What was found
LEVEL FL 190 280 KTS OCN LT TURB MAIN CARGO DOOR WARNING LIGHT ILLUMINATED STEADY THEN WENT DIM AND EXTINGUISHED AFTER 30 SEC AS WE COMPLIED WITH RED TABS. CHECKED OPERATION AND INDICATION OF MAIN CARGO DOOR, ONLY DISCREPANCY NOTED WAS INCORRECT ADJUSTMENT OF THE NR3 AND NR 5 OVERCENTER PROXIMITY SWITCHES. LATCHES ALIGNED WITH WHITE STRIPES IAW MM, DOWN SEQUENCE SWITCH WITHIN ADJUSTMENT. ADJUSTED NR 3 AND NR 5 OVERCTR. PROX SWITCHES IAW B727MM 52-34-009-5 PARA. 1 F.(1). MAIN CARGO DOOR OPERATES AND INDICATES NORMAL.