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Old 15th Apr 2018, 10:55 am   #11
stevehertz
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Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
Default Re: PYE LV20/B18T 1948. Heart transplant.

Quote:
Originally Posted by Heatercathodeshort View Post
Thanks guys. The line linearity is very bad due to miss match. I have introduced a linearity coil and played about with the line drive but all attempts are to no avail. It's just a bad match but goes unnoticed on the average picture. The ion burn on the straight gun non aluminised tube can easily be seen.

In the 1950's Direct TV Replacements used to manufacture a 'fit all' transformer for these simple line output circuits with a selection of taps. It would be interesting to wind a transformer with tappings brought out from the last 1/3rd of the primary and secondary [scan coil]windings and experiment with various combinations to see if a better match could be achieved. Maybe an experiment I could carry out in the Victorian Home for Faded Television Service men. John.
Have you seen the line linearity of the little Baird Everyman?! When working 'perfectly' a large circle appears on the screen as an egg shape! But for those who could only afford the minimalist Baird, I suppose it was still magic to watch those moving pictures on a 'silver screen'.

It's nice to think how people sat waiting for the evening TV program (singular!) to begin and would be preparing the room, drawing curtains, extinguishing lights, adjusting chairs, making cups of tea.. Lovely.
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