I recently started to mod my retro consoles with a universal RGB output port. Basically I'm using an old VGA extension lead with the male plug replaced with a scary plug, wired up to my own pinout design. The male connector, which is normally used as the cable connector of VGA, I use on the console to add the new output port. And the female side, which is the output/input port connector for VGA on hardware, I use as the cable connector. As the different consoles have different components inside the retail RGB Scart leads, I have decided to make little boards for each console and place them inside the consoles themselves, in-between the output pins of the consoles standard port and my new port. That way my new cable is a straight pin-to-pin cable with no components between the console and TV at all. I have all the boards designed and all the components available to me. I am building them as and when I need them. I chose the VGA connector, as it's 14/15 pins is more than enough to have all of the needed connections with a compact and neat design. With VGA being a standard for such a long time, it also means there is a wide supply of these ports available, with little to no worry of bing unable to get one. I am using this inverted connector setup, so as standard VGA cables won't physically connect. It also distinguishes the port from the VGA port I have on my Dreamcast. As that console can output VGA, with a similar mod I did a while back. So far I've added my new port to my Gamecube, and my SNES. Both PAL, both UK. The Gamecube was the prototype and test for weather this mod was worth the effort. I attempted it twice on the same console, as the first being a failure. But, I eventually got it working as it should. The SNES was an instant success, as the learning experience from my errors before meant I didn't make the same mistakes. Both consoles now output RGB via a dedicated port. The only issues I found is a very slight picture issue. On the Gamecube there seems to be faint diagonal lines showing. But only when something is in motion. I've seen these lines before a few years ago, while using the Wii to play The Legend of Zelda: Wind Waker. That game is 60Hz only, and it caused these diagonal lines to scroll across the screen. Most noticeable around the edges of solid colours, like menu text or symbols. At the time I was limited to using the composite (Yellow RCA plug) connection. And I was using an old CRT. So, I jut put it down to thats what happens in 60Hz. And, that suspicion is fortified somewhat with previous experiences, as whenever I 'forceed' a Gamecube into 60Hz mode, this issue became more visible. This happening on both my Wii and my Gamecube. But, it now happens on my Gamecube, with my modification in both 50Hz and 'forced' 60Hz. (By "'forced' 60Hz" I mean hold 'B' while booting.) On the SNES, I encountered a similar issue, but rather than being diagonal lines, all solid colours had a kind of 'checkerboard' effect, displaying 2 shades of the same colour alternating. But, as I've never seen a SNES in RGB before, I assumed this was normal, and I was ready to accept it. But, on a whim I Google'd it and found out; if I exchange the composite output from the console (pin 9, which is needed for the TV to display RGB picture) and use the 'Luma' (pin 7), which is usually used for S-Video, it removes this effect and the colours display as solid. So, now my SNES displays a perfect RGB picture, with no more 'checkerboard' effect. The only drawback is that if I use this mod on a display that doesn't have RGB capabilities, the picture is monochrome. Not a major issue, as I don't think I'll ever encounter such a display again. And it's an acceptable trade-off for the benefits to the RGB picture. Plus, I always have the Composite around leads if I ever need them. Unfortunately the PAL Gamecube doesn't have S-Video for me to change pin 9 to pin 7. As those pins aren't connected to anything. I've looked online for an alternative source. But, because the PAL console doesn't have any S-Video capabilities at all, I can't seem to find anything to resolve my issue. Ironically, as I'm sure most of you will already know; the US NTSC console does have S-Video, but doesn't have RGB. (Not unless you're willing to spend a lot of money on a special cable) I did however learn of something called 'Sync Stripper'. I found a guide to make a little board using a LM1881 8-pin chip, a couple of ceramic capacitors and a resistor. (I have a load of capacitors and resistors, am just missing the chip at the moment) The guide is on a site called MMMonkey. It's a site I have used regularly in the past (before the redesign) to modify my console for Composite RCA, S-Video, region switches and such. I have ordered one of these chips, they are really cheap, and you can find them easily. It was less than £3, including postage. And I have the skills and abilities to build the board is needs. It was a lot cheaper than trying to hunt down a pre-built board, as I've seen them for $20+ (about £13) on some sites. But, before I get my hopes up, and possibly waste my time, I thought I'd get some advice. As it stands, it's playable, and not that noticeable. But, I'd like to get the picture perfect, if I can. Also, as all of my consoles have S-Video, I can use the 'Luma' pin on those. That is except for the Gamecube, which doesn't output S-Video. (I could be wrong, but I think the US N46 doesn't have S-Video either. But, I only have the console, without any games to try on it to find out.) So, I intend to add this circuit inside the console, as I can get a sync signal from the S-Video on my other consoles, as and when I mod them. My question is; will adding a 'Sync Stripper' clean up my picture, especially in 60Hz? If not, I think I can live with it. But, I'd rather have it fixed. Any information to help me understand what this LM1881 chip does, and if/how it will benefit me will be greatly appreciated. My lack of understanding on weather this will improve what I already have is why I opted for the cheaper 'home-made' route, rather than paying more for a pre-made board. I can't seem to find any information on using the composite as sync compared with using a 'Sync Stripper'. I don't seem to be able to find clear information on what results the end-user would get either. Lot's of technical details, and descriptions of what the chip does, but no actual 'what you see on screen' information. Again, any information is appreciated. Thanks. Sisee, out.
It sounds like you are using composite video for Sync. This method is terrible for many TVs/upscalers. Use C-Sync instead as it is pure Sync unlike composite video, which introduces those artifacts you've seen. C-Sync does not have these issues on proper cables. As for the GameCube (which technically isn't retro), don't use the native 15KHz RGBS output. There is a thread here in the modding section that talks about the GameCube GCVideo mods. The analog version gives you 480p YPbPr Component Video, 480p 31Khz RGBS via SCART/JP-21, and 480p RGBHV VGA. The RGBS output with this mod is superior to the native RGBS output in PAL GameCubes as it is 31KHz and it supports 480p whereas the native output is 15KHz and does not support 480p mode. The digital version is a true digital HDMI (technically DVI-D) output at 480p. It is superior to the official Component cables and SCART cables as it takes the digital signals the GameCube natively outputs and converts it to a useable DVI-D signal. The Component cable has it's own DAC chip inside that converts the digital signals to analog YPbPr Component video and analog RGB (requires mod to enable this mode). The multi-out SCART cables use the system's built-in DAC.
