There are HDMI to component (720p) converters out there, but that's not what you want. If you truly have an old school RGB CRT (RGBs not YUV/YPbPr), it won't work.
First off, what kind of RGB monitor do you have? Some won't take component correctly without other gadgets in the conversion chain.
Have you tried connecting a Wii or Xbox 1, etc with component cable outputting 480p to your RGB monitor? If yes did it work? Sometimes even 480p doesn't work (you get a "double image"). However 240p would work, but you would need more "exotic devices" to give you 240p. On the other hand, the OUYA menu may not be usable at that res.
But 480i should work every time. That's why it's safer to just go with something that will *transcode* it down to 480i. All of them should work that.
Bottom line... based your monitor and model number, there will be experimentation and possibly buying things that may not work. So I'm hesitant to do that. However I do know what is guaranteed to work. At this point I would just recommend to go with an HDMI to s-video converter.
Yeah that's a Sony PVM RGB monitor. I love them. I think I've got 7-8 of them now in different sizes. One of them is NOS complete with box. Others come in really neat travel cases. I also got an RGB CRT from Japan that accepts a J21 RGB input (similar to EUR SCART) and some other RGB monitors. Got a closet full of diff converters/processors, home theater grade stand alone video processors and those Micomsoft XRGB processors.
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