image on tv goes green

I have a large Samsung DLP that has started to ocassionally flash to black outlines on a bright green screen. It looks almost like a solarized photograph. This occurs independent of source - both on DVD/blue-ray and on satellite TV.

This might occur once in five or ten hours and might last 5 to 20 seconds.

Any tech types out there have a guess as to what's going on here.

Thanks in advance.

Marty