It's not a great sign. You don't mention the make or model.  But I had a similar problem. I had a 52" RCA rear projection tv.  It would do this when I initially turned on the television, but then after a few "on/off, on/off, on/off" cycles it would stay on. Eventually it started doing it more; until … Read more

I've got bad news for you. Your power board is about to 'fry & die'.
It happened to me a month ago with my 3 1/2 yr old RCA model D52W27D (6 months after my warranty expired).
It will cost about $400 to repair.