What was found
AIRCRAFT NOT GROUNDED: PILOT REPORTS AFTER TAKEOFF BELOW 5000 FEET AUTO FAIL LIGHT ILLUMINATED AND ALTN LIGHT ILLUMINATED, PAN QRH CHECKLIST AND SWITCHED PRESS CONTROL TO ALTN IAW CHECKLIST. NOTE: THIS OCCURED WHILE RUNNING THE REQUIRED PACK REINSTATE CHECKLIST IAW CURRENT MEL PLACARD 2101A.***SUPPLEMENTAL INFORMATION: MAINTENANCE ACCOMPLISHED FIM 21-31-00-810-801. REPLACED NR 2 CABIN PRESSURE CONTROLLER IAW AMM 21-31-01. OPS CHECKS OK.***(CLOSED)