Today's Mystery Guest (RCA CTC-4)
 

Time for a pop quiz! What model of television followed me home today?

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

http://antiqueradio.org/art/temp/Mystery1.jpg

http://antiqueradio.org/art/temp/Mystery2.jpg

I don't know, but I know I will enjoy the restoration article immensely!

CTC-4?

jr

Wow.. Twin speakers..

RCA model 21CT662 director, CTC-4 chassis.
It could be a different model console cabinet or a CTC-4 re-brand, but I'm certain that it is a CTC-4 chassis from owning a 4 myself.

Nice Score.
What did ya pay for it, is the 21AXP22 there working and not gassy, and when do ya plan on restoring it?

Why, of course!! It's "The Director", otherwise known as a CTC-4. Great find. Was watching mine yesterday, live sports. Hope your CRT is as new!
Kevin :D

Nice find - and please, I hope you didn't drink all the Two-Buck Chuck on the way home......:)

Cheers,

Pretty easy quiz, I guess!

A local pet shelter ran a rummage sale to raise funds and this TV (a donation to their sale) was crammed amongst loads of rubbish. After I tried testing the CRT on my Sencore CR70 with no visible signs of life, I offered $60, which they accepted. After thinking it over, I gave them an extra $20.

It's a one-owner local set. All the parts & pieces seem to be there. The cabinet looks better in dim light than daylight, but the decals are unworn and I think the various boo-boos will be easy to touch up. It has the inevitable ding on the brass bezel surround, but I can try the trick (Nick's?) of pushing out the ding as best I can and then putting that brass piece on top where the ding's less noticeable. The grille cloth isn't perfect, but that style should not be impossible to find. The Deluxe logo is all in one piece.

Chassis looks pretty clean after a light dust and wipe. Nothing frightening underneath. I haven't peeked at the flyback yet. The 21AXP22 CRT shows no emission whatsoever on the R and G guns, which I only tested briefly. The filament does have continuity. Tomorrow there will be time for a closer look.

I need more projects like a hole in the head, but this sale was so poorly advertised & attended that I felt like I was rescuing this set from a cruel fate (Goodwill or the dump). I spent about two hours at the sale, between testing things, gabbing with the sales person, and disassembling the set for transport. During that time there was only one other shopper . . . who bought nothing.

Phil Nelson

P.S. The cardboard box in the car held tools for testing & disassembling, not refreshments :)

http://antiqueradio.org/art/temp/Mystery4.jpg

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80$ DANG, you STOLE that! I paid 400$ for my barberized Seville....If you ever want to trade for a table model I think we could make a deal.

I would have happily paid them more if I'd had any hint that the CRT is good. I have never seen anything look so dead on this tester. Maybe tomorrow will tell a different story.

Phil Nelson

Nice looking tv, good luck with it !

So, just for the heck of it.... Exactly why do you take the chassis out...? Not much of a weight savings moving the cabinet.... If all the bolts are there it ain't gunna move... They were surely shipped in one piece from the factory.... When I was a kid I moved floor model sets on a lawn mower bottom with the tv up side down for miles, and never lost anything..... And when I got my zenith roundie it only had one nut in the chassis, I made reasonable sure it wasn't gunna hit the tube, and off I went... So I really don't get all the work takin out the chassis....?

I don't think I would have stood around testing the tube either.... Just load it up and get outa-there before someone else showed up who might have wanted to start a bidding war on it cause he thought he could resell it on ebay for more....

Its very clean inside...... really nice..... Christmas came early fer you....

Did ya get up and pinch yerself today yet....?

I guess its good to have a minivan in the stables..... I got my 9t240 in my '86 prelude, almost didn't fit in the front seat.....

Phil, send me the serial number for our database. Nice find.

Wow, nice find! It's must have been stored in good conditions; even the yoke cover is in fine shape. I sure hope the CRT comes back to life!

It is very clean. I was told it never left the owner's living room since new. It has some replaced capacitors underneath and I found a couple of little solder splashes on the floor of the cabinet. I suspect that whatever service it got was given right there in the lady's house.

It's too tall to stand up in my SUV. I know because I transported my (much shorter) CTC-7 upright in that vehicle and it barely cleared the ceiling. There was nobody to load it but skinny old me and the lady running the sale. (She was also baby-sitting a toddler and two dogs, but they were more trouble than help.) I didn't want to chance dropping it or gouging up the front while grunting it face-down into the back.

Steve, the serial number is B8085878.

Phil Nelson

http://antiqueradio.org/art/RCACTC-4SerialNumber.jpg

Great find Phil. Look forward to reading your comments as you restore the set. Hope you can wake up that CRT.:boring:

-Steve D.

Testing the CRT with my Sencore CR-70 doesn't have me dancing, so far. I measure .7 ohms between pins 1 and 14, so the heaters are not completely open.

Before connecting the universal adapter to the CRT, I set the heater voltage to 6.3. When I connect the UA clips to the pins and turn on the tester, the voltage drops to around 3 volts and the CR-70 makes a high whining noise. If I disconnect a heater pin, the noise goes away and the voltage goes back to normal.

The CRT passes the H-K shorts and G1 shorts test, but the needle doesn't move at all for cutoff test or emission test. This is the same for all three guns.

Suspecting operator error, I double-checked the manual and looked at an old photo of my tester connected to the 21CYP22 in my CTC-7. With exactly the same settings, the tester worked normally and checked the emission, etc., for each gun in that tube. I even hauled the tester out to check a B/W tube, and the tester works normally.

Not sure what is going on here. For an old B/W tube, I'd just let it sit on the tester for a while, to see if it wakes up under normal or slightly elevated filament voltage. I don't see any glowing inside the base, but the base is getting warm.

Phil Nelson

http://antiqueradio.org/art/RCACTC-4CRTNumber.jpg

http://antiqueradio.org/art/RCACTC-4CRTCheck.jpg

Can you actually see the heaters lit inside the neck?

Unfortunately, continuity but drawing excessive heater current and not lighting up sounds an awful lot like the tube has gone to air. Can you pull some of the neck components loose to get a look at the getter flash?

Sounds like air. The getter is under the yoke somewhere, a slotted area around the neck provides a window to view it.

Selenium rectifiers AND a power transformer? Usually Selenium rectifiers are used in hot chassis sets, and transformer sets have tubes like 5U4 for the power supply B+ production. Or are these seleniums used for another function?
http://antiqueradio.org/art/temp/Mystery2.jpg

Hopefully the CRT's vacuum hasn't leaked out.

The base getting warm that quickly certainly points to air.

:tears:

Area inside these slots looks milky :(

Phil Nelson

http://antiqueradio.org/art/RCACTC-4CRTGetter.jpg

http://antiqueradio.org/art/RCACTC-4CRTGetter1.jpg

Yes, similar to the CT-100.

Phil Nelson

Seems like an air dud. Sorry it's gone to air. :tears:
Anyone ever install a 21CY in a CTC-4 without modifying the mask area, or other mounting hardware? I know about cutting the yoke flange when using an FB.
Kevin

Cutting the yoke flange for a 21FBP22?! I still entertain hope of getting a good AXP for mine so I just used a modern cup HV connector and stuck several layers of a THICK plastic bag between the yoke and HV connector area to prevent arcing/corona...It works fine, and I did not hack up any OEM parts.

Too bad, the 21AXP22 went to air. You paid less than I did for my Director, I think it was $125 and I had to drive to Indy to get it. Great scroe!

So, I guess the CRT replacement options are pretty limited . . . .

Phil Nelson

Phil,

We have the technology to locate the leak with the Helium leak detector. The leak will be located somewhere on the weld where the front and rear sections of the tube are welded together.

I believe Nick did some welding recently on some part of a 21axp22 that he is playing around with and commented that the material welded suprisingly easy.

So if we are able to locate the leak (which is easy) and Nick can re-weld the area where the leak is located, then it should be an easy task to re-gun the tube some day at ETF. I know somebody who has a stash of delta guns in the event we are able to get a rebuilding plant up and running at ETF some day.

Moral of the story is SAVE YOUR LEAKING 21AXP22 crt's. We might be able to fix them some day.

BTW: there is so much air in that tube that I can see corrosion on some of the gun elements.

The AXP in my CTC-4 is gassy so I used a 21FBP22 as a substitute, and I can tell you it does work.
Any 21" good roundy color jug will work. With the glass jugs you need to remove the plastic CRT cover, make a new HV lead/plug, unscrew all the screen purity magnets so they are as far from the screen as they go, and ground the CRT's dag. On the non-21CYP22 tubes(I can't speak for the 21CPYP as I've never owned one) you will need to put some thick plastic between the metal yoke shell and HV connection on the side of the CRT to prevent arcing(because the grounded yoke will practically overlap the HV connector) According to a previous post I guess that some collectors prefer to cut a notch out of the yoke shell instead of using insulation to prevent arcing.

I'm not going to try to find my thread now, but to give you an idea of how good a deal you got...I shelled out over 400 clams for my CTC-4 pictured here http://s1095.photobucket.com/user/El...?sort=3&page=1 , and I have seen nice 4's on the bay go for north of a grand.
My restoration is on hold now as I moved and since then I have not been able to clear enough bench space to work on it....That and it has IF/AGC intermittents and alignment problems that I don't have the experience or equipment to properly address at present.

There was something else I was going to say, but I'm so groggy right now that I for got it as I was typing the last sentence...

EDIT: Bob's post jogged my memory. I was going to say the 21AXP22 CRT's are about as bad about going to air as the 15GP22....Only there is not as much of if any effort to create a successful rebuilding process.

PS: I'm saving my AXP and it's plastic insulator for the day when they can once more be rebuilt.

Thanks, that sounds more encouraging. This set has a lot of potential. I really want to restore it to operating condition, not just keep it around as a doorstop.

Phil Nelson

Thanks for the SN, Phil. Your set is now in the database.

The CTC4 was a good performer, much more robust than the CTC5s.

Too bad about the crt. Electronic M has a good point, put the tube in plastic, better yet, do what you can to bring it down to a vacuum and then seal it. Even if all you can do is HVAC level vacuum, heat it too and boil out as much water as you can..... Then seal it.

I did not seal mine in plastic. There is a plastic CRT insulator to keep prying fingers from touching the metal bell. That insulator is unnecessary with a glass CRT so I have it stored on my removed, dead AXP. Mine still holds some vacuum so I plan to leave it be.

If I was in Phill's position (with a tube that is completely down to air) I'd remove the base and the pinch-off stem and try to fill the tube with a noble gas that is heavier than air. Noble gas is non-reactive(unlike air) so it would be chemically about the same as having the tube under vacuum and, as long as it does not leak out, would preserve the phosphor and metals inside the CRT preventing further corrosion. After filling it through the pinch-off I'd store it face down and seal the pinch-off with caulk or some such.

Sorry, I misunderstood you.

As to Phil's tube, Any chemical is likely to out-gas something that can react with the phosphorous so I would not seal it with anything but hot wax. I did see in his photos, that he is correct, it does look like some of the elements are corroding.... Since its corroding in the gun area, I wonder if the leak is down there as well... Like at the metal pinch off...?

Anyway, my original thought still is what I would do, Put it in a box, metal, glass, plastic, heat it to 90 degrees, pull a vacuum for a few days, then seal it. If you find the leak, and its down at the gun, then even better, seal it there after trying to get the moisture out.

Unfortunately, if the tube has been down to air long enough for the gun to start rusting, it may already be a goner. Back when CRT rebuilding was a viable option, rebuilders would generally not accept duds that had lost vacuum, as they weren't considered rebuildable.

The aluminum coating over the phosphors is likely corroded as well as the shadow mask.

As soon as the air came in, the oxide cathode coatings started absorbing CO2 from the air to form inactive carbonates.

At the very least, the gun will need to be replaced. But if the mask or screen is damaged, the tube is worthless.

Well why don't you just poop on our parade..... : )

Still have to wonder how long it took to form rust on the gun....?

I would still vacuum it and seal it... Even as a test, you gotta give it every chance as the number of usable duds still needs to be protected....

Well, when the ETF rebuilding project gets off the ground, maybe I can donate this 21AXP22 as a test subject.

Meanwhile, I guess I'm in the market for a 21" color tube that can be adapted to work in this TV. Anybody got a spare?

Phil Nelson

While all of the above seems logical in regards to elements being damaged by exposure to air, keep in mind that RACS in France when they were still in business a couple years ago successfully rebuilt a necked 15gp22 that was exposed to air for many years. The screenshot after rebuilding seems to indicate that air did not cause any damage to the mask or phosphors.

Well there ya go-

Better take steps to protect this dud from further oxidation....

IIRC there were some poor condition phosphor patches (could have been caused by water dripping in) on the necked RACS tube...It was not ruined but it was not perfect either.

I still think a noble gas is better than a vacuum. You can probably get something heavier than helium for about the same price(making it cheaper than sourcing any usable vacuum pump and suitable accessories). Also consider that if you have a poor vacuum (not as good as factory) there WILL still be many corrosive air molecules inside...Make that trapped inside where they will continue to corrode the tube. Noble gas does not react with anything (anything includes metal, glass, cathode surface, and phosphor), and thus will not cause corrosion or degradation to the CRT. If the tube is stored face down, the gas is poured in through the neck, and the gas is heavier than the main constituent gasses in our atmosphere then the noble gas will sink to the bottom of the tube and slowly displace the air upwards and out through the neck. Think of this filling process like like filling the tube with water(don't fill your tube with water), the noble gas has a similar comparative density to air as does water so as you introduce noble gas gravity and negative buoyancy (relative to air) forces it to the bottom and it fills up the tube from the bottom as if you were pouring water in. If the leak is in the face the noble gas may slowly leak out (if the leak is only big enough for air molecules to pass through then heavier and thus larger noble gas molecules won't get through), but if the tube is face down a lot of gas would have to leak out before air could again reach the shadow mask and phosphors. The shadow mask and phosphors are the most critical part to preserve as they are the least replaceable, and permanent damage to them will affect the picture quality of a rebuild more than any other part that can be damaged by air.