An A1200 can run 31Khz modes (vga) if you
copy the "multiscan productivity", "dblntsc",
"vgaonly" and "dblpal" monitor drivers from
sys:storage/monitors into devs:monitors/
However you will have to select a 31Khz
screenmode in the prefs and save it before
you can use these modes on a VGA monitor.
This will only work with system friendly
software though and not booting game floppies
or similar. It's fine for running most applications
and you should also set "modepromotion" in
"Icontrol" prefs for better results...