Having issues with my DJM 400 mixer

Hi

I'm having a issue with my RCA ports both outputs ( master output and the other beside that ) on the mixer on the middle meter it shows left and right at the same level but only the right side comes out through my stereo also through my mini disc player and my laptop I'm not sure what the problem is a friend of mine said it could be dry joints I haven't a clue about the inside of this mixer does anyone know of this happening or has this happened before please someone help me feel lost with my music

Thanks Gary