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I brightened up your linearity picture so I could see it well.
Its really bad. Mine started out bad, but not anywhere near that bad.
Something is seriously wrong with the generation of the signals.
First make sure that the HV for the CRT is up to snuff with a reliable HV probe.
Next make sure that the HV voltage divider resistors are correct and not partially
shorting to ground. Note that the linearity is dependant on what is somewhat like
a current source from the HV chain. Be sure that that 0.002 uf cap on the focus
center wiper is OK. You might add another one from the top of the focus pot to
ground. That picture looks a bit out of focus ... that's an important symptom!
Then get out the oscilloscope with a 10 meg
probe and start snooping around. The waveforms at the plates of the two
video output sections should be reasonably linear and also important,
approximately equal size. If not, make sure that the B+ and B- voltages are
reasonably what the table says and that the voltage divider for the second stage
grid is right. Try different tubes. Wholesale parts replacement may be in order.
But first, get the HV and focus chain exactly right!
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