I would say check your squelch setting. It may be set just high enough to not break the scan cycle. Other than that, check your antenna connections. Maybe something has come loose. The only other thing I can think of is if your local dept. changed their power output on their transmit tower and you are not receiving it as strong or they changed the tower they are transmitting on to a different location that is farther away from you. Hope this helps.
I have a BCT15X scanner and it works very well. I am very satisfied with the performance I get. Good luck.
Actually I think it's a scanning issue, since you hear the frequency if you put it on the channel manually. Did you create a group under a system, put the frequency in, then create a System Quick Key and Group Quick Key for it?
If you don't understand what I just said, this will help...
Thankyou all for your help I figured it out there's more than one way to lock channels out I went an unlocked everything I don't know what I locked but it works lol thanks again all very helpful site here