Turbografx-16 RGB mod issues

it290 · Post by **it290** » Mon May 26, 2008 6:40 pm

Well, I finally got around to putting RGB on my Turbo; so far, though, the image is, well - weird. Basically, all the bright colors are REALLY saturated and intense, and the midtones get blown out by this. I have read that the PC-Engine and Turbo require an RGB amp to get a good picture; however, the image isn't really dark per se (well, the dark colors are), just weird. The RGB amp is a bit of a project and I'd rather not build one if I don't have to. I haven't tried putting resistors on the line yet as I don't have any with the appropriate values handy, but I was just wondering if anyone had experienced the same, and if so if resistors helped and what a good value would be. I'm assuming 75ohm for now, but if anyone knows otherwise or feels the RGB amp is really required, let me know.

matt · Post by **matt** » Tue May 27, 2008 12:20 am

The signal does need to be amplified - resistors will just make the problem worse.

it290 · Post by **it290** » Tue May 27, 2008 1:28 am

Hmm, thanks matt. Seems a bit odd though, since it honestly appears to be too bright at the moment. I guess I will try to build that amp when I have the time, not to mention internalizing the mod, since right now I just have all of the wires hanging out the back of the console.

matt · Post by **matt** » Wed May 28, 2008 9:11 am

It usually looks like that because you need to bump up the contrast to make the picture visible, which washes out the bright colours.

it290 · Post by **it290** » Thu May 29, 2008 1:47 am

Hmm, well, I built the amp using the schematic from gamesx. I'll have to double check to make sure everything's wired up correctly (although I'm pretty sure it is), but as of right now having the unit connected through the amp makes a very unstable picture with really dark colors on everything. It doesn't seem to make any difference whether the sync pin is running through the amp or straight through. I suppose this could be my odd hardware setup (RGB running into an RGB->component transcoder), although it works with everything else I've thrown at it (Saturn, Genesis, SNES, Dreamcast through SCART and an LM1881 circuit and Neo MVS straight off the JAMMA connector). Ever seen anything like this before?

Also, as a side note, I don't have the bright/contrast jacked up on the TV at all, they are at their normal settings which work perfectly with all of the above.