First time posting on this forum.  Found the RX 5030 in a garage sale yesterday.  It was very dirty from storage.  After cleanup and detoxing the controls, found that the left channel plays very weak and no amount of Deox helps.  If the balance knob is hard left, I can hear it very weakly, but it gets overwhelmed by the right channel without much moving the balance knob to the right.  It doesn't seem to be a speaker issue as I hear the same problem when using headphones. Anyone have any suggestions on what to look at/fix?

It has other other issues with tuner alignment and I'm not sure if the multiplex works, but I need to resolve the weak channel issue first.

If anyone has a source of a service manual, I would appreciate that information.

Thanks