Musical Fidelity X-10v3 Problem.....

I am experiencing a problem with the left output RCA not working. After troubleshooting with different I/C's placed on this output jack, the issue still seems to be something with the actual RCA jack. Have I disrupted something internally? All other functions of the unit perform flawlessly... Any idea where to go from here? I have this placed Pre>X10v3>Amp. Thanks