As the title suggests, I am having a problem focusing the CRT on my HP 8566B. When adjusting the focus on the front panel it is like I just need a half a rotation more and then it would focus but the focus screw doesn't allow for that.
Is the CRT just weak?
I just got this machine from an auction without any description on how it works, so I am turning it on for the first time.
Check all voltages at the CRT.
Check resistance of all resistors and potentiometer in the focus resistor chain and check solder joints.
May be this helps:
https://www.jvgavila.com/hp8566a.htm