I found a fairly new (September 2008) Hello Kitty boom box; has the option to play cd's and cassettes. It works fine, powers up, etc. but the only problem I am having is the volume knob does not adjust the volume. When the unit is on it basically is set to "very loud". The knob does turn and I can see the POT turning. When I turn the knob I don't hear the volume change; I also do not hear any pops or cracks to indicate a dirty POT. I did spray some electrical contact cleaner inside the POT but that did not seem to help at all. Any suggestions?