Hey Matt, Component->RGB

Started by seen, September 23, 2003, 02:55:48 AM

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seen

On the old RGB board there was a topic about converting RGB to component. You(Matt) wrote that you had a friend that had the RGB-> component setup with a component based TV. Basically what I'm asking is: Did he have to do any special conversions to the sync before the connection to the YPbPr Converter. You said he connects Genesis and (something else) to it, does he run them through something else before the Converter box. The reason I say this is that I think the box acceps TTL level syncs OR is it ok just to have an arcade or console Sync levels with the converter.

seen

acem77

i just bought a audio authority vga to component converter because of the post from matt.
but i have had luck. seem there is a problem with the sync signal.
i made a 9 to 15 pin adapter to make my game systems rgb plug into its vga input.
i know a vga crt needs a h v sync but a game system does not work like that.
how did his friend get this to work.
only a few screens will show up.

seen

Quotei just bought a audio authority vga to component converter because of the post from matt.
but i have had luck. seem there is a problem with the sync signal.
i made a 9 to 15 pin adapter to make my game systems rgb plug into its vga input.
i know a vga crt needs a h v sync but a game system does not work like that.
how did his friend get this to work.
only a few screens will show up.
See, that's the problem I was talking about. The VGA level sync is a TTL digital sync(I think) and the levels are different. Here's what I got from an auction with JROK's RGB converter here:

please note that sync input level is TTL (5Vp-p). Many sources output 0.7 - 1 Vp-p sync, but worry not! Included is a popular LM1881 sync stripper Chip and datasheet, it will restore the sync to TTL levels. it could also strip the sync off the green video on SYNC ON GREEN RGsB video formats, so you could convert from RGsB to Composite without a problem.

So I have to assume that you need the LM1881 sync stripper before you connect to the Component adapter. Could someone try this or verify that this is true? No pressure of course ;)  

Guest

i think ttl sync stripper would do the trick.
i need to take the composite sync and split it into a h and v sync.
then run those into the vga to component converter.
now i neeed a good place to get a
composite to h and v sync converter.

seen

#4
Quotei think ttl sync stripper would do the trick.
i need to take the composite sync and split it into a h and v sync.
then run those into the vga to component converter.
now i neeed a good place to get a
composite to h and v sync converter.
LM1881 will split the signal to H and V syncs from a composite sync source. The one problem is that you don't get a pure H sync signal on output, but a composite sync which is good for most monitors.  This page explains the problem and the solution. But really the problem is not really a problem like I said.

I'm going to do the same thing that you're trying to do. I'm about 80% confident that it will work.

acem77


Endymion

Why do I get the feeling Matt's buddy upscans his 15KHz with an XRGB2+?

seen

QuoteWhy do I get the feeling Matt's buddy upscans his 15KHz with an XRGB2+?
That would suck bigtime, however I don't think that he did it that way. I think it's just a matter of fiddling with the sync.
1) Get it to a TTL level using the LM1881.
2) Feed it to an RGB-Component converter
3) Pray that the TV receives it and doesn't blow up (the key point). I would try Sony.

Also, there are other lines in that RGB->Component connection than the R G B H sync and V Sync. I would open up the Audio Authority box and take a look inside with an Ohm Meter.

PS I will probably buy an RCA(VHDC300) box for this, because Circuit City uses them and somehow I feel they're more adaptive to signals in general.

acem77

gave up on the audio authority vga to component converter. i sent it back.
i tried everything.  

matt

QuoteWhy do I get the feeling Matt's buddy upscans his 15KHz with an XRGB2+?
No, he doesn't.  He's using a 3-year-old regular JVC 27" TV.

Like I've said many times in the past, when I made the circuit I just used an LM1881 sync stripper, and routed the Csync and Vsync to the appropriate pins on the VGA connector.  I couldn't get it working using the stock sync from any of my consoles.

However, I wouldn't recommend buying one based on this, unless you're prepared to deal with the fact that it may not work.  Personally, I think it probably has something to do with the TV as opposed to what's going into the converter.

If you do decide to try it, I'd recommend the RCA converter over the AA one for a few reasons:  I found the image quality to be a tiny bit better, it's cheaper, it's got a horizontal position pot, and the VGA plug is raised so it's easier to make custom cables for.  

One thing you should be aware of also is that the picture isn't very well centred, so if you plan on using this it's a good idea to check if your TV has a readily accessible service mode.

If you want more solid results, it might be a good idea to go with the X-Select D4 instead.  It's expensive, but it's designed for game consoles so it'll probably do the job a lot better.  You'd have to make yourself a D-Terminal to 3-RCA adaptor, but that's not a big deal.

Guest

Quotemore solid results, it might be a good idea to go with the X-Select D4
matt do you know this will convert rgb from the genesis,neogeo,truboduo to component??

matt

Probably - I don't see why not.  Jeremy Pallant's review of the thing seems to imply that it does a good conversion job.

Jeremy Pallant

Just a minor correction, but apart from the 15-pin RGB output (VGA basically), the only other video output on the XSELECT-D4 is D-Terminal. That's basically Component Video, but you'd need some kind of adaptor. All the Component Video ports on the XSELECT-D4 are input only.

matt

Making a D-Terminal to 3-RCA adaptor should be easy.  You can buy the D-Terminal plugs from www.digikey.com (although they're a little pricey), and the pinout is listed on GameSX.

Guest_ShuckNasty

Well, I tried to register, but the server gave me a sendmail error, so I have to post this as a guest.

First off, here's a few links to show what I am talking about...

My page with the pics: http://www.geocities.com/rshuck03/page.html
neo-geo.com thread about this: http://www.neo-geo.com/forums/showthread.p...&threadid=77087

Let me say this real quick: If someone else did this first, don't let me steal your thunder. Come forward with how to do it and let all the other people that are trying to get it working.




I didn't know that the information from the thread at the neo-geo.com forums had spread, as it seemed there wasn't much interest there.

I'm not *real* technical, but I understand a little bit about this stuff. I will try to help as much as I can.

I actually feel kinda stupid posting this, but I didn't realize that I had swapped + and - when I was trying to hook up the audio authority board to run off the MVS board's power. I made a cap on the Green line explode, which has caused me to lose sync. I didn't think that component video was sync-on-green, but it apparently is. Note: I still get the Blue and Red channels, just badly garbled.

Acem 77 - I have acutally read about compatibility problems with the Wega series. I guess trinitron tubes have something about them that makes them incompatible.

Like I said though, I am new to this, I just started messing with this stuff in December. Also... the Audio Authority box does nothing with the HSYNC even with a computer hooked into it. I got some visible screen space on my tv, but since the video card was putting out 31kHz and the TV does 15kHz, it didn't sync. I think this is why it works.

Also, they make SCART to Component Video convertors. Someone pointed this out, and it truly is an easier solution. If you were modding a console, you'd need a little room, and you'd have to order from the UK or Japan, but a Scart connector is simple to hook up. I currently live in the UK, so I can get them fairly easily.

Let me know if anyone has any questions about this and I will try to answer them the best I can. The only system I have tested with is the Neo-Geo MVS. There may actually be another person doing this... I don't know anybody named Matt that does this sort of thing.

And yes, it's the same 27" JVC TV, and it's a hell of a bargain for $250.

rshuck03@yahoo.com <--- I am there.

matt

QuoteThere may actually be another person doing this... I don't know anybody named Matt that does this sort of thing.
That would be me, it seems.  Did you read the rest of the thread?

ShuckNasty

Cool. I read it as you had a friend who has done it.

I thought about making a circuit similar to what you said, but I wasn't sure it would work so I passed on it.

Good to see someone else knows it's possible though.

Endymion

QuoteLet me know if anyone has any questions about this and I will try to answer them the best I can. The only system I have tested with is the Neo-Geo MVS.
The question is obvious then. Are you going to do this with anything else?

matt

I got it to work nicely on the DC, Saturn, and Playstation.

Still wouldn't recommend it, though.  I don't think the converter works reliably on all brands of TV.  Make sure you buy from somewhere with a good return policy, or get it cheap enough that you can sell it again and make your modey back.

Endymion

Well isn't the SCART->Component device people have linked to here before more costly than the Audio Authority? Add in the steeper total for an import of the thing and it may be just as much of a crap shoot if it will work, as well. Since we at least know you guys have had some success with certain  TVs and the AA, that might be a better domestic route for a lot of people.

Beta

I just started playing with my genesis, it's a ver1.5 I belive.  I've noticed many people have been successful with the LM1881, has anyone tried a EL4583 ?  It appears to be a much better solution giving you true H/V-sync off a C-sync

RARusk

Have you guys considered looking at this particular schematic?......

http://elm-chan.org/works/yuv2rgb/rgb2yuv.png

Could be a good alternative.....
Console hacking is like sex. For best results you got to know where to poke.....