RGB to S-video

[flooby]

Hi folks. I need help adding s-video to my Duo and TG16.

I've tapped the the RGB signals off the chip directly in my Duo.  I'm using a commercial pre-made rgb to s-video convertor.  It wouldn't sync, so I built an amp for the sync signal.  After that, the image was dark, so I built amps for the RGB signals.  Unfortunately, the image was still dark.  It seems the amps didn't really help the image much.

So...what I was wondering is if I were to get the sync signal off the composite line, would it help to brighten up the image? Thanks.

[CkRtech]

Hey flooby.

I am certainly not an authority in this area by any means. As far as the TG16 is concerned, I have owned one for less than a week at this point. That said, I'll get the ball rolling in this thread before some of the other guys come to your rescue.

Which RGB to S-Video converter are you using? You said "commercial pre-made" - is it internal or external? If is is external and you are pulling the RGB information directly from the video chip, you would certainly need to amp your RGB signals as they are not up to spec. I saw that you posted in the "complete DUO S-Video mod" thread and mentioned acquiring CXA1645 chips. Did you see the link that nat provided to this page? It mentions building the amp for each signal. With that up to spec, your converter would probably convert it naturally.

As for your brightness issue - I do not think sync would cause you to have a darker picture. I would think if the sync signal wasn't good enough it would either look "weird" or the picture would roll. Someone else can clear that part up for you.

Here's a link to another gamesx page - Adding RGB.

Hope some of that helps. I am sure some of the other guys here will jump in and help.

[flooby]

Here's an image of the RGB to s-video convertor.  It's a generic one off of e-bay.  I've used the same type with success with my Neo-Geo MVS:



Like I said before, it would not sync without an amp on the sync line.  There are 3 pots to adjust the RGB levels, but even then the image is a little bit dark.  I added amps to the RGB lines, but they didn't do anything.

Thanks!

[nat]

It's a good idea to pull the sync off the composite line. D-Lite can probably provide more information.

[D-Lite]

Strip the sync from the composite video line.  I use an LM1881 chip. 

Commercial S-Video encoders don't typically work with the NEC systems.  The JROK or NeoBitz both have issues and I don't know if anyone has solved them.  I build my own encoders from scratch and they seem to work as well as you can make them work. 

Shoulda come here first.  I could have sold you one I made.

[nat]

I'm in the process of building a few, too.

I finally got all the components save a few capacitors.

Yeah, I coulda just bought one off D-Lite but DIY is more fun I think.

[D-Lite]

I'm in the process of building a few, too.

I finally got all the components save a few capacitors.

Yeah, I coulda just bought one off D-Lite but DIY is more fun I think.

Been thinking about doing a DIY kit.  Supply all the caps and whatnot, maybe +/- the encoder option too.  Hardest part is getting all the little parts together.

[flooby]

Just an update.

I was messing around with the RGB amps.  I took a 300ohm resistor and connected the RGB signal from the chip to the  RGB output portion of the amps.  I left the amps in place.  For some reason, with both the resistor and amp relaying the signal, the end result is a much, much brighter signal.

Also, stripping the sync from the composite out didn't affect brightness.

Thanks.

[Michael Helgeson]

Just to revive this for a bit,I was wondering where you tapped the power. This looks like the Yanton one. If I remember right it needs inetween +9-12 volts to run well. I never tried to power them off +5 so I was wondering how well you got this going,and how well a fit it was in your system too?

[flooby]

I didn't put it internal.  The RGB amps and my Rat's Nest of wiring for the region mod pretty much precluded that.  I'm sure you could fit it inside...somewhere...but I didn't.

As for power, I have it running on it's own power supply.  The documentation from the manufacturer says it will take between 9-15v.  I haven't started looking for 12v from the Duo, but you could always pull it directly from the power supply plug in the back..

[Michael Helgeson]

Thats true,you could pull it off directly from the AC area,but prob not something Id be willing to do,since I wouldn't be sure how much more taxing it would be on the AC adapter.I would be fine with a encoder only needing 5 volts,but a little more iffy past that. All I ever hear is Dup power supplies are wimpy. Plus I was wondering more in general as  a use for other systems besides the Duo,as these encoders are very easy to get and very cheap. I have used them alot in superguns due to the great s-video from them.

I guess the best idea would be to just make a break out box with one and use DB15 ports,ect.

[D-Lite]

Do you have a link for this encoder?  It's been a long time since I've seen it on eBay and I can't find it now.  I'd love to get one and try it out.  I also can't see why it would need 12V since the key components don't.  I see the 7805 or whatever it is there to transform the voltage, but it's probably not needed.

[Michael Helgeson]

Do you have a link for this encoder?  It's been a long time since I've seen it on eBay and I can't find it now.  I'd love to get one and try it out.  I also can't see why it would need 12V since the key components don't.  I see the 7805 or whatever it is there to transform the voltage, but it's probably not needed.

I always bought mine from Yanton. They are pretty good,and in some cases will sync to some games fine that the jrok needs a sync cleaner for.In other cases though,it had issues with Power Instinct 2 and Wrestlefest,and I had to use a sync cleaner to get them working fine. I was alot happier with these composite and s-video wise then anyone elses. I got less noise/interference with them then the Jrok with the composite especially. Hit Yanton up,see if he still has them in stock.

[Duo_R]

PCH - sorry to revive an old thread, this Yanton is no longer a member correct?

[nat]

To my knowledge, Yanton was never a member here.