Predicta 17" HV question

[Phil Nelson]

It's sweeping the whole screen, but I don't consider the vertical fixed. It's not very stable, and when the sync is far off, it occasionally blinks to a horizontal line as if something (a shorted turn in the output transformer?) was arcing.

By clipping another cap in parallel with C16 (raising its value a bit), I can reduce the height to nearly fit the whole image on the screen, but still with poor linearity.

The best compromise between height & linearity doesn't seem too awful at first:



Until you look at a pattern:



I could live with that degree of non-linearity, but the instability really ain't acceptable. I'll keep pokin' around.

Phil Nelson