Yes, I have a thought. Get yourself a RPTV with VGA/RGB input! Failing that, you'll need to use a RGB to component transcoder cable; you won't use the loop-back in this case, and you'll have to run a component cable into each of your two HD component input or use a component video switcher if you have only one open input. Your experience with using both the loopback cable and transcoder cable sounds weird to me, but anyway don't use the loopback cable when you use the transcoder cable.
On my set, I use the VGA loopback cable and run a single VGA cable into my set's VGA input.
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