Ok that clears a few things up. But conclusion is the same, symptoms indicate a sync issue (since it can misinterpret the interlaced signal which should be pretty much standard coming from a video camera). I’m curious though, when the ossc locka onto the interlaced signal, there really is no picture on the capture card, or on any other display?
Possible I guess that there is some sync shenanigans going on in the control unit. If it’s altering voltage level that may be a bad thing.
Didyou try playing with the sync settings on the OSSC at all?
Any chance of getting hold of a manual for the control unit? Perhaps you can take a picture of the back of the unit so we can see the output labels?
Just as a note, for best result I think you should capture in passthrough so you can do more advanced de-interlacing afterwards. The ossc bob-deinterlace is not suitable for normal video camera content at all.
Sorry for the many new questions, just throwing some ideas out there.