The problem seemed to be trying to output 480i from the Mac. Thank you Daniel for the extensive testing! I reviewed your response as soon as you posted it but forgot to send a 'thank you' so I'm doing that now. So perhaps look at changing output of the MBPro to 720p or 480p (am guessing currently doing 480i but that is a guess!) Did not appear to be any consistent reason for that. I did find that with both converters performed inconsistently. Sorry don't have time for more extensive testing. Have used it with windows laptops, this is a desktop. It was not powered by that machine, which may be an issue. Plugged into DVI extender it worked well (initially but then didn't) Did display at start up but then would go away and could not get it back. plugged into the HDMI to SDI converter, did work but had to fiddle to make sure the resolution was right (1920x1080i, 30Hz but could be machine dependent)

I also tried it on a windows machine with a Display port to HDMi lead.

Also tried 720p and 1080i at 50Hz and 1080p at 30Hzįound 720p was the best setting both devices (but that may have to do with our configuration going to a vaddio mixer and then crestron system) Found the following:ġ080P- black screen at 60 and 50 Hz, worked at 30Hz didn't look greatġ080i- worked but looked terrible at 50 and 60 MDP to DVI adaptor, then used a DVI to HDMI socket then an HDMI lead. Tested on a HDMI to SDI mini converter (sorry only have a battery model). So there are some definitive settings difference and graphics card differences First thing tested on a new iMac running 10.8.2.

Blackmagic matrix