I have a very nice Technics turntable (from the 80s/late 70s most likely) that had a bit of a problem. It plays LPs and 45s perfectly fine, but it always lags. You know how the dots on the plate thing are supposed to stay in one place? Mine move around about every 3/4 second. I will take a video and post it later.
Look for your manual on vinylengine.com, or one similar to it. Or do you mean adjusted all the way, its still wont stabilize? If that is the case, some minor repair is in order, not uncommon on a lot of older direct drive tables.