Power Antenna Issue

Antenna on my recently purchased '89 has stopped working, won't automatically go up and down when radio is turned off and on.  I can hear the antenna motor 'whrring' but no action.  New motor needed? Other solution?  Approximate repair cost ??  Thanks.  Teton24  Bucks County, PA

Guessing the nylon spline that raises and lowers the antenna has broken, or a gear inside the motor has gotten stripped.  A repair kit may be available from most of the parts outfits.  If a repair kit isn't found a new motor unit will be your only option.  Have done that repair on other cars but not on a Corvette.