KDS50A3000 led powerlight flashes 3 red

Hello all, I have the Sony Bravia KDS-50A3000. When I turn it on the power light goes green then turns red and flashes 3 times in sequence. I have replaced the bulb. It still does it. I have tried researching the problem and have found differening solutions. One says its the lamp door sensor another says it's either the power board or logic board. I am hoping someone here can give me a more definitve answer. Thanks.