My new to me 466 2nd version has a strange issue.
I see a background image related to the display. Hard to describe so there is a picture in photos under Edward Prest.
It may be a blanking issue or a horizontal issue. I see two lines at the peak and valley of all signals across the CRT. There is no DMM. I have to turn up the intensity some to see them. The bright parts do interfere with the display. Sine or square - same issue - only at the peak and valley. In the images the positions are shifted far to the side to show the artifact clearly. Shifting it left or right has a tiny effect but more or less glitch remains in place.
I have the service manual but its a big read and it will take me a while before i dig in. I have measured the power supplies, all low voltage rails are are just barely above the book spec except for 140v which is 127V - a few volts under min spec.
(p.s. I am using 60hz line noise for the sine wave in the image -that's all I have for the moment)