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1936 Baird T5 TV Receiver restoration

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Till Eulenspiegel
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Hi Mike,  like this one perhaps?

Baird T5 Flexy Coupling 4

 Till Eulenspiegel.

 
Posted : 19/08/2023 9:42 pm
Cathovisor
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@till That's it, like those.

 
Posted : 19/08/2023 10:15 pm
Till Eulenspiegel
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The only item holding up the completion of the Baird T5 restoration was the flexible coupling between the vision receiver local oscillator tuning mechanism and the control cable.

Yesterday, I finally managed to remove the remains of the flexy coupler attached to the worm gear.  It was hoped that the securing pin could be driven out the shaft. That task proved unsuccessful. The only answer to the problem was to cut off the remains of the old coupler and drill out the end of the worm gear. This has been done so now a new stub shaft must be made to adapt the 3mm worm gear to 6.35mm for the replacement coupler. Another adaptor stub shaft for the other end of the flexible coupler, 6.35mm to 9mm.  

Baird T5 Worm Gear 2
Baird T5 Worm Gear 3
Baird T5 Worm Gear 4
Baird T5 Worm Gear 5
Baird T5 Worm Gear 6

Till Eulenspiegel.

 
Posted : 18/10/2023 10:52 am
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slidertogrid
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Getting there now! It will be great to see it working! 😎 

Rich

 
Posted : 18/10/2023 2:57 pm
Till Eulenspiegel
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The special parts for the vision local oscillator arrived today.

The attachment shows one type of flexible coupling test fitted.

Baird T5 Worm Gear 7

Till Eulenspiegel.

 

 
Posted : 26/10/2023 8:32 pm
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Till Eulenspiegel
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Until I'm fit enough to install the CRT the tube will remain in it's cradle.                                                                                                                                                                                                        In the meantime a 10mm ex-valve top cap connector has been fitted to the CRT base. The CRT will be positioned so that the EHT connector is facing the front of the cabinet.

Baird T5 CRT Base Connector 8

 

Till Eulenspiegel.

 
Posted : 15/11/2023 3:45 pm
peterscott, colourmaster, Lloyd and 1 people reacted
Till Eulenspiegel
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Preparing the T5 to accept its CRT.

To avoid glass to wood contact three rings made from felt material are attached to the aperture in the CRT support shelf.

Baird T5 CRT Support

 Till Eulenspiegel.

 
Posted : 29/11/2023 4:21 pm
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Jac Janssen
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Good job David!

You can't be too careful with these old monsters.
I think ideally the mounting of the tube is a two person job for safety and guidance reasons.

Jac

 
Posted : 30/11/2023 8:28 am
Till Eulenspiegel
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Hello Jac, the sight of this tube is enough to compel anyone to take extreme care when handling it. As much of the CRT bulb will be protected when the re-installation takes place.   Until 1939 Baird Television was the only manufacturer to market a 15" CRT TV receiver. In late 1939 EMI offered a 15" CRT model. Also one with a 14" CRT. The EMI sets were direct view models.

This is one scary tube.

Baird T5 15MW4

 Till Eulenspiegel.

 
Posted : 30/11/2023 2:55 pm
Cathovisor
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@till I thought Cossor had a 15" set, David? The 1210 comes to mind.

 
Posted : 30/11/2023 4:07 pm
slidertogrid
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Posted by: @till

This is one scary tube.

-- attachment is not available --

 

 Till Eulenspiegel.

Yes 😮 I am nervous enough of a TV22 tube let alone that monster. I would take a lot of precautions fitting that! My precautions would be "get someone else to do it for me" 😀 

 

 
Posted : 30/11/2023 4:51 pm
Cathovisor
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@slidertogrid I have the "baby" 12" version in my Baird T21.

 
Posted : 30/11/2023 5:22 pm
Till Eulenspiegel
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Posted by: @cathovisor
@till I thought Cossor had a 15" set, David? The 1210 comes to mind.

Hi Mike,   I forgot about the Cossor 1210. That set was introduced in 1938 as a direct view model.  Also in 1938 another large CRT TV receiver, the GEC BT8161 employed a 16" round electrostatic deflection and focus CRT.  

The Cossor 137T employed a 14" electrostatic CRT. The bulb was very spherical so the mask viewable area was reduced to a 12" X 8" picture.

Some Baird T23 sets were adapted to accept the 15" Cossor CRT.

Hi Slidertogrid, it's just as wise to treat those little 9" tubes with as much respect as any of the larger types.

There was a discussion elsewhere about the safety of rebuilt colour CRTs. Concerns about the fitment of the P band.

Till Eulenspiegel.

 

 

 
Posted : 30/11/2023 5:35 pm
gschwab
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What an amazing project, really can’t wait to see it working!

 
Posted : 30/11/2023 7:45 pm
Till Eulenspiegel
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Posted by: @gschwab
What an amazing project, really can’t wait to see it working!

I'm looking forward to seeing pictures on the CRT screen. I just need to summon up courage to fit the tube into it's cradle inside the cabinet. Tomorrow, I'll post up a picture of the tube with protection fitted around the bulb.   

Till Eulenspiegel.

 

 
Posted : 30/11/2023 11:41 pm
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slidertogrid
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I remember the picture of Gerry Wells in the BVWS magazine sitting on a bench holding what looked like a huge pre war tube, the only PPE he was wearing was his lab coat! 😯

 
Posted : 01/12/2023 12:57 pm
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Till Eulenspiegel
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Many old-timer TV engineers had a very laissez-faire attitude to handling CRTs.   From the Television Engineers' Handbook. Advice about handling CR tubes:

CRRT Safety

The precautions I'm taking with the Baird T5 CRT:

Baird T5 CRT Cradle 3

 The CRT faceplate is protected with a thick cushion and the sides bubble-wrap and a cardboard box.

 

This rolled metal tube is fitted on the CRT neck, close to the base.

Baird T5 CRT Metal Sleeve

 Till Eulenspiegel.

 

 

 
Posted : 02/12/2023 5:31 pm
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Cathovisor
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Posted by: @till

Many old-timer TV engineers had a very laissez-faire attitude to handling CRTs. 

Not just service engineers: I don't think it'd been let down to air but I do remember a physics teacher at school picking up a 14" CRT by its neck in class - and everyone wondered why I ducked under the desk...

 

 
Posted : 03/12/2023 1:10 pm
Till Eulenspiegel
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Yesterday, I attempted to re-install the Baird Cathodevisor CRT. The tube in it's cradle was brought along side the cabinet, everything was prepared to drop the tube into the receiver.

Baird T5 CRT Shelf

 Well, like everything about this set nothing is easy. It proved impossible to insert the CRT neck through the focus coil. I'm taking no chances with this tube so it has been returned to it's storage cradle. We know that the 15MW4 CRT is not the original tube and was fitted just after WW2. Because the tube bulb is 20mm shorter than the 15MW1 an adaptor block was fitted to raise up the focus coil.  Even though every care was taken to ensure the tube neck would pass through the coil and that rolled metal tube the tube would just not go in. Can't use force with this one.

Baird T5 CRT Shelf 2 Copy
Baird T5 CRT Shelf 2

A solution to this problem will be to raise up the focus coil support by 20mm. This was applied to the Baird T23 which has the much shorted 15" Cossor CRT, except the focus coil support is raised up more than 100mm. 

So tomorrow two wood battens will be made to raise up the focus coil. That crudely made adaptor block will be discarded. 

Till Eulenspiegel.

 

 
Posted : 17/12/2023 7:44 pm
Jac Janssen
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Hello David,
The set certainly is doing it's utmost to make your life very difficult!

Jac

 
Posted : 18/12/2023 8:18 am
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