I guess we shouldn't post any longer to this thread, because Inna is bored, but I was rather surprised to read that go4vinyl and Raul suggest the problem of unequal gain in one channel vs the other could be due to azimuth maladjustment. In fact (this has been said many times too, Inna, so you can stop reading here), azimuth has very little effect on channel balance and adjusting azimuth is not a good way to address channel imbalance.
As to why the OP perceives that AS is affecting channel balance, it could be because badly out of whack AS is inducing distortions that are perceived as more or less output on the affected channel. Just a guess. Cleaning all mechanical contact areas, as Raul did mention, is a good idea.
I agree with a few others who stated that AS should be adjusted while playing music with the stylus in the groove, not on the run-out or grooveless surface of an LP. Since skating force is due to stylus friction in the groove, a smooth patch of vinyl does not generate a force that is representative of the problem. Almarg's method for adjusting AS seems fine; I just don't have the patience or the visual acuity for that. I am not quite in Stringreen's camp, either. I just set AS to the most minimal value possible, and then I forget about it.