Weird CRT needed

[toober]

OK, please forgive me, this actually not for a television - but you television guys just might have one laying about in your CRT stashes.

I am in need of an oddball CRT for a Control Data Cyber console - a
21M44P31A. It pretty much looks like an old 40s/50s era tube, but the neck
is long - really long. I do not know why. And yes, green. I suppose I
should not be too picky about the phosphor! The Cyber consoles are vector displays, used for old Cyber mainframe computers.

In the B&K CRT book, there is an entry for 21MP_ and 21M133P_, but no
21M44P_. What is the significance of the middle number in a CRT
designation? I thought originally it designated the number of electron
guns, but clearly this is not the case.

[JB5pro]

Maybe you can get a newer CRT tester and rejuvenate it? I would check the CRT rebuilder that does radar CRT's etc. but I would first try the newer CRT tester/rejuvenator unless you are sure it can't be rejuvenated because of filaments, etc. Surely there is a replacement available somewhere.

[jr_tech]

Was the crt a "roundie" like in this console ?
Some of these consoles may have used a type of "Charactron" CRT, where the beam first is deflected to plate that is like a stencil for typically, 64 alpha-numeric characters. Then the beam (now with the shape of the desired character) is re-centered in the electron gun by another deflection system, and then it is deflected to the screen by yet another deflection system. These guns were very long, because of the complex deflection scheme and the character mask.

http://en.wikipedia.org/wiki/Charactron

P31 would be a Blue-Green phosphor.

jr

[bandersen]

Woah, that 's cool! Another wish list item

[Einar72]

All of the television CRT's I have seen discussed on this forum haven't a number in the middle at all. This jug sounds pretty application-specific and rare! I'd check with Sphere Research in Kelowna, B.C. They have an amazing selection of CRT's and tubes!

I used to work with medical CRT-display systems in the 80's into the 90's. Those CRT's had some hard-to-decipher numbers, and no one would explain when I asked. By the time I came to the industry, all the CRT's used in this factory were rectangular, and were orange or nice and green. Speaking of green, check this 1984 system out; this once-common system used both a dot-matrix scan mode and a classic 'scope-trace mode to display both alphanumerics and ECG traces (no idea who the guy in the video is):

http://www.youtube.com/watch?v=mLjYf...eature=related

[toober]

The tube is kaput - busted. There is pretty much no chance of a rebuild. The console is the later single tube version of the 1970s. I also do not think it is a Charactron (or derivative).

--
Will

[kx250rider]

P31 isn't just green phosphor, if I recall.. It has something weird about, like slower or faster time response. I'd suggest internet searching, and also check out the military/industrial electronics surplus dealers (such as Apex Electronics near Los Angeles). You never know where there might be a pallet of new ones for $1.00. (Just to clarify, I haven't seen anything like that at Apex, but wasn't looking). They have tons of old computer and military gear with CRTs in it.

Charles

[Einar72]

http://columbiaisa.50webs.com/crt_phosphors.htm

[jr_tech]

Originally Posted by jr_tech

P31 would be a Blue-Green phosphor.
jr

Ok, color me wrong on that one... wonder why my wife thinks that I am blue-green color blind.

P-31 on the left (Tek 211) ... Green P-1 on the right (Heathkit OL-1)

jr

toober ... could you post a pix of the remains of the CRT in question?

[jeyurkon]

Maybe not a TV, but interesting. The attached schematic shows the display section. This is from Console Hardware Manual

Except this appears to be a 12" version and not 21"

John

[toober]

Here are some pictures of the Cyber console:

http://members.iinet.net.au/~tom-hunter/photos.html

Monday I will try to remember to get an internal shot of the console.

I have tried the usual sources, I have even turned over every rock at Fair Radio, but figure I ought to extend a tendril into this group.

--
Will

[toober]

This is not a DD60, but a CC545A.

--
Will

[jr_tech]

Is this an optical illusion, or is the tube square rather than rectangular (4:3 ratio)?
jr
Nice pix!

[peterke1]

I believe the tube desination is most likely a Thomas Electronics "house number" for a custom CRT. Thomas used the "M" to designate magnetic deflection and an "E" to designate electrostatic. 44 should indicate their 44th design of a 21" magnetically deflected tube.

Peter Keller