Vintage Oscilloscope Tube - How can I identify it

Getters are typically silvery or can be blackish in a good getter flashing procedure.

Sadly, some audiofools think silver gettering means the tube is bad. Sigh. ( I had a heated arguments at a hamfair on that subject from an idiot that wanted "clear gettering" because the "sound was better." ).

It is most likely a P4 or a P1 CRT. The blue and orange CRT are pretty rare. If the CRT had a metal pin in the center of the screen, IIRC, it would have been a PPI (Target indicator?) usage CRT. Have a few of those stored away.

Hello again everyone and thank you so much for all of your helpful suggestions and references. I went thru the tube spreadsheet that CHAS referenced and checked everyone one of the pdfs associated with the code CRO and CRT. I believe that based on the overall dimension of the tube (14 3/4") and the base pin configuration (B12-43) and other descriptors, that my oscilloscope tube is a 5DEP-*, where the number after the P is undeterminable. Thanks Frank for the suggestion in your reply, I believe you nailed the tube correctly as 5DEP*. The only other remaining determination is the persistence of the phosphor. I have shown a very bright led light all around the tube and only able to see a white illuminance at the end of the tube. I have tried to charge the tube in bright sunlight and then quickly into a dark room, but I got nothing, so I doubt that it is a radar tube. 

To Chas, I have located the filament (pins 1 and 12) and verified continuity. The getter silver is all silvery and I believe the tube has never been in a scope or ever energized. I guess I could put 6.3 volts on the filament, but don't feel its necessary since I have verified continuity.

It is most likely a 5BP1, 5UP1, 5DEP1, or a 5UP4.
 Those were the most common types used, based on my remembering.
 If it one of the ones with the blue or orange phosphor, they are quite collectible.

 Dumont used a blue phospher tube in some of their scopes. I have one of those scopes.

This might help
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Sounds like the type number was on that old sticker. You could just try listing it for sale as a "5 Inch Round Oscilloscope CRT Cathode Ray Tube". That might get it a new home. Potential buyers will be willing to take a chance on it if the price is right (low priced). Good luck.
73, Roderick  WB6FBF

Cliff: thank  you so much for responding and being so informative. Unfortunately, I tried all of your recommendations with a bright LED (white led, then green, then with red led light) and there is nothing (no markings, numbers, letters, etc)  on tube, bakelite, or inside. The only thing is the pin out numbers next to the crt socket identifying each pin by number. 
 
Thank you so much for your valuable information.

It will take some poking around to discover what family of 'scope example this is from. Very likely there will be more than one type number...

IMHO this is from an inexpensive service scope probably a spare...

Try this web site, the top of the page is a CRO with a diheptal 12 pin base.

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Scope tube classifications start with the first number which is the diameter of the screen, for yours probably 5 inch. The following letters do have a meaning but I don't really know. The number that follows the two letters is the persistence of the phosphor. P1 is green fast persistence, P4 is white (usually for television) and P7 is a long persistence for radar. A radar tube phosphor will charge in daylight or a well lit room and glow for a few minutes after the room is darkened.

Most of these CRO's from that type era are 6 volt filament. The one you have also appears to be electrostatic deflected. Use a LED torch focused, and peer into the neck looking at the screen, there should be two pairs of plates.

Also, darken the room, use the LED torch and scan the neck from the socket to the interior aquadag coating. The somewhat coherent light of the LED torch will slightly illuminate faded type number etchings so they will appear to very faintly glow. Change the angle while looking for a 8 sided shield with the numbers inside the shield.. Try on the base Bakelite too, just in case.

Locate the filament pins and check for filament continuity, look if the getter silvering has turned white. If the filament has continuity and the getter is still all silvery then the tube still could be sold as: Filament OK and getter OK. no other warranty.

Don't expect much, someone has to gamble. IMHO 10 to 30$ US. Really has to be packed very well to ship.

GL

Chas WA1JFD

Hello Everyone: My name is Herman and I am a new member and a first time poster. I am retired and trying to deal with my late father in law's estate. He was an avid amateur radio enthusiast and repaired cb radios and car radios before he died. I am trying to go thru his parts and came across this vintage oscilloscope tube. It appears brand new and perhaps was used as a spare. I know that he had a tectronic scope at one time, but he has had so many scopes, I couldn't recall all his equipment. 

My dilemma is the following: I have sold all of his scopes and have now come across the following oscilloscope tube (spare). It appears that there might have been a paper identifying sticker on the tube atone time (based on the rectangular glue marks on the tube), however, it must have fallen off.  Also,  I can't find a single number or manufacture listed on the tube, describing  what make or part number is on the oscilloscope tube. I was thinking of offering the tube for sale, but its hard to sell something when all I can do is put a picture of it with out a part number, or what equipment it is associated with. 

Here is what I know so far:
It has 12 male socket pins concentrically around a plastic keyway for the connections. The glass neck is 1.616 inches (41mm). The widest part of the screen (end) is 5.195 inches (131.9mm). The overall length of the tube is 14 5/8" from the screen face to the outer most center plastic alignment pin in the socket. There are no numbers or manufacture codes on the glass.  Here is a picture of it if this helps. If anyone has any ideas on what tube this could be or who might, it would be greatly appreciated.  Thank you

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