Mac Pro 2x2.8 GHz Quad Core Intel Xeon, 10 GB RAM
Mac Os X 10.6.8
Multibridge Pro 2
Software (checked in order) - Multibridge pro for Mac 9.7.2; 9.7.1; 9.5.3; 7.9.4
The problem is that device is no configurable in System Preferences/Blackmagic (all inactive - there's inactive settings: Set output: All Outputs Active; Set input: SDI Video & Sdi Audio etc.).
No comunication via input output (Final Cut Pro 6.0.6, Media Express) .
When I plug it via USB, in Blackmagic Multibridge Utility I can change settings for Bi-Directional Converter. As device there is Multibridge Pro.
When I try to run LiveKey - information appears: Blackmagic LiveKey requires Decklink hardware instelled.
The problem occured when I was change settings for device in System Preferences/Blackmagic Design from component to SDI (Multibridge 9.7.1) and connected Panasonic AG-AC 160 via SDI. From this time I cannot work with Multibridge Pro.
Fan is working as usually, there's still white power light. Everything is connected in a right way.
it is not probably your case, but the PCI-E cable and HBA have the same DVI-I connector of the GPU, so sometimes anybody can plug the cable to the wrong PC port or use a wrong cable (It is similar to the DVI but BMD recommeds to use the dedicated cable only).
Be sure to unplug the USB cable, otherwise the PCI-E doesn't work.
Other problems could be on the internal PCI-E adapter card (have you tried to clean the contacts or to swap slot?) or in a damaged PCI-E cable.