Modding the GameCube component cable

I've asked the same question on GC forever, but I'm posting it here too so as to widen the net so to speak.

So I have a D-Terminal cable for my cube (same as component, different connector) and I've read that it's possible to mod this to output an RGB signal as opposed to YPbPr. My question is, if you perform the RGB mod and attach a SCART connector to the end instead, does it retain the ability to output 480p? Or is that only possible over component/D? Has anyone done this and knows from experience?

 

I could be mistaken, but IIRC, the guide I read for using a component cable to make a SCART cable said it was only 480i-compatible.

Now, you CAN make a VGA cable out of a component cable, which is capable of 480p.

 

D-Terminal is more than just the same as component. It has extra data lines that tell the resolution, aspect ratio, and whether the image is interlaced or progressive. It also has a plug insert detect pin and 3 reserve link pins. It is better to use the RCA connectors in some cases.

The RGBS mod to the cable still retains 480p. The only way to disable 480p support on the Component cable is to disconnect the DetectCable pin and/or the 54MHz pin. Whether or not your TV/upscaler supports 480p/60Hz at 31KHz over SCART is a different story. You will have to experiment to see if it does. RGBHV (VGA) would look better but many games and even the BIOS are 240p/288p or 480i/576i, meaning they most likely won't work on a stock modern VGA monitor.

To do the mod, simply lift pin 6 of the DAC and send it to ground. You would then need to get sync from either Composite video (not recommended) or luma (better but see below for best) from the Analog AV Multi-Out. You can get sound from there as well unless you want to mod the cable further for TOSLINK, which might provide sounds not possible on the analog audio output from the Multi-Out.

C-Sync is the best sync signal for RGBS and can't be obtained normally on the GC or the official cable. There is two ways to get it: use GCVideo lite, a clone of the official component cable, or create a sync combiner circuit using H-Sync and V-Sync from the official cable's DAC.

I don't recommend modding the cable anymore because GCVideo lite can do everything the official cable can (it's a clone of it) and also has a true C-Sync pin unlike the official cable. Other than that, it is just as good as the official cable. You could build GCVideo lite for under $60. There is also an HDMI version which looks better than YPbPr, RGBS, and RGBHV. The only advantage the official cable has over the clone is that it can be attached to the GC solderless. This problem is being worked on by BuffaloWing.

If you want 31KHz 480p RGBS on the NTSC GC easily, simply bridge the jumper for RGB on GCVideo lite then wire RGB and C-Sync to the analog multi-out. After that, use NTSC SNES C-Sync RGB SCART cables (might be called raw sync cables by some sellers).

EDIT: The correct way to do the RGB mod is to lift leg 12, add a 10K resistor and solder it to pin 1. After that, get sync from either H-Sync and V-Sync for VGA, use a sync combiner to get C-Sync, use Composite Video as Sync, use Luma as sync, or use a sync stripper on composite video.

 

Interesting. I have a Framemeister, and I know that can accept 31KHz RGBS from a Toro Dreamcast box, so I would assume that it can do the same from the component cable. Also, I have a sync stripper, so wouldn't that effectively enable me to get CSync from sync on luma?

 

Also, the guide I'm looking at that tells you how to mod the cable for RGB mentions nothing of leg 6 on the DAC, only that you need to lift leg 12, add a 10K resistor and solder it to pin 1.

 

If the sync stripper is smart enough to handle luma instead.
I hope your ultimate goal is something cool I've overlooked. As far as I know the GameCube digital out isn't RGB-based, making 31KHz RGBS technically further from the original signal than an unmodded cable.

 

I hadn't actually looked at it like that, the digital port outputs YCbCr, right? so converting to RGB would technically involve more processing than to YPbPr. Hmmm. Perhaps I won't bother, then.

 

Well I guess it's possible Framemeister processes RGB better than component.

 

This is possible, but from my limited experience with YPbPr and the Framemeister, there seems to be less noise and ringing when converting a component signal compared to an RGB one. My Mega Drive, SNES and N64 all are equipped to output RGB, and all of them exhibit ringing, but the GC? Not so. I don't know whether it's due to the higher resolution of the GC so it becomes less noticeable, but take all of that with a pinch of salt because it's not something that I have tested extensively.

 

My apologies, I misread the guide I saw. Yes, you are correct about lifting leg 12 and connecting it to pin 1 with a 10K resistor.

Since your XRGB mini works with 31KHz RGBS, you should be good to go and will get a good picture. Not sure how much better it will be than YPbPr since the GC does output a form of digital YCbCr and not digital RGB. Using the HDMI mod would be the best option since there will be no loss in quality like with the Component cable's Digital to Analog converter. HDMI uses YCbCr. If you wanted to make it external, you could attach the mod board to the component cable's Digital AV port pins.

While a sync stripper will give you C-Sync, it's best to use the source of C-Sync. It's really simple to get C-Sync from combining the two separate sync signals. Run H-Sync through a 1N4148 diode and then run V-Sync through an 820 ohm resistor. After that, connect the two wires and you have C-Sync. If you decide to use strip board, it should be small enough to fit in the SCART plug.

 

Any clues on where I can get info about how to build/purchase a HDMI mod?

 

There are two versions I recommend. One is universal and will work (in theory) with any game console or computer that has access to Digital AV signals. The other is GCVideo DVI, which is designed specifically for the GC and uses DVI-D over an HDMI connection.

OzOnE is making the universal one and has been confirmed working on the GC, GG, N64, and DC. It hasn't been released yet. One of his threads can be found here.

GCVideo is made by Unseen and is already out. You just need to purchase the FPGA board, solder it to either the GC motherboard, the external Digital AV port, or to the Digital AV pins on your cable. It also has an optional linedoubler for LD and SD games and a scanline generator. His thread is here and his github with all the parts needed and instructions (DOL-001 only, DOL-101s use different instructions) are found here.

 

This is amazing information, thank you for that. Those Pluto boards only seem to be sold by one supplier that I can find, seems pretty elusive.

 

You're quite welcome.

KNJN is the only place I can find that sells them. I put everything in a shopping cart and it appears to be just $66.90 for the FPGA and the required programmer (uses 9 pin serial port). You will need some wire (30 gauge/30 AWG should work or wires from old PC IDE cables) and either a PC with a serial port or a serial to USB adapter. Keep the wires under 10cm or else the board starts having issues. Also, keep the 54MHz wire separate from the rest of the wires.

The latest firmware allows for Digital Audio output via TOSLINK should you have a sound system. Many GC games support DOLBY Pro Logic so it should sound better via TOSLINK.

(If the shopping cart link doesn't work, get the Item#6112 Pluto-IIx XC3S200 HDMI board and Item#6130 TXDI programmer found in the first link)

 

I don't have a decoder, can't really justify one just for the GC. I may pick one up, though. I wonder why those interface boards use the old 9 pin serial interface, surely they would have updated to USB by now. I have some kynar wire lying around, you think that will suffice?

 

They used to have a USB version available but I have no idea what happened to it. I think they offer a flashing service for free if you send them the files. I'm not too sure so you may have to ask them. You could always sell the programmer and the converter afterwards or keep it in case an update comes out for the board, which I think he said might happen in the future. You never know when old tech will come in handy. My friend's PC needs a floppy to fix it and it's not even 4 years old.

Not sure why they still use serial ports. PCs dropped them years ago and USB 2.0 or even 3.0 could both power the device and program it at the same time. I guess it might be because a lot of people who use these boards still have older PCs and it's cheaper to use it. All of my desktop PCs have them so it's not a huge loss for me personally. Modern PC motherboards should still have the headers for them so simply hook up one to it and turn it on in the BIOS. I think they are labelled as COM1, COM2, etc.

Kynar should work. People use it for the Japanese/English region switch mod in the GC, which has really small points. That's a neat mod btw but make sure to have two separate Memory Cards, one for NTSC-J games and one for NTSC-U/C games.

 

I'm not sure that my motherboard even has the COM ports on it, it doesn't even have the old PS/2 ports for keyboard and mouse, it's all USB. I'll get the programmer anyway as it's always good to be able to update the software myself.

I probably won't bother with the region mod as I'm waiting for a megadrive board to turn up in the mail, at which point I'll install a WiiKey Fusion in my cube, that takes care of any region locking.

 

The switch isn't just for region locking. It's needed to play Japanese games properly. If you don't install it, it can corrupt Japanese save games and cause those games to display text improperly. You would need a separate memory card for Japanese games. PAL game saves can be stored on the same memory card as NTSC-U/C saves.

 

The basic principal is similar to systems like Genesis or Saturn. Modchips, Action Replay, and Freeloader, load imports without changing the system's internal region.

In the strictest sense, separate memory cards are only required with a region switch or actual Japanese console.
When you play Japanese games that can save/load under PAL/US mode their data is stored in western format. Japanese consoles won't be able to read the data.

If you don't want a region switch, just work around it. Adhere to a compatibility list and avoid games with known issues.

I've also heard that the Swiss homebrew is working on software switching, instead of hardware.

 

So I've taken the plunge, I've just ordered the Pluto board and the programmer as per your saved basket, @MonkeyBoyJoey. If it works out, then I'll likely sell my D Terminal cable before word gets around too much about this mod and the price drops.