Samsung HL-R5078W, buzzing, not lamp

[mitchwell]

I have a Samsung 50' tv that stop working, and there is a big humming sound, like "waa, waa, waaa"..sounds like it's gonna blow up. I tried replacing the bulb with no success. What could it be?

[grayfox]

Hello,
That can be one of three things, Colorwheel, Ballast or maybe even a Cooling Fan.
If it is more of an electronic arcing sound it can be the ballast, If it is more of a mechanical grinding humming or even screeching sound this would be your colorwheel...