Hi,
I used this to configure Groovymame:
To get GroovyMAME working with ArcadeVGA 3000,
1.- Create an empty folder, place GM's executable inside. Launch it from command line, with -cc to create mame.ini. Enter mame.ini and edit as usual to point your roms path etc. Don't touch any other video option (syncrefresh, etc.)
2.- In mame.ini, set 'lock_system_modes 0', 'refresh_dont_care 1' -> these options are to deal with ArcadeVGA peculiarities.
3.- Start lauching games
Next to this I modified mame.ini for Monitor= custom and entered the presets from Calamity for a Hantarex Polostar. I use the monitor in Horizontal position. Also this was set in mame.ini
The old vertical games played fine like Donkey-Kong, Pac Man, Space Invaders, Galaga in perfect resulution. But when I choose Dig Dug or Frogger the monitor switches to a resolution that I can not lock/set manually.
What do I wrong for trying to play those vertical games on my horizontal screen in perfect resolution?
Thanks for helping me out.