Dreamcast VGA vertical line issues and possible solution

[astro-g]

I have search everywhere (including the Dreamcast VGA megathread) and cannot find a solution or a definitive reason why the vertical lines show up on lcd tv's and monitors. Here is what I have figured out thus far-

I have 2 Dreamcast's with manufacture dates of July 1999 and September 1999. I have a Retrobit vga box, handmade vga cable I got off ebay and I made the vga booster circuit from mmmonkey.co.uk. All three of these output options yield vertical lines on my tv. I even soldered the booster circuit directly to the Dreamcast mobo. I have tried several different televisions of varying brands and several different lcd monitors all with the same result. The only device that was vertical line free is my Dell 22" UltraSharp.

The interesting thing to note from my tests is the July 1999 Dreamcast has more prominent vertical line than the September 1999 Dreamcast. Is the vertical line problem not as prevalent in Dreamcast manufactured in the year 2000 because they fixed it? I have no idea but I would like to know. Could it be a capacitor issue and simply changing them all out potentially fix the problem? I suppose it is possible the Retrobit box, cable and booster circuit are all flawed. Is the Dreamcast vga output calibrated to be within the tolerances of a crt monitor and modern lcds have much lower signal tolerances? I don't think the vertical lines are created by the lcd tv's crappy internal upscaling because I have tested other devices at 640x480 vga and those do not yield vertical lines. I think the vertical lines are being generated within the Dreamcast. If not, then why do my 2 Dreamcast's display the lines differently?

I do have possible solutions for those whom this issue is driving mad. It can be very tedious but you can adjust the clock/phase option in your televisions vga settings. In my experience, this method has varying results and probably will not remove the line completely. I have a GBS-8200 and if I run the Dreamcast vga through it and set it's output to 1024x768 that buffs out and greatly reduces the vertical line intensity. I assume any decent upscaling device will have the same effect.

[Ziggy]

Retrobit makes garbage and I wouldn't doubt it if that's your problem. Have you ever tried using a different VGA box?

You seem to know what you're doing... Why not just try and build your own VGA box?

[astro-g]

I would love to make my own vga box but I just don't have the time or the knowledge. I have thought about buying a different vga box but I am worried if it doesn't fix the problem I will be out of $60 to $100. I'm really trying to figure out what specific component if any is causing the problem.

[jay_red]

I would love to make my own vga box but I just don't have the time or the knowledge. I have thought about buying a different vga box but I am worried if it doesn't fix the problem I will be out of $60 to $100. I'm really trying to figure out what specific component if any is causing the problem.

I have the clear VGA box that has the VGA on one side, and composet/s-video on the other and I get the vertical lines on my 40" Toshiba LCD. It is noticeable, but not distracting, and I have never looked any farther into it.

Mine is this one:

[Ziggy]

Well the only way to prove or disprove the theory that it's the Retrobit VGA box is to try and use another box. If you're unable to borrow a buddy's (or bring your DC to a buddy's house) then you're only other options are to roll the dice on another brand box or build your own.

Now, this is all theoretical since I've never done it, so keep that in mind. The VGA box is a relatively simple thing, it should be an easy build. There's guides out there to make an internal VGA box for the Dreamcast, like this one:

http://www.mmmonkey.co.uk/dreamcast-internal-vga-mod/

You just put that in a project box. Or, do the actual internal mod and forgo the box.


My first guess would be that the Retrobit VGA box sucks. After that, you said you're using a "homemade VGA cable" that you got off eBay. Well, have you ever questioned it? Maybe you can swap the VGA cable out for a brand name one and see if that does anything. A cable that isn't properly shielded can create all sorts of problems, possibly the one you're having. If you do try swapping the VGA cable, be sure that the other cable is of quality. For example, don't use a Radio Shack brand, bargain bin, $.99 on Amazon, etc.

[ninjainspandex]

get a Hanzo VGA box, has built in scanlines. you won't see any jailbars and it will make your LCD HDTV look like a crispy PVM
http://www.assemblergames.com/forums/sh ... -generator

[astro-g]

I have done that exact vga internal box mod and I even wired it all up with heavy shielded wires I pulled from a quality spare vga cable. The vertical lines were still there and identical to what I see on the Retrobit box. My local used game store has a used Madness Gameware vga box. I might try to talk them down on price or see if I can return it if it doesn't fix the vertical line issue. I have never heard of Madness Gameware and I assume they are probably not much better than Retrobit. I have many different vga cable all varying in quality and they all have the same result.

I wish I new someone else who has a vga box. None of my friends are as passionate about retro gaming as I am lol.

What is the manufacture date of your Dreamcast? I would love to get a Hanzo. I acutally made my own SLG which works great but it doesn't hide the vertical lines at all. I thought that it would but it just doesn't. I still really would love a Hanzo.

[astro-g]

Alright, so I decided to pickup the Madness Gameware vga box at my local used game store. It for the most part has removed the vertical lines although it did need some maintenance. The blue channel completely did not work giving me a bright yellow image on screen. It took some trial and error and soldering skills to solve the issue. The problem was the capacitor on the blue line became loose and broke the trace. I just simply soldered a shielded wire from the capacitor directly to the vga output blue pin. Also, the screen would distort whenever any audio was played. Cleaning the corrosion off the vga connector fixed the problem creating a better grounding source.

Basically what I learned is if you have terrible vertical lines on your dreamcast vga, buy a better vga box. I would avoid the cables since they lack any booster circuitry. The Retrobit vga boxes are total crap although built fairly solid. If you buy an older vga box be warned that it might need slight maintenance to get it working properly. If you know what you are doing, the older boxes do not use modern micro parts and you could easily replace the capacitors, diodes, resisters, etc pretty easily.