It’s possible that:
1) Cable is defective, too long or of bad quality.
2) Potential defective Intensity Pro card. (you’ll need to swap it out)
Have you tried another HDMI cable or the current HDMI cable with another device like the output of a camera or something?
If you use Media Express to play something out? Do you get anything?
View > External Video in Final Cut Pro set to “All Frames”?
regards
Kristian Lam
Blackmagic Design