Can anyone improve the rgb output on my duo?

[incrediblehark]

Thanks for the info thesteve, I don't think I have any spare 1uF so I'll take a trip out to Radioshack and hopefully give it a shot today.

[incrediblehark]

So I tried adding the caps as suggested and still no change, although I could have just done it comepletely wrong. I tried taking pics but didn't come out well. I also tried a different power supply but no change. In all honesty its not that noticeable except for solid colors and when the screen is moving. I think if I can figure out how to make the picture brighter like the pc engine it might look the same. In the end I'll probably have to have someone else take a look at it.

[HercTNT]

I have the same problem to, my rgb modded system also has jailbars.  steve, did you add your own encoder to your duo, or can you get rid of the jailbars by switching the rgb mod to green sync, instead of composite sync?

[thesteve]

my duo isnt modded, as i didnt have an amp setup handy.
one of me genny2's is and its running sync on green for direct connection to my monitor.

[HercTNT]

is it possible to resolder the internal wiring to put sync on green instead of composite?  I would be a matter of changing just one wire would it not? the jailbars can be pretty noticable depending on the game.

[thesteve]

it would take a couple parts to bring the sync up to ttl level and then a diode and cap to integrate it

[grahf]

And if that doesn't work out, you can also try using an LM1881 sync separator. They use a super simple circuit, and usually produce a rock solid, clean, sync signal.

[incrediblehark]

If its something I could easily solder to together then i could probably do it, otherwise I'm going to have to have someone look at the system for me.

[grahf]

If you can solder at all, it's super easy. If you get stuck, just ask.

[incrediblehark]

Thanks for all of the help everyone So what would I need to do with a sync separator? is this something I would build?

[thesteve]

yes its something to build.
you would use it to give true sync instead of composite to your monitor.
the "less bright" condition bugs me a bit. what amp are you using (chip, transistor, numbers)?

[incrediblehark]

Just opened it up and took a look. I had this installed by someone else (my other, better picture rgb system I had the same person build the amp but i did the rest of the work myself) The 2 chips read as follows:

2267D
JRC
7028B

[BlueBMW]

NJM2267, the same amps I had planned on using on my amp chip.  I've seen them used before with good success.  According to steve's calculations, it should be good if the surrounding components are done properly.

[incrediblehark]

And my pc engine rgb amp is the same, but for some reason the picture is brighter / jailbars virtually nonexistant on the pc engine. 

[thesteve]

look at wire routing (especially before the amp)
you could be getting crosstalk from the composite wire.