I would check the ac winding that looks like it been very hot and check continuity to the metal case ground, and the other lead from the VOM volt ohm meter on continuity you should not read any shorts or resistance from ground to either side the ac plug that feeds that winding IF YOU READ ANY RESISTANCE THE TRANSFORMER WINDING IS SHORTED TO THE CASE AND IS TOAST OR SHOT. if you do not read any resistance to the case and threw the winding you probably can clean up the winding with a pencil eraser and go from there, there is always a possibility you can clean it up Providing the winding is not shorted to metal case ground winding of the transformer!