weird video artifacts on arcade monitor

[cyberbaud]

Hi,

I have CWC-203 cabinet that I use for MAME and I experience some image distortion that I am not able to fix through the usual adjustments on the monitor.

Most modes display strangely offset lines at the top of the picture (see attached images). Looks like lines are shifted alternatively to the left and to the right while the amount of shifting decreases from the top down. It goes away after the first 10-15 lines. The rest of the picture is perfect. I was not able to use any adjustments on the monitor (like H-Hold etc) to get rid of this.
The monitor has a hardware feature to flip the image, so that it is displayed upside down. If I activate this, the distortion moves from the top of the tube to the bottom, but stays otherwise the same.

The monitor is a 29" Orion 2901 arcade monitor (made in Korea). I get the distortion/artifacts on most video resolutions. Most pronounced seems to be the resolution 352x256.

The monitor is usually driven by a PCIe ArcadeVGA card, but I get the same image distortion when I use advancemame with a standard nvidia video card, so I am pretty sure that the problem is with the monitor.

Anybody seen something similar? Any idea what exactly the problem is and how it could be adjusted/repaired?

Many thanks.

[Kevin Mullins]

Looks like the convergence is a bit off.

Take a look here: http://forum.arcadecontrols.com/index.php?topic=93774.0

[cyberbaud]

Don't think it is a convergence issue, or the colors (red/green/blue) would be off? The colors are perfectly aligned here however. It looks more like an issue with the underlying signal or the monitors ability to handle that signal.