View Full Version : Square screen CTC-2B?


miniman82
05-04-2016, 01:17 AM
So I have this spare CTC-2B chassis I got from Chuck Pharis, and I'm wondering: can I use this thing with a square tube? I mean I got it for spare parts in case something terrible happens to my nice chassis, but wouldn't it be sweet to have a square tube running on it? If for no other reason just to see what it would look like. It's been slightly hacked already, someone put a compactron HO tube socket in there and there was a 6JS6 where the 6CB5 should have been. I'm already converting it back, but I'm just pointing out that I don't have to be overly worried about messing with it.

So the question is are there any big neck delta gun square tubes out there, or would I be stuck trying to adapt convergence stuff for the small neck tubes? I unfortunately don't have a spare CTC-3A chassis to use with this crazy scheme, so I'd have to either borrow the one from my 21-CT-55 or make another one. That's fine with me, so if someone out there has a spare 19-25" tube with the stuff still on the neck I'd give it a try.

Electronic M
05-04-2016, 11:39 AM
IIRC the only big neck delta CRTs were early small screen Japanese stuff (14-16" IIRC), 2 surviving 1958 rectangular Westinghouse sets, and some broadcast monitors that seem to no longer exist. Finding a fat neck rectangular is going to be a tall order if you choose to do so.

You missed a good opportunity to get a tube with sweep hardware at the meet. I brought a Zenith CCII console with a good 25" delta CRT that someone landed for a buck.

You should get the right set in the second picture in this thread to put your creation in...http://videokarma.org/showthread.php?t=266920

miniman82
05-04-2016, 03:10 PM
That's what I remember Tom, guess I'm in for a penny/in for a pound when it comes to modifying this thing to suit a later 23V or 25A/X style tube eh? The CTC-2B puts out more than enough HV to run those CRT's, it's just the sweep angles that could be a pain. I do believe the vertical won't be much of an issue, but horizontal could be tricky to get wide enough for a full raster. I guess we'll find out, I'm looking for a square tube set nearby on Craigslist right now.

Kamakiri
05-04-2016, 05:16 PM
Hey Nick, Ed has a couple of those 15" Japanese Delta gun sets. I bet you could talk him out of one.

miniman82
05-04-2016, 06:25 PM
Are they the big neck ones though?


Since I have you, you left your fleece and Ed left his tube of sillycone in my van. What address am I sending them to? lol

Kamakiri
05-04-2016, 08:05 PM
Yeah, they're the big neck ones. If I remember right, he has one that's really nice that's in his living room, and one sorta crappy one that he saved for parts or something.

Which fleece, that jacket that I gave to you wear while you were there? I totally forgot about it till just now! Hang on to it till the next time you're in Al's neck of the woods and just leave it with him....he'll be coming up this way eventually :)

BigDavesTV
05-05-2016, 12:30 PM
LOL...if we weren't all TV nerds, already...somebody'd be a wonderin' what was going on in the van, with three guys, a Fleece, and a tube of sillycone! Sorry, I just couldn't help it!:)

old_coot88
05-05-2016, 04:27 PM
Seems like dynamic convergence and pincushion correction might be a major issue. Don't square tubes require extra pincushion circuitry?

miniman82
05-05-2016, 05:59 PM
Yes, but if I have to build my own convergence panel I could probably incorporate a pincushion circuit.

Phil Nelson
05-06-2016, 02:28 PM
Nick, I would be very interested in hearing whether you can adapt the chassis to use some CRT other than a 15GP22. The supply of good 15GP22s is limited, and even a seemingly-good CRT, like the one in my CT-100, may start to leak at any time.

The 15GP22 rebuild process is fraught with difficulties, as we all know, and who knows when -- if ever -- a foolproof rebuild can be developed. In the meantime, it would be great to have some alternative that lets people watch these historic sets without fearing that the picture may go dark at any moment.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Electronic M
05-06-2016, 03:30 PM
Nick, I would be very interested in hearing whether you can adapt the chassis to use some CRT other than a 15GP22. The supply of good 15GP22s is limited, and even a seemingly-good CRT, like the one in my CT-100, may start to leak at any time.

The 15GP22 rebuild process is fraught with difficulties, as we all know, and who knows when -- if ever -- a foolproof rebuild can be developed. In the meantime, it would be great to have some alternative that lets people watch these historic sets without fearing that the picture may go dark at any moment.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Nick is talking about the ctc-2B from a 21ct55 which is designed to drive a 21AXP22 CRT, NOT a plain ctc-2 from a CT-100 that drives a 15GP22 like you are thinking of.

Nick's work probably would not directly work if connected to a CT-100, but would lay out a template on how to go about finding a way to make a CT-100 drive another tube...

miniman82
05-06-2016, 04:24 PM
The CTC-2 (CT-100) chassis also makes a lot less HV, so would only be suited to tubes in the 19" or so range. The 2B has a way stiffer HV output (makes 25kv easily), and should have no problem getting a decent picture on a 25" tube with the correct convergence circuits in place.

Phil Nelson
05-06-2016, 07:42 PM
Duh, right. Well, good luck with this project, anyway.

Phil

miniman82
05-06-2016, 09:50 PM
Thanks Phil, it's gonna take some tinkering but I'll get it working.

old_coot88
05-06-2016, 10:02 PM
Man you got more grit than a Army mule.

:D

wkand
05-12-2016, 12:59 AM
Agree, oldcoot, this guy is tenacious!! Way to go miniman82....

I have often wondered the same thing, whether a successful "transplant" of a more modern tube could be done.

All the best in this huge challenge... :thmbsp:

andy
05-12-2016, 12:41 PM
I'd start by experimenting with a test jig.

miniman82
05-12-2016, 08:18 PM
I have a test jig, but it's a Roundie unfortunately. Right now it's being used to help restore the Silvertone I dragged out of Queens last year. I figure if I can find a 70's 25" square console that should work nicely, but no one near me seems to have one. I put up a want ad, just waiting for something to come of it.

old_tv_nut
05-13-2016, 12:34 AM
Think this should be called the "Back to the Future" project? Sounds like a real learning experience.