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-   -   Baird T5 restoration project. (https://www.vintage-radio.net/forum/showthread.php?t=152005)

peter_scott 17th Nov 2019 7:54 pm

Re: Baird T5 restoration project.
 
I see in TV&SWW in March 1935 they have the 15" CRT in a different cabinet and described the picture as black & white with no flicker.

Peter

Panrock 17th Nov 2019 8:36 pm

Re: Baird T5 restoration project.
 
Peter, your post inspired me to look up details of the television transmissions of the time from the Baird station at Crystal Palace, which pre-dated the BBC. They were on 180 and 240 lines. Vision: 42.8MHz (10kW). Sound: 35.3MHz.

http://www.ambisonic.net/bairdcp.html

Steve

peter_scott 17th Nov 2019 9:08 pm

Re: Baird T5 restoration project.
 
Hi Steve,

I see from the ambisonic site that the T5 was equipped by 8th November 1935 for dual standard 240/405 operation so perhaps I didn't interpret the photo with Sydney Moseley correctly after all and that in the period from February to June 1935 Baird's Crystal Palace Transmitter was radiating 180 line transmissions.

Peter

Heatercathodeshort 18th Nov 2019 11:09 am

Re: Baird T5 restoration project.
 
4 Attachment(s)
A few scans from TV&SWW December 1936.

beery 19th Nov 2019 9:11 am

Re: Baird T5 restoration project.
 
Hi John,
I notice the cabinet style in those adverts in the alternative to the one that David is restoring. It has no vertical flutes on it, it has two decorative horizontal stripes and a "V" shape inlaid into the front veneer.
This is like David's own T23. I know that an American collector owned a T5 with this style of cabinet at one time.

Hi Peter,
I like the look of that early 15" set - nice and cubist :)
I wonder about the flicker free claim. Could it be that the earlier tube had a bit of lag built into the phosphor mixture? I've yet to establish the difference between the 15MW1 and 15MW2 crts, maybe that was it? Also the question of phosphor colour comes into play as well. We know that the EMI sets were first to be supplied with green screens, as often shown by the crossed out early tube type number on the internal labels (though it would seem that white phosphor became available to EMI just in time...).

Cheers
Andy

peter_scott 19th Nov 2019 2:00 pm

Re: Baird T5 restoration project.
 
Hi Andy,

Yes, a longer persistence phosphor with its rather slow response to moving objects might have been more acceptable than the flicker. I wonder if the after glow would also be white? Or would it be yellow or green perhaps?

Peter

FERNSEH 19th Nov 2019 3:15 pm

Re: Baird T5 restoration project.
 
"Could it be that the earlier tube had a bit of lag built into the phosphor mixture? I've yet to establish the difference between the 15MW1 and 15MW2 crts,"
Hi Andy,
The CRT in the T5 the subject of this discussion is a Cathodevisor 15MW4. A post-war replacement?
I believe the formulation for the white phosphor arrived just in time for the high definition television service in 1936. Even so wasn't the Emiscope 6/1 a green screen tube?

DFWB.

Jac 19th Nov 2019 3:24 pm

Re: Baird T5 restoration project.
 
1 Attachment(s)
Yes it was David, like the 6/3.

Ad in the September 1937 issue of Television and SW world:

Attachment 193950

Jac

Panrock 19th Nov 2019 4:44 pm

Re: Baird T5 restoration project.
 
That's an interesting ad, Jac. I wonder what the difference was between the 6/4 and the (later?) 6/6?

Steve

Jac 19th Nov 2019 5:22 pm

Re: Baird T5 restoration project.
 
1 Attachment(s)
Steve, it certainly would be very interesting to have more info on the pre-war EMI tubes!

No data book I have (but I don't have that many...) mentions the 6/4.

But certainly data must be in possession of someone on this forum.
Let's hope something turns up!

Perhaps "Catkins" (on this forum) might have a relevant data-book. He has posted this photo of data on the 3/1 and 3/2 (I hope it is OK to mention this here):

Attachment 193953

Jac

peter_scott 19th Nov 2019 6:53 pm

Re: Baird T5 restoration project.
 
Quote:

Originally Posted by Panrock (Post 1192918)
That's an interesting ad, Jac. I wonder what the difference was between the 6/4 and the (later?) 6/6?

I wonder if the 6/4 was the CRT with the totally blown envelope and the 6/6 the one with the moulded screen?

Peter

Panrock 19th Nov 2019 7:47 pm

Re: Baird T5 restoration project.
 
Could be... Looking HERE has reminded me that my old 702 listed a 6/4 on its valve label. Maybe the 6/6 was fitted on those first generation sets produced from 1938 on. It would be interesting to hear what's on the label of 12-inch EMI sets belonging to others, though probably off-topic for this thread.

Steve

Jac 19th Nov 2019 8:01 pm

Re: Baird T5 restoration project.
 
Steve,

Both my 702 and 900 have 6/4 on the label.

Jac

Panrock 19th Nov 2019 8:20 pm

Re: Baird T5 restoration project.
 
Back to Baird... I've just noticed I have an ex-Tudor Rees photocopy of the manual for the T5C. Included are details of the "scanning equipment" and the Cathovisor tube. I haven't checked back in this thread but it's likely David B. and others already have this. However I can scan and post it here if requested.

Steve

Jac 19th Nov 2019 8:25 pm

Re: Baird T5 restoration project.
 
It would certainly be of interest Steve!

Jac

FERNSEH 19th Nov 2019 9:03 pm

Re: Baird T5 restoration project.
 
Hello Jac,
I still have that very early production HMV 900 in my possession but up to now I've been unable to ascertain the type of Emiscope CRT installed in the metal box. Never worked out how the tube can be removed from it's box. It's impossible lift it out vertically.
But we'll leave in there for the time being because there is plenty work to do on the two Baird sets, the T5 and T23.

DFWB.

Panrock 20th Nov 2019 12:53 pm

Re: Baird T5 restoration project.
 
Quote:

Originally Posted by Jac (Post 1192972)
It would certainly be of interest Steve!

Here is the handbook for the Baird T5C c/w comments on the scan apparatus.

What is the difference between the T5 and T5C?

It's in a .zip file, containing 7 .gifs titled by page no.

Click HERE to download.

Steve

PS. There seem to be some folder layers in the .zip from my computer, but the Baird files are at the bottom...

Jac 20th Nov 2019 2:45 pm

Re: Baird T5 restoration project.
 
2 Attachment(s)
Quote:

Originally Posted by Panrock (Post 1193080)
Here is the handbook for the Baird T5C c/w comments on the scan apparatus.

What is the difference between the T5 and T5C?

Thanks Steve!
I found different cabinet fronts (and sides) for the T5 and T5C, but I'm not sure if that is all there is to it:

Attachment 194004 Attachment 194005

Jac

FERNSEH 20th Nov 2019 3:20 pm

Re: Baird T5 restoration project.
 
The black banding around the front and sides of the T5C is only painted on. That's how it is on my T23.

DFWB.

FERNSEH 25th Nov 2019 6:02 pm

Re: Baird T5 restoration project.
 
2 Attachment(s)
Now that the Freeview retuning has settled down it's time to make a start on laying on the veneers. And very nice veneers they are.
Supplied by Original Marquetry Ltd, Westbury on Trym, Bristol.

So let's this started before anything else happens to me.

DFWB.


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