those tuning slugs, is off. Incidentally, I discovered that the size for said slugs is a 2.5mm allen wrench, in case someone needs to know and decides to hit up Mother Google for the answer.

It's watchable, but dammit, I can almost never get proper convergence on an old color set....either the plastics holding something together crumble like an Egyptian scroll, or I can feel one of the control wipers skipping, or I turn it and it just does nothing :sigh:

Can these pots be replaced with anything off the shelf? I have a spare convergence board that I'd give a shot at rebuilding, IF I could get new pots.

Thought I'd share this....

I replaced tubes in the one CTC-36 parts set that I got from Bryan (bgadow), and managed to get a faint picture with bad foldover at the bottom, and no sound. Okay, well, let's try and save this set....

Figuring that I could start with a recap of the set to see how far that'd take me, I pulled the chassis last night. When you know how, it's child's play to do, just remove the yoke and convergence board first, then unbolt the tuner, and everything kinda slides right out :)

Underneath, this is what I saw. Ugh. Note the jumper wire unceremoniously tucked under the chassis on the right hand side bypassing the circuit breaker :no:

I was surprised that the jumpered caps didn't short something out on the underside. There's quite a bit of rust on the chassis, but I still think I can save this thing.

...

I'm honestly wondering if this set is even worth rebuilding, given the condition....opinions?

It's not all that rare or valuable, part it out and smash the rest in the dumpster. Your other one is great but when these get this beat up, they're hardly worth the effort to bring back. Unless, you're into that sort of thing... Nice work on the good one BTW:D

The cabinet's about half as ugly, too. Good picture tube though......

So....back on the CTC-36.....the good one ;)

Did some work on it, and replaced 4 caps in the vertical. One, much to my surprise, had a loose solder joint.

The set looks great, but I'm having one problem that I just can't shake. I just can't get the red horizontal convergence correct....it's off to the right on the crosshatch. I won't say that it's off linearly, but close. Vertical is right on. No matter what I do, I can't bring the red back to the left about 1/2". What the heck could be causing this?

can you post a pic of the convergence problem? with the cross hatch.

Wasn't able to get a good one last night, but I did this morning. Also, as you can tell, it needs degaussing, but all I manage to do with my degaussing coil is make it worse.....

Picture is pretty watchable, but as you know, the crosshatch brings the issues to the forefront.

thats mostly a center converge problem. double check the posistion of the convergence cluster, should be able to correct with the RG magnets that are attached to small rotating knobs on that set. the RG are the ones on the sides of the cluster approx 4 and 8 o'clock. once you get the center convergence done the rest will be a LOT easier.

do you have the setup procedure for that set?

always start with the degauss then purity, then static, then dynamic with static touch up after each dynamic.

a few other tips

set brighness down some, make sure focus is as good as it can be, get up close to the screen to check, use a resistor to turn off the blue and focus on the RG, to the blue last.

not sure I follow about the degaussing coil making it worse, you need the purity good 1st as if not then you will waste your time on the convergence as it will be messed up when purity is corrected.

Here are scans of the setup instructions. Bear in mind that I've never done this before....for convergence, I've pretty much just done a board setup (tweak the pots on the convergence board with a crosshatch and just get as close as I can). If you wouldn't mind walking me through the setup, I'd much appreciate it.

I ammended my post above, but most of that problem looks like static, fix that with the RG rotating knob type magnets. Use dots and only look at the center.

After the RG dots in the center are done (the move diagonally so you have to work both those magnets knobs at 4 and 8 o'clock at once to intersect) then move the blue dot up and down and side to side to land on top of the now yellow dots. Only the blue can move any direction so its last to adjust.

again only worry about the center. And you must do the purity 1st.

thats mostly a center converge problem. double check the posistion of the convergence cluster, should be able to correct with the RG magnets that are attached to small rotating knobs on that set. the RG are the ones on the sides of the cluster approx 4 and 8 o'clock. once you get the center convergence done the rest will be a LOT easier.

That's kind of what I was aiming for.

Unfortunately, I don't have a center dot setup, I only have crosshatch, white screen, gray scale, and color bars (using a test pattern DVD transmitting via agile modulator). One thing I should note, the purity rings on the tube have a light coat of rust on them, and to be frank, I'm not exactly sure *how* they work to begin with.

I tried rotating them on the crosshatch screen to try to affect something, but if I'm understanding this correctly, I need to do that on a white screen first.

The purity rings align the electron guns to the shadow mask, you side the yoke back, bias off the green and blue guns (or just turn down the screens), aim for a red blob in the middle with 3 green and 3 blue blobs of color around it. the rings have min effect when tabs are together, start there, rotate the whole assy to move the red blob AROUND, spread the tabs to move the red blob radially, do this until the red is centered. then move the yoke back towards the crt until the red spreads out and covers the screen. try each color (use the G2 screen drives one at a time to see if you have good color on each gun. Then you can move on to convergence. There are a few examples of this on you tube. call me later to discuss. its not hard and will make a HUGE improvement if the purity is off.


of course if the purity is ok you can skip this, just turn off all the screens and turn up one at a time and see how pure the color is to start with. You may not need to set it up.

The give away to bad purity is color shifts in different parts of the screen, like a all red dragnet scene that has purple splotches in the red, classic purity problem.

Tim, This is a great lesson here. I'm anxious to see how well this turns out, and it will too.

You get this right and you can converge any round-tube color set even better!

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I took a minute, and did a purity setup on a white screen. Took me about 10 minutes, it's as close to perfect as I can get it, which I'm satisfied with.

The convergence assembly does have a pivot on it, and a stationary point. I'm not sure how it would affect anything, but I tried to move it, and I was right....it doesn't affect anything ;)

so if you turn all the screen drives down and turn only the red up, you get a uniform red screen? if so then purity is good to go, next is the static magnets, the 3 around the convergence board at 8/12/4 o clock.. use those and see if you can get the center of the screen cross hatch good. Note the blue lateral will have to be used as well to move the blue from side to side the top blue magnet is up and down, the 4 and 8 move the R and G diagonally. Do the RG 1st then move the blue to match them.

I'll be back on this set in a couple days. Just knocked out a '52 Admiral resto, and want to give it some playing time before I button it up.

Now have a new tool at my disposal! Gonna resume this week, and hopefully, get it right :)

http://farm7.staticflickr.com/6170/6239051694_0fd86a5671_z.jpg

Couple of years back I found one of those for 2$ at a thrift that had been WELL used. It has been my go to crosshatch generator since. Tip:If it is not working or goes funky pull and reseat each socketed IC....This goes for most heath gear of this era.

Also before doing convergence play with the channel tuning of the generator and brightness/contrast controls of the set for thinnest least blury cross hatch lines. Also the three clip leads for CRT grids/cathodes to allow those switches to turn off guns are a waste of time in most sets IMO.

i have 2 of these units

I've been looking at my RCA 19" portable CTC-36 and found this old thread. I'm adding on to this one to keep all the past notes in one place. And great notes they are. My dad bought the set in 1969 as an extra set for his early Super Bowl parties (Madmen in Rockford, IL). I have powered it every few years or so and it still powers with a full raster and a working but tired picture (with color), but not a tired CRT. The 19HNP22 tests like new on my REM tester. The Beltron did not like it but I think the Beltron has issues. The first problem is the service switch. It has rotted out in pieces thus no pix of the set operating for now. I do have a NOS but I think it is for another model with slightly different pin bending on the bottom. It should fit. A sample testing of tubes was an exercise in just order a whole new tube lineup. My plan is to retube first and see where I am as I have everything else needed for a picture. Now I need to figure out how to get the chassis out unless I decide to jumper the service switch so as to not disturb the rest. Any thoughts on that path?. Does anyone have a CTC36 .pdf they can spare? It's a summer project so don't expect overnight news on this one. This one is for dad.