John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

Since a lot of crt vga monitors don't have any trouble accepting a PC resolution of 320x240/240p, does that equal to a 15k hz signal from a modded Dreamcast VGA box? Here is the example on how to do that, http://forum.arcadeotaku.com/viewtopic.php?f=26&t=1870 (http://forum.arcadeotaku.com/viewtopic.php?f=26&t=1870).

I find this important because not only will that make bangai-o playable (it doesnt output in 480p, just 240p). But I can get real authentic scanlines, not generated by a scanline generator but are genuine scanlines.

On this picture of bangai-O running, you see the scanlines, on a old Jamma cabinet accepting 15k hz input.(http://i11.photobucket.com/albums/a160/davidlory/dc15khz-3.jpg)

I am looving those scanlines, a real reason for me to get a good crt monitor and ro removing the casing and inputting it in a self made cabinet. But will a typical crt vga monitor accept a 15k hz signal as it would a 240p PC signal?

The article you linked to only shows how to mod a Dreamcast VGA box output to a CGA arcade monitor, but does not show how to use a VGA monitor to display the 15khz signal.

The problem here is that while resolution can be made to match, the scan rates between the two are much different, and can cause damage to monitors if the wrong signal is input directly.


It is technically possible to use a 15khz signal on the 31khz monitor, but it would require a converter/scaler box, which costs around $100. USD and does add some lag into the equation, so isn't really cheap or a quality solution.

interesting, I never knew that

Ah thanks, this does complicate my plans since vga monitors are much easier to get then these old fashioned specific arcade monitors. I'll try and find some good reading material on those monitors to see what I can do.

After reading up on this, it seems that the best way forward is a more rare monitor capable of multiple inputs. One seems to be the Sony Trinitron Multiscan 200ES (CPD-200ES).. I'll stay on the lookout for some and make sure to notice if I see one on ebay for cheap enough.

edit: the best possible monitor seems to be the makviision 25", which is specifically made to portray the old arcade classics as genuine as possible. I mostly want just a dreamcast cabinet to have just one cabinet with as many games without resorting to emulation. I will be putting money aside for this one..

vga monitors are 31khz.

old cga or amiga monitors can take 15khz. some sony broadcast monitors can do it.

also check the GBS8220 converter

Upscaling a 15k hz signal would actually get rid of the scanlines, which would be the point of getting a lowres signal. After looking at different things, including the very expensive, one of the very last crt screens to be produced of makviision, is that they do accept all three inputs, but there is a switch inside it which has to be altered.

The much cheaper options would be getting a vga box, with a scanline generator included. Hanzo makes some good ones. http://www.ebay.com/itm/Sega-Dreamcast-VGA-Cable-with-Scanline-Generator-instead-of-VGA-BOX-HANZO-/171368267720?pt=US_Video_Game_Cables_Adapters&hash=item27e6583fc8

Any reason you want to use a dream cast over a naomi?

All the older arcade ports for the Dreamcast, Street Fighter Third Strike or Super Street Fighter II Turbo, it might be a japanese release but it is considered to be the only arcade perfect homeport. The HD version was reportedly made off of that version instead of the arcade version.

You might get extra memory on the noami, but a home Dreamcast will get me more older games.

Since you are interested in using a VGA monitor, and show interest in playing older arcade titles, is there any particular reason you don't want to use a MAME PC?  ???

Consider this: Mame has the real arcade versions of most titles, and there are other emulators that support the games Mame doesn't have.
Scanline support is typically built in to emulators and it can output to a VGA monitor directly, with no hacking,  or a PC can also be made to interface with a arcade monitor very easily with the proper drivers, and a JPAC will allow you to interface it directly with any Jamma cabinet.
If you aren't using a Jamma cab, a IPAC is also available that works great too.

Not saying you can't go with an old console to get games running, but it isn't the easiest thing to get going, I originally threw a Sega Saturn into a cab many years ago when I was just starting out, and I was pretty unhappy with it pretty quickly as home ports are usually inferior to the real arcade games, not to mention sticking my hand into a cab to swap discs hurt my arms pretty bad after a while.  ;D

Not trying to be a jerk or anything I'm just curious.

Hah it's ok. I guess I don't want to have too much emulation. It may not  be entirely rational but I like the idea of a game running on actual hardware. As far as home ports being close to the arcade no home consoles comes closer then on the Dreamcast. It even had a special function where if you used 2d, you could turn the 128 bit cpu functionally into two 64-bit cpu's to both read and write.

That and I'm also a big Dreamcast fanboy ;).

As far as arcade accuracy with older games, They come as close as any platform. I dpn't see any significant difference oin the neo geo ports either.  This discussion explains a lot http://www.neo-geo.com/forums/showthread.php?117207-Need-arcade-perfect-ports-for-Dreamcast.
So you have the naomi ports, which only might have less high resolution textures and some of the better ports of older 2d games. In order to get true scanlines a CRT VGA monitor would work fines with the hanzo VGA box which has the option of half scanlines/scanline wthickness. Since you get some scanlines on a 31k hz vga monitor, but you need half of one added for the higher resolution to get as close to true scanlines without buying an expensive actual arcade monitor.

https://www.youtube.com/watch?v=XiCsiZFs6DE  (a very bad game to use a scanline generator on, older pixel games are much better to show the difference).