How to setup on turntable

I have problem on Thoren 318 MKII turntable. Somehow the sound of one channel has less sound and more humb. I opened turntable and try to see inside. I wonder that if I want to setup or install the arm, catridge or niddles. How can I start from ground up? I do not have manual to setup or any idea to do it. Can you explain how to setup? Maybe learn to setup. I use Sunfire amp and processor to setup. Any way to buy or look for manual 318 MKII.
It seems to me that, barring a defect in the turntable itself, the first thing I would check is the connections at the cartridge, ensuring their tightness and phase.
Good luck.
You cartridge needs alignment, you need to adjust the Azimuth, the cantilevers perpendicular relationship to the record groove. Put a small mirror under the stylus tip and look for a perfectly straight line through the cantilever and its reflection. If there's a bend in the reflection at the mirror, the azimuth is wrong. Some tonearms are designed to allow ease of azimuth adjustment; those that aren't require you to insert tiny shims between headshell and cartridge.Azimuth alignment is vital to correct left-right channel balance, and consequently to soundstaging and imaging. Azimuth can als be checked with a dual-trace oscilloscope and a test record. With each channel feeding one inpute of the 'scope, play the test record with a pure tone.Perfect azimuth alignment will produce identical amplitudes from both 'scope channels. If any of this in not understood, save yourself a problem and take the complete turntable arm and cartridge to your local high end shop and ask for their help. Good Luck, Rob
Thanks. I will try do it now
I would give Jeff @ audible arts a call. He's a terrific guy and will help out with your setup. I don't live in San Jose anymore, but he was the only dealer that didn't throw a certain brand or upsell me.