My RCA LYRA rd-1080 does not allow sound to come out of the left earphone. I know this isn't something wrong with the headphones, because I've tried more than one pair of otherwise working headphones. If you know how to solve this problem, please respond soon.
Are you handy with electronic repair? Do you know how to use a soldering iron?
If you can say yes to both questions, then you need to open your player and check the connection to the headphone jacks. Resolder any loose connections.
If the connections are okay, then check the way your music was encoded.
You must be very handy with electronic repair, since all of this may be surface mounted parts, you must be very careful and patient, the problem must be a cold spot on the soldering terminal...