An interesting test color CRT.

http://cgi.ebay.com/NIB-RCA-1828P22-Cathode-Ray-Test-Tube-Television-TV_W0QQitemZ110574656245

John

Bid placed, let's see where this goes!

Some have told me the 'TEST' letters could be buffed out of the front, but I'm not sure I'd be willing to try that...

Are the letters in the glass or the phosphor? If it's the glass it should come out for the most part, I just can't tell which it is from the pictures.

If they're just etched a little paste wax should make them nearly invisible too.

John

As I recall reading somewhere....those 'test tubes" were "rejects" from the assembly line" that did NOT pass RCA standards, and often had some kind of "mechanical problem",(most likely this would mean a shadow mask defect or such) and RCA did not feel they could be used for normal CRT"s--so they often "gave them away" if someone bought a new tube or test jig or such. They were claimed to be "electrically perfect" though...and good enough for a "jig".



But..that was THEN...when a nice roundie color crt was readily available. and THIS is NOW...

And MANY of us would NOT be unwilling to use a "somewhat imperfect tube" if that is all we could find., for a 21CYP22, or 21AXP22 or such. Maybe even in a "lesser set" even for a 21FBP22--too. IN ANY case--that tube is NOT "junk" anymore!!

Slightly off topic - what does the letters in the different tubes mean - CYP, AXP, FBP, etc. Just wondering - never really paid attention when I was dealing with CRT sets years ago.

JUST a Guess...

"CYP--"Color Yttritum Phosporpous".

AXP "aluminized Xperemiental Phospors"

FBP-"Frit bonded Plate".

Thanks rca2000 - very interesting, I never would have guessed that it would be related to the mechanical components of the tube. I am assuming that the different types of phosphors would require different electron gun characteristics too.

I have one of the 21" test tubes, out of a jig I found. I probably should have kept it intact but considering it was basically a CTC-11 table model sans chassis, well, it was a real space hog! One of these days I may try buffing that glass-it looks to be in there pretty good. The tech I got it from had a story: early in his career he was able to buy a late model RCA roundie which had its crt busted by a moving company. He pulled this crt from his jig and used it for a few years until he could afford to buy a "real" one. He said it had some phosphor defects but was otherwise okay.

Sonofa... I can tell this auction is gonna get ridiculous.

If that auction goes up another dime, the seller will be laughing all the way to the bank! Those were flawed/seconds tubes which were used in test jigs, and in tv repair class models. Usually they have a problem such as a purity blob that won't correct, or the gun is installed funny, etc.

Charles

At least you'll get a great vintage box to store a good tube! I paid like over $125.00 to create a replica to ship my 21FJ to Scotty a couple years ago. I was an idiot to ship it UPS. When the van arrived it was almost upside-down in a pile of boxes and had clearly been thrown around and beaten without any thought to my labels on all sides and on top: "GLASS". The tube was fine inside thanks to my expert design which protected better than what this factory model appears to be likely to do if it was handled the same way.

Slightly off topic - what does the letters in the different tubes mean - CYP, AXP, FBP, etc. Just wondering - never really paid attention when I was dealing with CRT sets years ago.


AFAIK, they were simply assigned in sequential order, like non-vanity amateur radio call signs.

In CRTs, the diagonal size replaces the filament voltage at the prefix of the tube type. The type of phosphor replaces the numeral for the number of connections at the suffix. P4 phosphor is medium-persistence white phosphor (far more suitable for a black-and-white TV then, say, the long-persistence green P1), whereas P22 is an array of red, blue and green phosphors (in English, a color tube).

It does seem they ran one sequence in each size to be shared with color and B&W (e.g, there is no 15GP4 nor any 21DEP22)

Still, there are inconsistencies. Why is there a 30BP4, but no 30AP4. The 1828P22 is, of course, out of left field, with no letter before the P, and hopefully not 1828" diagonal (or our winning bidder will pay through the nose for shipping!).

These inconsistencies are found in receiving tubes, too. The 1DN5 seems to have jumped the sequence by a wide margin. At an antique radio show last winter, I met someone with a large supply of 6R-SP22 tubes - they weren't even picture tubes! (by outward appearance, they resembled type 6CL6).

Another use of "letters in place of numbers" sequential identification is found in projection lamps. Looking at most of the bulbs, the oldest types are "C** (e.g. the quite old CDS from the 1940's and newer CZX from the 1950's), through the D**, E** and F** (like FCS that is only seen in equipment from the late 1970's and later). Inconsistencies occur here, too, with some quite new designs of bulb being C** or even B**.

What exactly is Cathode Ray Tube Television Test. Can you explain?

It is keyword spamming.

What exactly is Cathode Ray Tube Television Test. Can you explain?

What is being discussed here is a 'test CRT', that is a CRT a technician
would keep on his test bench to verify the operation of a TV chassis
that is separated from its own picture tube. 8-inch monochrome test
CRTs are quite common.

CRT = cathode ray tube = 'tube cathodique' in French

Sorry I don't know the usual Italian word, maybe you can tell me...

Test catodico valvola

http://www.videokarma.org/showthread.php?p=722283

I give up. :sigh:

Who thinks that tube was worth $202.50? :thumbsdn:

I give up. :sigh:

Who thinks that tube was worth $202.50? :thumbsdn:

The winner I guess.:dunno: I've certainly spent more on rebuilding B/W crts.

Hopefully if it was someone here they'll be kind enough to report on how it performs.

John