DBX 162 ouput levels unbalanced

[the riff]

I have an old DBX 162 where the level of the right side is coming out about half as hot as the left. I have tried running test tones through it to make sure it wasn't just the mix, tried different cables, etc and still nothing.. Anyone ever have this problem and have any suggestions? I'm willing to take it in for repair, but thought I'd ask first...