Question: Truss Rod on Axis Not Changing Action

I have a 2002 Axis which appears to have developed concave bow after sitting unplayed for a number of years. I attempted to do a truss rod adjustment by turning the carousel wheel clockwise in gradual increments over a period of days, however, the wheel seems to just keep turning without having any effect on the neck. Any insight into this issue would be much appreciated.

Thanks!

Casey