21fb j p22

[timmy]

Originally Posted by 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.

cleanliness meaning how would this be done ?

[Electronic M]

Originally Posted by nasadowsk

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

In 1958 CBS rolled out a rectangular color CRT that was so lousy they ended up recalling almost all the sets made using it (3 survivors are known).
Compared to that the 23EGP22, which had longevity issues from bad manufacturing, and weird phosphor colors that made accurate color hard to achieve, was basically successful in that the sets actually DID work from new and weren't recalled.... While the EGP wasn't the first rectangular tube to market and wasn't the best, one can argue it was successful compared to the 1958 CBS tube.

Originally Posted by 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.

Sylvania I sort of regard as the best and worst color CRT maker.....They had a great phosphor formula that yields BEAUTIFUL color on the one Sylvania round tube I have and some of their rectangular tubes were comparably beautiful in action, but the guns were not as long lived as most other brands... I'd argue Sylvania color tube longevity was among the worst of the big players in the industry.

RCA and Zenith tubes tended to have good life and good performance. For RCA Hi-Lite was the newly built high quality label and Colorama was the lower tier rebuild stuff.

I think I heard the screen grading went all the way to grade E and that most of those were test Jig CRTs.

[reeferman]

Bad news: 23EGP22 CRTs were absolute garbage along with most of the Motorola sets they went in. I know. I worked on a LOT of them. Many wound up in the dumpster. Not only did they not last long, (gassy & low emission) the 23" direct replacements were more than twice the price and the quality wasn't very reliable. Occasionally a good one slipped through QC. Sometimes we could shoe horn a 25" in its place.

The Motorola sets were plentiful where I lived. The retailer E J Korvette literally had a large wall of them always on. Flipper was on Saturday night and that large wall of blue ocean (it was impressive!) sold a lot of Motorolas.

Good news: Those sets put a lot of bread on the table.

[reeferman]

Originally Posted by 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.

The rest of the set would be dead long before then.

[trinescope]

I have a 21FBP22 branded GE on the base and a 1962 date code. The EIA code is rubbed off, but the "font" of the date code looks more like something RCA used instead of GE, so I think the CRT is a rebranded RCA. I don't think Zenith was making color CRTs around that time, and my 27KC20Q has a 1962 RCA tube in it. Sylvania did make 21AXP22 tubes in the 1950s, and of course CBS/Hytron did as well, being they had quite a few patents in that arena. The vast majority were RCA, at least until the mid 1960s or so.

[timmy]

So why is it that they say the red gun is very inefficient and seems to be the first gun to go in the 21fb j tubes. I would think that they have to put out even.

[Yamamaya42]

I don't think that it's that the red gun is inefficient vs the others, it's more sort of the set it's in, how hard the guns are driven, and if you have a 21FJP22 vs a 21FJP22A / 21fbj22 21fbj22a that matters.

[DavGoodlin]

Originally Posted by reeferman

Bad news: 23EGP22 CRTs were absolute garbage along with most of the Motorola sets they went in. I know. I worked on a LOT of them. Many wound up in the dumpster. Not only did they not last long, (gassy & low emission) the 23" direct replacements were more than twice the price and the quality wasn't very reliable. Occasionally a good one slipped through QC. Sometimes we could shoe horn a 25" in its place.

The Motorola sets were plentiful where I lived. The retailer E J Korvette literally had a large wall of them always on. Flipper was on Saturday night and that large wall of blue ocean (it was impressive!) sold a lot of Motorolas.

Good news: Those sets put a lot of bread on the table.

Great story! E J Korvette sold many Motorola sets in mid Atlantic, even the 19" BW my parents got in 63, but did they have a service department?

[timmy]

Originally Posted by Yamamaya42

I don't think that it's that the red gun is inefficient vs the others, it's more sort of the set it's in, how hard the guns are driven, and if you have a 21FJP22 vs a 21FJP22A that matters.

What’s the difference between the 22 and 22a

[Yamamaya42]

Originally Posted by timmy

What’s the difference between the 22 and 22a

old_tv_nut could prob go into it in much more detail, but it has to do with the type of phosphor chemicals used, the purity of color they give off, and how hard they had to be driven.

[timmy]

Originally Posted by Yamamaya42

old_tv_nut could prob go into it in much more detail, but it has to do with the type of phosphor chemicals used, the purity of color they give off, and how hard they had to be driven.

Which was the worst 22 or 22a

[Yamamaya42]

From what I understand, the A, is the better version.

[timmy]

Originally Posted by Yamamaya42

From what I understand, the A, is the better version.

Out of all the color sets I have had I never seen a 22a

[old_tv_nut]

Originally Posted by timmy

So why is it that they say the red gun is very inefficient and seems to be the first gun to go in the 21fb j tubes. I would think that they have to put out even.

This has been discussed in various places on AK. The problem is not differences in the three guns but differences in the efficacy of the three phosphors. Red phosphors always had seriously less efficacy than green or blue until the rare-earth reds came along. This required the red gun to supply correspondingly higher current to get good color balance, hence the red gun would wear out first. When a rare earth tube was used to replace the tube in an older set, there was usually a service bulletin to change some resistor values in the video output so the three guns would be driven more equally.

[Yamamaya42]

My RCA CTC-16XL has one, and so did the CTC-20, but not the CTC-15 or CTC-16. :/