Error Detection, CD changer

The radio displays CHECK CD # if any of the following conditions exist:
^ Moisture impairs the focusing mechanism
^ A tracking problem occurs
^ A servo problem occurs
^ A disc has been inserted into the cartridge tray with the label surface facing down

CHECK CD # remains lit in the display for 5 seconds, along with the normal information.

If you insert CD upside down, the following actions occur:
^ CHECk CD # is lit in the display
^ The next available disk in selected and begins to play

CHECK CD # will turn off under one of the following conditions:
^ 5 seconds expire
^ The CD is reinserted correctly
^ The radio becomes the active source
^ Another radio mode is selected

CHECK CD # display does not light unless the following conditions are true:
^ The CD changer is active
^ The CD changer is in the play mode