Turntable adjustment question

I have recently purchased a used Micro Seiki BL-51 table with SME tonearm and Grado Gold cartridge. It sounds fantastic; however, I think that the left channel is more predominate than the right. I love stereo equipment and know a fair bit about most audio equipment but this was the first good table I have ever purchased (and I know it isn't fantastic but I got the package for $350 and I couldn't rationalize getting a clearaudio champion or VPI scout for more than 4 times that cost when the Micro sounds as good as it does) I am pretty sure taht the left bias is due to an incorrect setting on the tonearm but I have no idea what to check or adjust and I don't want to start adjusting random things and end up worse then I was to start. The arm has an anti-skate weight that hangs on a fishing-wire-type line and it has several different counterweights on the arm that are adjustable. The cartridge also seems to have a bit of twist to it (I can move it to the left and right but I think I have it perfectly centered right now and still the bias is there) so that might be the cause. Anyone have any idea where I should start or as a newbie is this going to get so frustrating that I want to hurt someone and I should just take it to a shop who will charge eighty bucks for the adjustments?!? The other weird thing is that the bias only appears on some albums but those same albums on my Dual 1214 never had a bias! Please help!
First make sure the cartridge is properly aligned, using a cartridge alignment protractor, and then tighten up enough so that it can't move. Try not to break it while doing this. Re-check after tightening to make sure it didn't move when you tightened it. Use the medium range of the recommended tracking force for the basic alignment process.

Once it is aligned, then go ahead with the final tracking force settings, and the anti-skate settings.

It sounds to me as though the anti-skate is too much. So you may have to back it off a little and listen each time. But first make sure all the other stuff is correct. If you look at the cantilever assembly from the front, while playing a record, you should see that the cantilever is centered under the cartridge. If it is angling to the left or to the right, then you have to adjust the anti-skate to correct it.
Check the cartridge's azimut.
It's also possible that one channel of the cartridge has slightly more output than the other. If you try everything that TWL has suggested and you still have the problem then a channel imbalance in the cartridge is quite possible.

The solution, of course, is a new, perfectly-balanced cartridge (nothing's ever perfect, is it?).

Why not do what I do? -- I just shift my listening position left or right a few inches to compensate for such imbalances, some of which are recording related, anyway. In my system, I think that there is a slight channel-balance difference between my CD and LP sources, so once again, I just shift my listening position as the source and recording dictates. You could also move the louder speaker closer, or the quieter speaker further away. There are really so many simple solutions to this problem. Pick one.
Pbb is right on azimuth.
To adjust it by-ear you can use either mono record or Chesky sweep record that has tracks to adjust azimuth by ear.
Don't know it it was mentioned, another thing is to make sure the turntable is level side to side and front to back.
I don't think that azimuth is adjustable on that table. You can check it for vertical, but if it is out, you may have to shim the cartridge where it mounts to the headshell. Hopefully, that is not the problem.
Swap cartridges with the Dual and see if it still happens. It could be the cartridge.
also, check all connections. i had a similiar problem not long ago, and discovered only after checking everything else that one of the interconnects going to the phono pre was not fully connected. sometimes it's the most obvious things that are overlooked.