Dreamcast VGA

[fragment]

ok, so it seams pretty simple to build on of these, but is it worth the trouble? I can only find the aftermarket VGA boxes for sale and not sure if that is a good idea. So far I have seen that the Naki is a good box, but I don't know about the Performance box. On the Atari forums, I have read that they were built with cheap components.

So, has anyone made their own VGA box, and where did you get the IC?

[RARusk]

There's no need to use an IC for a homebrew VGA box. I recently built mine using a small project box (that I got at Fry's in Austin TX) and I had it done in about two hours. I used a leftover cable from a NAKI VGA box that I turned into my RGB box. The only thing inside the VGA box is a small little Radio Shack project board that I used as a bridge for my wires and to run the RGB signals through 220uf capacitors. That's it really. The only thing you really need to make sure of is that both pin 6 and pin 7 (the mode pins) on the Dreamcast plug are attached to ground. This will tell the Dreamcast to go into VGA mode.

If this forum will allow the posting of pictures I will try to post pictures of my homebrew box.

[Endymion]

He's right, the Dreamcast is what is actually creating the VGA signal. When certain pins are tapped the Dreamcast activates different modes (RGB, Composite, VGA, etc.) so you can actually make a simple VGA cable if you so desire, there is no need for switches, a "box" or anything else if you don't need it. The reason the VGA Box is in fact a "box" is because they figured people might have different needs for audio (RCA stereo or headphone jacks) and want to use different video modes (S-video, Composite, VGA, etc.) and it's nice to be able to do that without constantly swapping cables--it's a matter of convenience.

It's a neat project but with as cheap as VGA boxes are, and considering that the signal is going to be the same no matter the build of the box, you might as well just buy one and save yourself a lot of time.

[RARusk]

I built my homebrew box because of what I consider a design flaw with all of the other boxes including the official Sega VGA box. When looking down at the top of a VGA box, you will see that the monitor plug is on the right and the audio plugs are on the left side of the box. This is fine if your monitor is on the right side of the desk and your audio equipment is on the left. But my setup is reversed so my cables crossover each other and makes for a messy setup. My homebrew box has both monitor and audio plugs on the same side (back side) which makes things neater plus the box is smaller and looks very nice.

I don't mess with Composite or S-Video unless I have to. It's VGA all the way for me. I wish the other companies (Sony, Nintendo, MicroSoft) would've followed suit. A lot of games would look very stunning in progressive scan RGB. At least I have a sync-on-green monitor and found a way to play "Soul Calibur II" (PS2) in VGA mode.....

[Agentspikey95]

So, all you have to do is lead pins 6 and 7 to ground, or will it be better to blow x amount of bucks on a performance or whatever the best VGA box is?

[Endymion]

Yes, that's all you have to do. Thing is, I don't know where you would get another plug for your Dreamcast, without cannibalizing something. That kinda makes the decision to get a VGA box a little easier to me.

I wouldn't bother with a Performance VGA box, either. I have one of these and I've just stopped using it for the one main reason that I acquired it--if you have a large monitor and use high resolutions (1600 lines) this thing will ghost, no matter what, no matter the quality of the VGA cable you use to patch your computer with. The Dreamcast signal is fine and clear and not a bit of ghosting is happening, but from my computer, there's a noticeable ghosting in every setting at 1600 lines or higher. So I've reverted to using a KVM switchbox for my computer's video, no ghosting or compromise with my computer image there.

Any VGA box is as good as any other unless it is inherently faulty somehow. The box isn't making the signal, the Dreamcast is.

[fragment]

There's no need to use an IC for a homebrew VGA box. I recently built mine using a small project box (that I got at Fry's in Austin TX) and I had it done in about two hours. I used a leftover cable from a NAKI VGA box that I turned into my RGB box. The only thing inside the VGA box is a small little Radio Shack project board that I used as a bridge for my wires and to run the RGB signals through 220uf capacitors. That's it really. The only thing you really need to make sure of is that both pin 6 and pin 7 (the mode pins) on the Dreamcast plug are attached to ground. This will tell the Dreamcast to go into VGA mode.

If this forum will allow the posting of pictures I will try to post pictures of my homebrew box.

there is a way to host pictures, when you post a new reply there is an option to upload an attachment. If you have several photos, please email to me and I will host them for you.

duo_r@sbcglobal.net

[Endymion]

Look in the console mods forum, Lesmot made a VGA circuit that he built inside his Dreamcast with pictures there, that would be a very worthwhile project.

[fragment]

ok, I got a Naki VGA box from ebay today for $12, and my question is what resolution modes does this work in?

thanks!

[Endymion]

Just one--640x480, standard Super VGA. That's all it needs.

Not every game will work with VGA mode, many that don't can be forced though.

[RARusk]

Attached to this message should be a picture of my homebrew Dreamcast VGA Box.....

[RARusk]

Here's a closeup of the back side.....

[RARusk]

And finally, the inside of the box. You can clearly see the 220uf caps on the little Radio Shack protoboard I used inside. What do you guys think?

[NFG]

That's a nice box.  I found my system wouldn't work without the chip inside to buffer the signals, you must have gotten lucky with your monitor - or is the chip hidden somewhere?

[RARusk]

There's no chip, period. I have opened up all of the VGA boxes I have owned (Madeness, NAKI) and found that the RGB signals go from where the cord is attached to the board straight to the 15-pin plug (after going through 220uf caps). I just mimicked that within my box. I think the chip has more to do with standard video (Composite Video, S-Video) than with RGB.

The grounding for pins 6 and 7 (to trigger VGA) is actually done within the DB9 plug that attaches the Dreamcast cable to the box. Pins 1 and 2 on the plug is for ground and I took the one ground wire for the Dreamcast and attached it to pin 1. Then I took the wires for DC pins 6 and 7 and soldered them to pin 2 on the DB9 plug. Then I soldered a wire to connect pins 1 and 2 on the DB9 plug together to ground everything. Pins 3, 4, and 5 on the DB9 plug is Blue, Green, and Red respectively. On the bottom row, pin 6 is Left Audio, pin 7 is Right Audio, pin 8 is Vertical Sync, and pin 9 is Horizontal Sync.

Originally this box was supposed to be a semi-universal VGA box for my Dreamcast, the PS2, and the Xbox. Trigger VGA mode within each system with either software or cables and route it through the box. But there are very few PS2 games that can do progressive scan and VGA has been disabled for the Xbox so I use this for the Dreamcast but it can also be used for future game consoles if the makers are smart enough (yeah right) to include progressive scan RGB.

As for my monitor, it is a NEC MultiSync 3D dual scan (15Khz and 31Khz). Never had a problem with it with any VGA box including my own.

[fragment]

That homebrew is awesome! I just got my NAki VGA box, and I can now put my 32" multimedia monitor to use! The picture is amazing. However, the audio has two problems:

* sound only out of one channel (L plug has no auido)
* the sound is a little distorted when there is a little bass in music


The box was brand new and still in the plastic packaging. Has anyone ever had this problem?  

[RARusk]

I had a similar bass related problem with the Madeness box. Had something to do with the IC on the motherboard. So I cut the traces for the RCA jacks on the motherboard and wired the sound jacks directly to where the wires from the cord meet the board. Solved that problem.

However, when I checked the motherboard of the Naki box, I found that the sound goes directly from where the cord meets the board to the RCA jacks. No IC to deal with. Puzzling. The only clue is a couple of capacitors just behind the small audio jack next to the monitor plug. By all means you really shouldn't have a bass problem.

But it is possible that you may have a earlier or later version of the Naki board. If yours has an IC and it appears that the sound is going through that then bypass it like I did my Madeness box.

[fragment]

well I opened up the Naki box and discovered a poor solder on one of the audio connections. There is this wire (like a straightened staple) that was cold soldered, and I could even move it by applying light pressure with a small flathead (off the solder point). I resoldered it all up, and the other audio connection and it is all good now! I got stereo sound, and a killer picture! Did you hack your old VGA box for the dreamcast cable?

[RARusk]

Yes, I used the cable from the Naki box for the homebrew project.

The box itself became my standard RGB box for 15Khz signals from my other consoles. Inside it contains a Radio Shack protoboard with a CXA1145 chip (for amplification purposes) and a EL1883 sync separation chip (for the sync lines).

As for the exterior, I cut away a section from a Microsoft Xbox S-Video box and grafted it to the back of the box plus used the gold plated audio plugs that came with it. The front has a 9-pin plug which I use to attach custom made cables (for all of my systems) to the box.

I have made cables for my PS1/2/Atari Jaguar (PS AV plug hacked in to replace busted Jaguar AV port), Super Nintendo/N64, Xbox, Sega Master System/Sega Genesis (Model 1), and Sega Genesis (Model 2).

This is a picture of the box I used for the AtariAge forums.....

[Endymion]

Yeah yeah, keep it up guys.

You're going to have me cramming a VGA board into my Dreamcast at this rate.

[NFG]

You're going to have me cramming a VGA board into my Dreamcast at this rate.

This was my plan for a long time, but I have several DCs and only one VGA box, so I gave it up.  And the fact there's shockingly little room in a DC for mods...

[Lesmot]

There's not much room in a DC, but there's enough. Here was my built in VGA 'box' photos again, if you were interested in walking a different path. I do have an external VGA box for other DC's, I just did the built in for fun, though it's not too practical.

click here for the photos

[fragment]

just an update on my dreamcast NAKI VGA box. The audio was only mono, but I fixed that. It sounds like it is overamplified, any bass noises and I get some distortion. I am going to cut the audio trace on the board, and wire directly. I fixed the S-video connector. I actually was getting a worse video signal on the S-video connector than on the composite connector. I cut the trace on the board, and wired directly from the cable to the S-video connector (just followed the board to the correct pin) and now I am getting a great picture! Before I had unbelievable dot crawl, and more visible scan lines. What the hell where they thinking when they made this box???