Hey thanks for the thought! It was a weird set of circumstances but it seems to be happy (no blackness anymore). I tried the following:
1 - swap the cable from HDMI 2 to HDMI 1 (still problems)
So I grabbed a different HDMI cable that I already had...
2 - use the new HDMI cable in HDMI 2 (still problems)
3 - swap the new cable over to HDMI 1... and its been fine ever since!
I guess I'll find out if HDMI 2 is also having issues as I've now got my PS3 hooked up to it. I've got my fingers crossed.
Weird combination from my perspective. But I'm just happy that its working again!