blank screen while gaming on Panasonic plasma?

[J.P.]

I have a Panasonic TC-P50S2 television and when I play my PlayStation 2 or Game Cube(only non-HD systems I've tried), if the game displays a mostly white screen the TV screen goes blank, showing the video1 input box in the upper left corner as if the signal was lost. Wondering what would cause this and how to fix it...