ctc 15 combo
 

got the call today-are you interested in an old tv? the 15 combo on ebay. of course it was robbed-no speakers,some tubes missing. got it home and did a slow start for a couple of hours. set played,sans a vertical issue. bad pot in
the centering. glad i got 3 on last order. set plays! decent picture,all 3 guns are
strong. a little gassy i think. shut it off and left. approx. 2 hours later,turned it on and the red gun went south. can get enough red to make a so-so picture with the screens turned down. the screen control for red does nothing. my crt tester checks bad-i am not too sure. when the set is turned on,it displays a nice red screen as the high voltage increases. when the horizontal spreads,the red decreases. are these old roundie crts that volatile? could it be something else? any help would be greatly appreciated.

Could be this set had a lot of ssues and that is why it got canabalized. Neither RCA nor Zenith roundie CRT's are at all volatile. The HV sections were the most unreliable parts, but most were good for a hi number of hours.

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let it burn for 3 hours and the tube seems to be getting weaker. red screen control has a slight effect on the picture. screen voltages are equal on all 3 guns. a booster increases red slightly,still not enough to make a good picture. green and blue check in the 7.5-8.0 on my tester. red is around 1.2-1.3. i have
a really good tube in a test jig i made last summer. i will try that . this set hasnt worked in over twenty years. i still cant believe a tube went bad that quickly. oh,well,it hads cataracts anyway!glad i didnt pay 75.00 for it.i wonder if the last guy used a rejuvenator on it?

What CRT tester do you have? If the last guy used one of those '60's vintage rejuvenators; then, he probably did more harm than good. I have a newer B&K 480 tester that has always done well for me. My first was a B&K 465 from the '60's. It checked tubes fine but the rejuvenate function ruined more tubes than it helped (especially the color tubes).

From what you say, it sounds like your tube is bad unless your checker is defective. It does seem weird that it fell off so fast.

I wonder if the tube was rejuvinated. I heard that some rejuvinated tubes will begin to fail quickly...

EDIT: what radiotvnut said basiclly...

i have an old rca with the roundie plug. my 21jfp22 in my test set is a strong tube-7.5-8.0 on all 3 guns. picture is very sharp. i didnt want to have to use it. this cabinet is very nice with few minor scratches. it is a good enough piece to restore. i do think the tube was hit once or twice. she died quickly. normally they come up. radio works -tunes in a station normally but has a very loud hum that will drive you insane. turntable is unfortunatly gone. if anyone has one,i am interested.

Sampson,

Check the pix tube socket and tube pins for corrosion. I've seen the chassis pix tube plug have pin connectors that would push back out of line and be intermittent.

Usually, when I have seen an older set with a suspect gassy tube, the HV would fade away as the tube warmed up. Unplug the kine socket, and HV would come back... fast!

Best of luck!

Bruce

(Been awhile since I posted. Been real sick for a few months. Better now.)

sad to say-that crt is a dead issue. couldn t bring it back to life. changed it out with a vdc 21fjp22 and it looked great! them the "thugs" vandalized it and now i have nothing. hoping to find a good crt for this set.

Will keep an eye out for ya buddy!

Did the person who bought it on the bay just scavenge it and then give it to you?

i am not sure. it was found on the curb on the other side of town. i got the call that there was a set over in arlington. a combo, looked 60s, round tube. i went after it and it was the ebay set.again,i had looked at it before and made an offer. they declined and it sold for 20.49 on ebay.i offered 75.00. they did rob a few parts:(some tubes and turntable). it had numerous issues and i spent too many hours getting it up and running. the crt faded quicky-i think someone jolted it once too much. the usual vertical problems,tuner rebuild,etc. was very nice looking when i got the bugs out. still looking for a crt and a turntable.

I saw this kind of problem in a Zenith set that was salvaged from the dumpster. The CRT base was in really bad shape. It worked great when first tested but several weeks later the CRT did nothing but arc and there was no vacuum left. There must have been micro-cracks in the CRT base caused by a blow to it.
If the crack is very small it can drain off the vacuum at a fairly slow rate.