AGA 4000 and games issue

[Matt_H]

Does the monitor support 50Hz? Do other PAL display modes work? The Indivision has additional circuitry to bump 50Hz PAL modes up to 60Hz to be displayable on pretty much any monitor. Older scandoublers don't do that since they were designed with CRTs in mind, which handle 50Hz no problem.

Other possibility: do you have an RTG card? CGX (and I assume P96 as well) has an option to automatically enable 56KHz Paula audio modes through some chipset tweaks. I've found that this setting messes with scandoubled video modes. Turn it off.

[Matt_H]

Make sure DblPAL, DBlNTSC, and VGAOnly are not in Devs:Monitors. In fact, make sure all you have in there is NTSC and PAL. Something could be amiss with mode promotion and disabling those modes will prevent that.