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  #1  
Old 05-05-2013, 06:27 PM
JBL_1 JBL_1 is offline
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Rejuvination of 15GP22's

Working on my CT-100 and have the horizontal, vertical and high voltage operating. The filaments on the 15GP22 light and the neck is not glowing but the raster is almost non existent. The brightness control does extinguish the light but it is really really dim. The room has to be pitch black. The getters are about 50% so the tube is/has been leaking. Anyone have cathode cleaner type rejuvinator??? Anyone had any luck bringing back a tube like this??
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Old 05-05-2013, 07:44 PM
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Pete Deksnis Pete Deksnis is offline
15GP22 demo @ ETF 2007
 
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Just a thought. Have you tried turning the Red Screen control fully clockwise and then adjusting the Green and Blue Screens for white? Maybe it'll squeeze out a bit more light.

Pete
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Old 05-06-2013, 12:55 AM
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miniman82 miniman82 is offline
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What does an emission test show, before you run off assuming it's got cathode issues? Could still be something with the chassis, for all we know.
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Old 05-06-2013, 09:51 AM
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John Folsom John Folsom is offline
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Measure the DC bias on the CRT pins before you consider rejuvenation. Use a scope to check the video AC drive on the grids.
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Old 05-06-2013, 08:00 PM
JBL_1 JBL_1 is offline
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Hi John,
Worked for RCA/GE/Thomson designing color television chassis for over 20 years. I know it is the kine.
Jeff
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Old 05-07-2013, 02:33 AM
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NewVista NewVista is offline
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Quote:
Originally Posted by JBL_1 View Post
Hi John,
Worked for RCA/GE/Thomson designing
Jeff
I had a 1980s Philips/Magnavox that I noticed used an electronic power supply taken right out of a Motorola applications book! Did Thompson also allow such free reign/plagiarism in their U.S. designs?
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Old 05-07-2013, 12:45 PM
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kx250rider kx250rider is offline
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I wouldn't try it until or unless it's 100% useless as-is. IMHO...

Charles
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Old 05-07-2013, 02:12 PM
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John Folsom John Folsom is offline
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Jeff, I guess you do indeed know what you are doing! :-) My personal favorite rejuvenating machine is the Beltron, but I am sure others have their favorites as well. Best of lick with it.
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Old 05-07-2013, 02:23 PM
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Zenith26kc20 Zenith26kc20 is offline
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I use a beltron and have great succeess with it. Some of the B&K's (my 467) seems to be a bit too rough on most tubes.
Real early tester/rejuvenators were brutal and did more harm than good. If it is a leaker, a rejuv won't help.
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Old 05-07-2013, 06:56 PM
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John Marinello John Marinello is offline
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I had a 21FJP22 that had a crack in the neck, and was definitly leaking. The picture was a little dimmer, but was mostly blurry. I thought at first the HV was down.
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Old 05-07-2013, 08:34 PM
JBL_1 JBL_1 is offline
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Anyone have a Beltron I can borrow??? It is not at all usable so I haven't much
to loose. I live in central NH but will consider driving with the tube or pay shipping.
I think a few of the senior members can vouch for me.
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Old 05-07-2013, 08:38 PM
JBL_1 JBL_1 is offline
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I had a 1980s Philips/Magnavox that I noticed used an electronic power supply taken right out of a Motorola applications book! Did Thompson also allow such free reign/plagiarism in their U.S. designs?


I am sure IC suppliers do not mind if you copy their circuit. If you are using and buying their ICs. ALmost always the application or reference design isn't close enough to steal but can give you an idea on how it works. I usually used more generic ICs and discrete transistors.
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Old 05-07-2013, 09:08 PM
Geist Geist is offline
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Hi All;
JBL, What era of Color TV's did You Design ?? Tube, Transistor, IC's, Etc.. And What Part of the Set did You Design ??
THANK YOU Marty
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Old 05-07-2013, 10:24 PM
WISCOJIM WISCOJIM is offline
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Quote:
Originally Posted by JBL_1 View Post
Anyone have a Beltron I can borrow???
Maybe it's time to have one of your own? They've been going very cheap on eBay lately.

http://www.ebay.com/itm/Beltron-Mode...-/290911612494
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  #15  
Old 05-08-2013, 12:29 PM
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kx250rider kx250rider is offline
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I like the B&K 467 / 470. It doesn't whack the heck out of the cathode; the way the 465 did, but honestly I've never had a Beltron, and don't know what method it uses. The 467 heats the tube, then gently does a burn-off of the cathode as the filaments cool. No loud pops, and in stead of a big yellow flash, there's a corona-like arc that you can see, as the oxidation falls away from the cathode coating.

Charles
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