you will not like this answer.
I do not have a solution for the mini converters that you own. Perhaps the Kramer will work – certainly a custom generic 12VDC power supply with a custom cable breakout would work.
These are the Blackmagic solutions –
1) buy an OpenGear chassis and the Blackmagic cards that fit into this chassis (Analog to SDI, SDI to Analog, etc.). Then you have a very clean installation. Of course, this costs more money, and of course, you already own the existing converters.
2) use the new (unreleased) Mini Teranex converters. All of these new converters use a normal power cord, and can also be powered from a POE ethernet switch.
Bob Zelin
Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com