I just picked up Contra 4 for my brother as an x-mas present. He has trouble with there being no sound comming from the system while playing. Occasionally he'll start the game up and it will actually work from time to time. I'd say about 80% of the time there is no sound at all. Anyone else have trouble with this? or do you think it could just be a defect? as far as I know, sound works for all his other games.