Hi,

I have a Barco 1208/2. Usually I run it a 1692x720P @ 72Hz.. I do see this same problem, but barely, much less than in these photos.

Over the weekend I tried running it at 1920x817 @ 72Hz, and the picture looked great, with the exception of the left hand side, which looks like this:

http://www.totallymac.com/images/forums/white.jpg
http://www.totallymac.com/images/forums/red.jpg
http://www.totallymac.com/images/forums/green.jpg
http://www.totallymac.com/images/forums/blue.jpg

Does anyone have any idea of the cause, and how to fix it? The signal is being feed via DVI..

Thanks
Daniel Parker

Have you always had this problem or have you changed anything in the video chain?

It has always been there.. but at lower horizontal resolutions it goes away.. In my usual 1692 horizontal it doesnt bother me.. but it does when set to 1920.

Video Chain goes from the back of my PC -> DVI Cable -> Johns Barco DVI Board -> Projector..

The Analogue path is only about 1 inch..

Daniel

your porches are way too tight. Relax them and the problem should go away.

Kschmit2 is right. This phenomenon is called "raster ringing" and is a result of the scan not being stable initially. Almost all CRTs have this at the higher frequencies (although my BarcoReality 909 does not have this, or at least VERY minimal).

your porches are way too tight. Relax them and the problem should go away.

I don´t understand "porches"... Can someone please explain, or use another word. I do have a bit of this problem myself....

http://en.wikipedia.org/wiki/Back_porch for a brief description. None of the pages with pictures of video waveforms that I could quickly find had good enough descriptions to be more helpful than that.

If the porch is too small, the projector circuits can't "get ready" in time to display the active image area, and the leading (left) edge will suffer.

On my setup, I shift the raster to the left and the active video area to the right (within the raster, so it still ends up centered on the tube/screen). This lets me run a higher horizontal frequency and still get a crisp left edge.

yep good old raster ringing, annoying as **** and on every CRT I have owned :mad:

In my case with my NEC 1352, I had a slight case of it, so I used the horz size control and moved the interference off screen and then used my DVDO VP50 scaler to adjust it back to correct size with the advanced image controls (= to powerstrip on a HTPC)

-Gary

This is raster ringing as said. Depending upon your sources and such you may not be able to get rid of it. You will see it on pretty much all Barco 8" machines when running 1920 (actually it is in pretty much all CRTs as Gary said), though yours looks worse then most. There are a couple things you can try (search "raster ringing" on Curt's and look for Kal's post).

Worst case, you can do what Gary said, but you don't have to use a scaler. Use H Phase to move the active image area way to the right, then use H Pos to bring it all back to center. Make sure you then apply blanking appropriately so electrons are not bombarding the side of the tube.

Dave