I guess that makes your notebook a Rev B, and maybe that's already the answer for the sound issues. Your MacBook uses a Core 2 Duo CPU, and the one we have here has the older Core Duo processor. There are probably some other differences between the two versions.
By the way, you can use the "Apple" menu, select "About this Mac" and then open the System Profiler to learn more about your machine. The revision code is usually printer on the bottom of the machine.
By the way, you can use the "Apple" menu, select "About this Mac" and then open the System Profiler to learn more about your machine. The revision code is usually printer on the bottom of the machine.