Some replace their worn power cords with heavy duty 14 to 12 gauge power cords bought locally. 12 to 15 ft length max. including the wire routed inside the headstock. Be sure to use the strain relief in the motor pan which is sized normally for a 14 gauge cord on a Mark V.
Slide back insulation boots from insulated connectors, crimp and solder them for best connectivity possible, sliding the connectors inslulating boots back in place. Use Western Union Splice as shown also soldered and covered with correctly sized and shrunk heat shrink tube.