What was found
AFTER TAKEOFF NR 5 SLAT REMAINED IN EXTENDED POSITION, DECLARED EMERGENCY, TURNED BACK. MX INSPECTED AND LUBRICATED NR 5 L/E SLAT ROD ENDS & TRACKS IAW BMM 12-22-71. CYCLED FLAPS SEVERAL TIMES, OPERATIONAL CHECK WAS NORMAL. MX WROTE A CRITICAL FOLLOW-UP TO LUBRICATE ALL L/E DEVICES AND REPLACED NR 5 SLAT ACTUATOR. MX LUBRICATED L/E SLAT TRACKS, MAIN / AUXILIARY TRACK ROLLERS, AND REPLACED NR 5 L/E SLAT ACTUATOR IAW R3M27020, PROBLEM STILL EXISTS. ISOLATED PROBLEM TO DEFECTIVE NR 5 L/E SLAT ACTUATOR ROD END SWITCH, REPLACED ROD END (REED) SWITCH IAW T/C R3M27019, OPERATIONAL CHECK GOOD.