I have a small Inn and decided to put CD's in the MCR230SL Clock radios. When I did I discovered that while the clocks/alarms work, I could get none of them to work for radio or CD. In all cases the AM/FM/CD selector was in the right place, the power button illuminated, the sound was turned up to max and in the case of the CD was spinning. But no sound on any of the 8 units. Seems odd. Can you help?