Jon,
I have just posted about the exact same issue. Brand new machine and card, blacks out when using SDI from DigiBeta.
I have no solution yet, but noticed an odd thing. If you hold the BNC connector at the back of the machine the image holds with no drop-out. This suggests some kind of “grounding” issue.
It’s seems to work when you go in component, but the sounds drifts out of sync.
I’m already beginning to regret my option to go for this card, it’s costing me time and money already :o(
Keith