Tomorrow night going to go take a look at this TV.... Seller is a retired TV tech and says it comes with a spare chassis and yoke! Also says the tube tests good. If all is well, it's going to follow me home. He says it hasn't been powered on in 15 years.

Anyone had a chance to work on one of these before?

Kewl ! Looks like a Good 'Un ! Good luck & keep us posted !

Don't be offended but if you don't grab that TV, you may be foolish. Certainly looks like a nice deal depending on what you have to pay...

i do intend to buy... Unless the place is full of cockroaches or something similar Will follow up with lots of pics, probably followed by lots of questions.

i do intend to buy... ;)


Unless the place is full of cockroaches or something similar Will follow up with lots of pics, probably followed by lots of questions.

Cool! Please keep us posted...

This should be real similar to an RCA CTC-15. I found one of these at an auto junkyard in a pile of junk which had a bad flyback. I substituted in a flyback from a Hoffman rectangular set and it did work but with slightly reduced width. I ended up using the set for parts for other round sets as it had a good CRT and the cabinet was severely damaged.

Burned wiring and terminal strips from the heat of power resistors and bad diodes, bad degaussing thermistor, bad power switch, bad electrolytic capacitors seem to be the usual problems

Get it....why not. If the tube is good and you have an extra chassis and the tube is good there is little risk. That set will produce a color picture you just cant get out of that Zenith.

My main worry right now is that the "seller who used to be a TV tech" will have other stuff which I also want to bring home!

If it can produce a better picture than the Zenith, that will be great. No doubt the sound will be better too, with a cabinet that size. I looked at the CTC15 schematic, and it looks like it has a ton of adjustments my Zenith doesn't have. I hope it isn't going to be full of paper capacitors, if so it's going to be a lot of work!

Will need some caps but not to bad. Really no paper. The flyback is the weak point but keep it cool and you have a backup so you should be ok.
If the guy has even more stuff, Great! Stock up. Its better you than the dumpster.
IMO the round tubes have brighter more vibrant colors.

A lot of their sets were made by Wells Gardner and they are very close design to the Rca chassis.

A lot of their sets were made by Wells Gardner and they are very close design to the Rca chassis.

W/G never built anything for Sears. Their sets were built by Warwick and most were RCA clones.

W/G!? they actually made chassis for TV's!?! They're HUGE in the arcade monitor world!

Those were vector, not raster scan though.

wells gardner also made sets for jc penny.the sears warwick sets were ok.they had a nice silvertone crt.i think it was an rca myself.that roundie is a very nice one to grab.i would take it quickly!

I have an older Silvertone roundy and like it's colorimetry the best out of all my tvs.

I have seen one Sears Silvertone TV from the 1960s with vacuum tubes. It had a fantastic picture. Also that model had a One Button Color button for automatic color. Maxhifi, I strongly suggest that you get that TV.

Went to the guy's house, he ran a TV repair shop for years, and has a small one out of his garage now. Really nice guy, he said he was put it together in 1971 from two broken TVs, and was planning on keeping it forever. Cabinet is nearly perfect. He gave me the service manual too.

Chassis is made by Fleetwood in Montreal. It's a Canadian Sears TV. It looks very much like RCA, but will take an expert to tell. The tube is a Sylvania.

Pictures are worth 1000 words, and here they are.

W/G!? they actually made chassis for TV's!?! They're HUGE in the arcade monitor world!

W/G has been around forever, going back to making radios in the 20's. They made the right decision to get into arcade games when they did.

I've never had the chance to play with a Sears tube color set (aside from an import). I suspect they were one of the top selling brands in the 60s, but not too many show up today.

Oh yeah, forgot to mention - it's mine!

Pic of blond girl is out of focus due to crappy cell phone camera (digital cam is dead)

The picture quality on this TV is astounding, I wasn't expecting it to be this good. The three colour controls really allow skin tone to be dialed in with precision. Even the Simpsons are just flawless.

The tube has a mild cateract... I've read instructions on how to fix Zenith and RCA round tubes, but how about Sylvania? I don't think I'm going to attempt to repair it yet.

The first "issue" the set has, is in the HV cage.

The HV rectifier, directly over the flyback, is in a plastic tube, which is a bit melted on one side... it looks like the flyback is a replacement. I can also hear some arcing sounds with the set running. I shut off the lights, and saw little sparks between the 6BK4 plate cap lead, and the HV cage. I moved it, but can still hear a little snapping sound - probably is arcing where I can't see it now. The wire needs to be replaced, or maybe a sleeve put over it? Surprisingly (to me) it seems to have no impact on the picture

Welcome to the "Roundie" family! I know you will enjoy it for years to come. I have 3 working ones now. My favorite so far is my 1966 CTC-16XL. Excellent color and sharp images! Congratulations!!:D

Beautiful picture, mine has that sort of "technicolor" look to it too!

I'm figuring out mine needs a little work, the picture jumps a bit in vertical height, and when the room is completely dark, I can see arcing inside the 6BK4 plate cap. Once the set is warm I can hear more or less constant arcing in the flyback zone, and also smell a bit of ozone.

The "fish bowl" shape of the screen is really not as hard to get used to as I imagined, since action is usually confined to the middle of the screen. I imagine it would be less nice for sports, etc, where the score is in the corner.

The sound also has quite a lot of noise in it, depending on what's going on on-screen.

The "fish bowl" shape of the screen is really not as hard to get used to as I imagined, since action is usually confined to the middle of the screen. I imagine it would be less nice for sports, etc, where the score is in the corner.



Sit farther away from the screen, it's less noticable the farther away you are.

The digital graphics(lettering) will always cause noise(buzzing) and there is always going to be some background noise in the audio. Just the nature of the beast. After a while you get used to it. Roundie sets when working right can have excellent color quality. The sets were also made to last and be repaired fairly easily. Try that with your LCD or Plasma set 45 years from now! You cant even get new parts for a 5 year old set now. They are obsolete already and if you find parts they are very expensive, so off to the landfill they go!

mstaton,

You raise a couple of good points!
Now, in the context of no more ntsc broadcasts, and digital cable, is it against the spirit of this hobby to add a little circuit board with audio and video inputs? I figure all i would need is a couple of op-amps.

It seems to me it would kill at least three birds with one stone... No more IF ghosting, no more audio noise, no need to align tuner or IF stages, etc.

Pete Deksnis detailed a circuit which does exactly that- it provides video to the set after the IF stages, which makes for a very nice picture!

What an impressive looking set and picture too :yes: The more I see these colour roundies, it makes we wish that we had colour TV here a lot earlier than 1974! Then there would be some cool old tube colour sets for me to collect and restore! I've never even seen a colour set with tubes in it, not even a hyrbid model either...:sigh: Maybe I'll have to import one to NZ?

The Sylvania cataract is the same as Zenith. Great set, all around!

miniman

I searched and searched, and came up with Pete's RCA circuit with the single 12AT7, and it also turned up this post http://www.videokarma.org/showthread.php?t=249148&page=12

I'm going to use Tom's single op-amp circuit, since it will be quick and easy to build and install. And it doesn't need any inductors.

Glennz

I am very happy with this set! It's the first roundie I've seen for sale around here, in over a year of looking.

bgadow

Thank you! I am happy with it too. Once I get the chassis how I want it, I might deal with the catreract - it does stain a nice white screen a bit green around the edges. This one would be a hot wire treatment I guess.

most of time heating the wire is not required, just warm the CRT face on in the sun on a hot day and use a strong steel wire to pull thur the adhesive. I use a couple large wood dowels to wrap SS .015 wire around them for hand holds, then you sort of saw thru. the adhesive should be like thick gel.

Personally if its just a very light green stain around the edges I would not be in a hurry to remove it. The CRT's are bulky and not easy to handle, and if you remove all the yoke/conv/purity gear you will have to reset it all up. Some ohter things, be very careful when removing the CRT socket and the yoke, you dont want to stress the CRT pin base, the glue that holds it on is fragile.

I have to say, I am a little bit afraid of handling the CRT that way. Sooner or later though I will feel the urge to make it perfect. I have to be 100% confident in my ability to set up a CRT from scratch though, and I'm not there yet.

I will also probably wait until I have a spare CRT before I do something which could possibly ruin this one or its lens - that said, I am pretty sure that sooner or later it's going to happen.

thats what I did, practice on one if you can to get the feel of it. My first one was a rectangle that had a very weak gun. There is a big diff in the green vs white, the white is VERY hard but not nasty, the green is gooey and makes a big mess, but cuts easy.

When I did this video in this thread http://www.videokarma.org/showthread.php?t=251762 I had all the neck hardware in place. I merely disconnected the yoke cable, CRT base, HV cable, and unpluged and unbolted the convergence board. All before unmounting the CRT. I then merely lifted and set the CRT in the bucket so the convergence board was in the bottom. After I finished and remounted the CRT I got the exact same picture quality (yes the purity and convergence were still as I had them) as before I pulled the CRT.
With how well leaving the neck hardware on worked I plan to do that on all future tubes that I decat.

Tom C.

Yes leaving the parts attached is an option, and will save on setup labor. Just be careful, more stuff dangling from the CRT (wireing from yoke and convegence coils). Prob be a good idea to secure that stuff with some tape or zip ties so it does not get in the way when moving the CRT around.

Well - I'm sure getting into this hobby... went back today for the parts chassis, and came home with the parts chassis for this set, as well as a zenith color console chassis, an Electrohome B&W chassis, and an Admiral color console chassis I left there, couldn't fit in the car.

Also got a B&K high voltage probe, and a B&K 415, with cables. He's going to look for the manual and give it to me when I return for the Admiral chassis.

The parts chassis had a good 6BK4 plate cap and wire.... cured the problem with arcing right away.

The Zenith, Admiral, and Electrohome are fairly complete, and flybacks look good... will post models on the classified section here after I pick up the Admiral they're no use to me.

Yes leaving the parts attached is an option, and will save on setup labor. Just be careful, more stuff dangling from the CRT (wireing from yoke and convegence coils). Prob be a good idea to secure that stuff with some tape or zip ties so it does not get in the way when moving the CRT around.

Heck, as long as you measure and take notes you should be able to get everything back to where it was. I'd hate the risk of breaking something or having wires come loose in the process. A digital camera and a sharpie pen are your friends! Plus, you get the fun of sharpening up your convergence skills! :D

Well, speaking of convergence skills, I did a full setup on the Silvertone (my first ever attempt to converge a direct view CRT TV). I thought the picture was great to begin with, but after a few hours noticed the reds looked pinkish in one corner.

Did a purity adjustment, followed by full convergence. Purity is awesome now, nice beautiful even red everywhere except the cataract.

I got the convergence very very close, but either the blue "lateral" magnet is too weak (well, I tried two of them), or, the blue lateral and the convergence coil assembly is not positioned properly.

Convergence is about perfect all over the screen, except blue is maybe 0.5mm too far to the right, all over, and the adjustment is just outside the lateral magnet's range. Since I tried two magnets, I am starting to think the whole assembly is in the wrong position.

Does anyone have a photo of the coils and magnets on the back of a CTC15 pic tube, in their correct positions?

Does anyone have a photo of the coils and magnets on the back of a CTC15 pic tube, in their correct positions?
Is the BL magnet centered directly over the 'pole piece' on the blue gun? That's a squarish little sheet metal thingy spotwelded on top the gun inside the CRT.
oc

Much better!

Everything was half an inch too far back on the CRT neck - BL magnet, Purity rings, and Conv. coils. I wasn't sure what was supposed to be the reference point.

I set it up properly, then re-did purity, then tried convergence a second time, with the result attached.

I tend to tweak the position of any neck hardware with little reguard for it's exact proper position. After all what matters is getting the best purity, convergence, etc.

You did quite well by the way.

Tom C.

looks extremely good!i wouldnt touch a thing as you are on the money.this was my job specifically back in the shop days.the other techs wanted no part of it,so it was my baby.from your picture,i couldnt have done any better.maybe not have done as well!

I think I am fortunate with this chassis, it has a ton of adjustments, and the demountable convergence board can be accessed from the front. Convergence sure was easier than I expected, although it did take me a while.

Purity is tricky though... mainly because the tube is so deep that it's difficult to adjust it and see the screen at the same time. I need to read up a bit about what the purity rings actually do to the electron beams - the function of the other magnets is fairly obvious, but the how the purity rings actually work seem a bit elusive to me.

I think I am fortunate with this chassis, it has a ton of adjustments, and the demountable convergence board can be accessed from the front. Convergence sure was easier than I expected, although it did take me a while.

Purity is tricky though... mainly because the tube is so deep that it's difficult to adjust it and see the screen at the same time. I need to read up a bit about what the purity rings actually do to the electron beams - the function of the other magnets is fairly obvious, but the how the purity rings actually work seem a bit elusive to me.
After a thorough degaussing here's how to set up purity on roundies, and this is from the original RCA factory procedure. It's worth bookmarking for future referance. (It applies to RCA clones of course, as well as Zenith.)
Set the service switch for blank raster and turn blue and green screens all the way down and red screen up. Loosen the yoke clamp and slide the yoke as far back as it will go. Use the purity rings to put the red blob as close to center as possible. Slide the yoke forward, watching to see where the best red purity occurs. This is counterintuitive, because normally the "sweet spot" will occur 1/2 to 1/4 inch before the yoke is fully seated against the CRT bell. Clamp the yoke at that point.
On rectangular sets up through the CTC-25 etc., the procedure is the same except the 'sweet spot' normally occurs about 1/4 to 1/8 inch before the yoke is fully seated.
oc

what i did, was use the rings to centre the blob, slide the yoke all the way forward, and then use the rings to touch up the purity of the red screen... Going to revisit this procedure, thank you!

just remember, the purity effects the convergence.

just remember, the purity effects the convergence.

Yep, I learned that the hard way... I'm not afraid of convergence anymore though.

I also learned that the BL magnet affects purity, making this an iterative process. I had the BL magnet pushed in all the way when I did purity the first time, and after convergence was done the BL magnet was about half out, and a nice green blob had appeared in the side of the red raster.

You guys always manage to coax such amazing pictures out of these roundies. I still need to find one, that'd be a fun project!

Nice save on the Silvertone. Wasn't Silvertone the one that had the 'Chromix' switch which IIRC did something to the chroma demodulating circuitry?

Sure does have a chromix control - I sure with my Zenith had one, between Chromix and Tint, I can dial the color bars in very nicely.

Turned on the TV tonight and purity was all screwed up. No idea why. Repeated purity and convergence procedure, and picture looks awesome. I hope this isn't a weekly thing! Hooked up the VCR and watched the movie Dual, hadn't seen it in years but it's still awesome, and Technicolor really suits the round CRT.

decided to use this tv today. the vertical size is jumping a bit, after it warms up. I am thinking filament winding on flyback might be arcing to ground inside cage.

color quality on this tv continues to impress me vs. modern tvs, it's like technicolor

RE: vert height

Bet any money the height pot is dirty/worn out. Usually they are fed with B+ Boost voltage from the horizontal sweep section, and the pot is 2.5 (or more) megs of resistance. It's a hard working pot, I've had to clean or replace just about every single one I've come across. Check any other resistor in that chain leading to the vert osc tube's plate circuit as well, they can drift dramatically. Always sub in a different vert tube as well, sweep circuits can be picky.

, it makes we wish that we had colour TV here a lot earlier than 1974! -- Maybe I'll have to import one to NZ?

NZ should have chose NTSC back in the sixties like nearby Philippines did.
At least they didn't pick SECAM like New Caledonia !