I found a couple of games not working with my Indivision ECS but come up fine through RGB/S-Video adapter.
Can't remember the titles off the top of my head has been awhile.
Using the Indi sound would work but no picture, flick it over to the RGB out and there's the picture :-)
Thought I'd mention that as you all seem to be using Indi's, although doesn't the 3000 have an onboard flicker fixer?