Original CRT in RCA CTC-11?

[Phil Nelson]

I wonder if my newly acquired CTC-11 has its original picture tube? The serial number tag on the kinescope matches the tag on the chassis.





I suppose that is a date code on the CRT base, but I can't decipher their mystical scheme.



The other signs point to a low-mileage set. The cabinet is like new. Apart from replacing a couple of small tubes, the only evidence of service (if you can call it that) is where the thermistor broke into pieces and the repairman twisted its leads together to replace the inrush limiter with a short circuit.

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

[Findm-Keepm]

Originally Posted by Phil Nelson

I wonder if my newly acquired CTC-11 has its original picture tube? The serial number tag on the kinescope matches the tag on the chassis.

I suppose that is a date code on the CRT base, but I can't decipher their mystical scheme.



The other signs point to a low-mileage set. The cabinet is like new. Apart from replacing a couple of small tubes, the only evidence of service (if you can call it that) is where the thermistor broke into pieces and the repairman twisted its leads together to replace the inrush limiter with a short circuit.

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

Probably so - all the RCA CRT replacement guides I have (starting in 1963) all show the RCA replacements to be 21FBP22A, the 21FBP22 is likely the original. I have no clue as to the difference between the non-A and the A.

[Tom S]

My CTC10 has an original CRT also. Serial tag is on it too.

[stromberg67]

Yes Phil, it's the original CRT. Hope it's still OK! I also have matching numbers on a CTC-11, including the cabinet, although the CRT is beyond toast LOL.
Kevin

[zeno]

I would say yes. I never heard of anyone moving the serial
tag from an old CRT. Only case I would believe would
be newer sets that under warranty had a strip of tags to
prove you opened the set ( NAP ).
With Zenith you would find matching #'s on the box,
back, CRT & engraved in the chassis that you could often see
through a slot. Saved my ass once when some anal orifice
claimed I swapped his back for another !!! Still cant figure
why I would commit such a felony.

73 Zeno

[Phil Nelson]

Originally Posted by stromberg67

Hope it's still OK!

Looks good so far. The emissions woke up quickly when I left it on the tester for a few minutes. Below is a snapshot after I had done nothing to the set except adjust some color controls and replace caps on the vertical sweep board to fix some instability.



I have done a lot of testing of resistances & voltages & waveforms to convince myself that it really is working as normally as it appears. I'm usually pretty gung-ho about replacing old electrolytics, but I'm inclined to keep my mitts out of this one, for the most part. The dilemma is that now I have a beautifully working CTC-11 in a great cabinet and no place to put it where it's convenient to watch.

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

[rca2000]

I STILL do not understand the fascination with the "wizard of oz" movie--for our oldsters...NONE Of them were around to show it new.

Myself--I like a "back to the future" approach, showing something like an advertisement for some ultra-tech device or service, especially when it has a "dot com" addy showing.

[rca2000]

Originally Posted by Phil Nelson

Looks good so far. The emissions woke up quickly when I left it on the tester for a few minutes. Below is a snapshot after I had done nothing to the set except adjust some color controls and replace caps on the vertical sweep board to fix some instability.




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

My OWN experience has been that a good majority of roundie tubes are either good when we get them, or they "wake up", pretty easily and then they work great. A BIG exception would be the "really old ones" like the 15G and 21AX--which tend to go to AIR--even if the cathodes were over 90% new--before they go to air. But the all glass ones with frit-bond seem to hold up pretty well--even OVER 50 years later.

But then again...I have my 29JC20 set with a BAD 21FBP22 and it is NOT gone to air--but the red gun is pretty weak and will NOT restore...though it WILL show a fairly good result at about 7.5 volts on the fils.

[DaveWM]

Originally Posted by rca2000

I STILL do not understand the fascination with the "wizard of oz" movie--for our oldsters...NONE Of them were around to show it new.

Myself--I like a "back to the future" approach, showing something like an advertisement for some ultra-tech device or service, especially when it has a "dot com" addy showing.

in the 1960's "the Wizard of Oz" was a once a year showing (generally) that most of us kids liked to watch. Besides the fact that the story is timeless, and Judy Garland has an incredible voice, it was one of the few color shows that really looked good on color tv.

Back in the day you had to make time and plan for the big event, then all the kids on the block would watch it and report back about it the next day at school.

Now a days with all the instant gratification and total lack of any planning required, and the lack of community from shared events I can understand the lack of a common show that draws so many of us "oldsters" to a single show.

besides all that, the color is rich and varied so it looks good on the set, and we know how it should look, so its almost a test pattern as well.

[consoleguy67]

Phil,
The picture on that set is beautiful!!

[kvflyer]

Phil, that is a beautiful picture. And, quite impressed that the set works so well with very little attention.

One day, one day, I will work on the CTC9 that I have. I just hope I have results that look as good!

[sampson159]

the correct way to see the wizard of oz is on a roundie.something about those beautiful colors in oz that came alive on a round screen set.your set looks fantastic

[kvflyer]

Originally Posted by sampson159

the correct way to see the wizard of oz is on a roundie.something about those beautiful colors in oz that came alive on a round screen set.your set looks fantastic

Yeah, I don't mind seeing it. I just hope to one day put a similar picture up here from my set. (And hear the barking ).

Just kidding ! .....

[Tomcomm]

Phill......Seems RCA finally got it right with your CTC 11! It uses X Y axis 12AZ7 demods, and 6CG7 grid drivers and the 21FBP22A CRT at 24KV ultor. I was very impressed with your screen shots of Dorothy's facial graduations. Reminds me of the low level chroma demods and matrix grid amps of the CTC2B 21CT55 running 27KV ultor on a 21FBP22A. Keep posting full screen shots......Tom

[Phil Nelson]

Thanks, this set does make a very pleasing picture -- at least as good, if not better, than my other CTC-11s where I spent hours gnashing my teeth over convergence adjustments, etc. I have taken lots of screen snapshots in the course of (gently!) working on this TV, but none of the others are good representations.

With my cheap camera, getting a photo that resembles the true picture quality requires a lot of fiddling with ambient lighting, contrast, brightness, color level, etc. Plus, with a front safety glass, reflections are always an issue, and my new workshop has lots of big windows. Good for working, lousy for screen photography! I had to tack a black curtain over one window to take that Dorothy shot.

Sometimes I think that using the Wizard of Oz is a bit of a copout. When a scene is full of bright colors, even a fairly lousy TV can look colorful (if not necessarily accurate). But the film does have a number of big close-ups, which are good for showing flesh tones. Perhaps I should go back to using Gone With the Wind. That's also a Technicolor movie but its palette is generally more subdued.

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