21fb j p22

[timmy]

Who made the 21fb or fj p22 crts in 1965 or during the 60s was this tube kind of proprietary to rca and we’re all these tubes made by thompson electronics and put different names on them.

[timmy]

Or did Motorola and sylvania and zenith produce there own tube for their sets.

[Electronic M]

Zenith/rauland made their own, RCA did, and so did Sylvania. Easiest way to know who REALLY made a tube is to look up the EIA number on the label. I've seen Zenith labeled roundy tubes that had Zenith, Rauland (Zenith subsidiary) and RCA EIA codes. The RCA tube appeared to be early into Zenith selling roundys.

During the color TV shortage of IIRC 1967 the smaller makes used any CRT they could pay hands on and sometimes the big makes would use each other's CRTs if in house production couldn't keep pace with set orders.

[timmy]

So Motorola could have been made by rca or the other

[Electronic M]

Originally Posted by timmy

So Motorola could have been made by rca or the other

IIRC Motorola had in house CRT production facilities. They developed the first basically successful rectangular color CRT the 23EGP22 and we're one of the suppliers of it. I would expect that they produced some roundy color tubes before developing it as it's easier to refine an existing technology you know than one you don't know.

[old_tv_nut]

The earliest Motorola roundies used 19 inch outside diameter CBS tubes. Adapter kits were later made to allow substitution of 21 inch tubes.

i realize now that I don't know if Motorola ever made their own 21 inch round tubes. Their rectangular tube was a joint project with National Video, and Motorola definitely did manufacture those.

[nasadowsk]

The 23EGP22 was basically successful? Ok, I mean, it worked, but wasn’t it kind of a dud?

[timmy]

Overall I was wondering if any of the companies that manufactured the round 21 inch tube we’re any better then the other. Who maybe built a longer lasting tube ? My experience with sylvania tubes were not good. The other question is was the rca hi lite made better or improved from the earlier versions. Not so much the rare earth materials but rather the gun itself.

[Yamamaya42]

The 21FJP22 in my GE made RCA CTC 15/16 clone has a RCA tube in it, but it's of a lower quality than you would have seen in an RCA or Zenith, GE most likely used tubes that RCA rejected, this one has a tiny but noticeable flaw in the shadow mask.

[timmy]

Originally Posted by Yamamaya42

The 21FJP22 in my GE made RCA CTC 15/16 clone has a RCA tube in it, but it's of a lower quality than you would have seen in an RCA or Zenith, GE most likely used tubes that RCA rejected, this one has a tiny but noticeable flaw in the shadow mask.

Wow these tubes were far from perfect to begin with they didn’t seem to last very long maybe it’s because of the materials that were available at the time but to call it a defect of sorts for just a mark on the mask.

[Yamamaya42]

From what I understood, there were different levels of quality in these tubes, grade A or B CRTs or even grade C, for a cheapo low grade TV, a top line RCA or Zenith would have a top quality grade A tube, and clones have tubes that did not meet the standard of A would have B or C, replacement tubes in shops would often also be B or C, unless one payed a premium for an A.
The one in my GE is clearly a B or C because of the mask flaw in the middle of the screen.

[timmy]

Originally Posted by Yamamaya42

From what I understood, there were different levels of quality in these tubes, grade A or B CRTs or even grade C, for a cheapo low grade TV, a top line RCA or Zenith would have a top quality grade A tube, and clones have tubes that did not meet the standard of A would have B or C, replacement tubes in shops would often also be B or C, unless one payed a premium for an A.
The one in my GE is clearly a B or C because of the mask flaw in the middle of the screen.

Well hopefully I have a grade a in this Motorola I have. Even if it was grade a it’s still old and old stuff don’t last forever.

[Yamamaya42]

Well, I don't believe that a grade A will last longer than a grade C, or vice versa, they were all most likely made in the same plants, from the same materials in the same way by the same people, it's more like a matter of that any given build of tube where the electron gun assembly, and / or shadow mask to screen placement was just a micron off of what may be considered grade A tolerance, making it harder to get ample convergence / purity w/o going beyond a set boundary, or, like in the case of the tube I have, a minor minuscule flaw in the phosphor or shadow mask that causes a tiny blemish that most won't notice unless you really look for it! :P

[timmy]

Well it would have been nice if when the guns were made they should have doubled up on the cathode material then they would last 40 years instead 20 years. But then again gasses build and of course render the tube no good.

[old_tv_nut]

I believe gun placement would be simply a pass/fail, and only screen blemishes were considered for grading. Some C grade or similar tubes were sold as bench substitutes, so that only the chassis had to be brought into the shop instead of an entire set. Edit: I seem to recall in some cases the faceplate for bench subs was etched with "reject" to prevent service shops from buying them for resale.

Regarding adding more cathode material for longer life, it's not that simple, as (I thnk) the degradation would be to the surface and having a much deeper coating wouldn't help. Also, I don't know how changing the thickness would actually affect performance. More is not always better.

Much of the life is determined by internal cleanliness and achievement of a persistently good vacuum.