Quote:
Originally Posted by John Folsom
Looks to me like you have a horizontal width problem, not a vertical linearity problem...??
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John,
You are 100% correct!
With only the image of the test pattern visible and the height stretched, I had assumed that the RCA roundie was flipped on its side for under-the-chassis checking, but a quick enhancement of the picture to see what is hidding in those shadows reveals that this is not the case.
Let's see if I can undo my rather large goof.
On page 24 of the Sams, you will see the horizontal adjustments.
I would suggest checking or replacing your 6BG6 and then trying (count your turns so you can undo any changes) adjusting the horizontal linearity and see if that helps. Warning: These linearity coils sometimes freeze with age and if forced, you can break the tube. I would suggest a gentle test wiggle with the power off, so you can feel if the core is stuck or not.
If this adjustment seems to be addressing the right problem, and you have recapped and and tested all the tubes in the horizontal section, you might consider doing all the procedure on page 24, with this warning: A mistake in doing the horizontal oscillator adjustment can sometimes be very difficult for a learner to resolve.
James