Yeah maybe get a piece of metal tubing or something to put over the handle of the turntable brake to act as a lever. get the lever in a position where you can push downward on it and basicially put all your weight on it. If that doesn't work, then I don't think anything will. maybe try to spray some WD-40 in the assembly? Good luck man.
2x AG200 13.6 oz Blue Gear/Isospeed Baseline Spin
1x MW200g, 1x Mfil200g