Sony Trinitron - Sharp in the middle, fuzzy on the borders. How would I fix?

[konp]

I'm thinking it'd be as simple as playing with the FOCUS and SCREEN knobs on the flyback, as it really does look like the borders of the screen are out of focus, almost like a vignette effect.

The model is KV-XJ29M31.

[Sarver Systems]

degauss? Just my uneducated guess.

[yatzr]

Is it a dynamic convergence problem?  If you display a plain white crosshatch picture, are the white lines still white on the edges, or do they turn into separate red, green, and blue lines?  Or do they stay white, but just get fuzzy?

[Sarver Systems]

Hmmm, convergence. Didn't think of that

[rCadeGaming]

Try the pots on the flyback, then convergence adjustments, but it could just be a low-quality tube or chassis.  Not all Trinitrons are made equally.  I have a bunch of KV-27FS120's, which have great picture.  I have also two KD-27FS170's, which have garbage focus in the corners, even though they use the same tubes.  No amount of tweaking at the flyback or yoke could fix it.  I even tried swapping tubes, flybacks, driver boards, and yokes, but the problem always stayed with the chassis.