Audio Systems: Phillips 3440 Home theater Popping noise at startup, rca cable, loudness

Question
When I turn on my Phillips 3440 home theater.  I get a loud popping without any other sound.  In the beginning it was just a few pops but now it lasts for several minutes.  If you turn the sound off the popping goes away.  No other sound is heard until the popping stops.
Any ideas as to the cause? Is it worth trying to fix?
I would appreciate any help you can provide.

Tim

Answer
I will assume that this popping is coming from the sub correct?  I'm not familiar with your specific model so I need to ask a few questions:
1) Is the sub a powered sub?  (Are you using an RCA cable to connect it and is it plugged into the wall separately?)
2) Is the loudness of the popping effected by the position of the volulme control?
3) Any other symptoms after the popping stops?

Thanks,
Dan