Samsung DLP Buzzing

[ljacobs]

Hi all,
We have a Samsung model # HL-P5067W tv, and have noticed a buzzing sound coming from the back. The noise started out as an intermittent issue, and now is constant when the tv is on.(more like a hum when it is powered on) It has gotten progressively worse, and sounds awful when you power down the tv. (almost like a something getting caught in a vacuum.) The picture has not been impacted at all. From what I have been reading it can be the color wheel or fan, but I need to investigate further. Does anyone have any advice on the issue, as well as an easy way to troubleshoot? I have not pulled the back off of it, and would love hear from people on what to do, and more importantly, what not to do!
Thanks for taking the time,
L