scroll saw delta 40-601 has variable speed motor that is surging from 0 rpm to 2000.does anyone know what is the problem or how to fix it? bob fallon roanoke,va

Howdy! Great to be part of this forum - woodworking has been a life-long hobby. I recently picked up a Delta Scroll Saw Model 40-601 for less than the value of the stand it was sitting on and needless to say it's in need of repair. Before I take the saw to the salvage yard I'ld like to take a...