hi, if you are reffering to the cd player section, then check the program or repeat feature. make sure that none of these features are enabled. if this does not help then activate the "master reset" procedure in your user manual. lastly check beneath your unit for any transport locks/screws applied to the cd mechanism. cheers.
It is possible you missed a connection and did not realize it, the only way to be sure is dis-assemble the unit and carefully check your ribbon connection that it is secure.
The problem you are describing is typical of audio output ic problem when there is a high current load the protection circuit kicks in preventing further damage. But lets check a couple things! turn down volume, power off, and remove speaker wires from the back. now power on, if protection kicks in the audio ic needs to be replaced, if it powers up properly checks wires for shorts and speaker issues and hook up one at a time until protect comes on revealing the problem.
mechanical error. a moving part is either broke or physically jammed. remove the cover (dont touch anything inside) and look for broken or jammed pieces, ssuch as gears or belts.
do not get your hopes up- you will probably not be able to fix it, and it will probably be too expensive to pay a professional to do it for you. the player is probably trashed.