My Mitsubishi HC900 has been acting strange lately. Sometimes when I press the power button it starts up just fine, but other times it doesn't. After pressing the power button, the power light will turn green and the fan will start but in less than a minute it shuts down again. Sometimes I have to go through this 3 or 4 times before it will remain on, and then it's fine for the rest of evening. The problem only occurs on the initial start up. Anyone have any ideas?