When I turn on my surround system it works correctly for about 5-10 min then it will make a loud buzzing sound from all the speakers, I have to turn the system off to get it to stop buzzing... any suggestion ?

Check that speaker wiring is not shorted, measure speaker resistance if possible.
Maybe disconnect front speakers and try, then rear speakers, try again, also any center speakers to determine if a speaker.
If the buzzing is more like a humming, I'm wondering if you have a bad Electrolytic.
May be cold solder joint on the capacitor, could try moving very lightly for an effect to maybe help determine a bad joint.
Don't work inside the unit if not familular with electrical/electronics, Not only can you hurt or kill yourself, you may destroy some good electronics.