I need some ps3 help please.?

My ps3 is supposed to be on hdmi1 but there is only sound the tv is black. Yet I can see the game on component1, yet I can't hear it. The things are all plugged in and in the right slot. The tv has no problem because the other channels are in color. I think my babysister has broken it or something. It is a plasma tv. If you can help me, what could the problem be.