double picture half size

slither

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Well that says it prety much, monitor had been redone, caps etc a while back , Im told, great picture but its half size and two of them divided by a black space in the middle, any ideas, thanks.
 
When making a post in this forum, please state the make and model of the monitor.

It sounds like the source of the signal is not correct. Like, feeding a VGA signal to a CGA monitor.
 
When making a post in this forum, please state the make and model of the monitor.

It sounds like the source of the signal is not correct. Like, feeding a VGA signal to a CGA monitor.

Other way around. CGA signal to a VGA monitor. :) And I agree. If I had to guess, I'd say he's hooked some JAMMA game up to a Wells U3000 and expected it to "just work".

What's the chassis? And what game do you have hooked up to it?
 
Other way around. CGA signal to a VGA monitor. :) And I agree. If I had to guess, I'd say he's hooked some JAMMA game up to a Wells U3000 and expected it to "just work".

What's the chassis? And what game do you have hooked up to it?

Perhaps it works both ways. I've hooked up a VGA signal from a Mame rig to quite a few CGA monitors, and it comes up with a double image. But, I've not done it the other way.
 
I'm thinking it should be set to the CGA-15.75Khz. That's what mine is, not the VGA.

Correct.... and I believe that is what he meant, that he found that the dipswitch was set wrong and that is what was causing the problem.
VGA signal to a standard res (CGA) monitor will in fact cause the double image scenario.
 
Perhaps it works both ways. I've hooked up a VGA signal from a Mame rig to quite a few CGA monitors, and it comes up with a double image. But, I've not done it the other way.

It just dawned on me. I was thinking top/bottom, not left/right. I can see a CGA monitor doing left/right (to be specific, odd lines on left, even lines on right) double image on a VGA signal.

Now that I really think about it, I think CGA on a VGA monitor would probably just not H-lock and you'd get an appropriately garbled picture. Or if the oscillator has a little bit of residual memory, Lines would be broken in half and you'd see "two" images interweaved together.

tl;dr I'm wrong, carry on.
 
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