Black spot on monitor

[lcdude]

Almost got my arcade cab running beautifully, however, now I've run into a problem I don't think that anyone else has had. (at least not finding it under a search)...

I was having problems with the screen "rolling up" on the bottom, so I found the 50-60hz pot and adjusted it.  I managed to fix that problem.  I also was doing some fine adjustments to the vertical rolling problem, trying to find the "sweet spot".  Most of the games were running fine, however, I tried to load up Smash TV, and a black retangular box shows up on the screen. approx 1-2" by 1-2".  If I exit the emulator, there is no black box on top of the desktop.  It's only when I run the emulator.  Also, It's only on some games.  Not all of the games are affected.  Something also must have changed, as games which were playing without the black box just 10 minutes before firing up smash tv were playing ok, and now have the problem.  Has anyone else experienced this?  If so, what did you do to fix?  Thanks for the responses.

[mattv]

It sounds like a software problem to me, what emulator are you using?

Also, can we have some more details on your setup? ArcadeVGA, advancemame?

Also, try total carnage (the sequel to smashTV) and see if oyu have the same problem with that.

finally, are all the games that have this same problem running in the same resolution or refresh rate or something? or are they all emulating the same hardware maybe?

[lcdude]

Thanks for the reply.  The funny thing is that I managed to fix the problem about as strangely as the problem appeared.  It was definately a software problem.  I changed the resolution for one random game to something outrageous, then changed it back.  **poof**...problem gone.    If you want to know, i'm using mame32 .79 with an arcadevga in my pc.

[Stiffler]

If the black box is in the lower right corner, then this is the same problem that I had.  There is a bug in the ArcadeVGA driver and Andy is aware of it but hasn't been able to fix it.  He has found a work arround get rid of it. It has been a while since I fixed mine so I don't remember all the details. The problem happens with higher resolutions like 800 x 600. If you switch your desktop res to 800 x 600 and reboot, this should fix your problem.  But I think I had to keep my desktop res at 800 x 600 or the problem would come back. Andy said he even had this problem on his system but it went away.