The Samsung Galaxy Camera is a point and shoot camera that uses the Android operating system. The camera features 21x optical zoom and a 16 Megapixel sensor, as well as Wi-Fi, GPS and cellular connectivity.
Since the sound is not working while built-in microphone is on, then the internal microphone might be broken and needs to be replaced. Follow Samsung Galaxy Camera troubleshooting guide to take the camera apart and replace the internal microphone. Troubleshooting guide