The MA6100 has a speaker balance feature on the same bass stick (same for trebel), so as to apply the bass more or less on one speaker vs other. The design of the stick is such that there are two concentric sticks one inside the other which allows to rotate the balance or bass independent of each other. I think the grease or oil between the two concentric sticks has dried out, so now if I rotate the inner bass knob, the outer balance knob also rotates, which should not happen. For now, I hold the outer knob and then rotate the inter bass knob so as not to affect the balance. Any idea if oil/grease is the right thing to apply between the two concentric sticks? If so, which oil/grease and how to apply it. Or is there another solution to this?