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Old 16th Sep 2019, 1:34 pm   #51
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Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Yet Another Bush TV22

There could be some interesting possibilities.

Looking at the video of it, it suggests the ripple is amplitude modulating the drive voltage coming out of the vertical oscillator. Probably you have already checked C59 (on trader sheet 1091/T38) that bypasses the blocking osc transformer primary from the supply with R56 a 220k. Also probably worth checking the grid resistor on G1 of the pentode part of the ECL80, even if this was nearly open circuit, the stage would still appear to work. And that C57 is not leaky.

Does your set have the original blocking osc transformer and is it mounted with the same orientation as the original ?

( the ripple rolls through it looks like it affects both the vertical scan linearity and height, so it must be in the raster)

Last edited by Argus25; 16th Sep 2019 at 1:41 pm.
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