Indivision ECS - Pulling my hair out

[paul1981]

Is it possible you could record a video of the actual fault so we can all see what we're dealing with? If we could see it, some people may have a good idea where the problem lies.

[paul1981]

Could it be dirty mains? Either on the A500, monitor or both? Do you have any interference in your vacinity that you know of?
Is there any way you could test your kit somewhere else? Like at a friends house?

If you've tried a different motherboard, different monitor, and AmigaKit says the Indi is okay, then there's a good chance it is.

How about your monitor cable? Could you try a different one? Or have you already?

[paul1981]

Could you try your kit in another room and without the plug board? Or try a different plugboard. If same, I'd take it along to a friends house and hook it up to his/her monitor and see how that goes. If it works at your friends, then there could be mains or RF interference at play in your house.
Have to admit, it seems unlikely, but I don't know what else to suggest.