I recently bought a Turbo Air/Green World GST 40DF 2 door freezer at auction. It worked fine for a while but is now not kicking out of defrost mode and becomes very warm is stops freezing. Refrigerant level is fine, etc. so my Tech figures we need a new control unit. We are having trouble locating this part (Green World is in Korea and US company dissolved?). Does anybody have any ideas?