Arcade VGA. stable in desktop, but rolls in selected games.

[danny_galaga]

So I finally have this thing running. Having trouble making it stable for everything though. If I adjust the arcade monitor so that it stops rolling in the windows desktop, then it starts rolling in a game. Different speeds for different games. I've found if I select a really low res for the desktop from the arcadevga resolution list, then it is stable for a select number of games that are also low resolution. If I then select say, Metal Slug it will roll again.

Is there something I am forgetting to do?

[2600]

Most arcade monitors do not autosync to different resolutions like a PC monitor does.  You either need to find a sweet spot on your sync pot with a few select resolutions, use a fixed resolution, or adjust the sync pot every time you switch resolutions.

[danny_galaga]

So I wonder what the point of this arcade vga is then? If I have to use a fixed resolution, what's all those other resolutions for?

Edit: I think I might just use a fixed resolution and let MAME work the same as it does on a PC monitor. So basically I'll have an RGB monitor. I know that means it wont be pixel perfect but honestly, none of this is what I thought it would be. But I didn't know to ask for these things before I started. Live and learn…
(well, in my case I'll probably forget and make the same mistakes, over and over  )

[danny_galaga]

Ok, did a few fixed resolution experiments and it actually looks fine (",)

Just have to decide on where I want to compromise. But I notice there isn't such a huge range in the games I like as I first thought.

[Malenko]

Ok, did a few fixed resolution experiments and it actually looks fine (",)

Just have to decide on where I want to compromise. But I notice there isn't such a huge range in the games I like as I first thought.

You need to manually force some games for better results, have fun with Mortal Kombat. I cant remember what the "magic resolution" for that one is, but I remember helping Lew with it years ago.

[2600]

So I wonder what the point of this arcade vga is then? If I have to use a fixed resolution, what's all those other resolutions for?

Edit: I think I might just use a fixed resolution and let MAME work the same as it does on a PC monitor. So basically I'll have an RGB monitor. I know that means it wont be pixel perfect but honestly, none of this is what I thought it would be. But I didn't know to ask for these things before I started. Live and learn…
(well, in my case I'll probably forget and make the same mistakes, over and over  )

There are hundreds of different types of monitors and not all of them work the same way as yours.  Some support all of those resolutions and people use the arcadevga for an easy way to use all those resolutions.  Some have a more fixed frequency monitor and use an arcadevga to have an easy way to drive an arcade monitor which it looks like you've now done. 

There are 100's of ways to get from A to B and not everyone wants or needs to do it the same way, but the way that is right for them.

[danny_galaga]

So I wonder what the point of this arcade vga is then? If I have to use a fixed resolution, what's all those other resolutions for?

Edit: I think I might just use a fixed resolution and let MAME work the same as it does on a PC monitor. So basically I'll have an RGB monitor. I know that means it wont be pixel perfect but honestly, none of this is what I thought it would be. But I didn't know to ask for these things before I started. Live and learn…
(well, in my case I'll probably forget and make the same mistakes, over and over  )

There are hundreds of different types of monitors and not all of them work the same way as yours.  Some support all of those resolutions and people use the arcadevga for an easy way to use all those resolutions.  Some have a more fixed frequency monitor and use an arcadevga to have an easy way to drive an arcade monitor which it looks like you've now done. 

There are 100's of ways to get from A to B and not everyone wants or needs to do it the same way, but the way that is right for them.

Yes, I think I have found 'The Way' for me 

However, I posed the same question on the Aussie Arcade Forum, and one guy (who lives in the next suburb) is not as happy with my decision as I am. To quote

Danny, if you go with a fixed res, I am coming to your house, kicking in your door and fixing it myself. I KNOW WHERE YOU LIVE!

You are wasting your AVGA if you don't use proper resolutions! If you keep it at fixed res, you would be better off using an LCD.

 

Anyway, for now I am happy going fixed because it means mentally I am ready to continue with building my cab. I am quite linear in my thinking and I really needed this to be ok for me to proceed. Just how I am. Once the cab is completely finished, maybe then I can play around with Groovymame etc...

[AndyWarne]

If the monitor is rolling in certain resolutions, the V Sync control just needs to be tweaked to find a setting which works at all resolutions.

[RandyT]

If the monitor is rolling in certain resolutions, the V Sync control just needs to be tweaked to find a setting which works at all resolutions.

Whether or not that works is going to depend on the range of the VSYNC control.  Some monitors can do this, while others can't.  Sometimes in order to get a vertically stable image, it's necessary to tweak the mode parameters, and live with a small bit of cropping.  The alternative to cropping is adjusting the vertical size control, which can lead to squashing the image in other modes.

Getting a usable image with all modes on a fixed frequency monitor tends to be a "pick your poison" scenario, but usually one can find something they can live with, even if not ideal.

[Tithis]

I've gone about modifying my monitor to somewhat resolve an issue like this. For my size pot on my remote board I have a switch and resistor bridging the legs. I normally keep it on a middling height for 224 and 240 line games, but with the switch flipped it it shrinks it down for rotated 256 line vertical games like DK and Centipede. Later on down the road I'm probably going to make it controllable by the computer itself.

I know the k7000 vertical hold pot is acting simply as a variable resistor. In it's case you would need to find the setting needed for your games and find out which of a couple settings is the one that uses the highest resistance on the pot. Then you could just experiment with a range of resistors that will act like resistors in parallel with the pot. You'd have to look at the schematics of your monitor to see if it could be done. 

[AndyWarne]

I have never come across, or heard of, any standard resolution monitor which will not lock on all of the resolutions the ArcadeVGA card sends, when the correct setting of the V Hold control has been found.

[danny_galaga]

*slaps forehead*

I am running the AVGA through a Jpac. Because I hadn't hooked up any controls, I didn't think to hook up the USB, which of course would power the video amp! It's working much better now, and of course more brightly

As it stands it's looking pretty good. I'm going to leave it as is for now and down the track try to set it up properly. But for now it's on to the touch controls (",)