judging from the basket case 15g that RACS resurrected, I wouldn't think that this tube would be an issue since they would need to redo the neck of the tube to rebuild it in any event.

Isn't there a place in France that still rebuilds picture tubes? if so, I'm sure the shipping alone would be outstanding..

Yes, it's just a simple neck weld. The problem comes from the fact that if the planar dot plate and mask are heated at a different rate than the rest of the tube, the plate can crack or the mask can bend. This is the same issue as with the 15G, but it's worse because the prototype tubes have more thermal mass than a 15G does because its internal supports are heavier. This means even longer bake out times, and more cost. I've read notes from early books on the developmental tubes that state the face should be shielded during cooldown, to avoid cracking.

Just a reminder to all convention goers, Steve will be talking about the proto set this year and I assume there will be a demo of it working for all to see. Should be an interesting speech, hope I can be there to see it.

Heyboer Transformers 616-842-5830.they could you one from scratch if you had all of the specs on the power tranformer to run the set..ask for Phil...tell him i sent you..he could make you the filter choke(s) also if the specs on them also... Jody

I also endorse Heybour Transformer. Here's what I have for contact information:
http://i573.photobucket.com/albums/ss171/MatzohHeppelwhite/Wolfeboro%20forum/Screenshot2013-04-22at114150PM_zpsaacb3245.png (http://s573.photobucket.com/user/MatzohHeppelwhite/media/Wolfeboro%20forum/Screenshot2013-04-22at114150PM_zpsaacb3245.png.html)

What's all the hubbub about transformers?

I think someone confused the comments about the power supply chassis being missing. The problem is not a missing power transformer - we don't even have the schematic for the power supply chassis.

Then make one my friend,
Steve,... they've designed me one for 1927'Colonial 31 AC highboy console radio, that the power supply and speaker was missing
when i bought her,..he 's came up with the power transformer, chokes and audio transformers from using my schematic that I've got,...sent a copy to Phil and the rest is history,now you said you've got no schematic of it....what about you're having the voltages requirements and currents i.e.(milliamps) of the tubes and other goodies reqired to operate the set...you could get close enough to build it within 20 % tolenece of operating the set...have sheet metal fabber make up the missing chassis....just and idea!
Jody:yes::yes:

We did make a supply some time ago. See the report on restoration of this chassis:

http://www.earlytelevision.org/rca_cpa_restoration.html

Designing a power supply isn't rocket science, and we used transformers we had pulled from junk chassis.

The problem, however, was that we don't have a schematic for either the main or power supply chassis, and don't have documentation of the supply voltages. We had to guess and experiment to come up with what we think are the correct voltages.

i have never posted here before,despite being from australia i can definitely confirm that that the large male socket at the lower left side of the chassis goes down underneath to the power transformer on a small chassis which had 3 screw in fuse sockets a large tagstrip bolted to the rear on this particular set 4 black wires leading to the tagstrip had been altered and it was obvious this power tranny had 2 primary 110 volt windings which been reconnected for the 240vac mains voltage some local tv tech had bolted down a small 240 to 17volt transformer connected in a bucking configuration to reduce the mains from 240 to 220 approx this small transfomer looked like it had been intended for a 12volt battery and was also connected to the same tagstrip using spare unused tags this tv was bought for $15 in 1971 from the scrapguy at the local garbage tip in milperra ( a suburb of sydney) i remember him saying something like what do you want that old black and white monster for my sister who used to go to the tip to help my scavenge old 5valve radios and other interesting looking junk said to this guy that olt tv looks so cosmic compared to the other hmvs awa or pyes that were also awaiting there fate we used to routinely rob these sets of all the valves and sometimes the line o/p or flyback trans as i had some idea of trying to build a tesla coil anyhow we finally dragged this beast homeon a wheelbarrow bolted crudely to my bicycle as soon as my mother saw this she said havent you got enough electrical junk to play around with anyhow we finally got it into my sisters bedroom and swichted it on waited for a few minutes connected up aset or rabbits ears to the aerial panel turned the tuner knob numbered from 2 to 13 and could hear the locat channel atn 7 on the 8 position however there was no picture and the damper a 6au4 and the horizontal output valve had dull red glows after switching off i pulled the the top cap off the eht rectifier a 1b3 mounted at a weird angle and tried again same result then isaw this 1x2b and thought why should a tv have 2 eht rectifiers the penny didnt drop at that time however when this valve was pulled the line output stage immediately seemed more healthy ie arcs could be drawn from the top caps of both valves ithen went to my pile of junk and took a 1x2 out of alocally made awa p1 portable tv which had been junked because it had been dropped shattering the case and causing the crt to collapse inward fitting this 1x2 to the old tv still no picture but i followed the cable coming out from the socket and it found it was cracked where it passed over a support strut of the chassis once this was patched up by using about fifty turns of electrical tape finally sucess i found it could receive the four tv stations we had at that time but i never knew it was a colour tv till now the sound if had been retuned from 4.5mhz to 5.5mhz by somebody else long ago having seen this post i still wish ihad that old tv of course after i moved out my mother had one of cleanouts and you know where ALL my old radios tvs and other stuff went i give you one guess

Boora2,

Welcome.

All information is appreciated here, but if you could post in separate sentences and paragraphs, we would have an easier time understanding.

Hi All;
Since I just stumbled onto this posting just Yesterday, and it took till today to read thru it all..
First, let me say How sorry I am about the Picture Tube going to Air..
Are You going to continue to Test and Work on it Using a different Picture Tube ?? To See what the Engineers saw back in 1952 or so ??
Or is there No other Tube that You can use ??
THANK YOU Marty

WOW! What a post! Much good info, and an amazing run-on "paragraph", without even a period at what could be considered the end. Kind of reminds me of German compound nouns lol.
He got the info out, so I look forward to more posts from our new friend from Australia! :yes:

Geist, we continued to work on the chassis. Here is a page with info:
www.earlytelevision.org/rca_cpa_restoration.html

I will be giving a talk at the Early Television Convention on May 18 detailing the work. It will be live on the internet, check our home page on the 18th:

www.earlytelevision.org

Is the (prototype) set going to be at the convention? If so ... will it
be working?

Doug McDonald

Doug, yes it will be there and yes it will be working.

What is the nonsensical text at the bottom of some of the earlytelevision pages?

trojanrabbit,

That is what happens when someone who barely speaks English buys advertising. We get several hundred dollars a year from this advertiser, who insisted on that text. The links are to various test exams. I pointed out that the text makes no sense, but that is the way they wanted it.