Just put my 90 back together after cleanup and bearing change, runs smooth but speed control does not speed the lathe up after about 1500 rpms it slows Down as you dial it down to stop, but does not speed up. When I put the dial on I had the belt off, placed the dial on above center on the 1000 rpm mark with micro switch lever tied down. Placed belt on and using vfd speed control brought it up to speed, the belt sank down on the pulley but not low enough to get anywhere near the 4000 mark, as I dial it down, around 1500 to 1000, it began to slow, but no change between 4000 and 1500. I know I must be doing something basic in the wrong dept, but need help figuring it out. Any thoughts would be appreciated.