When I am scanning banks no problem, but when I tune manual to a three digit channel I have programmed, after about two seconds, it just shuts down completely! I have to turn it off and back on to get it to work, if I go back to scanning it stays on, if I leave it on the manually tuned channel it shuts off everytime, am I doing something wrong or does it sound like something has gone wrong? I hit manual, three digits, then manual, then it shuts down. thanks.