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.

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

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.

So Motorola could have been made by rca or the other

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.

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.

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

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.

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.

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.

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.

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.

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

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.

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.

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 ?

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.


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.

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.

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.

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.

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.

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.

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?

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

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.

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

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

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

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

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.

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

Well at least I know I have a good tube in this Motorola because the RGB adjustments are all even alittle less then half up and have a nice white screen.

Another thing that tells the health of your tube is how far up you must set the crt bias adjustment to get a balance on the grayscale setup, the lower the better, or "master G1" as they call in on your set.

Another thing that tells the health of your tube is how far up you must set the crt bias adjustment to get a balance on the grayscale setup, the lower the better, or "master G1" as they call in on your set.

The G1 is set like a 1/4 up very low.

I have a spare 21fb and testing it on 2 different bk440 testers shows the red gun is weak but when I check the tube in the moto it shows all 3 guns are good on the 440 testers but I have a bk tester from 1978 and both tubes show good all 3 guns I don’t get why the newer bk shows the tube with the weak red gun as good. I know 2 different testers but all work fine it’s odd. Which one do I believe.

Before you believe what the tester is telling you, hook a DVM to the heaters as you are doing the testing, to be sure that the heater voltage is not dropping below 6.3 VAC, that's the problem my tester has, b&k model 490b, it does NOT have the power to light up a color roundie, and drops below 5 VAC, I have to rig up a separate 3 amp 6.3 VAC source to test them correctly.

Before you believe what the tester is telling you, hook a DVM to the heaters as you are doing the testing, to be sure that the heater voltage is not dropping below 6.3 VAC, that's the problem my tester has, b&k model 490b, it does NOT have the power to light up a color roundie, and drops below 5 VAC, I have to rig up a separate 3 amp 6.3 VAC source to test them correctly.

These 440 testers I have had for awhile now and all my other tubes in my sets tested good the heaters lit good only this one tube so I don’t think it would be the power that supply’s the heaters. The 440 testers on color is 7 vac

Well, it won't hurt to have that added insurance of sticking the DVM in ac mode on there to be sure when you test, I was in panic mode for a week before I worked it on on mine that it was over a volt too low. And if it's OK, you can look for other reasons.

Well, it won't hurt to have that added insurance of sticking the DVM in ac mode on there to be sure when you test, I was in panic mode for a week before I worked it on on mine that it was over a volt too low. And if it's OK, you can look for other reasons.

Well there’s not much to look for so maybe that red gun heater is drawing more then the other 2 and not heating to the right level but then again the newer tester may put more current out to overcome that.

Or, (speculation), red is the weakest, and if... I mean IF the heater voltage is a tad low on the tester vs running at full power on a TV, or any other known good state, it could be the equivalent to a “life test” where the heater voltage is deliberately lowered to see which tired gun drops of first, not saying that this IS what is happening, but a simple DVM test will make sure, cause you never know what the voltage is at the tube test socket for sure.

Or, (speculation), red is the weakest, and if... I mean IF the heater voltage is a tad low on the tester vs running at full power on a TV, or any other known good state, it could be the equivalent to a “life test” where the heater voltage is deliberately lowered to see which tired gun drops of first, not saying that this IS what is happening, but a simple DVM test will make sure, cause you never know what the voltage is at the tube test socket for sure.
I’ll have to check the voltage but if all 3 are good then it’s a mystery

I there any focus gain in using 3 22 meg resistors in series to make 66 meg or would it be the same as using a single 66 meg stick resistor.

Not really, other than improved HV creepage and clearance handling perhaps, the specialty 66m 6kv resistor will do fine as it was made for just that application, the only reason that early color sets had 3 22m resistors was that they had not created the specialty 66m one at the time and was not in mass production as it was later.

Not really, other than improved HV creepage and clearance handling perhaps, the specialty 66m 6kv resistor will do fine as it was made for just that application, the only reason that early color sets had 3 22m resistors was that they had not created the specialty 66m one at the time and was not in mass production as it was later. the 1963 silvertone I had with the ctc12 clone had the stick resistor unless Motorola decided to keep using 3 resistors maybe they didn’t trust the new stick resistor.

did you ever do the heater voltage tests?

the 1963 silvertone I had with the ctc12 clone had the stick resistor unless Motorola decided to keep using 3 resistors maybe they didn’t trust the new stick resistor.

Or they just had a HUGE stock of 22m 6k resistors on hand! :D

Or they just had a HUGE stock of 22m 6k resistors on hand! :D

Or, at the time, they could buy three 22M for less than one 66M.

did you ever do the heater voltage tests?

I didn’t do the heater voltage test yet

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?

Not in St Louis.

Not in St Louis.

I worked in the EJ Korvette in Catonsville (Baltimore), MD right out of right school. I worked in the Audio Department. The only repair facility was in our Audio Department and it was only for the equipment that we sold in that department. Televisions were in the department next to us. And remember how color sets were always in a darkened room?

Years ago in working with Zenith TV's I came across a Zenith roundie with a CRT that had a Zenith brand sticker/label on the top of a RCA label. They were either too lazy or didn't care.

[QUOTE=Electronic M;3253618]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.


Many years ago the CRT's were in somewhat short supply. If you made your own tubes you were in the drivers' seat for making as many sets as you wanted. Smaller manufacturers had to depend on what ever they could get ie; Curtis Mathis and others like them. Yes, they also traded around as in contract marketing. Smaller vacuum tubes were also treated and traded the same way.

Anyone know how these work I have used one in the past but don’t know how this works by boosting the gun but does not change heater voltage. They do work good without changing the heater voltage.

Anyone know how these work I have used one in the past but don’t know how this works by boosting the gun but does not change heater voltage. They do work good without changing the heater voltage.

Are you sure? I can't imagine how that's possible.

Are you sure? I can't imagine how that's possible.

I did post the same question years ago but don’t remember the result. I think it was taking voltage from somewhere else within the plug there is an adjusting pot and no transformer inside since I took one apart befor and all there is inside is a resistor and a pot.

I'm not sure which one you got and opened, but the way that most work is on 2 levels, first is by boosting heater voltage from 6.3 to at least a volt or more higher via a transformer in most cases, second is by isolation which may sometimes help in H-K shorts.

I'm not sure which one you got and opened, but the way that most work is on 2 levels, first is by boosting heater voltage from 6.3 to at least a volt or more higher via a transformer in most cases, second is by isolation which may sometimes help in H-K shorts.

These brighteners came red green and blue depending on what gun is weak the pic is for the red gun they are colored. I had taken a green one apart and the heater connection is not touched at all just wires from the gun that will be boosted to a resistor and a pot that’s it

I'm unfamiliar with how those type might work, never having seen one, they must be trying to alter the bias of the “weak” gun in relation to the others to try and balance things out, but I can't imagine that working out so well vs a real booster that kicks up the heater voltage, which is only a Band-Aid to start with.

I used one on another set with a really weak red gun could not get a white screen not enough red but after plugging one of these in it never changed the green and blue adjustment only the red just turned the pot up alittle and viola had more the enough of red. It is odd not to increase the heater voltage but it don’t but they do work well.

These brighteners came red green and blue depending on what gun is weak the pic is for the red gun they are colored. I had taken a green one apart and the heater connection is not touched at all just wires from the gun that will be boosted to a resistor and a pot that’s it

It has a pot that is accessible for adjustment (not visible in the photo)? Must be changing the G2 range on the affected gun.

The only thing I think it may have been doing is altering the cathode bias beyond the standard ranges on the tube for the weak gun, and thus pushing the drive level even harder, but that can't be very good for a weak gun on a tube, likely to burn it up fast.

It seems to me changing the G2 on one gun could get the mid grays about right, but the tracking would be poor. I really would like to have seen one in operation.

Someone here years back had mentioned that some voltage is changed with this maybe how it’s wired like maybe the G2 The post is here somewhere but it was awhile ago. They still show up on eBay sometimes and this has a 7 meg pot and a high ohm resistor

Another thought is that if it's adjusting the cathode drives, since it's passive, it can only reduce them, so the correction would be at the expense of reduced brightness.

Another thought is that if it's adjusting the cathode drives, since it's passive, it can only reduce them, so the correction would be at the expense of reduced brightness.

I do know with the red all but almost gone after plugging this in the red was really strong

I remember setting up this set and the red gun pot was maxed and bearly able to see the red that was there.

Well w/o seeing it, we can only guess at how it worked. :./

I have one for red and one for green but I don’t need either one thankfully.

I have one for red and one for green but I don’t need either one thankfully.

Well, if you have 2, why not post detailed pix of them to help us understand how the work?:yes:

Well, if you have 2, why not post detailed pix of them to help us understand how the work?:yes:

Do you mean take one apart ? The pic I posted just don’t show the pot

Do you mean take one apart ? The pic I posted just don’t show the pot

Yes, if available.
Also the one you posted is not very clear, it would help if it was higher definition, and all markings / words written on it could be seen to help ID it, cause it's kinda blurry and partial, looks like “Colorite” or something.
There are also other numbers on it, can't tell what they are, or if they mean anything at all.

This one is the same all three just got to get it apart

That thing seems to be a mystery device, can find no info on them at all, but lots on the normal heater type boosters.

This is odd it just looks like the pot and resistor is wired in series with the two green wires from the plug.

This looks like it’s in series but I don’t see anything that ties in for extra voltage

This is odd it just looks like the pot and resistor is wired in series with the two green wires from the plug.

which ones on the socket??

I suspect it's on pins 4 ,13 or 5, depending on what ever color it was made for.

Those types of "boosters" were advertised in a lot of the electronic magazines back in the day. The most basic ones came with splice connectors to use on which ever gun needed it. It's just a pot and limiting resistor connected between the screen and grid of the gun.

which ones on the socket??

This brightened is for the green gun so there is solid green and green and white the solid green goes to center of pot and the green and white goes to a resistor and soldered to one end of the pot and both go out to the tube.

I found the basic patent with a schematic:
https://patents.google.com/patent/US4139861

The idea is to reduce the negative g1-cathode bias, increasing the current in the gun (but also ruining the lowlight tracking, which is then restored by adjusting the cutoff with the set's G2 controls).

edit, Ahhh so my first thought was right!
Lower the cathode voltage a bit! :P

Ok so now we all have a better understanding of this anomaly device.

Of course, regardless of how it's done, it's like putting a band-aid on a gunshot wound, only will delay the inevitable, for a wile. :(

While it is a weird device it does work and it probably would work longer then a brightener that increases the heater voltage for that gun it’s being used for. Increasing the heater voltage creates more heat and would burn off more cathode material faster then if it were at the proper voltage. Just my thought on this.

Early thread discussion of the booster:


http://www.videokarma.org/showthread.php?t=258583&highlight=booster

jr