Author Topic: [SOLVED] Converting RGB SCART to VGA. (Read 23368 times)

tyguy2 · « **on:** February 03, 2016, 02:39:29 am »

I've been working on this project recently:
http://members.optusnet.com.au/eviltim/ggrgb/ggrgb.html
http://etim.net.au/ggtv/ggtv2.pdf

I've finished wiring the circuit, but I have no SCART compatible monitors. I bought a SCART to AV adapter online, but I failed to realize that SCART has a built in composite video out, completely missing my RBG out pins. I figured VGA would be my best bet because it uses RGB. Does anyone have any idea how i would convert between the two without buying a cable?
Would this work if I needed to resort to buying a cable?
http://www.ebay.com/itm/Valueline-1-00-m-SCART-Male-to-VGA-Female-Cable-Black-/331766121850?hash=item4d3ecd457a:g:beoAAOSwXshWrC9G
Does anyone have a better recommendation? I've added the diagram for the boards and the pinouts for SCART and VGA. Thanks for the help.

miguelvp · « **Reply #1 on:** February 03, 2016, 02:53:26 am »

I haven't tried this but I came across them:
http://www.geocities.ws/podernixie/htpc/cables-en.html#scartvga

Also you might find more information in here:
http://members.optusnet.com.au/eviltim/

Also I've have found out lately about the GBS-8200/8220 and someone moded it to suport SCART:

http://www.theisozone.com/forum/viewtopic.php?f=20&t=47226

tyguy2 · « **Reply #2 on:** February 03, 2016, 03:13:26 am »

Thanks, I'll try that, but I don't know if it will work. Here is the schematic for anyone interested

Edit:
Found this:
https://nobitleftbehind.wordpress.com/2013/10/18/sega-game-gear-rgb-composite-s-video-out-mod-with-lcd-upgrade/
But it doesn't really help

tyguy2 · « **Reply #3 on:** February 03, 2016, 03:19:14 am »

Quote from: miguelvp on February 03, 2016, 02:53:26 am

I haven't tried this but I came across them:
http://www.geocities.ws/podernixie/htpc/cables-en.html#scartvga

Also you might find more information in here:
http://members.optusnet.com.au/eviltim/

Also I've have found out lately about the GBS-8200/8220 and someone moded it to suport SCART:

http://www.theisozone.com/forum/viewtopic.php?f=20&t=47226

Oooh, this looks promising. Do you know the pricing on the converter?

tyguy2 · « **Reply #4 on:** February 03, 2016, 03:21:54 am »

Nevermind, I found it. I think I might go with this, it looks like a perfect fit. It uses all of the connection I use. Thank you so much, I'll get back in a few weeks to see if it works.

miguelvp · « **Reply #5 on:** February 03, 2016, 03:23:59 am »

They are fairly cheap well under $50 I think.

Also there are a ton of SCART to HDMI converters if you don't want to stick with legacy VGA

Just google "SCART to HDMI" and you'll find a lot of them, originally they were around $60 but they have been cloned and there are cheaper offerings now.

miguelvp · « **Reply #6 on:** February 03, 2016, 03:33:02 am »

Quote from: tyguy2 on February 03, 2016, 03:21:54 am

Nevermind, I found it. I think I might go with this, it looks like a perfect fit. It uses all of the connection I use. Thank you so much, I'll get back in a few weeks to see if it works.

Also it seems people are hacking it to improve it:
http://shmups.system11.org/viewtopic.php?f=6&t=52172

TVIA Trueview 5725 datasheet in case you need it:
http://file.yizimg.com/420856/2013041613555642.pdf

The MCU MTV230GMV is an 8051 MCU, can't find the datasheet for it, but that's not needed to alter the Multimedia processor chip.

Edit: never mind, the MCU datasheet in on the google drive link on that post along with a lot of other documentation.

tyguy2 · « **Reply #7 on:** February 03, 2016, 03:34:19 am »

The project I'm working on requires that I use VGA, and be under $30. I would use HDMI and be done with it, but I can't. Thanks for the suggestion though.

miguelvp · « **Reply #8 on:** February 03, 2016, 03:50:19 am »

The thanks should go to Ian.M in this forum, he is the one that pointed me out to that video converter.

tyguy2 · « **Reply #9 on:** February 09, 2016, 01:52:37 am »

The board arrived today, hopefully I will update in a few days with a working project.

miguelvp · « **Reply #10 on:** February 11, 2016, 06:56:06 am »

Cool, I'm taking a trip and I won't be back for 2 weeks or so.

But let us know of any progress or if you get stuck.

tyguy2 · « **Reply #11 on:** February 12, 2016, 02:00:26 am »

Alright, I've connected the board, and nothing. I think the board detects that the game gear is outputting a signal, but no image comes up. I think this has something to do with the 32 mhz clock connection. I'm pretty sure I haven't connected it to the correct pin. The place to connect it to is called FB1, but I can't find it on my motherboard. Any ideas?

tyguy2 · « **Reply #12 on:** February 12, 2016, 02:25:55 am »

I just soldered a bunch of the fine pitch pins together, now I'm going to have to get some solder wick.

miguelvp · « **Reply #13 on:** February 12, 2016, 02:29:14 am »

Did you connect the sync stripper (LM1881N)?

Have you deviated from that schematic?

Where is the SCART signal coming from?
I do have a Saturn and a Genesis, but I won't be able to do anything for a bit over a week.

Aso, did you get the GBS-8200 or the GBS-8220 not that it will matter, I do have the GBS-8220 with two VGA outputs and the connector to hook the signals to is labeled P3 on my board, I think it's the same on the GBS-8200

Manual GBS-8200:
https://www.mikesarcade.com/estore/datasheets/GBS-8200-booklet.pdf
Manual GBS-8220:
https://www.jammaboards.com/arcade_manuals/GBS-8220_CGA_to_VGA_HD-Converter.pdf

tyguy2 · « **Reply #14 on:** February 12, 2016, 04:45:05 am »

Quote from: miguelvp on February 12, 2016, 02:29:14 am

Did you connect the sync stripper (LM1881N)?

Have you deviated from that schematic?

Where is the SCART signal coming from?
I do have a Saturn and a Genesis, but I won't be able to do anything for a bit over a week.

Aso, did you get the GBS-8200 or the GBS-8220 not that it will matter, I do have the GBS-8220 with two VGA outputs and the connector to hook the signals to is labeled P3 on my board, I think it's the same on the GBS-8200

Manual GBS-8200:
https://www.mikesarcade.com/estore/datasheets/GBS-8200-booklet.pdf
Manual GBS-8220:
https://www.jammaboards.com/arcade_manuals/GBS-8220_CGA_to_VGA_HD-Converter.pdf

Yes, the stripper is attached,
The scart signal is coming from the item described above, and the only thing I added was a 5v reg. I think The problem is with the connections to the motherboard. I've got a newer one, and some of the connections are a bit odd. I don't know if I'm connected to the board correctly or not (definitely not the 32 mhz). I've attached a picture of the motherboard I have. The model number is 171-7923A. Can anyone find a pinout for a chip called SEGA 315-5682? I think that would help a lot with the troubleshooting.

tyguy2 · « **Reply #15 on:** February 12, 2016, 04:49:40 am »

Here are some pictures of the converter board + stripper

Malichite · « **Reply #16 on:** February 16, 2016, 04:11:42 am »

Quote from: tyguy2 on February 09, 2016, 01:52:37 am

The board arrived today, hopefully I will update in a few days with a working project.

I have being thinking about getting a GBS-8200/8220 for an Atari ST video mod, but it seems like Amazon, eBay, and AliExpress are filled with questionable versions, usually where the silkscreen on the pictures doesn't even match the item description. Did you find a reliable source for your GBS-8220 that you could recommend?

tyguy2 · « **Reply #17 on:** February 16, 2016, 10:06:57 pm »

I bought the 8200 from amazon.
http://www.amazon.com/Andoer-Genuine-GBS8200-Channel-Converter/dp/B00W3460UU/ref=pd_sim_23_3?ie=UTF8&dpID=61xPVN0vBZL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=1WPZ2Q3TW41CXMD6D3W4
It did come with some bad caps, however. Be careful of that.

Malichite · « **Reply #18 on:** February 17, 2016, 03:07:47 am »

OK thanks. Yeah it sounds like the first thing I have to do if I pick up a GBS-8200/8220 is replace all the caps since it sounds like it isn't uncommon to get at least one bad one per board.

I wish there were better sources for them, but I guess I am late to this show and the only things around anymore are clone/knock-offs of the original design.

tyguy2 · « **Reply #19 on:** February 20, 2016, 01:07:03 am »

I've probed the circuit, and the video signal and clock signal just seem to stop once the enter the circuit. None of the chips are outputting a signal.

tyguy2 · « **Reply #20 on:** February 20, 2016, 01:27:05 am »

I got it to work, I had a broken connector/ cold solder joint.

tyguy2 · « **Reply #21 on:** February 20, 2016, 03:36:26 am »

Ok, here are some pictures of the final product. Thank you so much for your help, everyone.

Malichite · « **Reply #22 on:** February 20, 2016, 07:04:35 pm »

Nice results.

I am definitely going to have to take the plunge and grab one, albeit from the questionable suppliers on eBay/Amazon, as apparently I really don't have any alternatives. The bad solder joint you mentioned above, was this on your connections to the GBS-8220 or did you find further issues on the board itself?

Also do you have any thoughts/leads on a nice case to mount everything into once done? I have seen a few places that sell a clear acrylic case to mount the GBS and project boards, but I don't really want a clear case and didn't know if you had already found something pre-made that could accommodate everything and still kinda match the retro theme.

tyguy2 · « **Reply #23 on:** February 20, 2016, 07:27:41 pm »

Quote from: Malichite on February 20, 2016, 07:04:35 pm

Nice results.

I am definitely going to have to take the plunge and grab one, albeit from the questionable suppliers on eBay/Amazon, as apparently I really don't have any alternatives. The bad solder joint you mentioned above, was this on your connections to the GBS-8220 or did you find further issues on the board itself?

Also do you have any thoughts/leads on a nice case to mount everything into once done? I have seen a few places that sell a clear acrylic case to mount the GBS and project boards, but I don't really want a clear case and didn't know if you had already found something pre-made that could accommodate everything and still kinda match the retro theme.

I had some issues with the board I had constructed. And yes, I am planning on making the project look nice. As a side note, the GBS doesn't seem to handle the fade transitions very well. The screen blinks and glitches out, but that could just be my board, I don't know.


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Author Topic: [SOLVED] Converting RGB SCART to VGA. (Read 23368 times)

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