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Old 8th Jul 2021, 4:24 pm   #401
kan_turk
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Default Re: Baird T5 restoration project.

Great work as usual

Rgds
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Old 8th Jul 2021, 8:42 pm   #402
FERNSEH
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Default Re: Baird T5 restoration project.

Hi John,
many thanks for the compliment.
The T23 power unit was refitted today. It was allowed to operate for over two hours and was trouble free.
The modules taken from T5 which can be considered to be fully restored are: the EHT unit, the timebase and the power pack. Although proved to be working the sound and vision receiver modules still need more work, mainly detailing to restore the original appearance.
The same goes for the T23, all the sloppy servicing procedures from 1993 have been corrected and the modules now resemble as close as possible to how the set was made in 1938.
The next stage of the electronic restoration of the T5 will be the sound receiver.
This is the version with the regenerative detector.

DFWB.
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Old 23rd Jul 2021, 8:20 pm   #403
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Default Re: Baird T5 restoration project.

The sound receiver unit in the T5 has the original B & I make capacitors.
I've started the messy task of restuffing these components. There's two 0.02mfd capacitors and two of 0.5mfd.

DFWB.
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Old 13th Oct 2021, 10:25 am   #404
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Default Re: Baird T5 restoration project.

The Baird T5 project has restarted now that a number of important components have been found to enable completion of the electrical restoration.
The self oscillating frame timebase transformer has a winding which is employed to cancel out the anode current in the Cossor 41MP triode.
The 75Kohms high wattage carbon resistor in series with the balancer winding has gone high in value, up to 132Kohms. Two wire-wound 75K resistors were purchased from an online parts seller. The resistors will be reliable replacement for the original carbon resistors. The other resistor has been fitted in the T23.

DFWB.
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Old 13th Oct 2021, 7:49 pm   #405
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Default Re: Baird T5 restoration project.

Hi David you are cooking on gas today kind regards Bob
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Old 13th Oct 2021, 9:00 pm   #406
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Default Re: Baird T5 restoration project.

Hi Bob, everything was going well and then the wire-wound focus potentiometer failed. Fortunately, a replacement was to hand.
These components are very expensive if you are buying new ones.

DFWB.
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Old 13th Oct 2021, 9:16 pm   #407
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Default Re: Baird T5 restoration project.

I love the brown crackle paint on the timebase control panel
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Old 13th Oct 2021, 10:19 pm   #408
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Default Re: Baird T5 restoration project.

Quote:
Originally Posted by FERNSEH View Post
Hi Bob, everything was going well and then the wire-wound focus potentiometer failed. Fortunately, a replacement was to hand.
These components are very expensive if you are buying new ones.

DFWB.
Hi David lucky you had a potentiometer at hand where could you have bought it when you first started out doing TV repairs ? kind regards Bob
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Old 21st Oct 2021, 8:26 pm   #409
FERNSEH
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Default Re: Baird T5 restoration project.

Baird T5. All the BICC make capacitors in the sound receiver unit have been restuffed. Three 0.5uF and two 0.02uF.

DFWB.
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Old 22nd Oct 2021, 7:42 am   #410
peter_scott
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Default Re: Baird T5 restoration project.

Looks really good!

Peter
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Old 28th Oct 2021, 8:06 pm   #411
FERNSEH
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Default Re: Baird T5 restoration project.

The frame of the lower cabinet back was reassembled today.
Diagonal measurements spot on, 31 7/8".

DFWB.
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Old 14th Nov 2021, 4:37 pm   #412
FERNSEH
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Default Re: Baird T5 restoration project.

For the Baird T23 sound receiver unit many of the capacitors fitted in the 1990s have been replaced with types having a more convincing appearance. Found one BICC capacitor.
The small 0.02mfd capacitor was originally made by NSF in the UK.
Now I have to restore both sound receiver units to working order.

DFWB.
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Old 27th Nov 2021, 10:58 am   #413
FERNSEH
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Default Re: Baird T5 restoration project.

New loudspeaker baffle fabric is needed to replace the worn out material.
A similar fabric is used on the T23.

DFWB.
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Old 28th Nov 2021, 9:19 am   #414
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Default Re: Baird T5 restoration project.

This thing is going to be fabulous!

Peter
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Old 28th Nov 2021, 5:01 pm   #415
FERNSEH
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Default Re: Baird T5 restoration project.

Hi Peter,
many thanks again for those words of encouragement.
The search is on for the correct pattern of loudspeaker fabric.
The last cabinet parts which will have be made are the three bars across the loudspeaker baffle. The outer bars are in good condition but three others fell victim to the woodworm invasion.

DFWB.
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