Jama in Mame cab with high-res monitor

[tester007]

I have finished my Mame cab. I decided I definitely also wanted Jamma inside for newer things. So I bought a cable, wired it all in, and got a Xevious 3D pcb. When I hooked it up, I get a 'out of range' error on the screen. The monitor I am using is a multisync 19" Tovis gaming monitor which can go to 1280x1024. So I know it cannot go low enough for the game. It reads the signal at 16.3Khz.
So I have a couple questions.

1) I have seen expensive upconverters and want to see if I can avoid paying that much. So I found a 'DC VGA box' which is a unit that takes a signal from a dreamcast to use on a monitor. It takes 15Khz and converts to 31Khz. I am wondering if anyone knows if this will take all the odd jamma signals, like my 16.3Khz and still convert them to 31Khz or does it need to be exactly 15Khz? Is there anything else out there that will do the trick?

2)Standard arcade monitors (std res) obviously scan this low. Has anyone used a standard res, which I thought was 320x240 for Mame, and how does it work with resolutions higher than that? Do you have to set windows very low at first prior to hooking up and force everything lower? My onboard video cannot even go down to 640x480..

[tom61]

So I found a 'DC VGA box' which is a unit that takes a signal from a dreamcast to use on a monitor. It takes 15Khz and converts to 31Khz.

Incorrect, the DC VGA box puts a Dreamcast into VGA mode, it does not convert any signals, that's why it's so cheap.

Is there anything else out there that will do the trick?

http://www.russprince.com/cabinet/ has a way to do it using two adapters. click the 'Jamma!' link.

2)Standard arcade monitors (std res) obviously scan this low. Has anyone used a standard res, which I thought was 320x240 for Mame, and how does it work with resolutions higher than that? Do you have to set windows very low at first prior to hooking up and force everything lower? My onboard video cannot even go down to 640x480..

:/ This really tough to explain. The situationis much more complex than just resolution. Hopefully this page will help you: http://www.ultimarc.com/monfaq.html

[tester007]

Thanks, but I read that already and he states he is sending the signal out to a standard monitor, not upconverting it to 31Khz. The link states only for 15Khz monitors.. My problem is mine cannot go down that low so I need to increase the signal. I don't need a converter since I could wire my computers VGA directly to the monitor fine. It has separate H/V sync so is basically like a computer monitor, with a minimum res of 640x480

How can Jamma be standard, if I have an old game with CGA resolution monitor at 15Khz and I buy a newer Jamma game at 640x480? Am I missing something in that Jamma really isn't as super compatable as I think?(you can only buy Jamma games that will work on your particular monitor)

[tom61]

Thanks, but I read that already and he states he is sending the signal out to a standard monitor, not upconverting it to 31Khz.

If you mean the Russ Prince link, he is upscanning the signal.

How can Jamma be standard, if I have an old game with CGA resolution monitor at 15Khz and I buy a newer Jamma game at 640x480? Am I missing something in that Jamma really isn't as super compatable as I think?(you can only buy Jamma games that will work on your particular monitor)

Jamma standard is 15Khz 'standard res' CGA monitor. Most Jamma games use this. Jamma+ on the other hand allows a game to use a 24KHz 'medium res' EGA monitor.

Every standard res game uses 15Khz horizontal sync, by varying the vertical refresh rate, a game can have more or less resolution. A standard res arcade monitor has a max res of 640x288.

[tester007]

ahhh.. ok.. I bought 4 multisync high-res monitors bypassing all the standard res ones and I guess I shouldn't have then..

[tester007]

So, if I had gone the other way.. had built a Jamma cabinet with a standard monitor in it, and now wanted to add on Mame..
I can't think of any video card that goes that low anymore..is my only choice the arcadeVGA card?

[tom61]

The ArcadeVGA isn't the only solution, just the best one at this time. If you're willing to run DOS it's not to hard to get mame running on an arcade monitor with arcadeOS and an average card. Windows with an average card on the other hand is fairly difficult (compared to DOS or the ArcadeVGA), programs have  a much harder time to access the hardware to lower the dot-clock.