I may put this out as a kit at some point. It is much better for one person to buy a lot of the cables and jacks needed for this mod than for others to buy them individually. For example, it is like 2$ worth of parts in bulk or 8$ in parts in a single unit.
People should do their own due diligence for this one. I made this based on math (http://tinyurl.com/y2eaw5cu)but I am not an EE and generally have no idea what I am doing. If someone has a better version that I can incorporate under the same license let me know. The Op-amp used (LMH6682) allegedly can go beyond the rails. I also wanted to try the MAX4392EUA+ but it doesn't go beyond the rails. Clipping if it were an issue would be on the bottom end. Pb with max Red, Max Green, and Min Blue. Or Pr with Max Green, Max Blue, and Min Red. This clipping should only be possible if you are feeding it 2V RGB and not 1.4/1.428V RGB. This is designed to be on the output of an op-amp that splits to provide RGB outputs and interface with this for YPbPr outputs. Y should have the same scale as RGB not counting Sync.
The major caveat here is that RGB and Y are not buffered together and maybe delayed from one another by the delay of the THS7374+LMH6682 (RGB) Vs the delay from the BH7236AF (Y). On testing, I didn't witness an issue on my TVs.
In situations where you have RGB and a clock but not Y this can be used: https://easyeda.com/hotdog6394/bh7236af-rgb-to-y-c-cv-and-ypbpr-expansion Which is the same circuit that is going on here pretty much. Those outputs should be matched delay wise except for the delay of the LMH6882. In regards to the BH7236AF, I have used that circuit to get CV, Y/C, and YPbPr but have not tested the actual voltages only eyeballing the video on my TV.
|19||220UF||C6,C7,C8||C1411 WITH JUMPER||3|
|21||JUMPER QUAD BRIDGE||SJ1||QUAD JUMPER BRIDGE||1|