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??

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

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.

Measure the DC bias on the CRT pins before you consider rejuvenation. Use a scope to check the video AC drive on the grids.

Hi John,
Worked for RCA/GE/Thomson designing color television chassis for over 20 years. I know it is the kine.
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?

I wouldn't try it until or unless it's 100% useless as-is. IMHO...

Charles

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.

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.

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.

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.

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.

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

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

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