CGA with VGA

Discussion about old graphics cards, monitors and video related things.

CGA with VGA

Postby lorecast162 » 2019-6-10 @ 22:18

Hello, I have a 8088 PC XT clone with both a MDA and CGA card.
I use this computer with the CGA card's composite output but it kinda looks like not good so I want to go the proper way.
Here where I live it's hard and expensive to get old CGA compatible CRTs so I cannot do it that way, for now at least.
I think VGA is the best step, I already have a really good looking Trinitron CRT with VGA I can use this with and if that breaks I have tons of LCDs with it.
Unfortunately though the "easiest" approach also requires a lot of money, which is the MCE2VGA by Serdashop, which is all nice and kind of ideal but way out of my league.
I thought about making my own adapter then but info I found is conflicting or old and without the needed resources anymore (e.g. the schematics) so here I am asking you this: how do I do this? Can you give me instructions and schematics on how to do this? I need it to be a cost-effective way if possible and I think even a half-assed adapter thingy would still be light years ahead of composite.
Thanks
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Re: CGA with VGA

Postby rmay635703 » 2019-6-11 @ 02:15

Your best bet is one of the older Sony LCD screens, if it has vga, rca and everything else there is a good chance it will sync up to cga with a simple adapter

Real CRTs unless they are quite old will need you to adjust the internal sync,v and h pot dials on the pcb (if it has them). Even then you may need an extron box to slide the image into the correct position
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Re: CGA with VGA

Postby lorecast162 » 2019-6-11 @ 06:32

rmay635703 wrote:Your best bet is one of the older Sony LCD screens, if it has vga, rca and everything else there is a good chance it will sync up to cga with a simple adapter

How do I make this simple adapter you speak about?
Also, I have a NEC multisync, that should work too, right? I know it has quite good compatibility with different sync frequencies.
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Re: CGA with VGA

Postby Jo22 » 2019-6-11 @ 14:39

Here are some threads about CGA to RGB (SCART) schematics. Depending on the VGA monitor, these can be adapted.
Keep in mind that these adapters can't do Composite CGA. If you like Composite CGA, a CVBS-VGA converter (Composite to VGA) might be needed.
Image quality is hit and miss, though. Some converters like this do try to "improve" the picture. Also, you may still have the 244p/288p vs 488i/576i problem.

CGA->RGB converters...
viewtopic.php?p=684545#p684545
viewtopic.php?p=578495#p578495
viewtopic.php?p=549562#p549562
viewtopic.php?p=447574#p447574
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In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Re: CGA with VGA

Postby lorecast162 » 2019-6-11 @ 15:06

Jo22 wrote:Here are some threads about CGA to RGB (SCART) schematics. Depending on the VGA monitor, these can be adapted.
Keep in mind that these adapters can't do Composite CGA. If you like Composite CGA, a CVBS-VGA converter (Composite to VGA) might be needed.
Image quality is hit and miss, though. Some converters like this do try to "improve" the picture. Also, you may still have the 244p/288p vs 488i/576i problem.

CGA->RGB converters...
viewtopic.php?p=684545#p684545
viewtopic.php?p=578495#p578495
viewtopic.php?p=549562#p549562
viewtopic.php?p=447574#p447574


I already saw the SCART converters actually, but I still need to find the BS170 and hoped that since VGA is already HVSync I could go straight to VGA but that is not possible I guess. Thanks
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Re: CGA with VGA

Postby Jo22 » 2019-6-11 @ 19:17

lorecast162 wrote:I already saw the SCART converters actually, but I still need to find the BS170 and hoped that since
VGA is already HVSync I could go straight to VGA but that is not possible I guess. Thanks

I see. How about the 2N7000 instead ? :)
https://en.wikipedia.org/wiki/2N7000
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bs170b.png
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"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Re: CGA with VGA

Postby lorecast162 » 2019-6-11 @ 21:20

I don't have that either, is there any difference between the two?
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