Sounds like maybe there is a misalignment between arm tube and arm rest? If so, adjusting the height of the arm rest, or the height of the arm lift, should fix it. Hard to visualize without pics, or knowing the arm model (at a minimum).
Turntable help
Good morning fellow music/equipment lovers! Dilemna: arm lock feature operates as should without arm in place. That is, it slides over to full lock position. However, when I return the arm to resting position, the arm latch doesn't full go over the arm to completely lock. More like half position. I even gently pushed down on the arm in hopes it would clear it and lock, but no avail. Any solutions?