Even tough what @Amiboy says is true, i can tell about my personal experience.
I have never ever seen a different mobo revision other than 1D4 in this part of the world (Argentina)
I have seen about 60/70 Amiga 1200 and belive me, ALL were 1D4.
My own Amigas (i have 4 A1200) have been tested succesfully with either a 040/060 and/or PPC cards & BVision cards
I never in my life suffered those timing issues problems
Maybe i was lucky and my mobos were already fixed?
IS there a way to know if the time fixing was made?
I can take some pics of the mobos and post them here if that helps
Cheers
Sebastian
