Prototype set is here - Page 15 - Videokarma.org TV - Video

Electronic M · #1 09-10-2011, 05:38 PM

So instead of using the proto chassis' original front mounting you are using the one from the monochrome set's cabbinet, or are you changing the the way the original proto set's front CRT mount from being attached so that it is mounted to the cabbinet instead of to the chassis as I beileve it originally was (only reason I can think of for the latter would be if the tube is too far back on the chassis to look right through the mask)?

Sorry for all the questions. I'm a bit confused as to what you plan to do with the cabinet.

Tom C.

miniman82 · #2 09-10-2011, 06:48 PM

I think you have that right. The problem is that the way is was originally had the tube at a funky angle, so it would have left gaps in the front of the set between the mounting bezel and the front of the cabinet. If it turns out that it's not possible to do this the way I want to, I can always just keep it the way it was and deal with the gaps.

Electronic M · #3 09-10-2011, 08:21 PM

If i were you I'd keep the CRT mountings as they were originaly. The possibilities of stress/breakage that come form sitting in, and mounting/unmounting the CRT in a setup that supports the front of the tube with the cabinet, and the back of the tube with the chassis frighten me. It is your set so do what you want, but if I were you I'd avoid doing that with a prototype CRT that is worth a few grand and which is one of only a handfull of survivors (though something like a 10BP4 or a generic 50's 21" I'd consider subjecting to that risk).

Tom C.

*Bill Cahill* · #4 09-17-2011, 06:46 PM

Wow! I just looked at this. Looks like you're gonna get that baby playing, again.... I remember it on ebay. Harry had a rare one there.
Wonder where he picked it up....
Bill Cahill

zenith2134 · #5 09-17-2011, 10:49 PM

+1...would love to hear the history of this unit.

miniman82 · #6 09-10-2011, 11:08 PM

If I do keep the CRT supports all on the chassis, I would have to get a new set of narrowed support arms for the side. Perhaps that's the easiest thing?

earlyfilm · #7 09-11-2011, 11:52 AM

Quote:

Originally Posted by miniman82

If I do keep the CRT supports all on the chassis, I would have to get a new set of narrowed support arms for the side. Perhaps that's the easiest thing?

I think that is an excellent idea, provided you have the round brown Bakelite(?) front support which was visible in Harry Poster's pictures, but not in your pictures.

I suspect that these brown and/or black brackets were actually used as part of the screen mask on the earliest prototypes.

Look at the color picture of the two color sets in the March 1950 RCA demonstration to the FCC (near the bottom in this link which shows very dark masks):

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

My guess is that one of the estimated 35 model (circa 1950) model No. 1 Receivers and Converters (modern term: monitors) was re-purposed for the newer system and this is the reason why there are so many joints in the chassis as they recycled parts and complete circuits from the old units.

http://www.earlytelevision.org/rca_model_1.html

This theory would also match the date on the tuner. If you notice the picture, this model uses strait support brackets. The uneven bends on your brackets could stem from the time that this set was converted from a (circa 1950) 16 inch CRT to a (circa 1953) 15 inch CRT. If anyone knows the bell-bottom dimensions of the 16 inch 1950 prototypes, this probably could be confirmed.

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

In the top right photo, notice how the HV cage in the converter is placed on the right (when viewed from the rear.) If you had a cage, it would go directly behind the crudely bolted on upper control panel.

Also notice how the left side of the receiver chassis (again, when viewed from the rear) has what seems to be the tuner side of the set below bolted on with similar tube placement. Also they used apparently identical CRT supports to your set on both model 2 and 3.

To me, all these indicate reused parts.

James.

miniman82 · #8 09-11-2011, 11:34 PM

Brother dropped off a connector for the power supply inputs, but I still need a backshell for it. It's really tight, so having something to grab on to will be a bonus.

Electronic M · #9 09-12-2011, 12:19 AM

The two prong plugs in the back ground were used extensively on early post war Webcor magnetic audio recorders. I even have spare two prong plugs and a socket if you need them.

miniman82 · #10 09-12-2011, 01:14 AM

I could use a single female one.

Steve McVoy · #11 09-12-2011, 12:42 PM

Hi NIck,

I have a new shell for the connector. I'll put it in the mail to you today.

Steve

miniman82 · #12 09-12-2011, 12:52 PM

Thanks, Steve!

zenith2134 · #13 09-12-2011, 02:02 PM

Fascination overcomes me after reading through this entire thread. Really great documentation of your progress so far-- I cannot wait to see the outcome. It is truly awe-inspiring to see these pieces resurrected after countless decades of in-operation. You already know this, but you've got a very unique piece of crt history there.

miniman82 · #14 09-12-2011, 02:53 PM

My only hope is that the chassis can be made operational again, then we will see what the engineers saw around 1953! To do that, we need to make certain what signal to pass through it. Best guess right now is CPA with the higher subcarrier frequency, but without the entire circuit being traced I'm still in the dark. Tim is still working on getting the electronic version ready, it's hard to find time what with just graduated and getting his first 'real' job.

Electronic M · #15 09-13-2011, 12:55 PM

Quote:

miniman82 I could use a single female one.

I could use a single female too.

Seriously though my only spare female webcor connector is hidden away in one of my parts boxes and college has resumed for me so it could be a while before I mannage to find it. When I do locate it I'll contact you then drop it in the mail.

Tom C.