Try a tape you know has good TC (VERY important)Verify that the 75 ohm terminator is attached to one of the parallel Vid Ref JacksVerify all connections (as outlined above)Verify configuration in the session setup window (frame rate and sample rate, positional reference and clock reference). Verify configuration in the peripherals window (synchronization = USD; port = Digiserial)If all else fails, trash the DAE prefs folder, Digisetup and Pro Tools preferences in MAC Hard Drive > System Folder > Preferences folder.