[old_tv_nut]

You asked about component, not composite - so, the answer depends on the particular set circuitry. You would inject the Y signal the same way as injecting a composite signal - following the video detector stage. Besides isolation, you may need some amplification if the normal video detector output is greater than 1 V pp.

Doing the Pr and Pb would depend on having appropriate R-Y and B-Y points. You could probably do this in most tube sets that use either R-Y/B-Y or X/Z demods, but you may need some amplification and/or adjustable levels to get the color saturation normal.

A set using separate R-Y, G-Y, B-Y demods (usually diodes) would not take the Pr, Pb directly unless you are willing to accept strange results from not having G-Y.

As N2IXK said, do NOT try this on a hot chassis set.

[Edit - we're talking tube sets or solid state with discrete components. Later sets that used IC demodulators may not have any accessible point to inject Pr and Pb.]