Ok....Help from the experts...

I adjusted the VTF (to 1.85) and that did it. Thanks gang!!!!

make sure that nothing is catching mechanically. occasionally you see this when the arm tube catches the arm lift or the arm housing catches the bearing housing on a unipivot
just watch the arm and the bearing housing when it's playing

Referring to LTA?... Best checked with something like Wally tractor tools. Simple way is make sure the arm is adjusted by checking as recommended by VPI..This is done before cart. mounting and is adjusted by the ring which sits at the base of the 10 arm..I dont know if the 10.5 does away with the ring..You should be able to call VPI with info. Basically you want to make sure the arm while unmounted, doesn't "tilt" to one side on the pivot. The Head shell should look perfectly straight and completely paralell to the platter surface. Then you can mount the cart, and go from there. But definately check the VTF first to see if that solves your jumpiness!

Ken

Thanks Ken..I will check the VTF. BTW...how do you chack and adjust the TTA???

Thanks again!

There are better experts than me....but Most likely VTF..The downforce tracking in gram weight is what keeps the stylus tracking properly in the groove. VTA will not be a key factor here unless it is so grossly off. Without knowing how old the Helikon is, I can't be sure of its use for worn sytlus, which will lead to untrackability, but if the stylus is in good cond., you have to suspect VTF as the problem. Have you used a stylus guage like a Shure or something to measure it on set up?...If so, you may want to check again and add some downforce weight. The Helikon should track well starting about 1.8-2.0 g and 2.2 is not unusuall in that arm as a Unipivot design. BTW.. Lateral tracking angle (LTA)where the cart is skewed from true perpindicular to the record will also cause a problem.. Hope this helps-Ken :)