Please help identify the problem.

[southpaw13]

Hello, I picked up 2 Wells Gardner monitors and the do the same thing!  The numbers on them are 19k8002 VGA.  I turned up the brightness on the attached picture so that you can see the blue line on the left hand side.  When I move the picture left or right, the line moves in the opposite direction.  If I need a cap kit, where do I get one for a 8000 series monitor.  ANY help would be most appreciated!

Thanks,
Mark

[MonitorGuru]

If this is a VGA monitor and you're driving it with Mame and an standard video card, it is likely an issue where the output of the card doesn't match the expected bandwidth of the monitor.

What you're probably seeing is image "fold over".  That is typical anytime you have a second image or line that moves in the opposite direction of the rest of the image when you adjust the screen position.

It is possible that the game you're using is only displaying graphics in a small portion of the screen area and therefore only using a small amount of the bandwidth (towards the center).  To compensate for a narrow image, you've adjusted the width of the image to be very wide, causing the image to fill the screen better.

The problem with this is that setting the width too wide will actually cause part of the line that is normally hidden under the overscan area to appear in reverse, on top of/under the regular image. That is because if the system is only using a part of the bandwidth, the extreme edges are still there, and sometimes carry garbage signals, and why they normally should be hidden under the overscan so you don't see them.

Try using different resolutions from the video card, adjusting the brightness/contrast, try different games with differnet resolutions/orientations and see if the problem changes or goes away on other games.  Then adjust the games that have problems to strech via hardware to a good resolution and adjust down the width on your monitor.

If these are new monitors then it likely is not the monitor. However old monitors with bad capacitors (or other components) in the deflection circuit could also cause similar problems (e.g. Nintendo arcade monitors have collapse problems on the top edge)


Perhaps Ken has more input?

[southpaw13]

WOW-that is exactly what I had to do, I had to take the width coil all the way open to make it work.  I am using a GeForce 4 Nvidia card straight to the monitor.  I tried 720x480 and it started to wrap the image, but the line was gone.  I've tried the contrast and brightness, but in order to get it to look right, it was pretty dark.  Should I try different frequencies?  Or are there any utilities to help adjust (powerstrip)?

Thanks for your help (so far) that has been the best explanation I've gotten.

Mark

[southpaw13]

More info from the monitor.
It runs at 50/60 HZ with a horizontal rate of 31.5...
Does this help?

Thanks,
Mark

[southpaw13]

Well, let's just say that the monitorguru got me thinking and I might have solved my issue.  I went back and adjusted the blue line off the screen, and then used PowerStrip to move the image over.  So far so good.

Thanks again,
Mark