I got the SM124 several days ago. I’ve noticed the picture is much smaller than the screen, and it’s closer to the left-upper corner. I’ve disassembled the monitor to find out if some capacitors are dead, also washed everything and removed all dust. The element placing is different than on the photos above though.

Some infos about the black border:

When properly adjusted, the SM124 has got a uniform black border around the viewing area. This will give you both a crystal clear picture, matching the sharpness of a LCD, and precisely72dpi (or 72ppi, since it’s a monitor, not a printer).

Some background: Inside CRT displays, there is a shadow mask. Quote: “it is a passive component that plays a crucial role in the display process. It is positioned between the electron guns and the phosphor-coated screen and acts as a barrier to prevent electrons from hitting the wrong phosphor dots.

Each hole in the shadow mask corresponds to a specific phosphor dot on the screen, and the arrangement of these holes is precisely calibrated to ensure accurate color reproduction. As electrons pass through the holes in the shadow mask, they strike the corresponding phosphor dots, causing them to emit light and produce the desired colors.” The standard adjustment of the SM124 results that each hole in the shadow mask corresponds with one pixel of the picture, resulting in the brilliant sharpness of the picture. You can adjust the monitor to get rid of the black boarder, but then the pixels won’t match individual holes in the shadow mask any more, and you would lose sharpness.