Adjust focus on a CRT?

[TheGooch69]

Does anyone know how to adjust the focus on a CRT? My Samsung 997DF is a bit blurry.

 

[vick1000]

What refersh rate are you using, try 85hz or lower.

 

[RedShark]

We had an old CRT that was adjusted by turning a screw in the back of it. I'd say check the manual