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  #31  
Old 05-09-2013, 11:19 PM
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Originally Posted by AVeturri View Post
I like the CTC-121 with the flip-up metal door atop and stereo speakers and on-screen-display.Those sets had a huge remote control and composite video inputs too. A neighbor has one and I always ask for it
Also, let's not forget it was just about the only set besides the CT-100 to have full I/Q color demodulation. I have one and the picture difference is very noticeable, especially with pastel colors.
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  #32  
Old 05-10-2013, 12:35 AM
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Originally Posted by AVeturri View Post
Where are all of those monitors from the '50s?
I have one: an RCA TM-10 using a 15GP22. Restoration is underway, but this is not a trivial project (for me, anyway), so it's taking a while.

http://antiqueradio.org/RCA_TM-10_15GP22_Monitor.htm

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  #33  
Old 05-10-2013, 01:39 AM
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One less Rube Goldberg-esq method I've heard of that was supposedly successful in fixing a gassy 15GP22 was to run the filament continuously for over a year to boil the crud off the cathode and cause the gas to move more so as to get it to hit the getters and be absorbed....I'm tempted to try it on my gassy 21AXP22.
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  #34  
Old 05-10-2013, 04:48 AM
JBL_1 JBL_1 is offline
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Originally Posted by zenithfan1 View Post
Also, let's not forget it was just about the only set besides the CT-100 to have full I/Q color demodulation. I have one and the picture difference is very noticeable, especially with pastel colors.
I worked on the CTC-131 and it was the first to have full wide I. The CTC-121 appeared a year earlier but was not wide I. The CTC-131 also has an auto kine bias set up. Which does track low lights over time.
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  #35  
Old 05-10-2013, 08:21 AM
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Originally Posted by Electronic M View Post
One less Rube Goldberg-esq method I've heard of that was supposedly successful in fixing a gassy 15GP22 was to run the filament continuously for over a year to boil the crud off the cathode and cause the gas to move more so as to get it to hit the getters and be absorbed....I'm tempted to try it on my gassy 21AXP22.
I tried this and was able to achieve a raster but it still had the fatal Purple Glow
Attached Images
File Type: jpg 15GP22 003.jpg (88.2 KB, 77 views)
File Type: jpg 15GP22 005.jpg (56.3 KB, 53 views)
File Type: jpg 15GP22 004.jpg (61.1 KB, 82 views)
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  #36  
Old 05-10-2013, 11:52 AM
pallophotophone pallophotophone is offline
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That's a nice General Electric tricolor receiver! Back around 1970 I had one of these in the goodwill repair shop in as a DONATION! We got it working very well and sent it out to be resold for $100.00. The 15gp22 was still under vacuum! It was the first and last one of that receiver I ever saw come through the door. Someone actually bought it.
I wish I knew then what I know now- I'd have paid the $100.00 to rescue it.

But then who wouldn't.

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  #37  
Old 05-10-2013, 12:56 PM
Phototone Phototone is offline
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Correct me if I am wrong, but I think it is normal for the getter flash in a vacuum tube to be used up over time, not specifically indicating a loss of vacuum.
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  #38  
Old 05-10-2013, 01:10 PM
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Originally Posted by Phototone View Post
Correct me if I am wrong, but I think it is normal for the getter flash in a vacuum tube to be used up over time, not specifically indicating a loss of vacuum.
The only thing that "uses up" a getter is adsorbing gas. But a depleted getter doesn't necessarily mean a leaky tube. Gases can also be released internally, usually as a result of overheating or arcing, but sometimes as a result of insufficient degassing of the mount during evacuation.

You often see faded/discolored getter spots on power tubes (like horizontal output tubes) that have seen many hours of hard service.
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  #39  
Old 05-10-2013, 02:23 PM
kvflyer kvflyer is offline
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Originally Posted by N2IXK View Post
...

You often see faded/discolored getter spots on power tubes (like horizontal output tubes) that have seen many hours of hard service.
Absolutely. 7591, 6L6GB, 6550, you will often see the getter flash that looks kinda like a cola color. But I have had many that still worked just fine albeit a little weaker than NOS but still worked fine...
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  #40  
Old 05-10-2013, 04:21 PM
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Originally Posted by JBL_1 View Post
I worked on the CTC-131 and it was the first to have full wide I. The CTC-121 appeared a year earlier but was not wide I. The CTC-131 also has an auto kine bias set up. Which does track low lights over time.
Doesn't the CTC-133 also have full I bandwidth?
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  #41  
Old 05-10-2013, 04:31 PM
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Originally Posted by JBL_1 View Post
I started in 1982 working on getting the CTC-120 and CTC-131 in production. Convergence for CTC-132. Designed deflection and power supply circuits for CTC-148/149. Power supply, analog stereo and YPRPB version of the CTC-169.

.
I wonder if we crossed paths back in the 80's. I used to work at the Sarnoff RCA LAB, developing frame comb filters, interlace to prog scan, picture in picture and more stuff. Werner Wedam was my boss. Invented some patents at RCA, but I still get bragging rights: http://pw2.netcom.com/~wa2ise/radios/patents.htm
I had a CTC101 TV (the one with the infamous flyback) and a CTC121.
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  #42  
Old 05-10-2013, 04:41 PM
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Originally Posted by andy View Post
The Beltron ...

You turn the heater up until the cathode current starts to rise, and keep it there until the current limiting bulbs glow brightly for a second or two, then stop and re-test. They recommend running the lower power "cleaning" mode after rejuvenation to blow out any shorts that might have developed.
When I did the tube in my RCA I more or less did this procedure (killing the Beltron after a second of the lights lighting up) by accident, in that when I saw those light light up, I pulled the cable going to the CRT from the plug on the Beltron. I wasn't sure what the lights meant. And then set the heater back down, and did a test and the CRT was alive again. I read and reread the instructions (all 3 pages of it) but I must have missed it, the instructions saying to shut it down once the lights light up... This is my first CRT, so there is this learning curve...
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