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Post by soop on Feb 19, 2019 13:49:14 GMT
Just wondering if anyone had any tips to convert a VGA screen Like this to RGB without the use of a bulky adaptor? It has composite and VGA on board, but is it a case of connecting the red, blue, green, csync ground and 5v from an RGB amp to the corresponding VGA pins, or will it expect something else, like Vsync and Hsync? Judging from what I see here, a minimum of 6 pins are used, I'd be able to supply a max of 10 pins from the PC Engine, and the input board has 12 pins. I'm not 100% sure if I'd have to supply a separate ground for each colour, or if common ground could be used (it might also share common ground on the board, which I can check with a DMM.
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Post by ClodBuster on Feb 19, 2019 19:53:55 GMT
Hi soop, so you'd like to use an RGB-S source (e.g. a videogame console) with an RGB-HV monitor? There's more to it than just splitting the Composite Sync into H-Sync and V-Sync. Your monitor would also need to support 15 kHz as well as the resolutions supplied by the video source. By googling 15kHz, I found this Wiki: 15khz.wikidot.com/The friendly guys at the NFG Games forum hosted by GameSX might also give some advice.
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Post by soop on Feb 19, 2019 21:22:26 GMT
I don't know if it's RGB-HV or what yet, I just know it has a Dsub connector :/ I think I'm just gonna try it
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Post by ClodBuster on Feb 19, 2019 21:41:35 GMT
VGA connector usually means RGB-HV w/o support for 15 kHz.
VGA monitors that do support other signals are in the minority.
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Post by majors on Feb 20, 2019 16:01:09 GMT
VGA monitors that do support other signals are in the minority. ^Truth Sounds like the OP is looking for an upscaler, and that defeats the "bulky adapter" requirement, plus all the good ones are $$$. Even if you went chinese cheap with some $15 composite to VGA box, it'll look like ass. I had a GBS-8200 once, it did the job for RGB 15kHz -> VGA 31kHz but it was not optimal for everything I ran it for...some consoles/PCBs have odd video signals it did not like.
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Post by soop on Feb 20, 2019 19:16:44 GMT
It does also take a composite signal, which does upscale, which is another reason I think it might work
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Post by ClodBuster on Feb 21, 2019 9:49:37 GMT
Then it's a matter of getting a datasheet for the monitor and it's electronics, to see if there are any pins assigned to accept more than just Composite Video and regular 31 kHz RGB-HV signals, and if the electronics are able to handle 15 kHz RGB with composite sync.
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Post by soop on Feb 21, 2019 15:20:17 GMT
Hmm. I bought it a few years ago, but it's worth taking a look and seeing if there's anything googleable
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Post by soop on Feb 22, 2019 18:19:37 GMT
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Post by soop on Feb 22, 2019 18:23:21 GMT
And in fact, this is on the underside. Hopefully c-sync will do the job Any idea what scl and sda are? Attachments:
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Post by ClodBuster on Feb 22, 2019 18:27:02 GMT
Great, this looks quite promising.
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Post by soop on Feb 23, 2019 11:53:38 GMT
Sad times. Wired everything up, and I get no sync.
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Post by ClodBuster on Feb 23, 2019 22:31:16 GMT
What/how did you wire up which way exactly?
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Post by soop on Feb 24, 2019 11:52:25 GMT
What/how did you wire up which way exactly? I'm using a turbo mullet (an RGB amp that plugs into the expansion port). It usually takes a megadrive 2 scart cable, so i desoldered the scart socket, then soldered the R,G,B, Ground and Csync to the board. Pretty sure I don't need the power line since the screen has a seperate 12v supply. I was pretty sure that would be all I needed to get it going
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Post by ClodBuster on Feb 24, 2019 14:49:43 GMT
I've downloaded the datasheet you linked to. Which exact pins did you connect? I see pin HSYNCIN acting as both H-sync as well as C-sync input. If your signal source for c-sync is c-video, you might also need a sync seperator. See this page for more information: gamesx.com/wiki/doku.php?id=av:lm1881Hope this helps.
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