So I purchased a Pro-107 a couple of days ago, and I am very close to taking it back. The reason is that the one channel that I really need to monitor won't come through. It is programmed into the scanner, but when I go to the frequency, it doesn't play any tones or voice. Not even static. No sound at all. I have no idea how to fix this, and I am a Mac user so I can't use the software that came with the scanner. Any help ASAP would be appreciated. Thanks.